American Samoan Reefs Lookin’ Pretty Good… For Now

coral reefBy Mark Kneubuhl -

(July 5, 2012)  Scientists don’t generally look at the bright side. For one thing, it’s not scientific. And even when prodding a scientist to offer the best case scenario, they’re usually leery to venture out on that unstable limb.

But according to American Samoa’s Coral Reef Monitoring Ecologist, Douglas Fenner, the situation for these colonies of micro-marine organisms in this small group of tropical Islands is, “enviable”.

Coral reefs are key indicators of the health of the oceans, which, like the canary in the mine, react sooner and with more detectable results to environmental stresses. Their health is measured by the “cover rate” which is the percentage of live coral found in a given area.

“We have about a 30% cover rate, which in comparison to most other oceans is quite good,” said the marine ecologist.

American Samoa is an unincorporated territory of the United States located in the South Pacific Ocean. It includes the main island of Tutuila, with the Manu’a Islands, Rose Atoll, and Swains Island also included in the territory. This island group is the only US terra firma, located south of the equator.

Fenner’s analysis of coral cover for Tutuila is based on 12 small sites that were picked by him, non-randomly and do not include sandy shelves or other geological features that coral cannot attach to.  Several others have determined the same average cover rate from different sets of sites (all picked non-randomly), including  NOAA scientists from their Pacific Reef and Monitoring Program (Ramp), which has been surveying the territory’s reefs at semi-regular intervals since 2002.

The culmination of the NOAA visits and their Ramp program produced a recent report, Coral Reef Ecosystems of American Samoa. This report claims a 20 percent cover rate for American Samoa.

This figure from the NOAA report is based on CRED’s towboard surveys -a sort of James Bond-ish, underwater “drive-by” that continuously photographs everything along the way.

Underwater Towboarder, coral reefsUsing the towboard method, the tiny remote US islands between American Samoa and Hawaii, such as Johnson and Palmyra Atolls, average about 25 percent; the uninhabited islands of the Northwest Hawaiian Islands average about 12 percent and the northern part of the Marianas, which also are uninhabited, about 8 percent.

Fenner, who has been keeping a watchful eye on the Amercan Samoa coral reefs since 2005, went on to tell Newsbyrd that in comparison and using the non-random method, the coral reef systems in most of the Caribbean have 8 percent cover while Florida only has about a 5 percent cover rate, at best.

In comparison to one of the healthiest and certainly the largest reef system, Australia’s Great Barrier Reef, the average live coral cover across the GBR declined from 28 to 22%, from 1986 to 2004.

While coral reefs in many parts of the world are in decline as a direct consequence of human pressures, Australia’s Great Barrier Reef is unusual in that direct human pressures are low and the entire system of 2,900 reefs has been managed as a marine park since the 1980s.

Why are reefs important?

Often called “rainforests of the sea”, coral reefs occupy less than 0.1% of the world’s ocean surface, yet they provide a home for 25% of all marine species, including fish, mollusks, worms, crustaceans, sponges, and many other organisms.  In its terrestrial counterpart, the trees are the most visible part of the rainforest, which are home to millions of species of animal life.  And just as massive extinction of many animal species would occur by removal of the trees in our rainforest, so would a similar extinction occur with the destruction of our planet’s corals reefs.

In addition, fish catches from coral reefs feed millions throughout developing countries, and they protect shorelines from erosion.  Their total economic value has been estimated at hundreds of billions of dollars per year.

The most common enemies of the coral reef have been around forever, while more recently scientists have concluded that our coral reefs are more resilient than once believed.

“Such events like hurricanes, El Nino induced Coral Bleaching, overfishing and destructive biological infestations like the Crown of Thorns starfish, come and go in a cyclic fashion,” according to Fenner.

Where human impact is concerned and aside from overfishing, land based sources of pollution like sediment from development, nutrients from faulty septic systems, fertilizers, detergents and other chemicals discharged into streams are also a large threat.

“These kinds of modern stresses and pollutants will make the corals more susceptible to climate change effects in the future,” said Dr. Philip Wiles, Pacific Islands Global Ocean Observing System Coordinator for SPREP(Samoa).

SPREP – The Secretariat of the Pacific Regional Environment Program, is roughly the equivalent of the U.S. Environmental Protection Agency in many countries such as American Samoa’s neighbor, the Independent Nation of Samoa.

What Does The Future Hold?

Researcher at  Stanford University have recently studied an outlying section of American Samoa reefs and are suggesting that some coral organisms may have evolved to resist higher ocean temperatures, at least for short periods of time in a 24-hour cycle.  But that “adaptation” is literally a matter of “degrees”, while scientists in general concede that corals are highly temperature sensitive and even a small rise in ocean temperature over the next couple of decades could be catastrophic.

For the moment, scientists who study the reefs in American Samoa are happy to engage in long conversations about re-generation, effective Marine Protected Areas (MPAs) and good coverage percentages, but when asked about the future outlook, their demeanor changes.

In the future, global warming stands alone as the biggest environmental threat for the entire planet.  For Coral reefs it may be the grand-slam of destructive events.

With higher sea temperatures scientists expect more frequent and severe coral bleaching events.  Increased ocean acidification as a direct result of more and more carbon being released into our atmosphere and absorbed by our ocean is also a huge threat with apocalyptic consequence -not only to coral, but the earth’s marine eco-system as a whole.  And last, an expected increase in monsoon and typhoon activity having a physically destructive effect on many of the planet’s coral reefs.

And even more unsettling, not a scientist alive can tell you with any certainty, what will happen to our grand bio-spheres, the Earth, if our coral reefs disappear.

When asked about the future of coral reefs in American Samoa with the looming threat of higher ocean temperatures, Fenner simply replied, “Bleak.”  Then after a moment of reflection he added, “But I really do think there is room for hope, as well as fear.  If the world controls greenhouse gas emissions the reefs’ fate will be much better than if we don’t… our fate really lies in our own hands.”

Towboard photo (NOAA) by Jake Asher and Molly Timmers

Feature Photo: American Samoa National Parks

Video: American Samoa’s Fagatele Bay National Marine Sanctuary

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Posted by at July 5, 2012
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