Reefs At Risk
pdustan at zeus.cofc.edu
Fri Jun 26 15:57:26 EDT 1998
At 02:07 PM 6/24/98 -0400, you wrote:
>I have a problem with the "chicken little" approach that is often used in
>public forums to generate support, controversy, or conflict. And even if
>"the sky is falling" I think that it's important not to oversimplify by
>suggesting simple solutions (or even any solution) to problems as complex as
>coral reef condition - especially in Florida. I don't think that anyone
>disagrees about the decline of reefs in Florida (and throughout the
>but since you imply that there are more actions to take - what exactly do you
>think anyone can do to make a difference?
I have a problem with the "chicken little" approach that is often used in
public forums to generate support, controversy, or conflict. And even if
"the sky is falling" I think that it's important not to oversimplify by
suggesting simple solutions (or even any solution) to problems as complex as
coral reef condition - especially in Florida. I don't think that anyone
disagrees about the decline of reefs in Florida (and throughout the
but since you imply that there are more actions to take - what exactly do you
think anyone can do to make a difference?
I think I speak from a slightly better vantage point than Chicken Little.
And the "sky" isn't about to fall- in many places large chunks have landed.
The reefs I have been working on have changed dramatically in my
scientific career- one than spans a very short period when compared to the
ecology and geology of reefs. In the northern Florida Keys the corals have
dropped like flies- from diseases, boat groundings, sedimentation, and a
host of other processes. For example, The fore reef terrace of Carysfort
reef has a measured 50 to 65% cover in 1975, now its about 12-13% . Key
Largo Dry Rocks has probably done the same, as has Molasses and most of the
other reefs in the area. This is not new- the decline has been going on at
least since the 70's or earlier. Denial masks many things.
Over the last few years, being a member of the EPA Coral Reef Monitoring
Project has given me the opportunity to place my observations from Key
Largo in context. And to my eyes, much, if not most of the outer reefs
along the Keys are in the same shape.
I have appended a manuscript I wrote for the World Bank which outlines
some large steps that we might want to address, but what can we do in the
Keys to "help" the reefs?
Judy Lang offers a good point- adopt a river. Address the problems of
watershed effluent where they originate- the great rivers.
Address the immediate problems facing the corals while we try to figure
out whats causing them:
Harold Hudson got named the reef doctor because he works towards the health
of individual corals.
What else could we do you ask?
"Don't you agree that the two biggest factors related to decreased coral
> and increased algae on reefs in Florida and throughout the Caribbean are
> band disease and the Diadema dieoff, respectively?"
I suppose we could hold a few more workshops, or start another monitoring
Or more seriously we could try to address the problem at the scales it
1. Corals are being killed by algal overgrowth and algal-sediment
encroachment at rates that far exceed their growth and/or recruitment
rates. Why not get experienced people together (interested naturalists) to
tend the reefs like we tend gardens to reduce these stresses. People could
play the role of herbivores. This would reduce the algal standing stock
(huge at present) and perhaps give the corals some relief.
2. We could do the same at a finer scale around colonial edges. Next time
you go diving look closely at the edges of the corals. They are fast being
"overgrown" by mats/carpets of filamentus algae and fine sediments. This is
not a new problem, but one that seems to be increasing, especially in the
keys. Careful hads could clean the edges.
3. While we are administering "first aid" it might be prudent to begin to
grow large quantities of diadema and other herbivores in culture. This is
not a simple issue, but if we can grow salmon, clownfish, abalone, and
other interesting collectibles and delectables, why not important
herbivores. And while we're at it, why not stop taking other important
4. We could address the problems of watershed effluent- the bleeding of
sediments, nutrients, and carbon into the sea. In the keys sewage and
nutrients top the list- so why not deal with it straight out- spend the
money for sewage treatment. There are lots of interesting "biological
systems" as well as the standard systems that could be brought to bear on
But still the land will bleed. People have got to begin to realize that the
terrestrial ecosystems are conservative, When we develop them, they leak,
like a cut open person. They spill their "guts" into the sea. In the Keys
this includes fine sediments, nutrients, carbon, and lots of pollutants.
People should try to move the system back to its conservative natural
state. Stop using pea gravel and other practices that generate fine
sediments, etc. Sure, a lot of the water quality issues come from other
places as the Keys are downstream of the whole Caribbean and Gulf of
Mexico, but to use this as an excuse for how you treat your home is shameful.
5. I'm sure theer are lots of other "action" things we could do to help
with the immediate while we attack the larger issues.
I don't think it takes a rocket scientist to figure a lot of this out.
Just some practical politics and some consciousness. We presently worry
about the reefs and are actively spending money on "restoring" the
structure of reefs rather than the system. The reefs are the indicators of
larger issues and perhaps, we need to become active at larger scales. And
we need to do it fast if we are going to leave more than algal carpeted
used-to-be-coral reef for the next generation. When the rains finally do
come to Florida, the ash and debris form the fires will create an even
greater challenge for the reefs. I, for one, am not convinced that we have
to keep a smiley face on the situation to get people to want to help the
reefs. I think that a lot of people would rather do something more than
watch. Don't you?
One last comment however. Unless the increase in the Earth's human
population is somehow brought into reasonable limitation, all we do will
probable be wasted in the long run.
Text of a manuscript in press with the World Bank on the Conservation of
Coral Reefs, harbingers of global change?
Department of Biology
University of Charleston
Charleston, SC 29424
on behalf of
The Cousteau Society
"Evolution produces a very few new species every million years. If we are
to assume that nature can cope with our feverish developments, it is
probable that mankind would be submitted to the fate of the dinosaurs.
Destruction is quick and easy. Construction is slow and difficult."
J.Y. Cousteau, 1973.
Coral reefs form in the tropical, equatorial waters of the world's oceans
and are the marine analogs of tropical rain forests. They are the oldest,
most diverse and productive ecosystems in the sea. Coral reefs are a
reservoir for much of the ocean's biodiversity, provide an estimated 10% of
the world's fisheries, and their productivity fuels intense biogeochemical
activity linking them to the global carbon cycle. Complex reef structures
house some of Nature's most amazing creatures while protecting miles of
coastline from the full fury of the sea.
Coral reefs develop to their greatest expression in clear tropical waters
under extremely nutrient-poor conditions. Abundant solar energy fuels
photosynthetic activity which is transferred to the food web by a host of
grazing herbivores (animals that eat plants). This lush development of
reefs under extreme oligotrophic conditions created the "paradox of reef"
until the role of symbiosis was fully recognized. Now we know that the
high productivity of reefs results from the evolution of many symbiotic
associations, mainly coral-algal (zooxanthellae), that increase the
retention of limiting nutrients, primarily nitrogen and phosphorus. Reef
corals are functionally both animals and plants. Ironically, the same
intricate patterns of survival that have developed over an immense span of
evolutionary time make the reef vulnerable to changes in environmental
conditions, especially temperature, sediment, and nutrient concentrations.
Anthropogenic stresses are thought to be contributing to the decline in
coral reef ecosystems, notably in the Caribbean and the western Atlantic.
Driven by the engine of ever increasing human population, more and more
land has been converted from its natural state. Generally, terrestrial
ecosystems tend to be conservative and export little in the way of
nutrients, carbon, and sediments. But, agriculture, urbanization, and
deforestation reduce the capacity of terrestrial ecosystems to trap and
retain materials. Development has altered the ecological characteristic of
watersheds overloading rivers with sediments, nutrients, and adding toxic
chemicals. Simple runoff has become an effluent that can have a
significant deleterious influence on water quality. The addition of
fertilizers, organic carbon, and urban and commercial dumping further
enrich the watershed's effluent as it flows into the sea. When these
ecological variables pass some threshold , the species composition of the
reef community becomes reorganized.
The addition of sediments and/or nutrients triggers a set of ecological
processes that alter the selective pressures facing corals. In disturbed
areas, increased loading of sediments and nutrients often co-occur, making
it difficult to isolate their individual effects. Generally, increased
sediment and nutrient loading favor the growth of macroalgae over corals.
Suspended sediments reduce light levels to the corals and coat their soft
tissue surfaces. Algae strip nutrients from the water column quickly
enabling them to grow faster than stony corals.
Excess sediment, coarse or fine, smothers coral tissue, impeding diffusive
gas exchange through the tissues while also reducing the amount of light
available for photosynthesis. Since corals work best when their surfaces
are sediment-free, their metabolic efficiency diminishes. Energy spent on
housekeeping is not available for prey capture, growth or reproduction. As
the sediment load increases, the tissues cannot maintain their status and
tissue death occurs. Microbes quickly claim the freshly exposed skeleton
which is followed by a successional process ending with an algal turf or
macroalgal community. Tissue losses increase when, through fishing and
collecting, levels of herbivory are reduced or at least altered. Such
reefs change from coral gardens to algal-covered rocks, precisely the type
of trend which is one of the key problems facing coral reef ecosystems in
the Caribbean and western Atlantic today.
Curiously, luxuriant reefs can be found naturally in areas with high
sediment loading such as could be found near the mouths of tropical rivers
along the Jamaica north coast. The difference is that these reefs
developed under these conditions rather than being subject to dramatic
environmental shifts after becoming established. Reef corals that have
developed under one set of conditions may not posses the necessary
flexibility in their physiology or genetic makeup to "cope" with the added
stress of rapid environmental change.
The death rate of coral tissue from sediment necrosis increases when algae
grow in close proximity to corals. Macroalgae can shade coral tissue
causing bleaching and eventually tissue necrosis. Large algal colonies can
also abrade the soft coral tissue as they wave in the surge. Microalgal
filaments at the edge of corals, form effective sediment dams which prevent
corals from clearing sediment off their surface, slowly suffocating the
live tissue. This process, termed edge damage, is a "functional disease"
and appears to be a significant source of coral tissue mortality.
Additionally, any lesion increases susceptibility to opportunistic
pathogens which can kill a colony in less than 1/100 of the time it takes
to grow. In the Florida Keys in 1974, I observed the process on reefs that
had increased amounts of fine sedimentation. The condition became much
more prevalent after the mass mortality of Diadema antuillarum greatly
reduced levels of herbivory. Today, throughout the Florida Keys and
Bahamas, almost anything that lives on hard substrate is being overgrown
by algae. It is abundant, almost metastatic, on the outer reefs of Key
Largo. Molasses Reef, the most heavily visited reef in the world, has
thick rug-like algal mats while Carysfort Reef has mats with finer
filaments. Both types of algal communities trap sediments and the finer
particulate organic snow which shade, smother, and rather quickly kill
The reefs in many parts of the Caribbean and western Atlantic are showing
signs of decreasing vitality; coral cover is decreasing while algae are
increasing. Coral regeneration is slowing and the increased levels of
algal biomass may be, in part, responsible for reduced levels of coral
larvae settlement. Signs of stress appear most evident on coastal reefs
near population centers. In the Florida Keys, one of the most dramatic
sites, I am frequently asked which single factor is responsible, sediments
or nutrients? My perspective is that the "factor" may actually be the
accumulation of a series of nested stresses which are as local as the
fisherman, as regional as the landowner, sugarcane field, or village, and
as global as deforestation in Amazonia, the ozone hole, and greenhouse
effect. Each factor compounds the rest, a synergy towards death for the
Locating the source of increased levels of nutrients and sediments, and
other stressors, has proven as elusive as defining the nested levels of
stress. In the Florida Keys, the effluent of cities, towns, farms, a
watershed too vast to control, slowly bleeds into the sea through canals,
rivers, and coastal bays. The origin can either be a steady and
well-defined point source stream or an effluent that seeps from the land
with each rainfall. Both push sediments, nutrients, and contaminants into
the sea. More of it upwells from injected sewage, some leaches from
shallow septic tanks, urban lawns, agricultural lands, or vacant lots.
Some washes into the sea along the west and east coast of Florida, the
Everglades, the Mississippi, and lands that are farther downstream. Bits
and pieces from a diffuse array of sources contribute to a pervasive level
of adverse stress for the reef.
The changes we are witnessing in reefs are echoes of the increased levels
of harmful algal blooms in coastal waters, beach closings, and the general
global decline in fisheries. The impact of man is extending into the seas.
Watershed effluent, runoff from increasingly urbanized landscapes, an
unprecedented manipulation by humans, is thought to be responsible for
increased levels of nutrients and sediments but the definitive data are not
yet in. The data are elusive because reef community metabolism has evolved
to rapidly take up and sequester the very nutrients signal we are trying to
detect. Increases in algal biomass are thought to reflect increased
nutrients but do not constitute proof. Carbonate sediments are almost as
hard to follow, so at this time we are left with correlation rather than
causality. It is my belief that the declining vitality of reefs is a metric
for the health of the oceans, analogous to the coal miner's canary in the
cage. They are the fragile harbingers of change warning us of declining
Coral reefs, rain forests, and human civilization are the three most
complex communities on Earth. The first two are the most productive
natural communities, while humanity, is rapidly encroaching on the entire
planet. Reefs are the oldest, having existed since there were organisms
with skeletons in the sea. Modern coral reefs date from about 250 million
years before present. Like rain forests, these communities have evolved an
ecological logic that allows them to flourish and persist on a planet that
is forever changing.
Over enormous spans of evolutionary time, very sophisticated relationships
emerge which form the core of biodiversity. The most elaborate ecosystems
tend to be found in places that are old, benign, predictable, and
frequently rich in solar energy. These ecosystems are very proficient at
elemental recycling so that the living portions of the habitat are richer
in nutrients, than their surrounding soils or seas. Both reefs and rain
forests develop to their highest expressions in habitats that seemingly
cannot support luxuriant growth. The soil of rain forests is extremely
poor, and the clear warm tropical seas that bath reefs have nutrient levels
at or below the level of minimum detection. In this case, more is not
always necessarily better.
Human civilization is undergoing an unprecedented population expansion
coupled with an economy driven by consumption and profit, as opposed to
efficiency and recycling. Humans treat biological resources like
agricultural systems in which net production is maximized rather than
managing for sustainable yields. Such systems are inherently unstable.
They require a constant input of nutrients, very little of which are
sequestered in the standing stock or "body" of the ecosystem. They grow at
the expense of other systems and greatly increase the entropy of
surrounding areas. But, since the earth is finite, this approach cannot
continue without increasingly severe degradation of the Biosphere.
One long range vision for future humanity suggests that the incorporation
of the logic of natural systems into our mode of living might, perhaps,
enable civilization to persist as long as coral reefs and rain forests.
Given humanity's commerce-driven dominance of ecosystems. the environmental
and long term costs of economic activities need to be reflected in market
prices. We must change our present practices, lest we leave only our
wastes for future generations.
The very first diving expedition of Calypso was to the Red Sea, beginning
the modern study of coral reefs using the Aqualung. It was there that
Cousteau became astounded and entranced by the splendor and extravagant
beauty of the coral world. In time his concern grew for the careless
destruction that our unchecked technological development is spreading into
the oceans. His legacy to us is a greater understanding and appreciation
for the marvels of life.
Recommendations for The World Bank
Recognizing that coral reefs may be indicators of oceanic health and that
their decline may forebode the decline of the oceans, The World Bank should
assume a leadership role in the global conservation of coral reefs for a
sustainable future by undertaking the following:
1. Establish an international interdisciplinary working group composed of
scientific, technical, and policy experts to ascertain the state of
knowledge of coral reef ecosystems and to make recommendations concerning
the sustainable future of coral reef ecosystems.
2. Establish collaborations with international space agencies to develop a
global capability to map and monitor the distribution of coral reef
communities, to ascertain their health, and to identify potential hazards
to their future.
3. Support a climate of stimulation for existing activities and fund
scientific programs on the health and vitality of coral reef ecosystems,
and support efforts to implement sustainable fisheries practices at all
4. Recognize the dynamics of population growth in coastal areas and focus
attention on protecting the ecology of the land-sea margin and watersheds
of coastlines and rivers. Address land-based sources of marine pollution,
including nutrient and chemical inputs, soil erosion, and forest and
5. Support the development of an industrial/technological ecology focused
both on remediation and an end to pollution of the seas, and develop new
environmental management techniques integrating ecology, economics,
technology and social sciences ("Ecotechnie") with the goal of
significantly reducing pollution in coastal areas, remediating ecological
harm, protecting human health, and enhancing human welfare.
6. Expand support for small-scale projects designed to eliminate
destructive fishing (i.e. cyanide and dynamite), implement reef surveys and
monitoring activities, and protect reefs from physical harm. Work at the
national and international level to address fisheries which exploit
children, and implement "certification" programs for aquarium fish to
assure they are caught in non-harmful manner. Explore the use of
microcredit loans for small-scale entrepreneurial activities to promote the
sustainable use of coral reef resources.
7. Insure that the knowledge and means for management are transferred to
tropical developing nations where most of the world's reefs are located,
and assist in developing the capacity of local communities to manage and
use these resources in a sustainable manner.
8. Support the establishment of marine protected areas and PSSAs
(Particularly Sensitive Sea Areas) to assure the conservation of marine
9. Support the full implementation of the Jakarta Mandate on Marine and
Coastal Biodiversity, and the development of a Protocol on Marine
Biodiversity Conservation to the Convention on Biological Diversity.
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