Lisa Carden SENTINEL TRAVEL EDITOR June 3, 2001
What does
Leatherman last week selected
Hawaii's other recognized beaches were Kaanapali (No. 3), Hamoa Beach (No. 7)
and Makena State Park (No. 12), all on Maui;
Leatherman, who has been picking the nation's top beaches for 11 years, uses 50
criteria to make his selections. They include such things as sand softness,
wave size, current strength, water color and quality, presence of pests,
lifeguard protection, visual obstructions and amenities. He considered 650
beaches nationwide before making his 2001 selections.
Previous No. 1 sand spots have been Kapalua Bay Beach, Hawaii ('91); Bahia
Honda State Park in the Florida Keys ('92); Hapuna, Hawaii ('93); Grayton Beach
State Park in Grayton Beach ('94); St. Andrews State Park near Panama City
('95); Lanikai Beach, Hawaii ('96); Hulopoe, Hawaii ('97); Kailua Beach Park,
Hawaii ('98); Wailea Beach, Hawaii ('99), and Mauna Kea Beach, Hawaii ('00).
Twenty-nine
The council's beach certification program, called the Blue Wave Campaign,
identifies clean and safe beaches while also promoting the protection of such
coastal assets. Program applicants are judged on water quality, beach and
intertidal conditions, safety, services, habitat conservation, erosion
management, public information and education.
Florida beaches winning the certification for 2001 are Hollywood Beach, Dania
Beach, Fort Lauderdale Beach, Pompano Beach and Deerfield Beach in southeast
Florida; Fort DeSoto Park, St. Pete Beach Access, St. Petersburg /Treasure
Island Beach, Sand Key Park, Clearwater Beach, Honeymoon Island State Park,
Caladesi Island State Park and Fred Howard Park Beach on the Gulf coast;
Atlantic Beach, Neptune Beach and Jacksonville Beach on the northeast coast;
and Inlet Beach, Rosemary Beach, Seacrest, Seagrove, Seaside, Watercolor, Grayton,
Blue Mountain, Santa Rosa, Dune Allen, Sandestin, Seascape and Miramar in the
Panhandle.
A list of beaches nationwide that received the certification can be found at
cleanbeaches.org.
Shifting Sands 2
Anthony
Wood 8/8/1993
Before tourism,
it didn’t matter if
Clement
“Coon” Boyd is sitting in front of enormous picture windows commanding a view
of the water that no Shore house could match.
That’s one perk of working on the water.
Boyd is sitting behind a console of exotic-looking monitors and levers
that looks as if it walked of the set of a science fiction movie. Not that Coon Boyd himself suggests an intergalactic
hero—the ancient mariner, maybe. His
white hair looks windblown, somewhat of a mystery given there’s no wind in here
to speak of. In fact, there’s no
evidence he’s been outside for a while.
Like so many of the crew aboard the
John Borders a construction inspector for the Army
Corps of Engineers, is visiting the
The
Some of that noise penetrates the cockpit area
where Boyd, the
While he works a set of levers, Boyd scans television
monitors that give him eyes on the inlet floor, 20 feet below. One monitor
shows him the “payload” area, where the cutterhead is stirring up the sediment.
Bright yellow lines slashing across a computer screen delineate the cuts and
help Boyd direct the cutterhead toward the best possible sand. All sand is not
created equal. If it is too fine, it can disappear from the beach in a hurry.
Boyd can slow down the cutterhead if he doesn’t like what he sees; he can speed
it up if he likes it.
It’s an operation
that will cost about $2.7 million, which comes to about $180,00O for a single
block’s strip of sand from the Boardwalk to the water.
The corps is
proud of the
Wait a minute.
Didn’t this happen last year? Weren’t they pumping sand a decade ago?
Yes, the sand
pumpers were there last year. and they were there in 1982, and they’ll be back
again and again for the next 50 years. The corps is committed to keeping sand
on the
Roger Soens, Sr.
timed the wave perfectly. In the 1960s, he saw what was happening to property
values in the barrier-island town of
career in Shore
real estate. His logic was unassailable “I was making more with less effort
than I was in
As a teenager,
he had worked as a counselor at Camp Cardinal Dougherty in
Soens’
investments in Avalon paid off handsomely, and today he is a partner in Avalon
Real Estate, the biggest show in town. The reception desk at the office, framed
by a dazzling wall of house keys for hundreds of rental and sale properties,
has the air of an airline counter on a holiday weekend. Soens figures that AvaIon
Real Estate controls close to 60 percent of the market in the borough. Today,
business laps into Soens’ personal life. He is trim and lanky and looks a good
decade younger than his 74 years. He just doesn’t get around as well as he used
to. He has a “For Sale” sign in front of his house in the north end, the second
from the beach on
In all, properties in Avalon — a town with &
full-time population of less than 2,000 have a market value of over $1.6
billion, according to the Cape May County assessor’s office. The property in
That is only part of what is at
stake along
It’s all because Homo sapiens evolved from the sea,
and some people insist on an unobstructed view of the evolutionary mother
country. They are perhaps only mildly conscious of two facts The sea may be
lovely but it is also deadly, and “acts of God” show’s up in the fine print for
a reason.
Still, over the last 25 years, development has
exploded at the
For New Jersey, 1992-93
was a sobering winter. For the first time, the dreaded “R”word—as in retreat,
as in pull back, as in maybe we should think about getting our mortal selves
out of here — was invoked by reputedly reasonable human beings, not members of
Green-peace or the American Littoral Society. After the December storm, a team
of federal, state and local officials assessed the damage. It suggested that
coastal communities acknowledge the dangers of living on the edge and the
futility of repairing the same properties storm after storm. Mark Mauriello,
supervisor of state’s coastal-development office, likened the situation to a
car that keeps breaking down. “This keeps happening and we keep repairing.
Maybe there’s something else we ought to look at.”
With exquisite timing,
the state will embark in October on developing a new master plan for protecting
the shoreline . With developers and the tourism industry on one side,
environmentalists and bureaucrats on the other — and the taxpayers in the
middle — it promises
be an onshore political hurricane that could go on
for the rest of the millennium.
THE FRONT OF
A THREE-STORY house on
Powerful winds have
continued (or three days, and the storm coincided with several high tides that
already were high because of the astronomical tidal cycle. The ocean and bay
have met at several points along barrier islands. About 280 houses have been
wiped out in
“Believe it or not, they put new houses in right
next to it,” says Roger Soens 31 years later. In those 31 years1 a
generation of visitors and property owners who haven’t seen anything like the
nor’easter of ‘62 has grown and replaced most of that storms survivors. Marty
Ross, a National Weather Service meteorologist who lives at the Shore, has a fact
for them: Storms like ‘62 occur roughly once every 30 years.
To a grain of sand, a storm is just one more method
of commuting. Sand. is rock-hard and resilient, and it somewhat predates the
condominium. Those acres of beach towels bearing oversunned bodies marinating
in tanning oil are resting on material whose origins may date to 500 million to
a billion years ago.
Much of the sand on the East Coast is the residue
of continent-making, the remnants of dissolved rock washed to the sea by rains,
floods, rivers and streams. By one
estimate, the sand on Jersey beaches today was deposited at the edge of the
continent several thousand years ago, when the coastline and its network of
river terminals were well east of where they are today. Sea level has been
slowly rising for about 15,000 years, as glaciers that locked up ocean water
during the last Ice Age have slowly melted. Eventually, the westward-spreading
ocean submerged vast portions of the sand deposits that the
The complex system of transporting all this sand is
a marvel of natural engineering. Human beings think of the beach as the narrow
strip of sand (not so narrow in the case of Wildwood) between the lifeguard
stands and the boardwalk. The sand-transport system involves the entire shore
face1 extending several miles offshore to depths of 40 feet. Sand
stored in offshore bars is delivered to the beach by wave action. When sand is
scrubbed from the face of beaches by storm waves, it doesn’t evaporate. It
returns to the bars for storage. In tranquil conditions, the sand is gradually
returned to shore. In severe storms, waves built on winds that have traveled
hundreds of miles can push sand through gaps in dunes or across whole islands.
The channels leave the island susceptible to further overwash. It is a way for
barrier islands such as make up most of the
Islands also share sand with fellow islands through
the processes of littoral drift — the technical term for the phenomenon
swimmers experience when they return to the beach, only to find themselves
yards away from where they entered the water. Waves frequently strike beaches
at angles. This induces currents parallel to the shore that create flowing
rivers of sand. From
For eons, all this
sand-sharing occurred without incident. At first, even the appearance of
intelligent life, did little to alter the shorescape. The barrier islands
evidently were visited by Indians, but they eschewed permanent encampments like
boardwalks and hotels. Barrier islands were considered unstable end unattractive
to early European settlers, who preferred the terra firma of the mainland. In
the late 17th century, inland real estate was far more expensive than
beachfront property. But by the late 1800s, human beings had changed their
collective minds and begun viewing barrier islands as summer playgrounds.
Entrepreneurial railroaders saw a market and filled it, linking the mainland to
places such as
The human response to
natural erosion and island migration was: You can’t do that. After thousands of
years of avoiding the fickle barrier islands, human beings became attached to
them exactly as they were, no more shifting sands, please. And so, today, the
In some ways Avalon is a model community. It has a
tough dune ordinance. Houses on the
southern half of the island are well protected by some of the most substantial
and aesthetically pleasing dunes along the
The northern tip is an utterly different
environment. It fronts Townsends Inlet.
Two dredging projects over the last 15 years have altered littoral currents,
and the beach is eroding badly. It has another problem. It faces northeast, not
what you want during a nor’easter.
Those storms tend to form off of
McClain, 45, now owns that distinctive Victorian
house on
Since 1987, with help from the state, Avalon has
pumped about 2.5 million cubic yards of sand onto its
This summer, Avalon is taking engineering to yet
another level. To keep sand from washing out to sea on the ocean side of the
On the
inlet side of the jetty, it has dumped beachfill behind a sand-filled fabric
barrier. “I’ll call it a beach along the
inlet. It isn’t really…It wont be a
place where people go swimming at all.
It’s there for storm protection,” says deButts. The beachfill and the reef will end up
costing $2 million, and ultimately, the jetty will have to be replaced, yet
another costly project.
Not that a beach could hurt property values in the
neighborhood. In 1986, recalls Steward
Farrell, a geologist at Stockton State College, a storm battered betweeb 23rd
and 25th streets right next to the Avalon Boardwalk. “The waves were breaking on the sliding
glass-door houses,” he says. Is so frightened the owner of one of those
properties that they decided they’d had enough. They sold the house in March
1987 for about $85,000 and were happy to get that. Such is the power of
nature. That summer, with help from the
state, Avalon began its fill project, pumping 1.5 million cubic yards of sand
onto the beach. Seven months later,
Farrell says, the new owner sold that very same property…for $365,000. Such is the lure of engineering.
“If I was the King of New Jersey, I know what I
would do. I’d get rid of the first row
of houses.” The man who would be king is Orrin Pilkey. Pilkey use to describe himself as a deep-sea
sedimentologist. Then in 1969, his
parent’s
Pilkey reasons that the winners in the armoring of
the
THAT THEY DID A DECADE AGO. In 1982, about one million cubic yards of
sand was placed on the
The public debate, says Pilkey, is lacking another
essential consideration: the incremental erosion due to rising sea level. Sea levels have risen about one-half foot per
century over the last 2000 years.
Norbert Psuty, a marine science professor at Rutgers University, has
documented that rates have accelerated along the east coast and that sea level
has risen about 1 foot during the last 100 years. That could be the result of glacial melting,
a rising of the Atlantic floor or the sinking of
Retreat, says Pilkey. Pull back. Get out of
there. Let the beach be the beach. The taxpayers are fighting a costly war that
the United States is destined to lose.
The interagency team that convened after the
December storm didn’t go quite that far—but it did take a radical step of
saying the state might have to consider buying up storm threatened properties.
Such a recommendation, not from whale watchers but from professionals in
government, will ensure that writing the states master plan for shoreline
protection goes political in no time.
The status quo in the Orrin Pilkey argument, is a
rotten cause to begin with. “The Corps
replenishment is only carried out because of beachfront property,” says Pilky.
“It’s a very, very small number of people that is costing us millions of
dollars. It’s a very small number of
people that is jamming this down our throats.”
“When people talk about shore protection, they are
really talking about real estate protection,” says Don Bennett, the head of the
American Littoral Society. Bennett
doesn't advocate ripping down that front row of properties. They can stay there, hey says—just make the
owners pick up the biggest share of the cost for shore protection.
The American littoral society operates out of a
building in the Gateway national Recreation Area in Sandy Hook, the north end
of the
An illustrated bird’s-eye-view map of
Today the north end is one of
Hughes is the author of the Coastal Barrier Resources Act, considered
one of the toughest coastal -conservation measures ever enacted. It is aimed at
protecting undeveloped barrier islands. He is regarded as a friend to
environmental causes. He is also probably the best friend that the
Hughes said that last winter, beachfill was a lifesaver for
Yes, he said, he personally had benefited from the taxpayers’ money, but
so what? ‘ Everybody uses the beach. Taxpayers fix highways and he uses
highways, too. Everybody uses highways. No, he said, filling a beach isn’t much
different from filling a pothole. Says Kenneth Smith of Coastal Advocate Inc. —
a lobbying group for developers — “That’s federalism.” He contributes to farm
subsidies in the Corn Belt, why shouldn’t every body contribute to
Come hell or high
water, Tina and Gary McCLain have no intention of retreating. They live in that
Victorian, the one directly facing the inlet on
The neighborhood has
changed mightily over the years. These days the street fronting the inlet is
the mailbox,
which was encased in a foot of concrete.
The interior of
the house has been redone remarkably, all new hardwood floors, all new wiring.
The McCLains live in Villanova, but this is also their home. Tina stays here
all summer, and they visit during the winter.
Its been almost 50
years since the
On a warm
evening in late May, Bob Sheets is lecturing at a Cape May Court House auditorium
on the mainland. His mission is to scare the daylights out of a couple hundred
residents at a town meeting. Sheet, runs the
He delivers more
bad news.
Among all
hurricane-susceptible regions,
William Gray, a hurricane researcher at
In early June,
the winter already is an ebbing memory at
Near the Ocean City Boardwalk,
seawater is trickling from a pipe off of
As the slurry gushes from the pipe
like a wave of gray water crashing on a seawall, a score of sea gulls gathers
for a feast. They think they’ve died and gone to heaven. Gourmet pickings from
the ocean floor. (“We might kill a few clams out here, I’ll be honest with
you,” John Borders had said out on the dredge.) The slurry creates a stir on
the Boardwalk. A crowd gathers at the
Frank Goifredo, 66, walks by, and
he’s in awe. Goifredo is a retired
schoolteacher. He’s wearing a Florida T-shirt, black shorts and sunglasses and
he is smoking a cigar. He’s deeply’
tanned. He’s been going to
Borden walks by. He
looks concerned. In 1982 the sand was too fine — too fine to draw a line in
against the tide. The Army Corps construction inspector knows there is better
sand out there somewhere, but the
BEACH RENOURISHMENT: 3
Are All Those Dollars Making Cents?
by DAVE GRANT
When not
teaching at
Lord Byron wrote, “Man marks the earth with ruin. His control...stops
with the shore.” By choosing to ignore the dynamic nature of the shore and
building along it, humans often find their homes and even whole towns in
precarious positions when beaches, as is their nature, move. In the past it
was not unusual to simply move structures back away from the shoreline when the
ocean threatened. The original building lots along many beaches were purposely
long and narrow, extending from ocean to bay. This allowed valuable structures
to be moved landward when necessary; a logical solution, but impractical today
considering the price of real estate on most shores and the crowding that has
occurred on those subdivided properties. Other obvious solutions like letting
the buildings wash away when their time is up, or not allowing construction in
the first place have rarely been considered. Neither idea is a very popular or
practical alternative to shore property owners or politicians.
In the last century a variety of schemes have been tried to “save”
beaches. These are collectively labeled “hard-technology” — jetties and groins
attempt shoreline stabilization; offshore wave-dampening structures to slow the
rate of beach drift; and various “sand-grabbing” devices, some of dubious and
even humorous design, to capture and hold beach sand in place. None appear to
work and most may actually exacerbate the erosion problems on neighboring
beaches that are starved of the sand they no longer receive.
Coast Issues
Beach replacement or renourishment is a different approach to the
problem, and from an environmental viewpoint would appear to be a preferred
application of “soft-technology,” but even it has problems. Replacement was
first tried beneath the eroding bluffs of
Some crucial considerations in deciding whether a beach will be
renourished, besides the social and political ones, are:
sand grain size, source of the fill, and
environmental impacts. Particles smaller than the original sand will wash away
too fast. Also, there is a limited supply of sand around, and not all of it is
available or suitable for nourishment projects (a quirk of coastal geology that
is often overlooked by anxious planners and the general public). Regardless,
replaced beaches tend to wash away about 10 times faster than natural beaches,
most lasting no longer than half a decade. Part of the loss occurs because the
offshore slope of the new beach is not replaced and remains unnaturally steep
compared to the original beach, encouraging wave attack and increased erosion
rates.
The jury is still out on the biological impacts of nourishment. Because
of the dynamic nature of burrowing organisms like coquinas and mole crabs that
live along the ever-changing shoreline, recolonization of nourished beaches
sometimes can be quick. However poor grain size match and the presence of
naturally occurring but toxic hydrogen sulfide from silt in the dredged
sediments, can inhibit the return of many creatures. Resuspension of
pollutants that have accumulated over the years is also a concern.
There may also be some
subtle effects on offshore environments when beaches are replaced, and these
are still poorly studied. We should worry about the sources of sand and the
damage to offshore environments that occur when they are dredged to gather that
fill. Neighboring reefs can be choked by dispersed sediments and destroyed by
the dredging. Some environmentalists have even expressed concerns that nesting
sea turtles might have problems digging through the carbonate “pavement” formed
by dredged shell fragments that create steeper, renourished beaches in tropical
areas.
Is beach nourishment
worth the expense? It is necessary to evaluate each site for environmental
impacts, as well as long and short-term benefits to society. Oftentimes,
critics of renourishment say the benefits of such projects are exaggerated by
vested interests such as local residents and developers, and that most projects
are designed to protect oceanfront structures that probably should not have
been built in the first place. Also, it can be argued that in light of global
warming and sea level rise, the costs will invariably outweigh the benefits in
the long run. In short, beach nourishment simply postpones the inevitable
destruction of coastal buildings.
At Sandy Hook, the second of two renourishment projects was completed in
1989 using sand from a dredge pit in the Navy’s ship channel in
A third project, recently begun for the beaches south of Sandy Hook,
will become the largest renourishment project in history, a quarter-billion
dollar effort (some say boondoggle) to buy more time for the
UN V20 #2 1991
Sand helps revive shore 4
Melissa Harris | Washington Bureau
Posted July 6, 2001
Increasingly,
This year, the House
has set aside a record $43 million for beach renourishment in 10
The $43 million would nearly double what the White House wants to spend on
beaches, with Congress ignoring President Bush's call to put a brake on funding
for such projects. The spending bill is expected to pass the Senate.
Each project is planned for 50 years because the sand transplanted to eroded
beaches eventually disappears during long-lasting winter storms called
northeasters, or is starved by human development and sand-trapping inlets.
The sand must be replaced repeatedly, at high costs.
And Congress regularly obliges, to the ire of environmental groups, the White
House and taxpayer advocates.
The result is increased spending on beach renourishment that benefits
tourist-driven economies and improves the tax base.
Under the leadership of U.S. Rep. C.W. "Bill" Young,
Nowhere is this more evident than in
U.S. Rep. Dave Weldon,
"This will enable us to continue this important project this year,"
Weldon said of the area's ongoing beach renourishment effort.
The White House is concerned that every dollar that goes toward beaches means
less money for other priorities.
The administration also is concerned that the appropriations bill passed last
week includes a funding formula in which the federal government pays two-thirds
of the bill. Nationwide, the bill to taxpayers from now until 2050 is expected
to be $6 billion.
Local benefits are obvious
The economic benefits to local communities are clear. Larger beaches mean more
room for parking, restrooms, volleyball nets and tents, which attract more
visitors.
As the number of visitors increases, hotels, condominiums and businesses begin
dotting the shorelines. Before long, a once sleepy coastal town possibly could
be picked to host MTV's spring break show.
Beach projects are under way in
About 40 percent of
People cause most erosion
Eighty-five percent of the erosion is caused by people, said Robert Dean, a
coastal-engineering professor at the
"Beach renourishment works in the state of
Dean said a 10-mile stretch of
Other experts, including Orrin Pilkey, professor emeritus of earth and ocean
sciences at
"We have a natural system overridden by people," said Pilkey, adding
that development should be pushed back from the shorelines. "When you dig
up sand off of the continental shelf, it kills everything there and it kills
everything where you dump it."
Taxpayer groups are outraged that inland taxpayers' money is going to pay for
Brevard work defended
Weldon and Virginia Barker, director of beaches for
The sand is trapped and builds up on the northern side of the inlet, leading to
sprawling, beautiful beaches. The southern side of the inlet, meanwhile, is
starved.
"This is not a natural process of erosion," said Brendan Curry,
Weldon's spokesman. "Brevard's problem was created by the federal
government in the 1960s when the Canaveral inlet was built."
Melissa Harris can be reached at mharris@tribune.com or 202-824-8229.
Copyright © 2001, Orlando Sentinel
The Mystery of the
Singing Sands 5
by Paul Brock
Readers Digest,,,world around us p171 1972
Scientists are trying
to solve a puzzling mystery—the phenomenon of
‘ ‘singing sands. ‘ ‘ At Britain ‘ s University of Newcastle-upon.-Tyne,
extensive field and lab— oratory experiments into sands and beaches that
“sing,” “whisper,” “squeak,” “roar,” “ring,” “hum” and “shriek” have been
carried out during the past decade. These investigations have attempted to
explain the cause of singing sands, which have mystified mankind for centuries.
Musical sands occur in many widely scattered places
on the Earth’s surface. Perhaps the best known exist on the
Sonorous sands have been found at many other beaches
and deserts around the world, including Long Island and Massachusetts Bay in
the continental United States; the Hawaiian Islands; the west coast of Wales;
the Northumberland coast of Britain; the island of Bornholm, Denmark; Kolberg,
Poland; a few spots in Australia including the coast of New South Wales; Brazil
and Chile; and several deserts in Asia, Africa and the Middle East. .
When walking over musical sand, the foot sinks
deep, as the grains Ware easily displaced. The highly polished .surfaces of millions
of grains set up a continuous vibration and produce a prolonged sound like a
note of music.
Charles Darwin was one among many 19th-century .
scientists to be intrigued by the growing mystery of the singing sands. In his
book, A Naturalist’s Voyage Round
the World, a journal entry dated
April 19, 1832, reads: “Leaving Socgo [in the vicinity of
very wearisome work, as the road generally ran
across a glaring, hot, sandy plain, not far from the coast. I noticed that each
time the horse put its foot on the fine siliceous sand a gentle chirping noise
was produced.” Three years later
Other allusions to sonorous sands are scattered
through the writings of a thousand years. The Arabian Nights mentions them, and old Chinese chronicles tell of
singing sands occurring in the
The phenomenon of singing sands probably accounts
for an old legend of a buried monastery somewhere in the
Some 200 years ago European pilgrims to
So the Gebel Nakous, or Mountain of the
Hearing of the puzzling ringing mountain, the
Scottish naturalist Sir David Brewster ( 1 7 8 1—1 868 ) visited Sinai and
conducted an investigation. “The Mountain of the Bell,” he reported in his Letters on Natural Magic, “is situated
about three miles from the Gulf of Suez in that land . . . in which the granite
peaks of Sinai and Horeb overlook an arid wilderness. . .
Brewster instructed one of his Bedouin guides to
climb up the “musical” slope of the mountain. It was not until the guide had
reached some distance, Brewster relates, that he perceived the sand in motion,
rolling down the hill. At first he thought the sounds might be compared to
those of a harp when its strings first catch the breeze. As the sand became
more violently agitated by the increased velocity of the descent, however, the
noise more nearly resembled that produced by drawing a moistened finger over
glass. As the avalanche of sand reached the base, the reverberations attained
the loud-ness of distant thunder, causing the rock on which Brewster sat to
vibrate.
The first truly scientific study of singing sands
did not come until the 1 940s, when British physicist R. A. Bagnold
investigated the phenomenon. Speaking of the “song” or “booming” of desert
sands, Bagnold wrote:
“I have heard it in southwestern
Bagnold found that
singing sands often occur in two general localities—on the seashore and on the
slip-faces ( or leeward slopes) of desert dunes and drifts. He applied the
word “whistling” to the sands of Eigg and to beach sands in general, while
using the term “booming” to describe desert sands. Tests showed that beach sand
emitted a squeak or whistle at a frequency of between 800 and 1 200 cycles per
second (in the range of high C a piano ) . The tone could be produced, he
wrote, “by any rapid disturbance of the dry top layer—walking over it, sweeping
it with the palm of the hand, plunging a stick vertically into it.”
The sound emitted by
desert sand, he found, is much lower in frequency when disturbed in the above
ways— 1 3 2 cycles per second. But when desert sand flows downslope in an
avalanche, he discovered, it may at-tam surface velocities that make it hum
quite audibly at roughly 260 cycles per second (about middle C) or at even
higher pitches, depending on the speed of the avalanche. When sand from the
Kalahari Desert in
Recently the
They discovered that
roundness of grain is not an essential characteristic of singing sands; rather,
uniformity in the size of the grains is most significant in making a volume of
sand exhibit musical properties. Moreover, the presence of fine particles
impairs the singing of the sand and sometimes stops it altogether. When the
grains are polished, unpolluted by other material and nearly all of the same
size, the sand sings.
The ability of such
sand to “sing” is destroyed by constant pounding, but is restored after the
fine fragments produced by such pounding are removed by sieving, washing or boiling.
what actually
gives singing sands their musical properties? A general explanation of singing
sands is advanced by the
producing shearing motions in laboratory
experiments, but this is effective only when the sand is supported by the sides
of a container1
Under certain conditions, say the British
researchers, a shearing motion can make a restricted volume of beach or desert
sand vibrate almost like a volume of air within an organ pipe. But as to
exactly how this happens, Bagnold still has the final word: “There is as yet no
real explanation,” he says.
Introduction Shoreline erosion caused by storm action,
impediments to sand movement, and other factors poses ongoing problems for
coastal managers. In the last 20 years, the State has suffered major property
losses due to coastal erosion in Marin,
Background The physical configuration of California's
beaches, coastal bluffs, bays, estuaries, and other shoreline features are
driven by the availability of inland sediments (that provide a source of beach
sand), as well as a number of ocean processes that affect the movement of that
sand. A constant supply of sand is necessary for beaches to form and be
maintained along this shoreline. This sand supply is transported along the
coast by nearshore currents (long shore transport) that provide a vital sand
supply for
Erosion - A Statewide Concern The natural phenomenon of coastal erosion is
probably one of the more difficult statewide planning issues for
Jurisdictional Overview. In
Issue Analysis It is unlikely that
Shoreline Management Approaches. The
following possible approaches to shoreline erosion illustrate the difficulties
faced by government planning and regulatory agencies, and members of the public
who own structures along the coast:
o1 Constructing a "Hard" Protection
Device. The construction of a hard protection device such as a revetment,
bulkhead, seawall, or breakwater is historically the most common approach to
protecting private or public structures. These structures reduce wave attack
and shoreline erosion, but can accelerate erosion down coast. These hard protective
structures can be constructed to protect existing development, but the Coastal
Act provides that no new developments should be built that will require the
construction of a protective device in the future.
o2 Beach Nourishment or Replenishment - A
"Soft" Approach. Beaches can be nourish by depositing sand up the
coast or directly on a beach to increase its width. The primary issue with this
approach includes the cost of the operation and the impacts of the
transportation of large quantities of sand to the site.
o3 Relocation of Ocean Front Structures. The
relocation of a structure farther inland, if feasible, can be far less
expensive than rebuilding the structure if it is destroyed. However, this
option is rarely seriously considered. Ironically, under the California Coastal
Act no coastal development permit is required for the re-construction of any
property destroyed by a natural disaster if the footprint of the replacement
structure remains within 10% of the original structure. This policy provides no
incentive for new development to avoid the same mistakes in design or location
that contributed to the first episode of property loss.
o4 Coastal Hazard Avoidance. Avoiding
development may be considered in areas where the construction of a new
structure would require extensive engineering solutions and even then could
pose hazards within the property itself and to adjacent properties. In such
cases avoidance could reduce costs associated with future disaster relief,
construction of protective devices, and with government assistance insurance.
Policy Options
1. Should the State of
2. What can the State of
3. Should the State of
Coastal and Nearshore
Erosion Scope of the Problem
Coastal erosion is a serious national
problem with long-term economic and
social consequences. All 30 States bordering an ocean or
Regional Studies of
Coastal Erosion: There is great
variability in the processes causing
coastal erosion and in the geologic framework within which the processes operate. Studies within
different regions will be undertaken to
understand the geologic framework within which erosion takes place, the diversity of processes, and
the sediment budget for specific
regions.
o West
Louisiana/East Texas: These coastal regions are experiencing high rates of
shoreline erosion and wetlands loss. This study addresses the long-term
evolution of shoreline and offshore areas in cooperation with the Texas Bureau
of Economic Geology and
o
o Delaware/Maryland/Virginia:
Regional-scale field surveys and mapping of the Delmarva coastal compartment
will delineate the geologic character and processes affecting a variety of
coastal features, including developed barrier islands and the NPS's National
Seashore reserves, which are under considerable natural and human stress.
o Southeast
Florida: The southeast coast of
o
o
o
Arctic: Reconnaissance mapping in
o
o
o
The Sentinel-Ledger of
Army Corps looking at
erosion to OC beaches
THE
In the late 1980s,
after Hurricane Gloria, some beach areas in
They extend from the
north end of the Boardwalk at
What You Can Do
* The Dune Patrol is dedicated to cleaning
up dune areas and maintaining them. They
ask that you help out by putting your trash in containers on the beach or taking it with you when you
leave.
* For more information on the Ocean City
Dune Patrol or the Dune Stabilization Committee, call the Ocean City Department
of Recreation and Parks at 410-250-0125.
ARGUS STATIONS
I am an Argus Station I am an Argus Station. I am named that way
following the Argus of Greek mythology, who was a giant with a hundred eyes,
ordered by Hera to watch Io. Argus was killed by Hermes, but we won't talk
about that now. In current mythology, I
am a computer controlled image processing station with one or more eyes,
watching ocean and lake cliffs for signs of erosion, and beaches for changes in
shape. I also watch immediately offshore, where bars form. The images I return are of two types. The
"snaps" are snapshot images of the beach or cliff. The second type of image I return is called a
"timex", or time exposure. I average all the images for 12 minutes,
and present that average as one image.
Why would I want time exposures? Well, when you look at individual
images, it is very hard to tell where the waves are breaking. Since waves
usually break where the bars are, if you could see where the waves break you
could see the bars. That is what a time exposure lets you do. It sums up all
the whitecaps, making a more solid picture of where the bars are hidden under
that water. A second reason has to do
with tide level and beach contours. If you can see where the waves break when
they hit the shore, and you know the tide level, you can determine the contour
of the beach at that level. Something like a "bathtub ring". If you
do this at different tide levels, you get a contour map of the beach. Normally,
this involves people spending a day surveying the beach. I can do it without
people having to go to the beach.
BARRIER ISLANDS
7
FORMED BY FURY,THEY ROAM AND
FADE
BY ORRIN H. PILKEY ILLUSTRATIONS BY LINDA J. NOBLE SF Dec 1990 v36
#6
Barrier islands are the
most dynamic real estate on the surface of the earth. Imagine, if you will,
islands that thrive when struck by the fiercest storms. Imagine islands that
actually migrate landward as the level of the sea rises. Barrier islands do
these things and more.
In fact, many believe the only natural enemy that barrier islands have
is humans. Only humans are capable of bringing to a halt the beautiful
combination of processes, biological and physical, that comprise migration and
evolution of barrier islands. Only humans can interfere in this dynamic
equilibrium involving sea level, sand supply, wave energy, and vegetation which
control the shape, size, and movement of the islands. Since we are the enemy, it is important that we understand the
mechanics of these islands.
Every barrier island is
different from every other. Principles gained from studying how one island
evolves may be only partially applicable to other islands. Sometimes even
adjacent islands are dramatically different. A good example is provided by two
islands of the Cape Lookout National Seashore in North Carolina: Shackleford
Banks and Core Banks. Shackleford is 0.5 mile wide and mostly covered by an
extensive vegetated field of high dunes. Core Banks is so low and narrow that
once, during a storm, when I landed on the lagoon side of the island, I could
see the crests of waves breaking on the ocean side.
Regional differences in
island processes are even stronger. For example, Padre Island, Texas builds out
into the lagoon behind it (Laguna
Madre) as sand blows from the island into the lagoon. On Core Banks, wind-blown
sand plays only a small role in widening; the island has historically widened
as salt marsh growing on sand gets carried into the lagoon by tidal currents
coursing through previously existing inlets.
Vegetation plays a
major role in the evolution of barrier islands. For example, imagine the
differences in surface processes on a rain-forest jungle-covered barrier island
on the Pacific shore of Colombia compared to a bare, windswept and ice-jammed
barrier island along the arctic shores of Siberia.
Barrier islands are diverse beyond belief but they have certain traits in common. They are elongated bodies of unconsolidated sand separated from one another by inlets and from the mainland by a lagoon.
Stage I: Dropping
sea level
A shoreline without barrier islands
It is 19,000 years BP. The sea level is still
dropping as the ice sheets of the high latitudes continue to capture water from
the sea and grow. The shoreline has no barrier islands, no estuaries, no
sounds, and few salt marshes. Rivers flow directly to the sea, and beaches are
charged with a new supply of sand every time the rivers flood. The continental
shelf is very narrow. The shoreline is many miles seaward of today’s shoreline.
Except for a thin band of dunes and maritime forest, the land area behind the
beaches is a broad smooth plain covered by a vast uninterrupted forest that
occupies what is now the continental shelf.
The stage is set for barrier islands to form when
sea level rises. The necessary ingredients are here: a gently sloping coastal
plain with a large supply of sand,
plus waves
rolling ashore that are large enough to move sand about. What happens next will
be controlled by events in high latitudes, where the massive continental
glaciers are about to melt.
No barrier-island chains exist on the Pacific coast
of North America due both to the lack of a large sand supply and to the steep
slope of the coastal zone. The northeast corner of the Gulf
of Mexico,
Florida’s “arm pit,” has no barrier islands in spite of abundant sand and a
gentle slope because of the lack of waves large enough to shape the sand into
barrier islands.
Stage II: Sea level begins to rise
It is 15,000 years BP. The sea level is beginning
to rise as the massive continental glaciers melt. The lower coastal plain
floods. The former river valleys are inundated and become estuaries. What once
were ridges separating the valleys now become headlands protruding out to sea.
These headlands are highly vulnerable to wave attack, and their destruction
begins to produce sand spits extending across the mouths of the newly drowned
river valleys.
The spits build
out across the mouths of the old river valleys because that’s the direction of
most efficient sand transport. This shortens the shoreline, and nature always
strives for the shortest shoreline possible. That’s why a chain of barrier islands
exists in front of most of the world’s coastal plains.
All along the length of the open-ocean shoreline,
including on the spit, ridges of sand dunes are forming just behind the beach.
These dunes, made of sand blown in from the beach and held in place by
vegetation, form more or less continuous ridges, called beach ridges. As sea
level rapidly rises, the beach ridges are inundated from behind which, in
effect, lengthens the spit.
As
the valleys continue to flood, and the estuaries expand, the spits begin to
shelter the estuaries from direct wave attack, forming the so-called back-barrier
lagoons. The now quiet shallow fringing areas begin to fill in with salt marsh.
This introduces a whole new fauna and flora taking advantage of a brand new
environment. Even the continental-shelf ecosystem is profoundly affected by
the formation of lagoons, because a number of continental-shelf organisms
spend the juvenile portion of their life cycle in quiet coastal waters.
The origin and evolution of a typical barrier-island chain is traced from
the edge of the continental shelf where it formed to its present location. The
models are designed to specifically fit the North and South Carolina
shorelines, but in broad outline, the scenarios outlined here apply to any barrier-island
chain in the world.
It is 14,000 years BP. The sea level has risen a
few meters from its lowest stand, and the continental shelf is widening. True
barrier islands have formed.
They formed in a number of ways. The most important
mechanism probably is storm breeching of spits, breaking them up into
individual islands. Simultaneously, the rising sea level flooded the lowlands
behind the sand-dune beach ridges adjacent to the shoreline, The now isolated
beach ridges become islands. In some cases, islands are formed by the
upbuilding of a submarine sandbar during a storm. When the storm goes away, an
island is left behind. Once islands form, a whole new set of processes takes
over, leading to their marvelous ability to migrate up the coastal plain apace
with the sea-level rise.
The most
critical ingredient of barrier-island evolution is sand. Large sand supply
leads to high, wide islands, small sand supply to low, narrow islands Every
grain comes across the beach, either blown by the wind, or washed up by storm
waves.
Barrier islands also constantly lose sand. Storm waves striking the
islands may carry sand far out to sea. Winds may blow it into the lagoons or out to sea. But without a constant resupply,
an island will virtually disappear.
The passages between islands are called inlets.
The tidal currents exchanging water between ocean and lagoon are responsible
for forming large lobes of sand both on the “inside” and “outside” of inlets.
The lobe of sand inside the lagoon is called the flood tidal delta. The lobe of
sand on the outside or ocean side of the inlet is called the ebb tidal delta.
The tidal deltas are an integral part of barrier-island chains. The volumes of
sand stored in the deltas can be very large, sometimes even larger than in the
islands themselves.
The size of tidal deltas is controlled by a
combination of high tide ranges, which produce strong currents that build out
large tidal deltas, and high
waves, which
tend to cut them back. Tidal deltas at North Carolina’s inlets are small
because the waves are large and tidal ranges are only 2 to 3 feet.
Inlets in
Georgia have huge tidal deltas (extending 2 to 3 miles out to sea) reflecting low wave height and large tidal
ranges (7 to Il feet).
At this stage, new sand no longer comes from the
rivers or the eroding headlands. Instead, the major supply is obtained as the
islands migrate and “run over” deposits of river sediment left behind where
once stood the head of estuaries. Judging from the curvatures of inlet channels
and the directions of spit extension in this diagram, the dominant direction
of longshore transportation of sand in the surf zone is from right to left.
Stage IV:
Island evolution When sea level is rapidly rising
It is 10,000
years BP, and the sea level is rising rapidly, perhaps at the rate of 3 to 4 feet per century. (This is the
rate of relative sea-level rise now occurring in Louisiana where the
Mississippi Delta is sinking.) A continuous sea-level rise of this magnitude
should produce shoreline retreats of I to 2 miles every century on the U.S.
east coast and double that on the Gulf coast. Along the flat U.S. Gulf-coast
continental shelf, it has been
estimated that between 18,000 and 5,000 years ago, the shoreline may have, at
times, retreated more than 100 feet per year for long periods of time. If
earliest people on this continent lived near the shorelines, villages would
have moved back frequently, and the evidence of their lifestyles and
civilization would be far out on the continental shelf.
Nature strives to keep a straight shoreline facing
the ocean, but during times of rapid sea-level rise, this is difficult to do.
The islands are moving too rapidly to accumulate much sand volume. They tend
to be thin and without extensive dune fields or maritime forests. Spits
reform. Sometimes wide inlets exist because not enough time is available for
sand movement to narrow them.
The islands migrate rapidly apace with the
sea-level rise. Island migration consists of two simultaneous events:
Shoreline
retreat on the ocean side and island widening on the lagoon side. Sea-level
rise pushes back the ocean side of the island. Island widening occurs via two
main processes. The most important of these, particularly on low, narrow
islands, is storm overwash, which pushes huge amounts of sand across the island
and into the lagoon. Sometimes in only one storm, entire islands are overwashed
and furnished a new layer of sand extending into the salt marsh on the lagoon
side. This happened on some islands in South Carolina as a result of Hurricane
Hugo. The overwashed sand simultaneously elevates and widens the island. The
same storm also pushes the ocean-front shoreline back. Thus, the island moves
back and up, a natural necessary and ingenuous response for a supposedly inert and
mindless body of sand, subjected to rising sea level.
The second most important mechanism of widening is
incorporation of flood tidal deltas once the inlet has closed. The ebb tidal
deltas on the ocean side are washed away by the waves, but the flood tidal
deltas remain in place and gradually become part of the island.
Needless to say, the mainland shoreline must
retreat simultaneously with island migration. Otherwise the islands would not
remain islands and, as shown here, sometimes the islands do catch up and “smash
into” the mainland. For example, the barrier island has caught up with the
mainland at Myrtle Beach, South Carolina and for a few miles of shoreline
there, the long chain of U.S. Atlantic barriers is broken.
Several barriers in North America today look the
way most of the islands probably looked when sea level was rapidly rising.
These islands amount to little more than unvegetated sandbars. They are so
active that vegetation does not have time to gain a significant foothold. These
include Assateague Island, Maryland; Masonboro Island, North Carolina; Capes
Island, South Carolina; and Matagorda Island, Texas. On some of these, the
highest elevations are the upper portions of the beach. Overwash, under these
circumstances, occurs in even minor storms.
Stage V: Island evolution When sea level is at a standstill or rising very slowly
It is 4,000 BP. The sea is close to its present
level, and the rate of sea-level rise is slight. Many islands widen as sand is
slowly pushed ashore by the fair-weather waves. Many islands are characterized
by significant width and elevation with distinct zonation of vegetation and
extensive maritime forests. Distinct rows of beach ridges are often present.
Island migration is slow and, in fact, many islands aren’t migrating at all.
Lagoons are wider now than they have ever been.
Islands can widen by a number of mechanisms. At
this stage, however, with an almost static sea level, island widening most
commonly occurs by the successive addition of beach ridges. These ridges of
dune sand are added one by one to the seaward side of the island.
Island length is, in part, controlled by the
amplitude of the tides. High tide range means lots of water to exchange between
sea and lagoon. Such exchange is facilitated by frequent inlets
which translates
to short islands. Small tidal ranges require less exchange of water, resulting
in less frequent inlets and longer islands.
This explains why the Outer Banks of North Carolina
consist of long islands and the Georgia islands are quite short. North
Carolina has low tidal ranges (2 to 3 feet) while Georgia has high tidal ranges
(7 to 11 feet).
Judging from the curvatures of the inlet channels
and the direction of spit extension, the dominant direction of longshore
transportation is from left to right in this diagram.
Stage VI: The future
It is 1990. The sea level has been more or less in
one place for 3,000 to 4,000 years. A fundamental change is occurring on our
barrier islands. With few exceptions, they are all getting narrower. The
open-ocean shoreline is retreating landward, and the lagoon shoreline is
retreating seaward. Islands such as Bogue Banks, North Carolina and Galveston
Island, Texas, which clearly owe their size and shape to dune processes that
built the island seaward, are dramatically changing in character.
Probably this change has occurred because the sea
level is rising. The barrier islands, ever sensitive to the behavior of sea
level, are thinning in preparation for their eventual migration in a landward
direction.
Why is thinning necessary for migration? It’s
because storm overwashing of sand all along the islands is the only way islands
can migrate quickly and on a broad front. The requisited extensive and frequent
overwash can only occur on a narrow island. Incorporation of tidal deltas on
the lagoon side is a spotty and slow method of widening, not suitable for an
island to respond to a rapid sea-level rise.
So the fat
islands will gradually slim down to a width of 100 to 200 yards or so, at which
point true migration can begin. Eventually, the islands will move off
themselves. The time frame in which this can occur can be a startlingly small
one. The northern 2 miles of Assateague Island, Maryland has, within less than
50 years, moved completely off itself. The surf zone of Assateague Island is
now landward of the position of the lagoon shoreline in 1933 when a jetty was
built on an adjacent inlet. In this case, the rapid movement of the island was
in response to a loss of its sand supply due to the jetties rather than to a
rise in sea level. As usual, sand supply and sea-level rise work hand in hand
to control island evolution.
The speed at which future island thinning and
eventual migration will occur depends on the future sea-level rise which
depends on the greenhouse effect and its role
in melting of the West Antarctic ice sheet, The faster the sea level rises, the
faster the island response. It also depends on the size of the islands. Thick
islands like Bogue Banks and Galveston Island will take a longer time to slim
down for migration. But some narrow islands such as Masonboro Island, North
Carolina are ready to go right now.
Finally, the rate of island migration will depend upon the slope of the lower coastal plain across which the islands must migrate. In North Carolina, this slope averages 1:2,000 except off the northern Outer Banks where the slopes are as slight as 1:10,000. This means that once islands are slimmed down, a 1-foot rise in sea level should move an island back 2,000 feet except on the northern Outer Banks where the same sea-level rise should push the islands back nearly 2 miles! Similar dramatic island migration rates will occur at the southern end of the Florida peninsula.
What role will humans play in the future migration
of our barrier islands? That’s difficult to answer, but we can he sure that our
role will be a major one. Islands can’t thin because of bulkheads, seawalls,
beach replenishment, etc. on both sides of the islands. The mainland
shorelines in developed areas are also stabilized so they can’t move back as
sea levels rise. When storms such as Hurricane Hugo occur, and the islands are
elevated and widened by storm overwashed sand, instead of maintaining the
natural changes in the island, we immediately “clean up” by removing the sand
from the islands, redredging the channels, and reopening the inlets.
Construction
of high-rise buildings, restaurants, shopping centers, malls, and movie
theaters may make us think that barrier islands are here to stay~ But don’t bet on it. It hardly seems likely that Miami Beach will be allowed to
migrate back toward Miami! But don’t bet on it for the long run. When it
comes to barrier islands, nature always bats last.
Conclusion: Three types of barrier islands
At any given moment in the history of a
barrier-island chain, there will be a wide variation in the appearance of the
islands. This variation will be due to a number of things such as sand supply,
range of the tides, wave height, orientation of the island relative to dominant
winds, orientation relative to dominant wave directions, and local variation in
sea-level change (due to sinking or rising of the land).
The stage VII diagram shows the three major types
of islands present in North Carolina. Number I is a wide, high island characterized
by extensive and high dune fields, extensive maritime forests, and relatively
restricted amounts of salt marsh. This island has a large sand supply.
The lack of salt marsh is due to the fact that the
island is so high that storm overwash events bringing in new sand to the lagoon
side of the island are uncommon. Without “fresh” sediment, salt marshes, which
effectively trap sand and mud, soon build up and choke themselves out.
Maritime forest is extensive because the high
elevation of the island reduces wind and salt spray, the main limiting factor
for such forests. Land plant species number more than 400. This island is
typified in North Carolina by Bogue Bank, Shackleford Bank, Ocracoke Island, Onslow Beach, and Bear
Island. At present, such islands are eroding on both sides and are not
migrating.
Number
2 is a narrow low island typified by Core Banks, Pea Island, and Hatteras
Island. These islands have a low sand supply. Dunes are generally low and
irregularly developed and occur only on the seaward portion of the island.
Between the dunes and the first occurrence of salt marsh on the lagoon side of
the island, is a gently landward sloping apron of overwash sediment. Maritime
forest is usually absent, but at the
edge of the salt marsh is a row of bushes, a
few tens of feet wide, tucked as far away from the salt spray as possible.
Perhaps 35 to 40 species of plants
exist on this type of island. The variety of plants is low because of lack of
dunes, island width, and elevation, which all lead to intense salt spray and
wind during storms.
Extensive salt marsh, often making up more than
half the island’s width, fringes the lagoon shoreline of the island. This marsh has a very irregular outline for
much of it exists on old flood tidal
deltas that once extended into the lagoon at the sites of old inlets, long
since closed. The irregular outline is also formed by lobes of overwash sand
carried across the island during big storms. This island type, eroding on both
sides, is not yet migrating.
Number
3, typified by Masonboro Island, North Carolina, is a rapidly migrating
barrier with no dunes, only overwash fans on its surface. The sand supply to
this island is almost zero. Probably only 10 to 20 species of plants exist on
this type of island which is washed over in even the most minor storm. This
type of island is actually migrating landward. It has the appearance of many
of the barrier islands in Stage IV.
Orrin H. Pilkey, a geologist at Duke University, Durham, North Carolina,
is coeditor and sometimes coauthor of the 12-going-on-20 volumes in the series
“Living with the Shore” published by Duke University Press
Life in a grain of sand 8
06/10/2001 17:49:11 Discover 4/95
On this typical
sunny morning on this southeastern Florida Beach, holiday-makers loll on their
blankets and splash in the waves.
Walking among them are two rather atypical beachcombers: Robert Higgins,
62 years old, dressed in a t-shirt, shorts and a floppy hat nthat covers his close-cropped hair: and
Marie Wallace, a dark-eyed woman in her
mid forties in similar garb. They carry
with them a shovel, buckets, plastic bottles, a fine-mesh screen, and a supply
of freshwater-all the tools they’ll need for todays scientific expedition.
Although other
people on the beach are completely unaware of it, beneath their feet, in the
seemingly sterile sand, there exists a microscopic jungle of surreal animals
waiting to be discovered. Some of these
miniscule invertebrates spend thir lives slithering between sand grains. Others flutter along by whirling hairlike
propellers on their heads. Still others, as waves crash over them, hold tight
to the sand grains with tiny claws, as if clinging desperately to giant beach
balls. Some of these tiny creatures
graze on algae. Some of the grazers themselves are food for predators who
insert lancelike tubes through their
bodies and suck out their innards.
The dynamic,
abrasive environment of a sandy beach might seem an impossibly inhospital place
to call home. Yet some of the greatest
diversity of life on earth hides here, on and between the grains of sand. “Its even richer, in taxonomy’s broadest
terms, than the Amazon rain forest” says
Higgins, one of the worlds’s experts on this hidden ecology: Those broad terms
he is referring to are phyla—the 40 major groups into which all animals are
divided. Humans, for example, belong to the phylum Chordata, which comprises
all the animals that have backbones and thus includes birds, reptiles, fish,
and lampreys. To fall into another phylum, you’ve got to be a radically
different beast, yet so far 22 phyla of animals have been discovered living in
sand.
Higgins has searched far and wide for such life, from the frigid beaches of Greenland to the rugged coast of
southern Chile. But this tame Florida shore is prime hunting ground. The
animals he has his eye out for are known collectively as meiofauna The word
means “lesser animals,” which is not a slight to the animals but a reference
to the tools that zoologists use to collect them. “Meiofauna describes animals that fall between two sizes of
collecting screens,” Higgins explains. The larger screens are made with
1-millimeter mesh, and scientists use them to winnow out big sand dwellers such
as sea urchins and sea anemones. Meiofauna readily pass through such sieves,
but scientists can gather them by using the 42-micrometer (.042 mm)
screen—a mesh finer than a silk stocking. (Those who want to catch smaller game
such as bacteria use an even finer mesh, with just 2-micrometer
openings.)
Despite their small size, meiofauna are far from
insignificant: they are as common and abundant as the grains of sand they call
home. One study calculated that a single handful of wet sand contains 10,000 of
these animals. Yet although meiofauia inhabit every seashore, as well as the sands and gravel far out at sea,
they remain virtually unknown and poorly understood. Only within the past
decade have ecologists begun to realize the important role they play in the
health of the marine ecosystem, consuming detritus and pollutants that filter
into the sands and serving as the primary food source for shrimp and
bottom-feeding fish.
“Very few
people, including some scientists who study the larger invertebrates, know
anything about them,” says Higgins. Consequently, the achievements of
meiofauna specialists often go unnoticed. Higgins, for example who recently retired
as a curator and researcher at the Smithsonian Institution in Washington, D.C.,
and is now an adjunct professor at three North Carolina universities has
discovered scores of new species, genera, and families of meiofauna over the
past 39 years. With fellow zoologist
Reinhardt Kristensen of the University of Copenhagen, he is responsible for
the creation of the newest phylum of animals. Only two other new phyla have been
created this century; simply because the existing categories are so broad and
all encompassing. But although 12 years have passed since Higgins and
Kristensen named their new sand-dwelling phylum, the word__Loncifera_has yet to
make it into Webster’s. “Most
meiofauna are what I call bibliocryptozoans,” says Higgins, an amused smile
lighting up his hazel eyes. “They are animals that are extremely common on
Earth but seldom found in our books.”
Common though they may be, it still takes effort
and expertise to find them. Today, on this Florida beach, Higgins knows exactly
where to look He chooses a spot three feet from last night’s high-tide mark and
scrapes away the dry surface sand. He then begins digging a hole—a scientific
skill that he says he perfected as a young Marine.
There are fewer animals in these upper, drier
sands,” Higgins explains as he shovels noting the most rneiofiiuna require at
least a thin film of water around their grain of sand to survive and that they
thrive best where the sands are always wet.
Out at sea Higgins can get
plenty of meiofauna by dredging the top few inches of the ocean floor, but here
on the beach he has to dig six feet down to reach slushy gravel. He shovels
this "prime meiofiauna habitat” into a bucket. then tops it with seawater
to keep the tiny creatures alive. To look at the stuff— wet, sloppy sand—you'd
never guess that an thing other than humble protozoans lives there.
Many of the mesofauna
cling in various tenacious ways to the sand grains, and so, Higgins says,
“people have invented a variety of collecting techniques, depending on what
animal they’re trying to catch.” The most common method is to wash the samples
of sand and gravel with magnesium chloride, which stuns the animals and causes
them to loosen their grip. But a bath of freshwater, Higgins has found, seems
to work just as well, causing the creatures to lose control of their salt
balance and thus their bodily functions. “If they’re exposed to the freshwater
for only 20 seconds, the bath seldom kills them,” he says, “so they’re still in
pretty good shape when you get them to the lab.”
Accordingly, Higgins puts handfuls of the sand into a bucket of
freshwater, then swirls the mixture into a slurry. Incapacitated, the
meiofauna surrender their grasp on the sand grains, which settle to the bottom
of the bucket as the animals continue to whirl. Wallace, Higgins’s assistant,
kneels next to him, holding the sieve over another bucket. Higgins deftly pours
the slurry through the sieve, leaving most of the sand behind. Wallace’s
bucket fills with water; trapped in the sieve is a frothy residue that contains
the meiofauna. Wallace rinses it into a bottle with squirts of filtered
seawater. hi this way she and Higgins fill several bottles, holding, Higgins promises,
thousands of meiofauna.
The idea of looking for animals among the seas’ sands
didn’t occur to biologists until this century. “Scientists wanted to know what
lived in the oceans, so they dredged the seafloor, then washed the gravel
through their 1-millimeter mesh screens,” says Higgins. “That way they
collected the macrofauna: the sea slugs and starfish. But they never thought to
look for animals in the material—the
sands and gravel—that was washed through the screens.” In the 1920s zoologist
Adolf Remane began using a finer screen to study the beach sands of Germany’s
North Sea. He revealed a profusion of creatures previously unknown to science,
and not a year has passed since without the discovery of at least a dozen new
meiofaunal species. “It’s a rich, complex world,’ says Higgins, “but it’s one
we’ve barely scratched the surface of. It’s impossible to say how many more
species are left to be found and identified; I’ve got hundreds of new ones
waiting right now to be described.” Higgins transports the collecting equipment
and bottles of meiofauna back to the Smithsonian Marine Station at Link Port,
Florida, where he has spent numerous field seasons. Only there, with the aid of
a dissecting microscope, does this lilliputian world become visible. Even when
enlarged 50 times, the animals are
minuscule. But now you can see that they’re busy. Swimming, crawling, flailing, and writhing
among the shiny chips of sand (some of which, when magnified, look as grand as
Yosemite’s El Capitan) are the flat, segmented worms known as gastrotriches,
bristling with spines. There are pear-shaped rotifers, their heads awhirl with
spinning cilia; wormlike rurbellarians that are so protean they can transform
their fat sausage bodies into slender threads as they maneuver between the
sands; and rigid, boxy tardigrades. Elsewhere there are shrimp-like
mvstacocarids and copepods. mite-like halacarids, and wormlike nematodes—all
of which look as alien as their names sound.
Around them glint the plants that also grow in this
world—emerald strands of algae, star-shaped radiolarians, golden foraminifers,
octagonal diatoms—as well as odd bits of detritus and cast-off body parts: here
a silvery piece of a sponge’s internal skeleton, there a sea urchins glassy
spine. Occasionally, a dinoflagellate (a one-celled alga), shaped like a
speedboat, zooms past as if on an urgent errand, while ciliated protozoans
glide about with the elegance of swans.
“Here’s an epsionematid nematode,” Higgins
announces triumphantly seconds after setting a petri dish of this morning’s
catch under his microscope. It’s a habit of Higgins to search dishes quickly
for the usual suspects (like nematodes) and for creatures he doesn’t recognize.
“Alter you’ve done this ft)r a while, you develop a sense like a good
bird-watcher,” he explains. “I’m just an amateur bird-watcher, so I'm always
amazed at what a top-notch birder—or a native in the forest—is able to see.
But here, searching for meiofauna, rm that person in the forest.” With only a
glimpse of a moving creature or a broken piece of meiofaunal anatomy, Higgins
can visualize the whole beast and name it.
The epsilonematid nematode that Higgins has spotted
is one of the easier ones to recognize since, as its name implies, the thin,
wormlike animal is shaped something like the Greek letter epsilon (s). It’s a
shape perfectly suited for living in the crevices of the beach sands: slightly
curved at both ends and nipped in at the waist. The nematode’s body is covered
with tiny spines, which protect it from its abrasive home and enable itto wedge
itself securely between the sandy partides.
“You want to be
able to do that,” says Higgins, “if you live at the shore, where the incoming
and outgoing tides can make it fairly turbulent.”
Most of the
meiofauna have some variation on these themes: a shape, or anatomic siructure,
that allows them to squeeze, like spelunkers, through the crevices between the
sand grains, and a gripping mechanism to keep them in place when the going gets
rough. A secure grip is particularly important since many meiofauna species
cannot swim and so are in constant danger of being washed out of the sand and
into the sea. The animals are also typically transparent (though they may take
on a golden or greenish hue after feeding on diatoms and algae) and flat,
elongated, or cylindrical. Nearly all have some kind of protection from
abrasion and collision, such as spines, shells, scales, or even body walls that
are padded like the bumpers of a car.
Searching his
petri dish further, Higgins soon finds a tardigrade, another creature for whom
a tight grip is crucial to survival. Tardigrades are also found in freshwater,
where they have plump little bodies with stumpy legs, a configuration that has
led to their popular name of “water bear.” But this marine tardigrade, all of
half a millimeter in length, looks more like a piece of silver confetti
equipped with legs and claws. “It uses the claws to grip and move over the
sands. Since these particular ones can’t swim, they really do have to hang on
for clear life,” says Higgins. Another tardigrade species has mechanical
suction toes to keep itself in place; while a third, which also inhabits the
Florida coast, boasts both suction toes and claws. Still another suction-toed
species has a tear-shaped bubble on the end of a long tail, which gives it
buoyancy. To feed, it lets go of its sandy particle and, with its tail aloft,
hovers over the gravel, grazing like a zeppelin-towed cow on the thin layer
of microscopic algae that covers the seafloor.
Other meiofauna, such as gastrotrichs and
rurbellarians, have mastered their dynamic habitat with the aid of special adhesive
organs. Depending on the species, these tubes—which appear as small bumps-may
be found near the animal’s mouth, along its sides, or near its tail. Some of
the glands secrete a substance sticky enough to rival epoxy, while the others
dispense a solvent. A gastrotrich for example, can glue itself securely to a
grain of sand with one squirt, then dissolve the bond with a second, freeing itself
to swim by beating the hundreds of cilia that line its underbelly.
A kinorhvnch, on
the other hand, moves with a bit less grace. Higgins describes the creature as
an “umbrella in a canister.” Its body is a hollow cylinder with a set of curved
arms that emerge from the front end. Inside the cylinderis the animal’s
head—the umbrella part— which is armed with a ring of nine spines. The animal
works its way through the world with a sort of breaststroke. As the arms come
into contact with sand or mud, they push against it to drag the body forward.
As they do so, the head emerges from the cylinder and unfolds its spines,
grabbing on to whatever’s in front of it. Once it's anchored in this fashion,
the kinorhynch retracts its arms into the cylinder and repeats the sequence.
Since sand grains are often much larger than the average kinorhynch, it may
take the creature several minutes to explore each one.
Unfortunately in
the laboratory ,it is nearly impossible to see these animals move—or do
anything else—as they normally would. After all, a petri dish of salt water is
vastly different from the snug sandy matrix meiofauna call home. When you
look through the microscope at tardigrades, for example, which normally live
attached to a grain of sand, they appear to be searching for something to
grasp: their clawed feet move back and forth, back and forth, but the animal
makes little headway. Consequently, to get a better idea of how meiofauna
usually live, zoologists sometimes place unfiltered samples under the scope.
“You can see them crawling over the sand grains, and that’s how we have some
idea about how they move,” explains Higgins.
Still, most of
Higgins’s work is the identification of new species, and for that he needs
screened and filtered water to get an unobscured view of the animals. But even
with a good view, it can take years to know what you’re really looking at, as
Higgins discovered with his new phylum, the Loricifera.
In 1974, Higgins
found an animal off the coast of North Carolina that sported feathery plumes on
its head and seemed radically different from other meiofauna he had seen. He
guessed it was a larval stage of some new species, but with only one sample, he
wouldn’t venture naming or describing it formally.
Eight years
later Reinhardt Kristensen brought some meiofauna for Higgins to examine.
“Reinhardt had collected some samples off the coast of Brittany and was rushing
to catch a train, and so he hurriedly flushed these with freshwater,” Higgins
recalls. There were 50 adult
specimens and even more larvae of a species that Kristensen had never seen
before, and their feathery plumes told Kristensen that these were strange animals
indeed. He wondered if Higgins could identify them for him.
“He showed them
to me,” says Higgins. “and Isaid, ‘Oh, I have one of those, too.’ “ What
Higgins had thought was a larva from North Carolina actually turned out to be
an adult of this bizarre new life-form. “We knew what we had was a new,
distinct animal.” Over two years, Higgins and Kristensen cataloged and
described the features that made their specimens unique. “It was a great deal
of work because the Loncifera are the most complex microscopic animals,” says
Higgins. The head segment alone, although only 50 micrometers long, is composed
of nine overlapping rings with more than 200 feathery appendages— and all had
to be counted, measured, drawn, and described. Most startling of all, Higgins
and Kristensen discovered that these creatures had the smallest cells of any
animal. “An appendage only 40 micrometers in length,” says Higgins, “will have
as many as seven specialized cells in it—cells for the muscles, nerves,
epithelium.”
Deciding that
their new animal did not fit any existing taxonomic category, Higgins and
Kristensen created a new phylum for it—in essence saving, “Here is a new group
of animals unlike any other on Earth.” The name Higgins chose comes from the
Latin lorica, meaning “corset,” and f’erre, “to bear,” because the
cuticle rings that sheathe the animals fit them like a girdle. Among the
Loricifera. Higgins and Kristensen initially described 3 genera and 5 species.
Today over 70 species have been identified from sites around the world—one was
even found five miles below the surface of the North Pacific Ocean. The list
keeps growing: Higgins himself has five new ones to describe from the Louisiana
coast.
Despite their
long labors, Higggins and Kristensen know next to nothing about the behavior of
Loricifera. The organisms are difficult to find and once caught, usually
expire before reaching the lab. “All of
the adults we’ve seen have been dead." Says Higgins. "Kristensen once
saw a live larva; it had two appendages that it kicked like a scuba diver. But
since the adults lack fins, these appendages are apparently lost as the
animals, on their way to maturity, pass through several stages and shed successive
exoskeletons. Higgins and Kristensen suspect that fbr locomotion the adults use
their feathery head appendages. “There are muscle cells in those plumes,” says
Higgins, “but whether the Loricifera spin them or wave them about, we just
don’t know.”
The zoologists
don’t know what the Loricifera eat, either, but guess that they may subsist as
parasites because their narrow snouts appear designed for piercing and
sucking. Equally mysterious are the Loricifera’s sex lives. “The males have
large, prominent testes that take up as much as 75 percent of the space in the
abdomen,” says Higgins, “while the females produce one or two eggs at a time.”
The eggs too are large; a single egg can occupy half the female’s abdomen.
Presumably the male transfers packets of sperm into the female’s body, but
Higgins can’t say for sure. “So many of these things depend on a chance sighting.
You find them by doing what we’re doing now, going carefully through each
sample, watching and searching.”
Much more is
known about the mating habits of some of the other meiofauna species. Like
the Loricifera, many of these creatures produce only one egg at a time. Animals
that lay hundreds of eggs (such as many species of fish) can afford to abandon
their offspring, since it is likely that many of their young will survive the
vagaries of nature. But these species of meiofauna, like humans, produce so
few offspring that they must jealously guard them to be sure they survive
their youth. Thus the hermaphroditic hydra, Otohydra
vagans (which looks like a gelatinous oval with a dozen fat tentacles
sprouting around its mouth), incubates its single egg in an internal pouch.
Only when its young is close to maturity does the hydra release it into the
sands. Many turbellarians (those protean flatworms) also produce a single egg
at a time, and with a squirt of an adhesive from their reproductive system,
they attach it to a grain of sand. They then cover the egg with a protective
secretion, effectively sealing it in a cocoon.
As he gazes
intently through his microscope, Higgins now spots one of these turbellarian
capsules, recognizing the almost metallic golden hue and the delicate wine-cup
shape. The young turbellarian inside, he realizes, is trying to get out,
struggling like someone jammed into a down sleeping bag. “Now, that’s something
I’ve not seen before,” Higgins says before he calls for others to admire his
hatching turbellarian. “I’ve seen these egg capsules hundreds of times,” he
adds, putting his own eye back to the microscope, “but this is the first time
I’ve ever seen one hatch.”
Once the
turbellanan is finally free, it hastily swims off in search of a meal.
Turbellarians are predators, and many of them lance their prey with a dartlike
structure in the mouth; after inserting the lance, they suck the animal dry.
There are many other predators among the meiofauna, and some omnivores as
well—nematodes will attack their fellow meiofauna, but they eat algae as well.
One nematode is even something of an “agriculturalist,” as Higgins puts it. As
it burrows through the sediments, it secretes a mucus that serves two
purposes: it stiffens the tunnel to prevent it from collapsing and acts as a
fertilizer on which algae thrive. When the nematode later comes slithering
through this tunnel again, it will find a fresh crop of algae to browse on.
Other forms of meiofauna, such as the rotifers and gastrorrichs. act like
vacuum cleaners, sucking up bacteria, algae, and organic detritus from the
sands. “They really are the garbage collectors of the system, consuming all
the dead bacteria and plankton left on the shore in the sands,” says Higgins.
So vital a role
do these tiny animals play in cleansing the marine sands that zoologists now
say that the healthiest beaches and estuaries are those with a rich and diverse
meiofaunal population.
They
are also particularly promising indicators of pollution since, as Higgins
notes, “they are in constant contact with the sediments.” If those sediments
are flill of pollutants, the meiofaunal populations often feel the effects
first. And because meiofauna are so far down the food chain, serving as the
primary dinner item for shrimp, in particular, any drop in their numbers
affects the many animals above them. “It used to be thought that you could
monitor the health of an estuary by studying the bottom-dwelling fish,” says
Higgins; many ecologists now think you get a better picture by keeping track of
the melofauna.
Although the day’s meiofauna hunt has not turned up
any new species, Higgins is pleased to have seen a rurbdlarian hatch for the
first time. “It’s rare not to see something new, something you haven’t seen
before, even in sands like these that I’ve studied many times. But it’s like I
always tell people: ‘If you look where people haven’t looked before, you’ll
find something new. Or if you look harder where people have looked before,
you’ll find something new.’”
For those hoping to catch a glimpse of this bidden
world, Higgins notes that one needs only a few basic naturalist’s tools: a
homemade sieve fashioned out of a nylon mesh net fastened over a funnel; a
spray bottle for rinsing it out; a petri dish to place the samples in; and a
stereomicroscope of at least 25 times
magnification. Higgins encourages people to explore other poorly understood
habitats with this gear as well, such as the moss on a river rock~ or the small
pools of water that form on ice fields. “You’ll find animals in all of these,”
he says, “and in some cases you’ll be the first person to see them.” New animals
are to be found everywhere—even, as Higgins~ colleague Kristensen recently
discovered, in the filmy ooze on the back of a crab’s shell. “He scraped off
that film and found this strange, wormlike new animal. He’s still studying it
and hasn’t named it yet; but it may very well prove to be another new phylum or
at least a new class of animals,” says Higgins.
None of the animals that live in such habitats will
be “big or sexy or bold,” he admits. “And they won't solve the world’s economic
problems. But we search for them because we need to know as much as we can
about what is there; we need to understand the biodiversitv that can exist
even in the beach’s sands.”
The world would, however, be a very different place without meiofauna. “A
beach without meiofauna would be like a forest without turkey vultures or other
scavengers,” says Higgins. “All the dead material—fish, shellfish, seaweed—that
washes up on shore would simply accumulate, and the bacteria would build up
until the beach became anoxic (starved of oxygen)”. Instead of a clean shore, there would he a
sticky, stinking mudflat. But as the sparkling sands of that
Name______________________________________pd_________8
readings 80 points….
1. What percent of the top 20 beaches are
found in
2. What are some of the criteria Dr. Leatherman uses to rate beaches?
3. Which state seems to have the best
beaches over the years?
4. Where can you find more information on
beach certification
1. What is the price for 1 block of sand
from the boardwalk to the water?
2.
Why does Boyd have a TV monitor of the bottom?
3.
How long are the Corps of Engineers committed to the beach pumping
process in
4.
How much has this project cost you?
5.
What is at stake from the erosion dollar wise?
6.
The article mentions the buildup of the coast is partially because
natural devistation skipped a generation. When did it return?
7.
When do storms like the '62 northeaster usually occur?
8.
What is a storm to a grain of sand?
9. Where is sand removed from the beach during storms, stored?
10.
Where is the dividing point where sand flows either norrth or south in
11.
What are the problems faced by the northern end of Avalon facing
Townsends Inlet?
12.
What was built to stop sand from washing away and how does it work?
13.
After the sand pumped in to
14.
What does Psuty contribute to the rising sea level?
15.
How is this project in
16.
How has
17.
What arguments to filling the beach at taxpayers expense does
Congressman Hughes use?
18. What have the McClains lost to the sea
over the last 2 years?
19.
What was Bob Sheet's role in his talk to the residents at the town
meeting?
20.
How much of the dredged substance is sand and how much is water?
21.
How much area can the dredge collect sand from?
22.
Would you spend all that money for a beachfront house even if the federal
flood insurance program was halted?
1. How did the shape of the housing lots in
the past help when the ocean threatened the shoreline?
2. Why does that method NOT work today?
3. What seems to be the results of most of
the "erosion control" structures?
4. What are 3 considerations on weather a
beach is renourished or not?
5. What does grain-size have to do with the
future "success or failure" of the project?
6. What are some of the environmental
concerns from pumping sand?
7. What happened to sand pumped into
8. Why did Sandy Hook have priority over
other threatened beaches in
Sand Helps Revive shore 4
1. How do
2. Why are these projects 50 year projects?
3. How much will these projects cost the
taxpayer for the next 50 years?
4. How much of the
5. Give evidence that the beach
renourishment is working and not unravelling.
6. What is Orrin Pilkey's problem?
7. How can
1. Have you heard the "singing
sands" while walking on sand? Yes /
no---if no, you better read this carefully---it will be something new!
2. How does the noise start?
3. When did "El Bramedor" make its
noise?
4. What terms did Dr. Bagnold apply to
sounds and what key (piano) was it?
5. What can destroy the ability of the sand
to make sounds?
6. Name some characteristics of sand grains
that made sounds?
Shoreline erosion questions
6
1. What is necessary for beaches to form and be
maintained along the shoreline?
2. What human activities reduce sand supply and
how does this reduction occur?
3. How much of
4.
What was the most common way to protect
the shoreline?
5. What is the difference between a “soft” and
“hard” approach to shoreline protection?
6. Of the 4 processes, which makes the most
sense?
7. Which agency is responsible for shoreline
erosion planing in
8.
List the states (regions) and the particular erosion problem(s) they are
having.
9. What purpose did the beach serve in
10. Why were dunes constructed in
11. What is the role of an Argus Station and how
can this be useful to coastal engineers?
Barrier Islands-formed by fury, they roam and fade .. 7
1.
What is the only Natural Enemy of Barrier Islands?
2.
Why is it so difficult to understand barrier islands?
3.
What is 1 trait all
4.
Stage 1--What ingredients are needed
for
5.
Why does the Pacific coast of North America have no
6. Why does
7. What does nature strive to do to the
coastlines?
8. What forms behind sand spits?
9.
Why are these areas (8) important?
10.
Describe ways
1.
2.
11. How does sand get to the island?
12.
What is an inlet?
13.
What controls the size of the delta?
14. What is the
dominant direction of longshore
transportation of sand in the surf zone?
15.
If the
16.
How does island widening occur?
17.
Explain how island length is controlled...give an example of each/
18.
1990---What fundamental change is
occurring to our
19.
Why must an island be narrow to migrate?
20.
What is the slope ratio of the Outer Banks (
21. How far would the outer banks migrate with a
1' rise in sea level?
22.
How do humans effect
23.
Describe 3 types of barrier islands.
1. How many phyla of animals have been found
living in the sand?
2. What is meant by the term meiofauna?
3. What have ecologists realized about the role
of these animals?
4. What is the new-sand dwelling phylum?
5. What is the most common method of collecting
these animals and what does this technique accomplish?
6. What roles do the epsilonematid
nematod spines play?
7. Why is the secure grip necessary for most
meiofauna?
8. What is the popular name of the tardigrade?
9. How do turbellarians and gastrothichs
attach and detach to and grains?
12. Describe how a turbellarian feeds?
13. What does a person need to study these
meiofauna?
14. What importand role do they play along our
shoreline?
15. T/F
The great diversity of life in the sand grains could be richer than the
16. Design draw and a simple food web which includes what the sand animals feed on and what feeds off of the sand animals.