Marine
Ecology
vEcology
is the study of the inter-relationships between the physical and biological aspects
of the environment. It is the study of how organisms adapt to their environment
and in turn alter it.
Marine
Ecology
vMarine
ecology is the branch of ecology dealing with the interdependence of all
organisms living in the ocean, in shallow coastal waters, and on the seashore.
Classification of Organisms
by Environment
v
horizontal:
neritic | oceanic
v
vertical:
epipelagic
(top) / euphotic (good)
mesopelagic
(middle) / disphotic (low)
bathypelagic
(deep) / aphotic (without)
abyssopelagic
(bottomless)
Divisions of the Marine Environment
Marine
Ecology
vThe
marine environment for all organisms consists of non-living, abiotic factors and living, biotic factors
Marine
Ecology
vAbiotic The abiotic
factors include all the physical, chemical and geological variables that have a
bearing on the type of life that can exist in an area. Included are: water
vLight dissolved gases
vpressure temperature
vtides pH
vcurrents salinity
vWaves substratum
vexposure to
air. nutrient
supply
Basic Ecology
v
factors
regulating the distribution and abundance of organisms in the ocean.
v
influence
of physical and chemical parameters on organisms in the various ecosystems that
constitute the ocean.
v
An ecosystem includes both the living
(biotic) and non-living (abiotic) portions of the
environment.
e.g.,
coral reefs, the North Pacific Gyre.
Hydrostatic Pressure
v
Hydrostatic pressure is the pressure
caused by the height of water.
v
It is a function of the density of water
and the total height of the water column.
v
Pressure generally increases at a rate of
1 atm per 10 m of water.
Hydrostatic Pressure
(Cont.)
v
enormous in
the deep sea yet animals live there.
v
Animals do not contain gases.
v
However, mesopelagic
fish have gas-filled swim bladders to help maintain neutral buoyancy
unable
to move rapidly between depths
pressure
change could cause bladder explode.
Temperature
v
The distribution of species closely follows
the shape of isotherms.
Temperature
Figure 9-10
v
controls rates
of chemical reactions and thus metabolic rates, growth rates, feeding rates,
etc.
Temperature
(Cont.)
v
Temperature tolerance varies tremendously
among marine organisms.
v
Young stages are generally less tolerant
of large changes.
v
e.g., eggs and young of the California sardine
cannot survive below 13 oC.
Temperature
Figure 9-11
v
Temperature may indirectly
effect a species due to a direct effect on its predator.
This is exemplified by the interrela-tionship of clams, crabs, and temperature in
Casco Bay,
ME.
Salinity
v
Many of the elements used for growth.
v
Salinity tolerance is also important in
limiting distribution.
Salinity
(Cont.)
v
Salinity fluctuates most in coastal waters
due to shifts in river flow.
Organisms
that are mobile can migrate offshore if they cannot tolerate a certain salinity, but attached organisms must cope
with the changes or die.
clams,
oysters, and barnacles manage to survive by closing their shells.
Diffusion:
molecules move from high to low concentrations
Diffusion
v
internal
fluids of marine organisms also contain salts
v
chemical
gradient - salts inside the body relative to the surrounding seawater
v
salts
will diffuse from an area of high concentration to low concentration.
nutrient
uptake and the elimination of waste products.
Diffusion
(Cont.)
v
Diffusion is also the mechanism by which
water molecules pass through cell membranes.
This is called osmosis.
Diffusion/Osmoregulation
Marine
Ecology
vBiotic
The biotic factors are the interactions
among living organisms.
Marine
Ecology
vZonation Two major divisions in the marine world.
vPelagic
zone...waters of the world and
vBenthic
zone..the
ocean bottom.
Marine
Ecology
vThe
pelagic zone include the productive coastal waters..neritic zone
vand deep
waters of the open ocean..oceanic
zone.
vAnother
division in the pelagic zone is related to light penetration..the photic and aphotic zones..
Marine
Ecology
vThe
benthic zone extends from the seashore to the deepest parts of the sea.
vThe material
that makes up the bottom is the substratum and the organisms living
there are the benthos.
Distribution of
Marine Lifestyles
v
16.7% of Earths animals are marine
v
2% inhabit pelagic environment (most of the
oceans are cold and dark)
v
98% are benthic!
Marine
Ecology
vTides
uncover parts of this zone and the area uncovered is the intertidal
zone, above is the supratidal zone, affected by salt
spray but not covered by sea water.
vBelow
the intertidal zone is the subtidal
zone..submerged and
extending seaward.
vThe
elevation and slope determines the length of time its
exposed.
Marine
Ecology
vThis
affects organisms living there because some are restricted to zones according
to their adaptations to this type of zone (intertidal
etc.).
Classification of Organisms
by Lifestyle
v
biota
based on lifestyle.
plankton
(floaters)
nekton
(swimmers)
benthos
(bottom dwellers)
Plankton
v
Plankton are
weak swimmers, and are known as drifters, unable to counteract currents.
Phytoplankton
(plants)
Zooplankton
(animals)
Nekton
v
Nekton are active swimmers capable of
counteracting currents
Fish
Squids
Reptiles
Birds
Mammals
Marine
Ecology
•Distribution
•Pelagic
world include the
•drifting
organisms...plankton and
•the
swimmers...nekton.
Marine
Ecology
•Plankton
comprise the large and small organisms that drift or
float while tides and currents move them through the water.
•Most
plankton do have a limited ability to move and can migrate vertically through
the water from day to night.
•Some
drifters can photosynthesize while others are consumers..
Marine
Ecology
•Plankton
is very important as it occupies the first two or three links in the marine
food chains.
•Nekton
use fins, jets of water, strong flippers, flukes and flippers to swim through
the water.
Marine
Ecology
vOrganisms
living in pelagic waters also put up with changes in salinity, temperature etc.
and inhabit the coastal areas etc. which fit their adaptations.
v(can withstand large changes (eury--
prefix) and narrow tolerance (steno))
Benthos
v
Epiflora or epifauna live on
the sea bottom.
v
Infauna live
in the sea bottom.
v
Benthic plants are restricted to shallow
waters - why?
v
Benthic animals occur everywhere from
shallow depths to the deep sea.
Marine
Ecology
vOther
zones include the surface waters of the coastal areas called the neritic zone and the waters of the ocean called the
epipelagic zone.
vThe
open ocean is less productive than the neritic zone
which contains plant plankton, fish larva, invertebrate larva that will
eventually end up near the coast.
Marine
Ecology
vThe
open ocean is divided into zones depending on the amount of light it
receives...from the epipelagic layer to the
mesopelagic zone 200-1000m in which daytime
inhabitants migrate upwards during the night, bringing back nutrients and some
exhibit bioluminescence (light producing organs called photophores).
The ocean can also be divided into zones based upon depth of light
penetration.
v
The photic zone
is the depth where light is sufficient for photosynthesis.
v
The dysphotic
zone is where illumination is too weak for photosynthesis.
v
The aphotic
zone receives no light from the surface because it is all absorbed by the water
above.
Marine
Ecology
vThe
deep sea layers bathypelagic 1000-4000m and the abyssopelagic
zone (below 4000m) have limited food supplies although
bacteria have been found that can make their own food.
Marine Ecosystems
v
Ecosystems
v
Ecosystems (or ecological systems) are systems of communities
in a large geographical area.
v
In order for an ecosystem
to be successful, four things are required:
Marine Ecosystems
.An energy source
Organisms
capable of capturing this energy in the form of organic molecules
.Organic
material must be available to all other organisms
Cycling of nutrients must occur between the abiotic and biotic portions of the system
Marine
Ecology
vTROPHIC
(FEEDING) RELATIONSHIPS
vEnergy
transfer is accomplished in a series of steps by groups of organisms known as autotrophs, heterotrophs, and
decomposers.
vEach
level on the pyramid represents a trophic level.
Marine
Ecology
vAutotrophs
absorb sunlight energy and transfer inorganic mineral nutrients into organic
molecules.
vThe
autotrophs of the marine environment include algae
and flowering plants and in the deep sea are chemosynthetic bacteria that
harness inorganic chemical energy to build organic matter
Marine
Ecology
vAUTOTROPHIC
NUTRITION..supply food
molecules to organisms that can't absorb sunlight.
vHETEROTROPHS
Consumers that must rely on primary producers as a source of
energy...heterotrophic nutrition.
Marine
Ecology
vThe
energy stored in the organic molecules is passed to consumers in a series of
steps of eating and being eaten and is known as a food chain.
vEach
step represents a trophic level and the complex food chains within a community interconnect and is known as a
food web.
Marine
Ecology
vDECOMPOSERS--
The final trophic level that connects consumer to
producer is that of the decomposers.
vThey
live on dead plant and animal material and the waste products excreted by
living things.
vThe
nutritional activity of these replenish nutrients that
are essential ingredients for primary production.
Marine
Ecology
vThe
dead and partially decayed plant and animal tissue and organic wastes from the
food chain are DETRITUS.
vThis
contains an enormous amount of energy and nutrients.
vMany
filter/deposit feeding animals use detritus as food.
vSaprophytes
decompose detritus completing the cycle.
Marine
Ecology
vENERGY
TRANSFERS IN MARINE ENVIRONMENTS
vPrimary
producers usually outnumber consumers and at each succeeding step of the food
chain the numbers decrease.
vThe
numerical relationship is called the pyramid of numbers. (base
as opposed to each step.)
Marine
Ecology
The energy pyramid is the
energy distribution at each trophic level as it
passes from producers through the consumers.
Some energy is lost as it
passes to the next level because
..
Marine
Ecology
•(a)
consumers don't usually consume the entire organism
•(b)
energy is used to capture food
•(c)
organisms used energy during their metabolism
v(d)
energy is lost as heat.
Marine
Ecology
vGenerally
only 10% will pass on to the next level. (The shorter the better..)
Marine
Ecology
•Scavengers..feed
on dead plants and animals that they have NOT killed...crabs ripping chunks of
flesh from fish on the beach are scavengers.
•Most
scavengers consume detritus rather than flesh and deep sea animals can feed on
both.
Marine
Ecology
Each chain or part of the
web serves to link phytoplankton to larger pelagic animals through the
zooplankton.
Herbivorus
zooplankton eat phytoplankton while carnivorus zooplankton occupy the third level as secondary
consumers.
Marine
Ecology
•Benthic
If the organism resides primarily in or
on the substrate and doesn't swim or drift for extended periods as an adult it
is considered benthic.
•They
either burrow , crawl, walk, (motile) or are sessile..permanently affixed to
the substrate or each other.
•Living
on the bottom are epifauna and living within are infauna. The substrate could be a source of food.
Marine
Ecology
Demersal
organisms, such as flounder alternate between swimming and resting on the
bottom.
Marine
Ecology
PLANKTON
Phytoplankton, plant plankton,are the important primary
food producers in the pelagic environment.
The animal members of the
plankton are the zooplankton which range from bacteria size to 15m jellyfish.
Phytoplankton are the
trees of the sea which float near the surface to make the most of the sunlight
for photosynthesis
Marine
Ecology
Two forms of
phytoplankton, dinoflagellates and diatoms are
particularly important as founders in the planktonic
food webs because most of the animal life in the oceans depend on these.
The dinoflagellates are usually found in warmer waters, and the
diatoms are usually more abundant in cooler waters.
Marine
Ecology
Other plankton, coccolithophores and silicoflagellates
are also abundant as well as blue-green algae (in certain locations it can
become the dominant) and green algae but usually in the coastal water (some are
in the open ocean as findings of chlorophyll b indicate.
Marine
Ecology
Phytoplankton have
adaptations which deal with methods of keeping them in the upper zones to stay
in the sunlight..
Size...small sizes
retards sinking, structure...
Shape/structure of the
diatoms effects sinking rate and
Density...decrease by
storing droplets of oil in the cytoplasm
Marine
Ecology
Blooms Although
unknown, the availability of nutrients, amount of vertical mixing, salinity,
density, temperature, and depth of water affect phytoplankton growth rates.
Blooms called red tides
have occurred in almost all oceans.
Marine
Ecology
Red tides usually refer
to the discoloration of the waters as a result of the absorption of light by
pigmentation in planktonic organisms.
The
red water usually results from actions of non-toxic organisms and the term red
tide is inadequate when used with reference to PSP (paralytic shellfish
poisoning) and toxic dinoflagellates will not always
discolor the water (too few) but may be numerous enough to toxify
shellfish.
Marine
Ecology
But evidence that PSP may
be increasing in intensity and spreading to new areas is surfacing.
About 60 species of dinoflagellates may color offshore waters however only 6
have been shown to produce toxic substances.
Some toxins, saxitoxin, is 50x more poisonous than curare (used by SA
Indians)
Marine
Ecology
Repeated cell divisions
as result of long period of dry weather following a violent storm which stirs
up bottom sediments, reach concentrations of 25,000 dinoflagellates
/ml of water.
Marine
Ecology
Bioluminescent phytoplankton bloom in the ocean and produce a bluish-green
light.
Phosphorescent
Bay in Puerto
Rico contains high concentrations of bioluminescent phytoplankton
throughout the year.
One type, Noctiluca sp., by disturbing water, passing of boat,
wave breaking, initiates bioluminescence.
Marine
Ecology
Zooplankton..500,000 per gal and range in size from single cell to jellyfish.
Almost any animal phylum
can be found wandering through the sea but the most common are Copepods (95%).
Two types of zooplankton....Holoplankton or permanent members of the community and
temporary residents called Meroplankton.
Marine
Ecology
Holoplankton
have evolved efficient means of remaining adrift...special appendages, droplets
of oil and wax, tread water, jelly-like layer, gas-filled float.
Marine
Ecology
.
A majority of inverts and many vertebrates have planktonic
stages (meroplankton).
Drifting eggs and larva of fish, crabs, barnacles, worms,
clams, snails, sponges, lobsters, etc.
They
use the water mass to feed and disperse their planktonic
young to new habitats.
Marine
Ecology
The reproductive cycles
often coincide with maximum concentrations of food and favorable currents.
EX. polar oceans, spring
phytoplankton bloom triggers increases in zooplankton coinciding with migration
patterns of whales, seals and penguins.
Marine
Ecology
Vertical migrations
refers to Copepods and other zooplankton moving up toward the surface to feed
in the evening responding to the changing light reducing predation during the
day because they are in deeper layers.
This varies among species
but light, shadows and pigments of phytoplankton (color) helps zooplankton
locate food.
Marine
Ecology
Thus buoyancy, mobility, vertical
migration, and chemical sensing enables Copepods to
search open water for concentrations of food.
Trophic
levels in zooplankton communities-- Energy incorporated in organic molecules by
marine plants flows to the zooplankton community in a complex series of
interconnected food chains.
Marine
Ecology
Nekton Free swimming
organisms equipped to direct their movements through the sea including
cephalopods, fishes, marine mammals, sea turtles and marine birds.
Many are at the top of
the trophic levels either as carnivores or herbivores
without natural predators..except
man.
Swimming allows escape or
movement toward food and methods of locomotion are very diverse, from jets of
water, flippers, large tail fins and flukes.
Marine
Ecology
Planktivorous
nekton are animals that feed directly on plankton such
as baleen whales and some fish.
Herbivorous Nekton are
ones that feed on large seaweeds and sea grasses (turtles and manatees)
Carnivorous Nekton are
the dominant carnivorous animals of the pelagic environment and generally these
animals migrate great distances in search of food.
Marine
Ecology
Production
Food production occurs
mainly through Photosynthesis.
It is measured and called
Primary food production which will occur in the photic
zone as phytoplankton manufacture organic matter during photosynthesis.
The primary productivity
varies seasonally and geographically.
It is
measured as g of Carbon/m2/year.
(Long
Island Sound 500g, Antarctica. 2-400g etc.)
Marine
Ecology
It
seems that the more vertical mixing that occurs in an area, the higher the
primary production is because in the tropics where there is little vertical
mixing, their Primary Productivity is low because of the depletion of nutrients
in the surface waters.
Marine
Ecology
Primary
productivity decreases as depth increases as there is less light and less
photosynthesis.
Accessory
pigments in algae enable them to make the most of the little light that does
get to them.
The
boundary where the food production (photosynthesis) is balanced out by the rate
of respiration (the use of the food) is called the compensation depth.
Marine
Ecology
Copepods
metabolize droplets of diatom oil to liquid waxes and fats which can be used as
long-term energy reserves. (waxes; long/fats short).
It
is these waxes and oils that get used for blubber when the Copepods/krill are
fed on by marine birds and mammals.
Marine
Ecology
Detritus
food chains are also secondary when decaying material enter
the detritus chain as decaying materials, wastes, pieces of animal tissue.
The
swarms of Copepods feeding on diatoms excrete packets of partially digested
matter called fecal pellets.
Marine
Ecology
These
pellets usually aren't eaten by other pelagic organisms and provide food for
bacteria when they settle as well as a host of detritus feeders on the bottom
(transfer of energy from the top to the bottom)
Marine
Ecology
While
there is a loss of energy to the grazers, many consumers are adapted to feed on
detritus thereby returning energy to the food chains.
Chitonolytic
bacteria can break down chitin which represents an enormous source of organic
carbon.
TK
9/16/2002
Marine
Ecology
These
bacteria play a big role in making sure the billions of tons of chitin produced
in the marine environment each year get broken down and their nutrients are
returned to the primary food makers.
Marine
Ecology
•Symbiotic...refers
to close nutritional relationship between two different species...
•commensalism- one
benefits
•mutualism
both benefit and parasitism
•one
benefits at hosts expense.
Marine
Ecology
•Population
Cycles ..density
or numbers of individuals depends on
•1.
natality or rate of
production of new organisms and
•2.
mortality..rate
of death in a population.
Marine
Ecology
•Now
to be stable the two must be in equilibrium but under favorable conditions,
populations can increase numbers (can be seasonal and geographical) but this
also increases mortality because of decreased food supply and living space and
increased predation.
•If
mortality is greater, then the population decreases.
Marine
Ecology
•These
favorable conditions depend on
•1. high concentration of nutrient rich water,
•2. rapid cycling of materials by decomposers,
•3. high numbers or rapid turnover of producer organisms
•4.
Light
•5. nutrients including nitrate, phosphate, silicon, potassium,
magnesium, copper, iron.
Marine
Ecology
•Silicon
dioxide needed for outer glass covering of diatoms and forms internal
structural parts of sponges, K and NO4 and PO4 needed in plant proteins, lipids
and carbohydrates during photosynthesis.
•The
nutrients can be considered a limiting factor as well as pH temp. light , depth salinity nesting sites and predation.
Marine Ecology Review ANS
1
t
2
f
3 t
4 f
5 t
6 t
7 t
8 t
9 f
10 t
11 t
12 f
13 t
14 t
15phytoplankton
16 Euryhaline
17.
Carnivores
18
makes food for other animals and becomes food for other animals
19mutualism
20. a
food chain
21.
hadopelagic, abyssopelagic, bathypelagic,mesopelagic, epipelagic
22. sofar layer
23. epipelagic
and euphotic
24
The word "significant" has not been adequately defined. ) Scientists
have been unable to measure the rate of loss of biodiversity. Governments have
not committed funding to study the loss of biodiversity.
25 mutualism.
26
the amount of radioactive carbon dioxide used up in a clear bottle of seawater
in sunlight in comparison to that in a dark bottle. the
amount of chlorophyll in the water by fluorescence or satellite cameras.
28
90%
29 benthos
30
homeotherms
Look
these up yourself!
31. What is the role of
decomposers in the marine environment?
32. What is detritus and why is it
important?
33 What happens to energy
as it passes through each trophic level? How is it
lost?
34.
What is a copepod and why is it important?