Saturday, January 22, 2011

Coral's Fight or Flight: Coral Sea reserve proposed, but some corals can migrate to the poles

The Coral Sea, while known to some as a World War II battle zone or the name of a super aircraft carrier, it is in reality a body of water off the northeastern coast of Australia, southeast of Papua New Guinea, that has remained relatively unscathed from industrial fishing and other human impacts due to its remoteness and sometimes rough seas.

To preserve its good health, efforts are underway to make it a protected marine reserve. The Australian-based Cairns and Far North Environment Centre (CAFNEC) is pushing for having the Coral Sea designated as a marine park that would provide for marine tourism, recreation, and scientific research, while limiting or prohibiting commercial fishing to protect the billfish, sharks , and tuna that either pass through or call the Coral Sea home.

While the idea of a Coral Sea marine reserve has been endorsed by many scientists (as many as 250 from 35 countries have gone on record in support of the reserve), there has been opposition from local recreational fishermen who see it as a step-by-step strategy leading to expansion along the entire east coast of Australia. However, proponents recognize the needs of the locals and say that expansion is not on their agenda. But protecting one of the few unspoiled tropical areas in the ocean is.

Corals head toward the poles
Protecting areas like the Coral Sea would be a good short-term strategy measure. In the long term, we need to consider what might be happening to coral reefs as ocean temperatures continue to rise. Coral thrives within a relatively narrow temperature range and as the waters become warmer, which has been documented as ongoing for several decades, coral reefs experience "bleaching" events where the symbiotic algae that lives within the soft tissues of the coral, providing much of their color, vanishes. This weakens the coral and often proves fatal.

But a new study, about to be published in Geophysical Research Letters, claims that many coral species are migrating towards the poles, to more suitable water temperatures. And the rate that these corals appear to be traveling is quite remarkable: up to 14 km (8.7 mi) annually. With average speeds of 1 km for terrestrial plants and animals and 5km for bottom dwelling sea creatures, these corals would appear to be sprinting. The study combined data with that of others who have tracked coral migrations for years and the researchers noted that of nine coral species studied, four species (all of which considered "near threatened" or "vulnerable" by the IUCN) had moved, most likely with floating larval polyps being aided by currents headed towards the poles, as found along the east coasts of the United States, South America, Africa, and Australia.

Does this mean that corals will simply out run climate change? Not necessarily. The components of climate change and the impacts on coral reefs are complex, from temperature increases to acidification to epidemics which could lead to shifts in the types of corals that stay and flourish, or migrate, or die. One way or another, the tropical reef zones will be disrupted.

In discussing coral's ability to persevere and survive in changing conditions by migrating to more hospitable environments, Paul Sammarco of the Louisiana Universities Marine Consortium was quoted in NatureNews,
"For corals it is good news, but for ecosystems, maybe not."

Read about the Coral Sea in

Read about coral on the move in

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