We investigated the mechanisms leading to rapid death of corals when exposed to runoff and resuspended sediments, postulating that the killing was microbially mediated. Microsensor measurements were conducted in mesocosm experiments and in naturally accumulated sediment on corals. In organic-rich, but not in organic-poor sediment, pH and oxygen started to decrease as soon as the sediment accumulated on the coral. Organic-rich sediments caused tissue degradation within 1 d, whereas organic-poor sediments had no effect after 6 d. In the harmful organic-rich sediment, hydrogen sulfide concentrations were low initially but increased progressively because of the degradation of coral mucus and dead tissue. Dark incubations of corals showed that separate exposures to darkness, anoxia, and low pH did not cause mortality within 4 d. However, the combination of anoxia and low pH led to colony death within 24 h. When hydrogen sulfide was added after 12 h of anoxia and low pH, colonies died after an additional 3 h. We suggest that sedimentation kills corals through microbial processes triggered by the organic matter in the sediments, namely respiration and presumably fermentation and desulfurylation of products from tissue degradation. First, increased microbial respiration results in reduced O₂ and pH, initiating tissue degradation. Subsequently, the hydrogen sulfide formed by bacterial decomposition of coral tissue and mucus diffuses to the neighboring tissues, accelerating the spread of colony mortality. Our data suggest that the organic enrichment of coastal sediments is a key process in the degradation of coral reefs exposed to terrestrial runoff.

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The aquarium trade and other wildlife consumers are at a crossroads forced by threats from global climate change and other anthropogenic stressors that have weakened coastal ecosystems. While the wildlife trade may put additional stress on coral reefs, it brings income into impoverished parts of the world and may stimulate interest in marine conservation. To better understand the influence of the trade, we must first be able to quantify coral reef fauna moving through it.  Herein, we discuss the lack of a data system for monitoring the wildlife aquarium trade and analyze problems that arise when trying to monitor the trade using a system not specifically designed for this purpose. To do this, we examined an entire year of import records of marine tropical fish entering the United States in detail, and discuss the relationship between trade volume, biodiversity and introduction of non-native marine fishes. Our analyses showed that biodiversity levels are higher than previous estimates. Additionally, more than half of government importation forms have numerical or other reporting discrepancies resulting in the overestimation of trade volumes by 27%. While some commonly imported species have been introduced into the coastal waters of the USA (as expected), we also found that some uncommon species in the trade have also been introduced. This is the first study of aquarium trade imports to compare commercial invoices to government forms and provides a means to, routinely and in real time, examine the biodiversity of the trade in coral reef wildlife species.

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The ocean covers 71 percent of the surface area of the globe and constitutes over 90 percent of the habitable space on the planet. It contains the largest animals ever to have lived on Earth and billions upon billions of the tiniest: there are more living things in the sea than there are stars in the universe.
From sandy shores to the darkest depths of the sea, the ocean and coasts support a rich tapestry of life: shorebirds that stalk across mudflats in search of shellfish prey; alligators that ease their way through mangrove swamps; kelp forests that sway beneath the waves; polar bears that stalk seals across the sea ice of the Arctic; penguins that seek to evade seals in the Southern Ocean of Antarctica; and tiny photosynthesizing plants called phytoplankton that provide 50 percent of all the oxygen on Earth. Even on the deep seabed, there is a unique ecosystem that few humans have ever seen—supported by vents through which super-heated water and gases erupt.The largest creature ever to have lived on Earth is in the ocean: the mighty blue whale, the largest known example of which measured over 33 metres from tip to tail and weighed more than 190 tonnes. At the other end of the scale, the smallest known fish in the sea is only 8 mm long and weighs less than 2 milligrams3. But even that is a giant compared to the bacteria and other similar-sized microorganisms that teem in the ocean; just one drop of seawater may contain as many as 350,000 of them, which means there are many, many more of them in the sea than there are stars in the entire universe4.
Ocean life is almost as varied as it is plentiful. Seahorses, the males of which carry their young in pouches, thread their way silently among reefs and seagrasses. Sea otters roll onto their backs at the water’s surface, opening shellfish by cracking them on rocks they rest on their stomachs. Humpback whales encircle schools of herring, herding them into place by blowing “nets” of bubbles before surging to the surface with their giant mouths agape. Sailfish, frequently cited as the fastest fish in the sea, race after their prey at speeds that may be as high as 110 kilometres an hour, swimming as fast as cheetahs can run. Octopuses change colour and pattern at will, blending into the background to avoid detection and then, when disturbed and frightened, turning a bright red and squirting a cloud of black ink as they propel themselves into the distance. Barnacles hitch rides on ships, whales and turtles. Wandering albatrosses extend their enormous wingspan and cruise above the sea surface for hours on end. Kelp fronds sway back and forth in rhythm with currents and tides. Sea stars devour shellfish in stomachs they extend outside their bodies. Sea anemones fire poison darts into any unsuspecting prey that swim or drift close enough to brush against their tentacles. Cleaner wrasses pick parasites from mouths and gills of grateful clients.

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Growth periodicity is a phenomenon occurring in fossil and modern corals. The most apparent feature is growth banding, and environmental changes are broadly accepted as controls on this phenomenon. If environment controls the growth, then all corallites within a colony should repeat the same growth pattern, as individuals are clones and must have shared the same environment. A study on several species of Alveolitidae (Anthozoa, Tabulata) from the Late Devonian (Early Frasnian) of the Holy Cross Mountains (Poland) shows that the growth pattern varies between neighbouring individuals within the same corallum. This contradicts observations of closely related Favositida as demonstrated on Pachyfavosites sp. from the Givetian of Avesnois, France, where neighbouring individuals repeat the same pattern. Therefore, environmental control on growth rhythm in Alveolitidae can be excluded; the causes of differences between individuals remain unknown.

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Extensive bleaching of the coral Porites lobata at Malpelo Island, Colombia, during a cold-water episode in 2009

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SocMonitor is an electronic bulletin about the Global Socio-economic Monitoring Initiative to update everyone on what is happening with socio-economic monitoring through the SocMon and SEM-Pasifika initiatives. This is the April 2012  issue of the SocMonitor. This issues include:

1. Preparations for 2012 SocMon Global Report
2. SocMon in Honduras: The Mosquito Coast
3. Philippine SocMon project in final year
4. Socio-economic monitoring field trials and baseline surveys in South Asia
5. Caribbean Challenge SocMon update
   
   
   
   

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