CORAL
I THE STATE OF CORAL REEFS IN THE WIDER
CARLOS GOENAGA
Interciencia JAN- FEB 1991, VOL. 16 N9 I
Coral reefs are tropical
and subtropical ecosystems that flourish at temperatures between 25 and 29 centigrade in
insular and continental platforms. Living coral cover and species diversity is
highest where waters are clear due to low input of nutrients and fine
sediments. Recent
Coral reefs are highly
susceptible to disturbance in relation to other nearshore ecosystems, such as
mangrove forests and seagrass beds (Ogden and Gladfelter, 1983). This report
should be viewed in the context of extensive coral bleaching events recently
occurring throughout the
Coral reef degradation
(in terms of observable changes in the relative abundance of major benthic
components resulting from human activities is well known to be underway in
Socioeconomic Importance of Coral Reefs
Although coral reefs are mainly known for their natural beauty and
high biotic diversity, this is only a minor portion of what they represent to
nations that possess them. Recently it has been suggested that their importance
for the maintenance of life on Earth transcends national barriers as explained
below. Following is a list of the socioeconomic importance of coral reefs:
Production of Pharmacological Compounds
A large diversity of chemical compounds have
resulted possibly as a consequence of complex interactions between species in
the coral reef. Some of these substances are highly active biocompoUnds whose
applications in medical research are just now being discovered. These include
antimicrobial, antileukemic, anticoagulant and cardioactive properties
(Fenical, 1980; Rinehart et al., 1981; Saim and Clark, 1982). Coral reef
organisms have been used as tools in the elucidation of phyriological
mechanisms (e.g., sea hare), (fertilizalion (e.g., sca urchin), regeneration
and cell association (c.g,, sponges) arid mechanisms of drug action (e.g,,
squids) (Angeles, 1981).
Prevention
of Coastal Erosion and Storm Damage
This is particularly important for regions with
low lying coastal plains. Coral reefs also contribute to the formation of sandy
beaches and sheltered harbors.
The importance of the maintenance of healthy coral
reef growth is accentuated in light of the observed sea level rise in the last
decades (Etkins and Epstein, 1982; Gornitz ci a!.. 1982). Coastal erosion is
likely to be felt more in areas where coral reefs are degenerated since large
waves are capable of penetrating more easily in the absence of these natural
barriers (Cubit et a!., 1984). Areas with reduced tidal fluctuations are more
likely to be affected.
Nutrition
Coral reefs are among
the most productive habitats of the world (Lewis, 1977). Fisheries in the
Recreation
Tourism on many
Extraction o/ Atmospheric Carbon Dioxide
Coral reefs constitute about 0.17% of the world
ocean area and about 15% of the shallow sea floor within the 0-30 m depth range
(Smith, 1978). These ecosystems play an important role in the marine carbon
budget primarily through the deposition of aragonitic calcium carbonate.
Surface tropical waters, which are stratified by a permanent thermocline, are
supersaturated with respect to calcium carbonate. The inorganic transfer of
atmospheric CO2 across the air-sea interface is, therefore,
limited. By extracting CaCO5, coral reef organisms provide a way of
bringing more CO2 into the ocean system. Reported rates of CaCO3
deposition by coral reefs demonstrate that these ecosystems are an
important buffer in the Earth’s CO2 cycle (Barnes ci a!., 1986).
Human
Activities Affecting Coral Reefs
In general, coral reefs within the Wider Caribbean
are threatened by pollution related to industry, domestic wastes and upland
vegetation clearing. Rodriguez (1981), in a review of environmental stress in
coastal waters of the Wider Caribbean, pointed our that there is no widespread
industrial pollution there, apart from contamination by petroleum hydrocarbons.
He added, however, that severe, localized problems do occur and stressed that
these problems threaten the development of economic activities which depend on
a healthy marine environment. The largest industrial concentrations occur
along the coast of
Marine pollution caused by dumping domestic wastes
into the ocean (Rodriguez, 1981), and upland vegetation clearing (i.e., be it for
industry, urbanization or agriculture) without concern towards appropriate land
conservation practices (Johannes, 1975) are two other activities, common to
the whole region, that have a negative impact upon coral reefs. These are
associated with all major cities in the area.
Other activities that are spatially and temporally
restricted, although not necessarily insignificant, are: mining of coral reefs, military activities,
standing and walking over coral, ship grounding, anchoring, coral collecting,
fishing with explosives and with bleach, dredging and thermal pollution. Of
these, the first seven destroy reef structure directly while the last three
modify the relative abundance of the living components. The effect of most of
these have been documented for the wider
A. Oil Pollution
Many coral reef scientists have expressed their
apprehension concerning the harmful effects of oil spills (e.g., Bak and
Elgershuizen, 1976). Degradation of some
Bak and Elgershuizen (1976) have suggested that
the water soluble fraction of oils in seawater is more harmful to corals than
their direct contact with oil. Riitzler and Sterrer (1970) suggested that
corals escaped observable damage from an oil spill in
Data from laboratory
experiments show that colonies of the scleractinian, Madrocis mirobilis were
more affected by mixtures of various crude oils and Shell dispersant (LTX type)
than by either the crude oils or the dispersant separately (Elgershuizen and de
Kruijf, 1976). These investigators hypothesized that the observed non additive
effects were related to a higher solubility of the toxic oil fraction in sea
water after emulsification by the dispersant. Active ingestion of oil drops by
corals do not occur and it is unlikely that oil is adsorbed to living coral
tissue (Bak and Elgershuizen, 1976). Mucus produced by corals, however, can
trap drops of oil that may be incorporated into the reef food web via the
mucus-eating fish and crustaceans (Elgershuizen a of,, 1975). Zooxanthellae
from the
Shinn (1972) observed that the scieractinian
Monto.strea onnuloris can survive two hours total immersion in Louisiana crude
oil and that Acroporo cervicornts, exposed for two hours to a mixture of
seawater containing one part crude to 6-12 parts seawater, caused immediate
retraction of polyps although recovery was complete after 24 hours. Based on
these observations he remarked that “it would seem safe to conclude then that
crude oil spills do not pose a significant threat to Atlantic coral reefs”.
However, as Johannes (1975) has noted, this statement is premature since Shinn
reported no subsequent observations on these corals. Dodge et ol. (1985) determined
experimentally that corals treated with chemically dispersed oil at concentrations
of 20 ppm showed no depression in calcification. Once again, it is unknown
whether long term impairment of vital functions, such as reproduction or
maintenance, had occurred in individuals of these species. Also, Shinn’s own
experiments illustrate the importance of interspecific response to oil.
Evidence of pathological responses, including impaired development of
reproductive tissues, atrophy of mucous secretory cells and muscle bundles,
has been observed in colonies of the shallow water Caribbean coral Manicina
oreolata during exposure to water accommodated fractions of No. 2 fuel oil
(Peters, et ol., 1981). This atrophy may help explain the decreased capacity of
corals to recover from injuries after subject to oil pollution reported in
Panami by Guzmán and Jackson (1989). Gooding (1971) also documented an
extensive destruction of reef associated biota, other than corals, by an oil
spill in
Other effects of oil and
the use of dispersants on coral reefs are the alteration of the physical
properties of the reef surface (which inhibits larval settlement), the
impairment of oxygen exchange across the air-water interface (Blumer, 1971;
Kinsey, 1973) and the interruption of light penetration by surface oil films
(Mergner, 1981). These have not been documented in the
B. Oil Drilling Muds
In addition to the danger of oil spills,
potentially detrimental effects of drilling near coral reefs include the
actual physical disturbances caused by anchoring, pipeline and drill rig construction,
the resuspension of bottom sediment created by such activities shadowing by the
rig platform and the discharge of drilling effluent which include sewage, deck
drainage, produced formation water, produced sand, materials for treating
wells, drill cuttings and drilling muds (Dodge and Szmant, press; Thompson and
Bright, 1977). The effects of drilling muds are discussed below.
Drilling muds are introduced in the marine
environment during offshore drilling operations. Then are discharged at low
levels and occasionally in bulk (up to 2,000 barrels or 14 tons in a few hours)
when the muds require renewal or on termination of drilling activities
(Thompson cx of., 1980)
Drilling muds are varied
in composition and those containing ferrochrome lignosulphonates and other
additives such as diesel fuel, appear to be more toxic. Their effect on coral
reefs have been recently reviewed by Dodg and Szmant (in press) - Their major
conclusion is that more research is needed urgently on this subject.
Exposure to
chromiolignosulphate drilling muds leads to the production of mucus as a
“stress” response in Porites divaricata,
P. furcata P. astreoldes, Montostrea annulari, .Acropora cervicornis and
Agoricia ogar cites (Thompson et of., 1980) and may be responsible for
decreased growth rate after short term exposure, by M. annularis (Hudson and
Robbin, l980~ Dodge (1982) suggested that lower calical relief in corals
exposed to usedb drilling muds can result in decrease sediment-shedding
capabilities which may remain effective for some time after the period of
exposure in M. annularis.
Szmant ci a!. (1981)
have further investigated the response of M. annularis to drilling muds. They
found that the rates of calcification and respiration of this species decreased
by 53% and 25%, respectively, after four weeks of exposure to 100 ppm drilling
mud and 84% arid 40% after six weeks of exposuse. Gross photosynthesis was
reduced by 36% after five weeks. Nitrate uptake rates decreased by 42% and 48%
after four and six weeks while ammonium uptake decreased by 32% and 49% after
five and six weeks of exposure. Colonies exposed to 100 ppm were not able to
feed on zooplankton and several of the experimental colonies died before
completion of the experiment.
C. Siltation From
Siltation of coral reefs results from
upland vegetation clearing and is generally considered an important factor
controlling coral reefs. It can limit coral reefs by: 1) increasing water
turbidity (Jerlov, 1968) and, thus, affecting the photosynthetic output of
zooxanthellae, 2) causing energy expenditure in particle rejection (Lasker,
1980), 3) increasing the potential for hacterial infection (Ducklow and
Mitchell, 1979; Peters, 1984), 4) abrasion (Wein, 1962; Slorr, 1964), 5)
creaeing conditions unsuitable for larval settlement (Maragos, 1972), 6)
reducing feeding periods (personal observations) and/or altering heterotrophic
and autotrophic feeding efficiencies
(Dodge and Szmant, j in press), 7) affecting planktonic food supply (Bak, 1978), and, 8) shifting the
relative abundance of fish and promoting the survival of those that graze on
the benthos (Galzin, 1981). The removaL of mangrove stands, generally
accompanying upland deforestation on developed coastal areas, magnifies the
problem of siltation.
These stands act as
natural barriers for runoff due to precipitation. In the Puerto Rican
southwestern coast it is not uncommon to observe large sediment plumes after
heavy rains where the mangroves have been removed and replaced with stilt
houses (personal observations). These
are located within the maritime zone and many dump raw sewage into the water.
Although coral reefs are known to occur under silt
laden and/or eutropinc waters (Goenaga, 1988), it is unknown whether these are
in the process of disappearing or whether the component biota is or will be
capable of adapting to these conditions. The available evidence suggests that
at least some of the biotic components which depend more upon sunlight die in
deeper, although are able to persist in shallower portions of reefs (Morelock
et a!., 1979; Acevedo, 1986; Goenaga, 1988).
D.
Sewage Discharge
Sewage discharge into
coastal waters may affect coral reef communities by 1) causing nutrient enrichment
and enhancing the growth of algae at the expense of corals (Marszatek, 1981),
2) depressing oxygen levels Wade a al., 1972), and 3) by introducing toxic
substances such as chlorine (cf. Muchmore and Epel, 1973). Coral morbidity and
mortality under experimental conditions is apparently the result of
competition for space with algae and light and not directly related to effluent
toxicity (Marszalek, 1981). Sewage is known to stress reefs in
The classical example of the effects of
eutrophication on coral reefs is
E. Dredging and Mining
The impact of dredging on coral
reef communities are of three basic types: 1) mechanical damage (resulting in
breakage of coral and octocoral colonies many of which subsequently die), 2)
sediment loading or siltation(i.e., rapid deposition of coarse silt and coastal
waters may affect coral reef com- sand size sediments resulting from sediment
laden water leaking from the dredge pumps) resulting in burial and death of
colonies, and, 3) increased turbidity resulting in loss of color, excessive
mucus secretion or death in scieractinians. Also, waters over dredged areas
have significantly more bacteria than neighboring seawater (Galzin, 1981).
This seems related to the suspension of fine sand particles that are utilized
as a substratum by the bacteria and may result in the elimination of certain
benthic faunal and floral species and the proliferation of tolerant species.
Galzin (1981) also found that sand dredging in Guadaloupe,
One effect of dredging that is usually ignored is
the resuspension of toxic materials, such as heavy metals, into the water
column. Metals may be detrimental to corals by impairing their physiological
processes and possibly by weakening the structure of the aragonite skeleton
(Howard and Brown, 1984).
Associated with dredging
operations are mining and smelting processes. Fiftysix large scale mining
operations are reported in the
F. Thermal Pollution
Activities generating thermal pollution, mainly
related to the energy industry, are known to be maintained in the vicinity of
G.
Anchoring
Anchoring on top of coral reefs can represent
considerable disruption to coral reef communities.
However, touristic sightseeing of coral reefs, if
well planned and with adequate supervision, seems to be highly compatible with
the preservation of these ecosystems and can be highly productive in terms of
education and in terms of the employment generated. The economy of many
H.
Military Activities
Although military maneuvers near coral reefs are
possibly not widely practiced in the Caribbean, an example from Vieques, off
eastern
In 1982, Antonius and Weiner concluded that the
“military impact of the Viequen reefs was negligible when compared to natural
damage caused by storm — generated wave action”. These conclusions are based on
comparisons made between the reefs from Vieques and those in the eastern coast
of St. Croix (presumably not subject to military activities) with which they
found no differences. A close look at their section on Materials and Methods,
however, reveals that, in their work, “the emphasis was on shallow water communities”.
It is widely known and has been extensively documented (e.g., Woodley a at,
1981; Graus a al., 1984; among many others) that damage to coral reefs by
storms occurs mainly in shallow waters. It is at these depths that corals with
the highest growth rates predominate (e.g., Acropora palinata and A. cervicornis).
This is one reason why hurricanes have minimal long term effects on coral reefs
(Graus a at, 1984). Deeper portions of coral reefs, where slower growing,
massive corals predominate, are not affected as heavily by storms. However,
military activities do not discriminate between shallow and deeper portions of
the reef and bombs drop in shallow and in deep substrates affecting them
equally. It seems reasonable, therefore, to question why did Antonius, a
consultant for the U.S. Navy, did not investigate the deeper portions of the
reefs in Vieques. The same critique applies to the work by Raymond and Dodge
(1980).
In another work, Dodge
(1981) also concluded that “...a general similarity between (bombing) ran and
control stations..." in Vieques, together with “...quantitative coral
abundance and diversity data of other namely, data by Antonius and Weint (1982)
indicate a lack of anomalous and adverse sedimentation/turbidity cotu tions
affecting coral on reefs near range area”. However, several commer must be
made. Reef corals, as well other organisms, need energy for processes other
than growth, namely reproduction and maintenance. The effet of the presence of
the range on these two other processes were not assessed. Coral colony
fragmentation, a process knowledged by Antonius and Wein (1982) and Dodge
(1982) to occur Vieques, is, in fact, known to. monotastrea annularic, the very
same spec utilized by Dodge (1981) in his study.
Aerial photographs eastern
Vieques do show extensive cratering resulting from bombing activities on land
as well as in the sea. Crater range in diameter from 5 to 13 m and larger
effects extend beyond the extent of direct disruption (Rogers et al., 1978).
The reefs are littered with artillery and
delivered exploded and unexploded ordnance (metal fragments, flare
casings, parachutes) which have sustained extensive damage. Damage to reefs in
Vieques has been categorized by Rogers et (1978) as follows: 1) damage by
direct hits and by shock waves which sheer colonies near the site of impact,
2)damage due to abrasion by steel and rough fragments generated by the blasts,
3)damage by fragments that come to remain on top of living coral tissue, 4)
fracturing and weakening of reef structure blasts and direct hits, 5)
dislodgement of colonies which can be transported by heavy seas causing greater
damage, 6) deposition of coarse sediments on top of living corals, 7) damage by
flare parachutes which drape around soft and stony corals, and others.
Large numbers of unexploded ordnance in these
reefs limit their future utilization as fishing and/or touristic centers. It is
hard to estimate the costs involved in their restoration. We can barely hope
that leaching substances from oxidizing and degenerating ordinance do not
pollute marine life in these areas.
I Ship Grounding
Ship grounding in coral reefs can abrade,
fracture or overturn reef biota and hull breakage can result in the spill of
hazardous substances. Also, alteration of the hydrodynamic regime while the
ship is grounded over the reef can generate sediment plumes that increase
water turbidity and smother corals downcurrent. Direct damage by ship grounding
is more localized than that of storms but may alter the reef contour and re1ief
to a much greater extent (Smith, 1985).
Curtis (1985) described how portions of Molasses
Reef,
J. Fishing with Bleach
and Explosives
Fishing
with bleach and With explosives occurs in the
Bleach (sodium hypoch1orite)
is applied to coral heads to drive commercially valuable species into range of
spears and granges,
K. Overfishing
The manner in
which overfishing may affect coral reefs is uncertain but it is likely that
the community structure is modified. For example, over-fishing of predator
species in
Capacity For Recovery
Denuded coral reef cornmunities can recover by
regeneration of partially damaged coLonies or fragments or through
recolonization by larval settlement. Factors which can influence coral
recolonization include tbe extent of damage and its location, the availability
of coral larvae, the requirement for a ‘conditioning” period of the substratum
before corals can settle, the availability and diversity of microhabitats for
settlements and survival, the role of grazers, and competition with other
organisms such as algae and soft corals (Pearson, 1981).
The available evidence
suggests that coral communities may recover from major natural disturbance
after several decades but are likely to suffer irreversible changes from
man-made disturbance (Weiss and Goddard, 1977). Full recovery from man-made
disturbances may be prolonged or prevented altogether because of permanent
change to the environment or a continuation of chronic, low level disturbances
(Pearson, 1981). In 1975 Johannes reviewed the known effects of pollution on
coral reef communities. He pointed out that reef corals are central to the
integrity of the reef community and when these are selectively killed,
migration or death of much of the other reef fauna ensues. Accordingly, the
environmental tolerance of the reef communtty as a whole cannot exceed that of
its corals.
At this point it is
necessary to mention that non-structural coral communities have the same
practical importance as coral reefs in terms of coastal protection,
nutritional importance, and others. Coral communities differ from coral reefs
essentially in the thickness of the biogenic framework. The former form thin
veneers over preexisting structures, such as cemented sand dunes, that drowned
after sea level rose during the last glacial period. Coral reefs, in contrast,
have a thicker framework which, to a larger extent, have been the product of
biogenic (i.e., versus physicochemical) activity. Non-structural coral communities
give integrity to the underlying structure and prevent its physical or
chemical erosion and eventual destruction.
The importance of habitats
neighboring coral reefs, such as seagrass beds and mangrove forests, has been
stressed by Ogden and Zieman (1977). Seagrass beds are important feeding
grounds for nocturnal feeding fishes, such as grunts and snappers, which
shelter on reefs by day. When they return to the reef these fishes deposit
organic compounds in the form of feces that become available to detritivores
and are introduced to the reef food web. Mangroves provide nurseries for juveniles
of certain reef fish (chactodontids, scarids, lutjanids) and are also feeding
grounds for fish that shelter on reefs; mangroves also introduce fixed nitrogen
and organic detritus into the trophic system or reefs as do reef flats and
seagrass beds. Consequently, damage to these neighboring communities can potentially
have an effect on nearby coral reefs.
Recommendations
Based on this review some recommendations seem
logical:
1) Compile a detailed bibliography on the factors
that contribute to the degeneration of coral reefs on a world basis.
2) Based on the literature,
define parameters known to be related to coral reef degeneration.
3) Monitor polluted and
non polluted reef habitats to differentiate between natural and man-induced
sources of variation.
4) Establish marine
parks in coordination with affected local communities; fishing communities must
have an active and principal role in the management of the park.
5) Consider and study the possibility of
restoring damaged areas.
6) Update coral reef
inventories.
Conclusions
Although in many cases a
causal nexus have not been shown conclusively, the correlation between
unplanned development and coral reef degradation makes it hard to attribute the
latter effect to causes other than the former. Stressed reef communities show
drastic reduction in live coral cover, overgrowth by filamentous algae, erosion
of physical framework and reduction of diversity of associated fish and invertebrates.
Reef degradation has already been shown to result in an increase in wave energy
at beaches, beach erosion and massive sediment movements (Head and Hendry,
1985) not to mention the decline in the catch of edible species. Touristic
development, of primordial importance to many
It is perhaps sad that statements related
to the preservation of coral reefs more than a decade ago by Johannes (1975)
are as timely as ever and acquire more significance today. Johannes stated
that: the allocation of money for coral
reef research and management is. - . very small in relation to the importance
of these communities to man and... their vulnerability to pollution.
"…environmental crises
(related to the destruction of coral reefs) develop faster than they can be completely
assessed. In this context it is more important to make interim decisions in
time than to make more scientifically satisfying decisions later” (i.e., after
the ecosystem is irreversibly damaged).
And also more timely than ever, he adds about scientists
that comfortably and cowardly sit over their data, knowledge and/or insights
that “those who remain silent when their observations point to environmental
decay are the undertaken of the environment; environmental post mortems become
their stock and trade.”
NOTES
1.
Other coral sicknesses have been studied recently by Peters (1914) and others.
2.
This phenomenon may be related to human activities. Preliminary observations
suggest that bleaching is related to higher than normal penetration of solar
radiation into the sea (R. Armstrong, C. Goensga and V. Vicente, personal
observations). This is consistent with the known fact that the thinning of the
ozone layer, particularly in the poles but also in the tropics, results from
the usage of chloroftuorocarbons and halons. This subject, however, is outside
of the scope of this report.
II
Florida’s Coral reefs Beautiful & Alive!
North
America's only coral barrier reef lies about six miles offshore and parallels
the Florida Keys, a 158-mile long string of islands, surrounded by mangrove
forests and seagrass beds, which together form a fragile, interdependent
ecosystem.
Mangroves
are saltwater-tolerant trees that provide a nesting area for birds. The
submerged roots are a nursery and breeding ground for most of the marine life
that migrates to the reef. Mangroves trap and produce nutrients for food and habitat,
stabilize the shoreline, and filter land-based pollutants.
Seagrasses
offer food and habitat for juvenile fish, crustaceans, and shellfish. They
filter the water of sediments, release oxygen into the water and stabilize the
bottom with their roots.
The
To
protect this spectacular marine ecosystem, the
A
comprehensive management plan and a water quality protection program are being
created for the new sanctuary in cooperation with the public, a citizen's
advisory council and several federal, state, and local government agencies for
implementation in 1994.
For more
information, contact:
Florida
Keys National Marine Sanctuary Planning Office
9499 Overseas Highway
For more
information on Refuges, contact the Refuge Manager at (305)872-2239.
Fragile
& Endangered
Coral, for
all its sturdy appearance, is fragile and vulnerable. The millions of annual
divers, snorkelers, and fishermen who visit the coral reef ecosystem threaten
its very existence!
The
careless toss of an anchor can destroy years of coral growth in minutes. Even
the lightest touch can damage sensitive coral polyps.
Nutrients
from sewage, fertilizers, stormwater run-off, and deteriorating Gulf waters
reduce water quality, causing increased occurrence of coral diseases and algal
blooms.
Monofilament line and trash wrapped around
delicate corals can smother or abrade coral and even break them. Trash can be
deadly for birds, fish, and turtles that become entangled or mistake it for
food and ingest it.
Boats that
stray into shallow waters may Prop dredge, uprooting seagrass beds and damaging
nursery and breeding areas. The noisy approach of a boat or jetski can disturb
nesting birds in the mangroves, exposing the eggs or nestlings to predators and
the intense sun. Disturbance of shallow feeding grounds can lead to the
starvation of birds.
What
You Can Do to Protect the Coral Reef Ecosystem
Tips
for Divers & Snorkelers:
What you do
(or don't do) can make a difference to the survival of the Coral Reef
Ecosystem:
Before
booking a reef trip, check weather conditions; it's best not to go out in rough
seas. Poor visibility, strong winds & waves reduce safe interaction at the
reef. Remember that even the lightest
touch with hands or equipment can damage sensitive coral polyps. Snorkelers should wear float-coats to allow
gear adjustments without standing on the coral.
To avoid
contact with the ocean bottom, divers should only use the weight needed and practice
proper buoyancy control. Lifeless areas may support new growth, if left
undisturbed. Avoid wearing gloves and touching or collecting marine life. Most
tropical fish captured die within a year. Queen conch is a protected species. Please don't feed the fish; it destroys their
natural feeding habits. Remember, it's
illegal to harvest coral in
Snorkeling is an enjoyable way to see the coral reef. Be sure to wear a
float coat to avoid standing, stepping on, or touching the fragile living organisms.
Tips
for Boaters & Fishermen
Dumping
trash at sea is illegal; plastic bags and other debris can injure or kill
marine animals. Try to retrieve fishing gear & equipment, especially
monofilament line.
Accidental boat groundings damage the reef. Prop damage destroys shallow
seagrass beds. Consult tide & navigational charts and steer clear of
shallow areas. Remember, "Brown, brown, run aground. Blue, blue, sail on
through." Use reef mooring buoys or
anchor in sandy areas away from coral and seagrasses so that anchor and chain
do not damage the coral or seagrass beds.
Use sewage pump-out facilities, biodegradable bilge cleaner, and never
discharge bilgewater at the reef.
Practice
good seamanship and safe boating. Maintain safe distances from fishermen.
Observe size & catch limits; release all fish you can't eat. Avoid wildlife disturbance: stay 200 feet or
more offshore; keep speed, noise, and wakes to a minimum near mangroves. Camping, campfires, and collecting of any
kind are prohibited on all National Wildlife Refuges. Personal watercraft &
airboats are illegal in all National Parks and Wildlife Refuges in the
Mangroves are home to nesting birds and other animals; maintain a safe
distance offshore and bring your trash back to shore.
Healthy
seagrass beds are an important part of the coral reef ecosystem; avoid prop
dredging by staying in marked channels and away from shallow areas.
REEF
RELIEF is a Key West-based non-profit conservation organization
dedicated to "Preserve and Protect the Living Coral Reef of the
Reef mooring buoys have been installed at most
heavily-visited coral reefs in the
John Halas and Harold Hudson of the Key Largo
National Marine Sanctuary (now part of the Florida Keys National Marine
Sanctuary) designed the original eyebolt and buoy assembly in use at most Keys
coral reefs. Buoy technology is developing and Reef Relief has designed the Big
Boat Buoy to allow for use of the buoys by large vessels. The Manta Ray design
has also been installed at Keys reefs in areas of rubble inappropriate for the
single eye or Big Boat moorings. The buoyassembly above the ocean surface is
uniform for all reef mooring buoys. The polypropylene pick-up lines are treated
for resistance to the damaging rays of the sun and are easily removed for
replacement when necessary. The buoy itself floats on the surface and is
recognizable from a distance. A reef tract surrounded by buoys provides a
warning to boaters that this is an area of shallow water.
" A few basic procedural steps should be
taken when using a mooring buoy:
1.Slowly approach the buoy from down wind and/or
down current.
2.Smaller
boats are encouraged to tie off to one another, thereby allowing larger vessels
access to buoys. Remember, the larger the vessel, the more potential damage to
the coral (if an anchor is used).
3.All
boats should put out extra scope by adding an extra line to create a horizontal
pull on the eyebolt. Otherwise, the eyebolt will be pulled out. A good rule to
remember is: if the buoy is pulled underwater, you must let out extra scope.
4.Inspect
the mooring buoy your boat is tied to -- you are still responsible for your
vessel.
5.Sailboats should not leave large sails up as steadying sails when on a
buoy; this puts too much strain on the eyebolt.
If you choose not to use a mooring buoy, anchoring
is only permitted in the sandy areas, NOT IN THE CORAL!
This is Florida State Law. Presented by The SportFishing WebSite
http://mgfx.com/reef/
III
Reefs In Danger: The State of
Coral reefs are among the world's most fragile and
endangered ecosystems. Reefs off of 93 countries have been damaged by human
activity, and unless the current trends are reversed, up to 70% of the world's
coral reefs may be killed within our lifetime.
Coral reefs are vital environmental and economic resources
that give shelter to one quarter of all marine life. Destruction of coral reefs
would mean the extinction of thousands of marine species and the elimination of
a primary source of income, employment and food for millions of people.
Some of the
most serious threats to coral reefs are:
Over-fishing and fishing with cyanide that upset the ecological balance
of coral reefs and allow algae or coral predators to overrun the reefs.
Silt
from deforestation that smothers coral reefs by blocking sunlight and
preventing photosynthesis.
Coral
mining and blast fishing that destroy coral reefs with explosives.
Untreated or improperly treated sewage that chokes coral reefs by
promoting algae growth.
Runoff
of pesticides, fertilizers and other chemicals that poison the reefs.
The
International Year of the Reef - 1997
Coral reefs
around the world are being threatened by factors such as over-fishing, coastal
development, runoff from agriculture and logging, high-impact tourism and many
other causes. Concern about the state of the world's reefs has inspired
scientists and environmental groups to accept the following challenges:
planning and executing
major programs of public
education and outreach
about coral reefs and coral reef
destruction
assessing the
conditions of coral reefs worldwide
collaborating with
governments, local communities and other reef managers to develop and
implement plans for the sustainable use
of irreplaceable reef resources
The
International Year of the Reef (IYOR) 1997 has begun a major effort of
assessment, education and collaboration. Scientists and volunteers from the
worldwide diving community are involved in diagnosing the condition of
representative reefs throughout the tropical seas. Aquariums, scientists, and
conservation organizations are collaborating to produce a variety of courses,
video tapes, brochures and other educational materials. Individual coral reef
areas are creating or revising management plans for their coastal zones. With
the involvement and financial support of governments, foundations and
individuals, all these initiatives are being put into place to insure that the
world's coral reefs are preserved for the future.
http://www.coral.org/IYOR/
IV Are
storms killing coral?
Tue Mar 7 2000 18:01 EST
Environmental News Network
Are huge dust storms
from Africa's deserts killing the coral
in the
"I've
been watching this for about 40 years," said U.S. Geological Survey
scientist Gene Shinn. "The years with high dust were the same years most
of the coral were damaged."
"No one has gotten into looking at the potential health effects or
what dust does to the environment,"
said Shinn, a self-proclaimed "dust nut" who's hoping to raise awareness and funds for his
cause. Coral reefs throughout the
Shinn believes algal infestation, coral bleaching
and coral killers such as "white
band" and "black band" diseases are connected to the nearly two
billion tons of dust that each year blow from North Africa to the Caribbean. "After we looked around and noticed
coral was dying all over the Caribbean, not just in
The best evidence of Shinn's theory is
Aspergillis, a fungus normally found in soil, that has devastated a particular
species of coral. Since 1983, when Aspergillis first appeared, it has killed
more than 90 percent of the
One theory
blamed deforestation runoff on coral demise. Shinn blames dust balls. "We
looked at the dust," said Shinn. "That would explain how it could be all
around the
V BLEACHING DAMAGE SPREADS
BEYOND CORALS
From Science News, Vol. 142 11/14/92
p334 from reports from geological
Society of America annual meeting
Tiny
marine organisms known as foraminifera exhibit damage similar to that observed
in bleached corals, reports Pamela
Hallock, an oceanographer at the
Both
foraminifera and coral play an important role in the global ecosystem. As these organisms "are very important
sources of organic matter and calcium carbonate production...such [bleaching]
phenomena could affect the global carbon cycle and the oceanic food
chain," Hallock says. Foraminifera
and coral filter carbon dioxide out of the atmosphere. If their numbers decline, the atmospheric
concentration of this greenhouse gas could potentially increase.
Many
foraminifera, like many coral, live in a symbiotic relationship with
microorganisms that provide their hosts with not only nourishment, but also
color (SN 12/8/90, p 364). A host
organism that has lost its symbiotic companion turns white, or bleaches, and
its health declines.
In the
first documented study of bleaching foraminifera, Hallock examined four species
of the genus Amphistegina collected from
Hallock
found that while most of the population appeared normal throughout the winter months, bleaching began to occur and
then increase during the spring of 1992.
Bleaching peaked in June and July, with 85 percent of the population
showing total or partial loss of color.
While
damaged foraminifera began to regain color as fall approached, the bleaching
appears to have had severe effects on reproduction and adult mortality. "There were very few juveniles in the
population at a time when you would expect them to be [abundant]," Hallock
says.
In the
laboratory, bleached foraminifera produce significantly fewer young, and up to
30 percent of these may be deformed or nonviable, the study shows.
Laboratory studies indicate the bleaching can be induced by increasing
the organisms' exposure to ultraviolet light.
Hallock speculates that the bleaching she observed may have resulted
from a minute increase in ultraviolet exposure related to
VI Coral Reefs To Be First Casualty Of CO2
Emissions
Coral reefs will become a casualty of the
industrialized world's growing carbon dioxide emissions by the middle of the
next century, according to a study published in the April 2 issue of the
journal Science.
Oceanic
surface waters will become more acidic as they absorb carbon dioxide in
increasing amounts from the atmosphere, say the study's co-authors, including
the
"It's an irrevocable thing that we're doing to the planet,"
said Archer, Associate Professor in Geophysical Sciences at
The
Science article's six co-authors, led by Joan Kleypas of the
In
1700, the concentration of carbon dioxide in the atmosphere was approximately
280 parts per million. Today, it is nearly 370 and rising as much as two parts
per million each year.
"It's almost going to double from the pre-industrial value some
time in the next century. That's almost unavoidable," Archer said.
Fossil-fuel combustion and deforestation both have contributed to rising
atmospheric carbon dioxide. "There was a long, broad rise of carbon
dioxide throughout the 19th century, which predates the use of coal and other fossil
fuels," Archer said. "They call it 'the pioneer effect,' for when the
This
increase in carbon dioxide adds to the greenhouse effect, which traps heat in
the atmosphere, possibly leading to global warming. Warming trends during the
last 10 years, whether from increased carbon dioxide emissions or natural
climatic variation, have already caused bleaching of coral reefs.
Corals
normally live in symbiosis with algal plants, but warm temperatures upset the
relationship. "For some reason that nobody really quite understands, when
corals get stressed they spit out the plants," Archer said. When that
happens, corals lose their color, changing from green or brown to white.
"This effect of carbon dioxide acidifying the ocean is on top of this
already well-known bleaching effect," Archer said.
The
findings are based on a series of studies showing that acidity interferes with
the growth of coral reefs. One of the studies was conducted in Biosphere 2 near
Coral reefs are mostly made of calcium
carbonate. When carbon dioxide dissolves in water it makes carbonic acid, which
causes calcium carbonate to deteriorate. Langdon and his colleagues observed a
slowdown in coral reef growth when Biosphere 2 contained higher levels of
carbon dioxide.
A key
element of the Science study was Archer's model of carbon movement from the
ocean surface to the deepest sea floor. The model takes into account such
factors as fluid dynamics, current velocity, water temperature, salinity and
chemistry.
"It's like the models they use to predict weather in the
atmosphere, only this is down in the ocean," said Archer, whose work is
supported by the David and Lucille Packard Foundation and the Petroleum Research
Fund.
Archer's
model produced rising carbon dioxide levels that rise over the decades at the
ocean surface where coral reefs grow. These areas are warmer than other parts
of the ocean and therefore more buoyant and in more continuous contact with the
atmosphere, he explained.
Similar
models are used to determine how much carbon is going into the ocean today. The
burning of fossil fuels and deforestation combined release approximately seven
billion metric tons (seven gigatons) of carbon into the atmosphere each year.
The amount in the atmosphere is increasing by three gigatons each year. Ocean
models predict that the ocean takes up another two gigatons annually.
Scientists suspect that the remaining two gigatons might be fertilizing
terrestrial plants and soil in the Northern Hemisphere.
"The fate of that two gigatons is still rather mysterious,"
Archer said. - By Steven N. Koppes
[Contact: Steve Koppes]
http://unisci.com/stories/19992/0402994.htm
Death Of Corals In
The dying
corals of the Florida Keys could be an early warning of tough times ahead for
the planet's environment,
Increasing global temperatures and worsening pollution, the ecologists
say, could place so much stress on ecosystems that organisms of all kinds will
face new challenges.
"When we see corals that have persisted for hundreds of years
suddenly die from opportunistic infections, we have to wonder what has changed
in their environment," says C. Drew Harvell, associate professor of
ecology at Cornell.
Harvell
organized a session, "Diseases of the Ocean: A New Environmental
Challenge," at the annual meeting of the American Association for the
Advancement of Science (AAAS) in Anaheim, Calif. on Jan. 22 to bring together
leading microbiologists, ecologists and pathologists to evaluate the
environmental threats from disease in the ocean. Speaking in the session was
Kiho Kim, a postdoctoral research associate with Harvell at Cornell, who
reported on an unusual disease in
Kim
said that monitoring of sea fan corals in the Keys, where up to 40 percent of
sea fans are infected by a fungal disease and many have already died, suggests
that lower water quality and higher ocean temperatures stress corals and
increase their susceptibility to disease. He said the
"We didn't begin our study of sea fans to monitor death and
destruction," Harvell said. "Originally, we were interested in the
natural disease-resistance properties of corals, such as the anti-bacterial and
anti-fungal chemicals they produce, because some of those compounds may be
useful in human medicine. That disease resistance normally keeps a coral alive
for hundreds of years, despite living in an ocean full of potential
pathogens."
She
said Garrett Smith of the
"Somehow, a soil pathogen that was best known for infecting aged
and immune-compromised humans has crossed the land-sea barrier," Harvell
said. "Now, one of our jobs is to discover what has compromised the
resistance of the corals at some sites. Although a significant number of sea
fans have died at a few sites, at many locales they recover from infections,
pointing to the success of their natural resistance."
While
coral disease is reported throughout the Caribbean, the reef ecosystems of the
"Then you have rising water temperatures of the oceans,"
Harvell added. "Whether you believe that global warming is a function of
human activity and whether last year's El Niño was a symptom of global warming,
the fact is that sea temperatures globally in 1998 were high. And 1998 was the
worst year ever recorded globally for coral bleaching."
Corals
bleach (or lose their symbiotic algae) when stressed by high temperatures,
Harvell explained, adding: "I think we have to question the relationship
between temperature stresses and diseases of the oceans."
Lately in the
"With a very few exceptions, we know so little about the pathogenic
organisms that are affecting the coral reefs," Harvell said. "We
don't know if new diseases are emerging, if the hosts are becoming more
susceptible or both. We need to identify these new diseases and we should do it
now while we have the chance. Disease ecology is poorly understood in the ocean
because diseases are like lightning strikes -- they hit unexpectedly, burn
through a population, and then they are often gone."
Harvell
and Kim conduct their studies from the Keys Marine Laboratory in Long Key, with
the assistance of Reef Relief in
VII Coral Killer Identified; Is Global Warming An
Accomplice?
The
culprit responsible for killing sea-fan coral from the Florida Keys to
The
group reports in the July 9 issue of the journal Nature that a fungus called
Aspergillus sydowii has been responsible for the mass destruction of this coral
over the last 15 years.
"Aspergillus sydowii is the fungus causing the disease that's
killing them," said John W. Taylor, UC Berkeley professor of plant and
microbial biology. "It's the same fungus throughout the
The sea
fan -- a type of animal life, as are all corals -- is an extremely important
component of coral reefs, said Ritchie. It hosts many reef organisms and
provides a refuge for reef fish.
What is
interesting about the attacking fungus Aspergillus sydowii, said
One
explanation for this is that the fungus mutated in recent years to become more
virulent. But more likely, the researchers said, the problem lies with the
coral itself. They suspect that weakening of the sea-fan immune system or some
other damage to the organism, possibly from changes in the environment, could
be making the coral more vulnerable to infection. Thus, the marine creatures
may no longer be able to fight off the fungus.
The
fungus was identified by genetic studies of DNA taken from infected corals. The
studies, done at UC Berkeley from samples provided by researchers at the other
two institutions, placed the pathogen solidly among other known samples of A.
sydowii, a well-known fungus described in the scientific literature in 1913 but
undoubtedly in existence much earlier.
"It's a temptation when you see a new disease to think that you
have a new organism," said Taylor, a fungi expert. "But that's not
necessarily true." In this case, explained
The
proof is that healthy sea-fan colonies exposed to A. sydowii from diseased tissue
also come down with sickness, the researchers found. Alarmingly, the incidence
of the coral reef disease "is increasing at a pretty intense rate,"
said Ritchie. "The reasons for this are highly debated and range from
global warming to human factors like pollution and land run-off."
Generally, she said, "disease occurs most frequently in organisms
that are stressed. If the sea fans are not healthy, that is an indication of
trouble, and the reefs are certainly not healthy."
Aspergillus fungi have been found not only in Caribbean waters, but in
many other places including soil from
A close
relative of penicillium, the fungus is well adapted to conditions of high salt
or other solutes, such as sugar. "If you open up a jelly jar in the
refrigerator and there's mold on it," said
Sea
fans are made up of polyps -- small finger-like cylinders of tissue -- attached
in a fan-like pattern to a central internal skeleton. Overlaid by the polyps,
the inert skeleton supports all branches of a colony. The polyps produce
blue-green spores for reproduction.
"Sea-fan colonies can get up to a meter and a half (about five
feet) or even larger, (but) these are really old colonies," said Ritchie.
"The colonies that we used for the inoculation experiments in our Nature
article were small -- around 20 centimeters (about eight inches)."
Two
species of sea fan, Gorgonia ventalin and Gorgonia flabellum, are found
throughout the
Sea-fan
disease has been reported in the Virgin Islands, Puerto Rico, the
"You can clearly see places where the coral has died," said
As for
the coral, the researchers said not to look for any solutions soon. Even if
there were a safe, effective cure to rescue the sea fans, which at the moment
there doesn't appear to be, "I don't think it would be economically
possible to treat sea fans in their natural environment," said
"We need to understand what is making the infection possible. If
we're lucky, it may be some kind of pollution or something else we could
prevent. But if it's something like rising ocean temperature, good luck."
- Kathleen Scalise
9-Jul-1998
http://unisci.com/stories/0709982.htm
VIII
Coral reefs are specialized
habitats that provide shelter, food and breeding sites for numerous plants and
animals. They form a breakwater for the adjacent coast, providing natural
storm protection. They are very important to southeast
Coral reef development
occurs only in areas with specific environmental characteristics: a solid
structure for the base; warm and predictable water temperatures; oceanic
salinities; clear, transparent waters low in phosphate and nitrogen nutrients,
and moderate wave action to disperse wastes and bring oxygen and plankton to
the reef.
YOUR
HELP IS NEEDED
The tropical setting in
Every year careless boaters run aground,
destroying coral colonies that are hundreds of years old. Seen from the surface,
reefs have a unique golden-brown color. If you see brown, you may be about to
run aground. Be cautious when anchoring your boat. Do not deploy the anchor
directly in coral. Usually there are sandy areas close by; anchor in the sand.
Many popular reefs off
Anglers should avoid shallow coral reefs when
trolling. Hooks can scar and injure the coral, leaving it vulnerable to
infection by microscopic organisms that can kill the animals. When fishing for
lobster, avoid placing traps on reefs. Heavy traps break corals and damage the
bottom when the traps are pulled.
When diving or snorkeling, look, but do not touch!
Do not grasp, stand or sit on living coral. You may damage the coral and hurt
yourself in the process. All coral is protected. It is against the law to
collect, harvest or sell
Department of
Environmental Protection Florida Marine Research Institute
IX
Crown-of-Thorns Starfish [Acanthaster planci ]
National
Geographic March 1970 p527
Once they head down the
windward side of the island, we’ll lose them,” the marine scientist shouted
over the outboard’s roar. “It’s too rough out there for small boats.”
Sounds like a sheriff leading his posse after a
gang of outlaws, I thought, as we knifed along the northern coast of
Rare nocturnal predators only a decade ago, these
spiny multipedes have undergone a mysterious population explosion and now, by
day as well as by night, menace coral reefs in widely scattered areas of the
Pacific.
Casualty List Spans Half
an Ocean
The prickly starfish, known commonly as the
crown-of-thorns and scientifically as Acanthaster planci, eats the tiny
coral polyps that create such reefs. In
a single day it can graze an area twice the size of its 6- to l2~inch central
disk.
Acanthaster has killed more than 90
percent of the coral along 24 miles of
At last our scientist
skipper, Dr. Richard H. Chesher of the
We strapped on scuba
gear and started down. Each of us carried a special hypodermic syringe with
which to inject a fatal dose of formaldehyde solution into our prey.
I soon spotted the sea
stars sixty feet below me. Their dark multi-armed bodies stood out clearly
against the pale sea floor. I could see scores of them traveling in a herd
about ten yards wide and perhaps a hundred yards long. Their orderly formation
reminded me of a parade moving to the cadence of a band. But I was sure that
these starfish marched only to the beat of their own private drum.
I dropped down for a
close look at one and was again reminded of the aptness of the name
“crown-of-thorns.” Dozens of sharp spines jut out from each of the animal’s
arms as well as from the central disk. Besides simple pricking power, these
thorns can poison: injuries from them sometimes cause swelling. pain, and even
nausea.
I drew my knife and
flipped a two-footwde creature onto its back. Its underside was covered with
tiny yellow tube feet which enabled it to move in any direction.
Those tube feet, I soon
discovered, function like suction cups. I lifted the star with my knife and
tried to balance it on my underwater camera. It immediately wrapped its arms
around the camera, enveloping everything but the strap. I used that to tow my
living pincushion to the boat, where I had to use my knife again to break the
grip of its arms and tube feet on the camera.
Spears
Are the Answer on Small Atolls
“Man,
I’ve never seen so many in one place before,” Mick gasped as he tried to catch
his breath. “They were all over the place, moving as if they were playing
follow-the-leader. It looked like a scene from a science-fiction movie—an
invasion from inner space.”
“We
can control the invasion here in
Driving home from the
dock, Dr. Chesher told me that people living on low-lying Pacific islands face
real danger as a result of the starfish’s depredations.
“When live coral is
killed, reefs may break down,” he said. “Then storm waves might eventually eat
away shorelines. But before this could happen, islanders might be forced to
leave or starve. They get almost all their protein from the sea. Once the reefs
die, food fish go too.”
The possibility that
such a disaster might strike the
But the team also studied the animal’s
behavior, particularly it’s eating habits. Dr. Ralph W. Brauer, of the
Wrightsville Marine BioMedical Laboratory in
I accompanied Dr. Brauer
and his two colleagues, David Barnes and Mike Jordan, on a collecting
expedition to an infested reef along
“Be careful when you handle these
critters.” Dr. Brauer warned us. “I don’t want you to damage the animals or
yourselves. Watch out for their spines!”
We headed for the
bottom. Here the seafloor was covered with coral heads of all shapes and sizes,
Only a few Acanthaster were feeding on top of the heads. Most of them were well hidden under the
coral, to which they held firmly with their arms and tube feet. To remove the
starfish, I used my knife with the care of a surgeon, heeding Dr. Brauers warnings
as I worked.
Spines
Can Cause Painful Wounds
The four of us shuttled
back and forth between the raft and the coral heads on the bottom. On each trip
up we brought one starfish to the surface, put it in a bucket on the raft, and
headed back down for another.
On Mikes last trip to
the surface, he handed a starfish to David, who was in the raft. A spine
brushed David’s finger. Light as the touch was, it gashed his skin. David yelped. “Force the cut to bleed” Dr.
Brauer told him, “get the stuff out of the wound. If you do it right
away, you’ll have less pain later.”
When
we released our starfish in glass walled tanks at the university, Dr. Brauer
ran sea water over some living coral, filled a hypodermic syringe with the
polyp flavored water, and squirted it under a starfish creeping up the glass
wall.
Mistaking
the coral taste for live coral, the starfish opened its mouth (located in the
center of its underside) and everted its stomach. The fleshy digestive sac
covered an area larger than a man’s palm.
Next
Dr. Brauer placed a hungry starfish on a piece of living coral. Out came the
stomach. It spread over the coral polyps and its
digestive juices began to dissolve them inside their limey shelters. After an
hour, the polyps were reduced to semifluid shreds. Where colonies of colorful
little animals had lived, there remained only a bleached white skeleton.
‘In a single night,” Dr. Brauer told me, ‘an adult
starfish can clear off a coral head that might have taken fifty years to grow’.
Giant
Tritons Prey on Stars
While such studies of
the sea star’s habits may lead eventually to a means of controlling the present
plague, some scientists are seeking more immediate solutions. Australian biologists,
concerned about the threat to the
“1 have calculated that
shell collectors took at least 100,000 tritons from the Great Barrier Reef
between 1949 and 1959,” says Dr. Robert Endean of the
Having once watched a
giant triton devour an Acanthaster, I can vouch for its voraciousness.
The triton first located the star with its two tentacles. The threatened
starfish tried to creep away, but its pursuer chased it across a coral head and
caught it. The mollusk first seized the starfish, holding it between shell and
foot, then began to tear it to shreds and eat it. Several hours later, it ejected the spines.
If
isolated or somehow contained within a given coral area, the crown-of-thorns
soon curbs its own population explosion—at the cost of a totally dead reef. “.‘Acanthaster
become so numerous they eat themselves out of house and home,” explained Richard
Randall, an expert on the corals of the
While I browsed
through the dozens of coral-laden racks in his house on
Man
May Have Set Off the Plague
Can
a reef recover from a starfish attack? Mr. Randall is trying to find out.
Coral
regeneration is difficult because the porous skeleton of a ruined reef is soon
covered with algae which prevent new growth. Within two or three days the white
skeleton becomes a dismal gray, coated with fuzz or festooned with long green
strands.
No single theory
offered to date has adequately explained the starfish plague and its wide
distribution. Some scientists speculate that the population explosion has no
unusual cause but is only a natural periodic phenomenon. Other theories seem
valid for certain areas but not for others. Many Australian scientists are
convinced that over-collection of giant tritons created the plague on the
In
his office at the
Dr.
Chesher explained that under normal conditions only a tiny percentage of the
millions of eggs spawned by the female Acanthaster ever reach adulthood
Many of the floating starfish larvae are devoured by living coral polyps. But when an area of reef is killed by man,
the vulnerable larvae can settle upon it and mature in safety.
Because
there is usually living coral immediately adjacent to the dead reef, the young
adults have a ready food source once they begin to eat polyps. As the adult
starfish destroy even more of the reef, they enlarge the sanctuary for their
young. The result of the reaction is a population explosion,
“Support
for my hypothesis,” Dr. Chesher pointed out. “comes from the fact that
infestations in Guam,
residues
washed into the oceans from the land.
Whatever the cause
may prove to be, all the theories advanced so far—except that of natural
periodic population growth—pointed to the activities of man. Whether by
dredging or shell collecting, or pollution, this latest disturbance of the
balance of nature seems be a further example of man’s disruption of his world.
The
END
Resource
Guide by Mike Mullins Hillsborough CC
1989
THE
PHYSICAL SETTING
Over
200 emerald green islands make up the
To the west of this island arc are the
nutrient rich, shallow waters of
Climate
Although
the Keys lie in the temperate zone about 70 miles north of the Tropic of
Cancer, they have a tropical climate due to the warming effect of the
The
AVERAGE
TENTERATURE AND RAINFALL -
J
F m A
m J J
A S 0 N D
TEMP. 71 72
73 75 77 79
80 81 79 75 73 71
PPT. 1.5 1.5 2.2 ,2.7 6.0 9.5 8.7
7.2 9.2 6.0 1.5 1.0
The dry season runs from October to
April and the wet season begins in May and extends through September. Although this climatic pattern is fairly
consistent throughout the Keys, occasional extreme weather conditions
exist. During the summer, afternoon
thundershowers are a significant factor in the weather.
A
rising column of air is created each summer day as the land heats up faster
than the surrounding water. This rising
air creates a localized low-pressure area over the islands. The area of low pressure is filled by air
rushing in across the water from both sides of the islands. This air is filled with water vapor, which
evaporates from the ocean surface more rapidly in the moving air. As this moisture rich air arrives over the
islands. it too rises. This cycle
creates a sea breeze. As the water vapor
rises. it begins to cool and condenses to form a cloud. This cumulus cloud grows until it reaches
cold air where the top flattens off forming a typical
Another significant weather factor
during the summer is the hurricane.
Tropical storms and hurricanes are a normal part of the summer in the
Keys. Even when they do not hit the
islands directly, they can make a major contribution to the summer
rainfall. During historic times, several
of these storms have had a major impact on the Keys.
A hurricane in 1622 sank the fabled
Nuestra Senora de Atocha near the Marques islands off the western end of the
Keys. In 1733 another hurricane
scattered a Spanish treasure fleet along the reefs of the middle keys. Many of these reefs were later marked by
lighthouses so that ships could detect their location during storms.
The most devastating storm to hit
the keys in this century was the Labor Day hurricane of 1935. It battered the Middle Keys with 200 mile an
hour winds. This storm left over 500
people dead in its wake including a large contingent of CCC workers who were
killed when a rescue train was destroyed by high winds and waves. A monument was erected on Islamorada as a
memorial to those who died in the storm.
A second great storm, hurricane Donna in 1960, caused millions of
dollars worth of property damage but thanks to advance warning, there was
little loss of life.
In the winter, cold fronts
occasionally move down through the Keys from the mainland. When this cold arctic air slides in under the
warm, moisture rich tropical air, it can bring cold temperatures and set off
heavy rainstorms. A series of such
fronts dropped 23.3 Inches of rain on
Geology
Geologically, the Keys are a chain of
small Iimerock islands witch average 3 to 4 feet above sea level in
elevation. The maximum natural elevation
of 18 feet is found on Lignum Vitae Key.
The keys are divided into two
distinct types of islands, which differ in shapes, orientation, and the
composition of their surface rocks. The
surface rocks of the upper Keys are composed of a collection of fossilized
coral reefs known as the Key Largo Formation.
This large fossilized reef system first outcrops at the surface at
Soldier Key in
The Key Largo Limestone Formation is
the older of the two formations. It is a
collection of fossilized coral reefs which vary in thickness from 35 to 180
feet. The ancient reef tract originated
about 100,000 to 125,000 years ago during the geological epoch known as the
Pleistocene. During this period sea
level fluctuated several hundred feet as water was taken lip into glaciers and
then released again as the glaciers melted.
The ancient reef system was
wider than the present reef system. In places it extended up to five miles
eastward to the edge of the continental shell Sea level at the time of its
formation was approximately 20 feet higher than it is at present. No islands existed to block the exchange of
water between the Gulf of Mexico and the
The ancient
Over time, the slow growing corals
built a wide, nearly solid reef system about 150 miles long. Before the system could became a completely
solid reef, glacier formation began and sea level began to fall. The former
reefs were exposed to the air and became a string of islands. As sea level
continued to fall the ancient reef tract became a solid landmass which blocked
the flow of water between. the
At the end of the Pleistocene some 6,000
to 10,000 years ago. the last glaciers began to melt and sea level began to
rise. Most of the present day
About 3.500 ago sea level rose to
the point where
Whereas the Key Largo Limestone was created
by the actions of sea animals, the Miami Oolite had chemical origins. Ooids are
small egg shaped spheres of calcium carbonate.
They are formed under ideal conditions in warm water seas.
Ooid formation begins when the
temperature of seawater reaches a level where calcium carbonate or lime can no
longer stay in solution. This chemical
begins to take on solid form in the water.
It begins to collect around tiny grains of sediment, microscopic plants
and animals or bacteria. The calcium
carbonate continues to collect in concentric layers until it reaches a mass
which causes the tiny egg-like particle to sink to the bottom. This process of ooid formation occurred over
a large portion of south
At a time when sea level was higher,
extensive areas of oolite ooze were deposited in the prehistoric
Both the Miami Oolite and the Key Largo
Limestone have been greatly affected by their exposure above sea level. Some of the original limestone structure has
been melted by the presence of tannic acids from the decay of plant
leaves. The paste-like material has
acted as cement to attach together the individual particles and to fill in the
spaces between individual coral heads.
At the same time, this acidic water has eroded portions of the
limerock. This process has created pits,
holes and even large solution cavities in the rock. These larger solution cavities form fresh
water catch basins which serve as watering holes for terrestrial wildlife.
Because of the orientation of the
ancient reel the islands where the Key Largo Formations outcrops are long and
thin. Their general orientation is
northeast to southwest. The southern
oolitic islands are much different in shape and orientation. They are generally wider than the northern
islands and their orientation is northwest to southeast. The transition between these two types of
islands is best noted on Big Pine Key where the big island is Miami Oolite in
origin and the small string of islands which make up the
The unique climate and geology of the
The higher portions of the
Surrounding most of the islands
throughout the Keys are fringing mangrove forests. In some places, the mangroves are absent,
replaced by a rocky intertidal community.
In the shallow portions of
In the shallow water just beyond the
edges of the mangrove community is found another community consisting of
calcareous green algae growing on soft carbonate sand and mud. As the water gets slightly deeper, the type
of algae changes to a soft green variety mixed with several species of sea
grasses. With increased water depth,
sponge and soft coral communities appear.
Scattered in a line between the islands
and the outer fringing reef communities are mounds of large corals known as
patch reef communities.
Of all the communities found in the
Keys. It is the outer reefs which
attract so many people to the islands.
And, of all the organisms, it is this human species which will
ultimately determine the ecology of this tropical paradise.
THE
The
islands of the
Hammock is the name used to describe
the rich, green, jungle-like growth which originally covered all of the high
ground in the upper keys. This community is typically compose of less than a
dozen species of tropical hardwood trees and several species of palm. Almost all of these plants are of
As is the case with manv tropical
forests. the vegetation of the hammock community is divided into a series of
layers. The upper or canopy layer is
dominated by giant mahogany, tamarind, poison wood. Jamaican dogwood, mastic and gumbo limbo trees. The trees of the second layer include pigeon
plum, black ironwood, and satinleaf. The
third layer is dominated by cat claw and
Growing in and on the trees are a variety
of epiphytes including orchids, bromeliads, resurrection fem and Spanish
moss. Growing up from the ground into
the trees are Virginia creeper, wild grape. nicker bean and cat briar
vines. A unique parasite of the hammock is
the strangler fig.
Among the abundant animal life of these
tropical hammocks are several types of swallowtail butterflies. blue land
crabs. several species of lizards, the Keys raccoon, and several endangered
species, the keys tree snails, the
The West Indian mahogany, Swietenia mahagoni grows to between 50
and 60 feet in height. This tree grows well in thin soils, limerock and brackish water conditions found
in the Keys. The West Indian Mahogany has a thick crown of
compound leaves with four to six leaflets.
The large seed pods contain winged seeds which are similar in appearance to maples trees. The wood of this mahogany tree is heavv, close-grained, hard,
strong and durable. It has a deep, dark
red-brown color which darkens with age.
This beautiful wood is highly
desirable for building and the mahogany tree has been cut since the coming of
the Spanish. As a result the
The gumbo limbo, Bursera simaruba,
is one of the largest growing trees of the hammock. It can attain a girth of 10 ft. and a height
of over 60 feet. The bark of the gumbo
limbo is a rich reddish green. On mature
trees it peels off in thin paper-like red sheets.
The lignum vitae. Guaiacum sancturyl now on the
endangered species list. was once common enough in the keys hammocks to support
a small commercial timber industry. Its
extremely hard, dense wood was used for the bearings of prop driven steam
ships.
The poison wood. Metopium toxiferuril is one of the
most common trees in the hammock. it is also one of the trees to avoid. The sap and the black gum-like resin exuded
when the bark is bruised are poisonous.
Contact with human skin causes a rash similar to that produced by poison
ivy. The poison wood is a pioneer plant
and usually colonizes an area after a fire.
The strangler fig, Ficus
aurea. which can grow from a seed planted in the ground, often begins life
as an epiphyte growing in the boot of a cabbage palm. In time, it sends out a root which winds its
way down the trunk of its host until it reaches the ground. As the roots grow downward, a thick crown of
glossy green leaves is produced. Down
from the spreading branches come a. large number of drop roots which support
the increasingly dense foliage. As it
continues. to grow the fig slowly, but completely, kills its host. '
The trees of the hammock typically
have shallow root systems due to the thin layer of black soil spread over the
solid rock below. Only a few of the
roots penetrate through cracks in the rock to tap the freshwater lens
below. The hammock vegetation protects
the soil from erosion and moderates the temperature in the hammock through
evaporation of water through openings in their large leaves.
The leaves which fall from these
trees are decomposed by leafmold. This
contributes humus to the sterile sandy soil.
When the hammock vegetation is cleared, the soil nutrients are quickly
lost and the land is largely unproductive.
Pine
Rockland Forests
Growing
on the large,
The islands have an abundance of
solution holes extending down from the surface into the water table. These breaks in the rocks provide homes and
habitats for a number of freshwater plant and animal species. They also serve as water holes for animals
such as the key deer and the rare white key raccoon.
In addition to the pines. a number of
other plants arc abundant in the pine rocklands. These include saw palmetto, key thatch
palm.
The pine rocklands are the home of the
diminutive key deer. These animals are
small subspecies of the
The pine rocklands environment is an
inviting one for building homes. As a
result, much of this habitat has been utilized for this purpose. This has created a problem for the deer herd. The development on the
THE
MANGROVE FORESTS
The
term "Mangrove" is applied to a diverse group of tropical salt
tolerant trees which are abundant in the
Types
of Mangrove Trees
There
are three species of mangroves found in
The red mangrove is the most noticeable
of the three. It grows in the deepest
water and its arching prop roots support the tree above the water as if it were
walking on stilts. Wart-like lenticels
on these prop roots provide openings where oxygen can be taken in and pumped
through the system to the underground roots growing in the anaerobic mud. Since red mangroves grow close together,
their roots form an impenetrable tangled network which slows down the movement
of water underneath the trees. This
causes a deposition of sediment and traps an enormous collection of debris. This build up of sediment and debris under
the right conditions can create a thick layer of organic peat.
The
leathery evergreen leaves of the red mangrove form a dense canopy which are
highly efficient in converting sunlight to organic molecules. Sprinkled in among the leaves are yellow and
white flowers. The red mangroves have an
unusual reproductive adaptation enabling the seedling to survive in the watery
environment. The seed germinates from
the fruit while it is still attached to the parent tree. Many fruits with finger-like seedlings, often
twelve or more inches in length, can be seen hanging in clusters. When mature, the seedlings break free from
the fruit and fail into the water. Some
may stick in the soft mud around the base of the parent tree and begin to
grow. Many more float around with the
tide. After floating in the water for a
short period of time, the pointed end absorbs water and begins to sink. When the seedling becomes grounded in the
mud, roots are quickly produced from the pointed end and the seedling begins to
put out leaves.
In the keys, the black or honey mangrove
usually forms a zone behind that of the red mangrove. This tree takes its name from its dark scaly
bark. Black mangroves usually grow in
soils that are exposed to the air at low tide but covered by high tide. Where they seldom experience frost, as in the
Keys, black mangroves can develop into large trees over 50 feet tall. Their 2 to 4 inch long leaves are dark green
above with silvery, hairy undersides. In
these leaves there are special glands that excrete salt extracted from the
water taken in by the roots. The salt
often forms a white crust-like coating on their upper surface. Black mangroves have small white flowers
which produce abundant nectar used by bees.
They have no prop roots but their root system produces many slender
upright aerating roots known as pneumatophores. They cover the muddy
soil around the base of the tree and supply the root system with oxygen.
Black mangrove seeds are the size and
shape of very large lima beans. They germinate
as soon as they fall into the water. The
seedlings are smaller than the red mangrove seedlings so they are washed
farther up into the forest by tides.
Here they become entangled in mats of detritus trapped by the mangrove
roots and begin to grow.
White mangroves grow in sandy soils at
the upper edge of the intertidal zone.
Their round pale green leaves are notched at the tip and have a pair of
salt excreting glands on either side of their petioles. The white mangroves have small peg roots
which help anchor them in the sandy soil.
The small green seeds of the white
mangroves begin to develop after they fall into the water. Over time they turn brown and wrinkled. Due to their small size, the white mangrove
seeds are carried high in the swamp by the tide. When the seeds are finally deposited in the
strand line, they germinate. The
seedlings quickly put down roots and produce a pair of notched tip leaves.
Above the normal high tide line grows a
relative of the white mangrove the buttonwood or grey mangrove. These trees get their name from their
spherical berry-like fruits. Like the
white mangrove, the buttonwood has salt glands on its leaf petioles. The buttonwood tree has a twisted trunk
covered with a loose bark. The bark is a
favored grow site for epiphytes.
On some of the lower keys, buttonwoods
are found growing in depressions on the interior of the islands surrounded by
hardwood hammock plants. Early residents
of the Keys used the wood of these trees to make charcoal.
Types
of Mangrove Forests
Because
of different conditions of tide, substrate, freshwater runoff, nutrients and
exposure, a variety of types of mangrove forests exist throughout the
world. Two scientists,
Overwash mangrove islands are
abundant along the Florida Keys and in
Because
of their isolation, mangrove overwash islands are an ideal habitat for the
nests and roosts of coastal birds
Overwash
mangrove islands:
1. Are overwashed by daily Tides
2. Have a high rate of organic export
3. Are dominated by red mangroves
Fringing
mangrove forests grow along the shorelines of the
Fringing mangrove wetlands may intermix
with basin mangroves behind them or may end abruptly at the top of a land
berm. If the shoreline is steep, white,
black and/or buttonwood trees-may grow behind the red mangrove and be
considered part of the fringing mangrove system. On a gently sloping beach, the width of red
mangroves may vary considerably.
Like the overwash islands, fringing
mangrove forests harbor extensive communities of plants and animals on their
roots. They also act as refuges for fish
and other wildlife during periods of rough weather and heavy seas. These fringing forests protect the shoreline
from storm damage and export a great amount of organic detritus into the
Coastal lagoons.
Small areas of basin mangrove forests
occur in the Florida Keys, primarly on the
Dwarf mangrove forests are the first mangrove
areas encountered on the trip dowm U.S. 1 from
Ecological
Value of Mangrove Forests
Every part of the mangrove forest, from
the roots to the top most branches, which may reach as high as 60 feet, provide
shelter or food for a multitude of creatures.
These organisms range from tiny sand flies to large tarpon offshore.
One of the birds that finds its home in
the tree tops of the mangroves is the brown pelican. The pelicans share their
"rookeries" with egrets, herons, wood storks, ospreys, and cormorants.
A host of other creatures make use of
the mangroves to forage. Racoons favor
the coon oysters that live on the prop root of the red mangrove. Spiders weave many webs to catch unsuspecting
insects; snakes slither up the tree trunks after birds' eggs and nestlings; and
cormorants dine chiefly on the fish in the nearby waters. Fiddler crabs and their larger relatives the
land crabs move out during the low tide to perform a large service. They aerate the soil as they probe the
sediment for food, thereby increasing the supply of oxygen to the trees that
attract the creatures.
However. when the tide comes in
covering the roots and pneumatophores of the mangrove forest, it becomes part
of a marine nursery. The mangrove forest
provides a place where young fish. as well as other organisms such as blue
crabs, are protected from predators and competing species which are unable to
enter the lower salinity water. The
young of herbivores and detritivores occur in hordes. Oysters, barnacles, and sponges along with
the ribbed mussels are found in great Quantities in the mangrove root zone.
It is well documented that the
mangrove forest plays an important role In the ecology of the Keys. The food chains and webs which begin in this
rich habitat extend all the way out to the reel. They also serve as a nursery and spawning
ground for many of the organisms which live in other key communities as
adults. Lastly they provide protection
for the delicate terrestrial communities from all but the most severe storms.
THE
CORAL REEFS
Coral reefs are marine communities built
of calcium carbonate secreted by a primitive types of animals called coral
polyps In addition to the polyps. certain red and green algae, polychaetes,
mollusks and bryozoans all play a role in the construction of coral reefs.
Coral reefs have been prominent
features in the warm, shallow waters of the world ocean for over two billion
years. They flourish in clear near-shore
waters where the average annual temperature is at least 23.0 C. and seldom
falls below 18.0 C. This puts them in a band that lies between the Tropic of
Cancer and the Tropic of Capricorn. The
warm water reduces the solubility of calcium carbonate and increases the
ability of the corals to produce their skeletons. In addition to temperature, light, salinity,
immersion, sedimentation, and substrate are the major factors influencing reef
development.
Coral polyps are similar to small sea
anemones. They have a circle of tentacles
surrounding single body opening which serves as both a mouth and an anus. Their sac shaped bodies are composed of two
cell layers and are internally divided into segments.
Polyps are nocturnal predators
which feed on microscopic animals called zooplankton. They trap their prey with specialized cells
located on their tentacles. These expode
when an animal brushes against them releasing threads which stab, entangle or
stick to the prey. The tentacles are
also covered by cilia. In some species,
a thick mucus curtain is secreted from the tentacles. Planktonic organisms become trapped in the
mucus and the cilia transfer them from the tentacles to the mouth. In most species, the cilia sweep back and
forth keeping the polyp free of silt and sediment.
The organisms which form the basic
structure of today's coral reefs are known as hermatypic, or
reef-building coral. These reef-building
corals are colonial animals that differ from other members of their phylum
(Cnidaria) primarily by the fact that each individual coral animal, or polyp,
secretes a calcareous skeletal cup around its soft body. These delicate polyps can withdraw inside
their rigid outer casing for protection.
This hard casing is one reason why corals are often thought of as rock
rather than the animals they are. In
fact, the living polyps occupy only the upper few millimeters the massive
limestone structures that their species have secreted and subsequently grown
out of over the past millennia.
Algae known at zooxanthellae are as
important to reef development as are the coral polyps. These tiny dinoflagellates in the genus Symbiodinium,live
in the tissues of the hermatypic corals.
They have a mutualisuc relationship with the coral polyps. The coral offers protection and nutrients to
the zooxanthellae. The zooxanthehae
remove metabolic waste and provide nutrients and oxygen to the coral. Zooxantheflae also aid in the calcification of
the coral skeleton. It is only with the assistance of the zooxanthellae that
the corals are able to form massive reefs.
Environmental factors such as increased turbidity, reduced light, and
fresh water effect the health of the zooxanthellae and thus the health of the
corals.
In the waters of continental United
States individual coral colonies are found are found as far north as North
Carolina in the Atlantic and Cedar Key in the Gulf. They are also found off the
There are three types of coral reef
communities commonly found in the
A typical outer bank reef
community is composed of three sections.
The fore reef is composed of large heads of star (Montastrea),
boulder and pillar coral. These thrive
in the turbulence created by the waves.
Behind the large colonies are found the branching elkhom coral and
frequently a branching form of fire coral.
In the shallowest portion of the outer reefs a ridge of the coralline
red algae forms the reef crest which breaks up the action of the waves and
protects the back side of the reef. On back reef the more delicate staghorn
coral grows.
During storms, the reef crest takes a
tremendous pounding. A great deal of
coral may be broken off during this process and, occasionally, new channels may
be carved through the reef. This creates
a pattern called spur and groove. The
impact from hurricanes and the constant pounding of the waves produce large
quantities of sand from the coral skeletons.
Rising from the quiet lagoons behind
the outer reefs is a different type of coral reef corrimunit3r called a patch
reel Ms type of reef community is primarily composed of species of large brain
corals overgrown in places by staghorn coral.
The patch reefs also support numerous species of soft corals called gargonians.
In addition to corals, reefs are
home to a large number of colorful and fascinating species. Blue tangs.
Acanthurus coeruleus, and princess parrotfish, Scarus
taeniopterus wander over the reef clipping or scraping algae from
the reef surface. Herbivorous damselflsh
defend their reef-top territories while trumpetfish, Aulostomus maculates,
search for prey among the coral heads and waving gorgonians. Yellow goatflsh, Mulloidichthys martinicus ,
probe the sandy bottoms in search of food and spotted drum, Equetus
punctatus, lurk under overhanging ledges.
Many symbiotic relationships exist
between various species of reef fish.
Pilot fish, Naucrates, form commensal associations with large
sharks. Shrimpfish, Aeloiscus
maintain a relationship with the sea urchin.
Centrechinus, and the man-of-war fish, Nomeus, swims among the
dangling tentacles of the Portuguese man-of-war, Physalia.
As alreadv mentioned, hurricanes and
tropical storms can devastate coral reefs.
Changes in water conditions can also take their toll. Mass bleaching (loss of zooxanthellac or
pigments) appears to be increasing in coral reef areas in both the Pacific and
the
4
- THE GRASS FLAT COMMUNITIES
Marine
grass flat communities occur both in
The
Sea Grasses
There are several types of flowering
marine plants are found in the sea grass community of the
In the Keys, the sea grass community
grows from near the low tide line to about 50 meters of water. This luxurious growth is possible due to the
protective action of the reefs which reduce the wave energy.
Like many, land grasses, sea grasses
have an underground stem known as rhizome.
These grow horizontally, occasionally sending up a cluster of leaves and
sending down a bundle of roots. The
leaves of the grasses slow down the flow of water and cause a deposition of
sediment.
The marine grass flat is a diverse
community of plants and animals. The
grass blades provide food for some organisms, refuge for many and a substrate
for others. Like wise the sediment
around and under the grasses provides a habitat which is exploited by a number
of organisms.
Epiphytic
Organisms
The
wide blades of the turtle grass and the smaller blades of manatee, shoal and
star grasses provide a habitat for a variety of plants and animals. In the
The
epiphytic animals found on sea grass leaves include both attached and mobile
forms. The attached forms such as
forams, hydroids, anemones, sponges, and bryozoans. These animals feed on both plankton and
particulate detritus.
The mobile fauna are primarily crustaceans
such as shrimp, amphipods, and isopods.
These feed on the sea grass leaves as well as the other epiphytic Plants
and animals.
Benthic
Epifauna
Like the epiphytic organisms, the
epifauna have both sessile and mobile forms.The sessile or attached animals
include soft corals, hard corals, anemones, sponges and tunicates. Patches of finger corals. Porites porities, are frequently common
in areas of the grass flats. Most of
these sessile organisms feed on plankton and detritus.
The mobile epifauna are dominated by
echinoderms. Sea stars. brittle stars,
sea urchins, sea biscuits. sand dollars and sea cucumbers are all abundant. One echinoderm, the long-spined black urchin,
Diadema antillarum, is a nocturnal feeder on sea grasses, but spends its
days tucked into the nooks and crannies of coral reefs. This grazing pattern
creates a zone of bare sand around the edges of the reefs. This "halo" Is especially evident
around patch reefs which are usually surrounded by grass beds.
Another unusual group of echinoderms
which are common in the sea grass beds are the sea cucumbers. Unlike most echinoderms which are radially symmetrical,
the sea cucumbers are built bilaterally.
The small ones resemble worms and the larger ones, which can stretch up
to 3 ft. in length, resemble the vegetables for which they are named. Sea cucumbers feed on benthic detritus using
five tentacles which protrude from their mouths.
The most common sea cucumber in the
Key's sea grass community is the donkey dung, Holothuria mexicana. Each one eats huge volumes of sand each day
and digest out the organic detritus. In
its wake it leaves a collection of elongated whit fecal pellets about the size
and shape of a human thumb.
The mollusks are also well represented
in the in the epifaunal habitat. The large edible queen conch, Strombus
gigas, from which the Key's natives take their nicknames, feeds on both
epiphytes and benthic detritus. Th king helmet conch, Cassis tuberose,
are active predators. They primarily
feed on echinoderms with the sea egg urchin, Tilpneustes ventricosus, being their favorite prey.
The
crustaceans are a common component of the sea grass epibenthic community. A variety of shrimp including grass, broken
back, and commercial shrimp feed on epiphytes, infauna, and detritus. The spider crab is a seldom seen resident of
the marine grass flat community.
HISTORY
The first people to live in the Keys were the
Pre Columbian Indians. Anthropologist
are not sure who these early groups Were but there evidence pointing to the
Tequesta in the Upper Keys and the fierce Vescayno and Matecumbes Indians in
the Lower Keys. There is very little
evidence of permanent villages in the Keys but these frequent visitors left
behind middens filled with the bones of fish, shellfish, turtles and manatees.
The natural resources harvested by the
Indians were occasionally supplemented by supplies salvaged from the ships of
the early Spanish explorers who fell victim to the treacherous coral reefs. ay
the 1570's, when the Spanish began to explore the Keys, these early visitors
had all but disappeared.
These early Indians who the Spanish
first encountered the Keys were replaced by the Calusa which ruled much of the
west
The last Indians who visited the Keys
were the Seminoles. They raided Indian
Key on August 7, 1840 in retaliation for bounty hunting of members of their
tribe by a resident, Jacob Houseman.
The Spanish explorer, Juan once de
Leon discovered the Keys during his 1513 expedition. With a dramatic flair he named them Los
Martires,.the martyrs, because they appeared to have a twisted and tortured
shape. The Spanish interest in the
islands was limited. They logged out
both hardwood and pine trees but did not establish any permanent settlements. There wasn't any gold, there was very little
fresh water and there were hordes of mosquitoes. Their principal interest was in mapping the
reefs which took a great toll on the Spanish treasure fleets.
For several centuries the keys were used
by a variety of pirates and wreckers who sometimes attacked Spanish shipping
but who more frequently plundered ships that wrecked on the reefs. Many of these were "conchs", They
were descendents of Englishmen who settled Eleuthera and the
The Teal pirates, such as Blackbeard
and his lueitenant Black Caesar, continued to prey on shipping. The situation remained bad enough however,
that in 1822 the United States Navy sent its West Indian Squadron of eight
small shallow draught schooners under the command of Commodore David
Porter. This small determined group soon
made the Keys an unsafe place to be a pirate.
One of these brave ships, the USS Alligator, went aground off Matecumbe
Key on a reef which now bears its name.
The ship was blown up by its own crew to prevent it falling into pirate
hands.
Many former pirates turned to the
practice of wrecking. The salvaged cargo
was taken to
The Spanish name for Indian Key was
The island was home to Dr. Henry
Perrine, a physician who was also a botanist. He
imported many plants to the island, many from
By 1840, the town of
On August 7, of 1846, the Indians took advantage of the fleet being away and attacked
the island. They burned most of the
buildings and killed sixteen of the residents including Dr. Perrine who tried
to plead with them to stop the attack.
Many of the people including Dr. Perrine's family and Houseman survived
by hiding in the water filled cisterns underneath their burning houses.
In, 1832 when Indian Key was just
beginning as a town it was visited by a budding birder and artist John James
Audubon. He continued on to Key Vaca,
Where as the wreckers of the Keys found
the reefs an aid to profit the owners of the wrecked ships did not. They demanded that the federal government
provide navigation aids to make the passage along the Keys safer. A string of light ships were anchored along
the reefs, but there were they were insufficient. Their lights were weak and they were frequently either blown off the reef or
wrecked themselves during storms. From
1850 to 1880 a string of seven steel light houses were built on the most
dangerous reefs. These' employed a
unique construction. A series of steel
piles were screwed into the bed rock of the reefs. The lighthouse was then attached to these
structures. The spider leg support
allowed storm waves to pass through the lighthouse with out doing much damage.
At the close of the War Between the States
in 1865, the key played a part in history.
They were the pipeline through which Judith P. Benjamin, the Confederate
Secretary of State was smuggled to safety in the
The Keys Have been the home of many
entrepheurs. Plantations which grew
pineapples, tomatoes and coconuts briefly flourished throughout the Kevs. Most
of the failed due to poor soil, mosquitoes, hurricanes or a combination there
of.
In the 1880's Vincent Ybor
established a cigar industry in
Around the turn of the century
sponging became important in the Keys.
The rich sponge beds provided a high yield cash crop. They were harvested from boats with three
pronged hooks and glass bottom buckets.
Financial problems created by World War I and finally the sponge blight
finished the industry in the 20's and it moved to Tarpon Springs.
In 1904, Henry Flagler, president of
the Florida East Coast Railroad realized the economic advantage of having a
railhead close to the Panama Canal and only 90 miles from Cuba. He gave to go ahead to extend his railroad
south from the farming community of
In March of 1926, bond sales were
approved by the voters to begin construction of an overseas highway linking
1 State
Of
1.How old is the
recent Caribbean Coral Reef System?
2. That “Coral
reefs are highly susceptible to disturbance in relation to other nearshore
ecosystems” Is this fact or
opinion? Where could you check this
statement?
3What is an
endodermal symbiont?
4. List 5 socioeconomic importance’s of coral
reefs and give an example of each.
5. How are reefs a buffer for the CO2 cycle?
6. What 3 human activities threaten
7. What part of oil is the most harmful to
corals?
8. How does upland clearing effect coral reef?
9. How does sewage discharge effect coral reefs?
10. The statement on page 16-G. Anchoring “Standing
and walking over coral and coral collecting can also ruin large portions of the
reefs..”is this fact or opinion and explain.
11. What type of damage was observed from
military activities on the reef?
12. Where is this place?
13. How can overfishing---fish, not coral, effect
the reefs?
14. Can these coral reefs
recover...explain.
15. Summarize the 6 recommendations the author
makes.
16. The discovery of what about coral has made the destruction of reefs an
international interest?
Questions...Coral
1.
What is the most diverse marine ecosystem in the world?
2.
Where do you find
3.
Where, when and why was the
4.
What human effect can harm corals?
5.
What is meant by prop-dredge?
6.
What is the saying for boaters around reefs?
7. What is the uses and benefits of a
mooring buoy?
8.
How much of the reefs may be killed in our lifetime?
9. List the serious threats to the reef.
10. What is IYOR...when was it and what was
done?
3 Are Storms Killing Coral?
1. How much dust is
blowing from North Africa to the
2. List how this
dust can harm the corals?
3. What organisms
may benefit from this dust?
4. What is found in the dust?
5. How is the dust tracked?
11.
What animals play a large role in taking CO2 out of the atmosphere?
12.
What species was studied?
13.
When did bleaching peak?
14.
What were effects of bleached foraminifera?
15.
What did Hallock speculate caused the bleaching?
5a
1st Casulaty of CO2 Emissions Name.................................................pd....
16.
How much has the CO2 levels risen since 1700?
17. What has lead to this increase?
18.
What happens when corals are stressed?
19.
What is this result known as?
20.
Where did they discover how acidity interfered with the growth of coral
reefs?
21.
What is this acidity effect on corals?
22.
What happens to the 2 gigatons of CO2 a year?
23.
Why are corals suddenly getting diseases?
24.
What causes sea fan disease?
25. Why is the sea fan important?
26. Give 2 reasons the seafan is now getting
this disease?
27. What 2 species of seafans are found in
the keys?
28. What attiude
does the author take if the cause is found to be from pollution? Rising sea temperature?
Read the statements carefully. If it is stated in the article, put TRUE...if
not, put False. Refer to these
statements for part 2 as well.
..........1.
Coral-killing starfish are destroying living reefs that shelter
coastlines from continual pounding of the sea.
...........2. Acanthaster
planci may be used to control a
population explosion that threatens coral reefs.
...........3. Scientists are following the
spread of the crown-of-thorn starfish.
............4. A major tactic in dealing with the
crown-of-thorns starfish involves hunting and killing the animals by man.
............5. Dead reefs pose few problems to the islands
they surround.
...........6. Shell collectors took at least 100,000
tritons from the
............7. Blasting for channels and channel dredging
kills the coral animals.
..........8.
Animal populations in nature tend to fluctuate.
..........9.
Pollution may have an effect on corAl reef growth.
Science deals with causes and effects. Effects are visable things brought about by a
cause. They are the results. The cause produces the effect. Most of the true statements above are either
cause or effect statements. Select the
cause and effect statements and put the number below the proper heading.
A.
Causes
10.________
11.
_________
12. ________
B.
Effects
13._________
14. _________
15.__________
Causes listed above should be testable using
scientific method (causes could be
formulated as an hypothesis). Read the
statements below releating to the details and authors interpretations drawn
from the selection and write the number of the causes (from the 1st part) the
statement is designed to test.
..........16. Austrailian biologists are raising tritons
for future release as adults along the
..........17. Marine Biologists in Guam and
..........18. Scientists in
7
The
1. What
causes the keys to have a tropical climate?
2.
How does a tropical wet-dry climate differ from a tropical wet climate?
3.
When is the dry season in the keys?
4.
How do the afternoon summer thundershowers form?
5.
Describe the most devastating hurricane that ever hit the keys?
6.
What is the highest natural elevation in the Keys? What is the average?
7.
What are the two distinct types of islands found in the Keys and
describe the differences between them?
8.
Describe the different types of trees throughout the Keys.
9.
What is the existence of slash pines growing an indicator of?
10.
What problems do mangrove trees have to cope with?
11.
What are the three species of mangroves in the Keys?
12.
Distinguish between these species.
13.
What is a pneumatophore.
14.
What is an overwash mangrove island?
15.
List 3 functions of the fringing mangrove forests.
16.
What organisms play a role in the construction of the reef?
17.
What environmental factors are bad for the zooxanthellae?
18.
Why do the reefs off
19.
Name the three types of reef communities
commonly found in the Keys.
20.
What types of coral are located on the fore reef?
21.
Which is more delicate, staghorne or
22. What is a gargonian and where are they usually
found?
23.
Name 3 fish found living in a symbiotic relationship with another
organism?
24.
What may be bringing about mass bleaching?
25.
What is the most dominant species of sea grass?
26.
What causes the zone of bare sand around edges of reefs?
27.
How do fish use the grass flat community?
28.
What happened on Aug. 7, 1840?
29.
What was the principle interest the Spanish had in the Keys?
30.
What strange practice became a major industry in the Keys?
31.
How did Jacob Houseman avoid the salvage rules and fees of
32.
How were the lighthouses constructed over the reefs?
33.
What mistake had the engineers building the railroad made when the 1st
hurricane destroyed part of it in 1909?
34.
What replaced the railroad in 1935 after the hurricane?
35.
Who built the railroad?