ic northern boundary for corals. Now, he says, that threshold has been surpassed at most if not all Florida reefs. In the more southern areas, the phosphorus-stripping influence of sediments has kept the phosphorus level from going so high that it supports the fleshy seaweeds, which require the most phosphorus. But levels there are still high enough to support the equally damaging spread of filamentous cyanobacteria (also known as blue-green algae), another form of harmful algal bloom. In time, if pollution inputs continue unabated, he says, his research suggests that the fleshy algae blooms will continue to move south. Sufficient nutrient levels, and associated seaweed growth, can effectively cause near or total loss of reef-building corals.

"We believe we've already seen regional extinctions of corals--in other words, a shrinking of the area where corals can now survive in Florida and elsewhere--as a result of nutrient inputs through various forms of pollution," says Lapointe. For instance, elkhorn corals have been almost completely eliminated from the Florida Keys.

Widespread precipitous coral declines are well documented at reefs around the world and indisputable. However, the debate about what factors are responsible for those declines continues to rage. Lapointe acknowledges that a variety of factors have likely played roles in this coral loss. However, he believes that nutrient pollution is one of the most serious if not the most serious current threat to corals in developed regions of the world.

"Certainly it appears that factors such as global warming leading to coral bleaching are having significant impacts, but I think it's a mistake to blame all the devastation we've witnessed in past decades on global factors. Local nutrient pollution problems can be addressed and if we do that, I think it's clear that corals will strongly benefit."

'"/>

Contact: Mark Schrope
schrope@hboi.edu
772-216-0390
Harbor Branch Oceanographic Institution
22-Feb-2006

Page: 1 2 3 4
Related biology news :

1. Changes in chromosomal constitution of preimplantation embryos suggest caution in genetic screening
2. Changes in west coast marine ecosystems significant
3. Changes in amino acids in the 1918 influenza virus cut transmission
4. Changes in dietary protein may override inherited skeletal abnormalities
5. Symposium Changes on Earth honors Yale Geologist Robert Berner
6. Changes to in utero environment may alter onset of cancer, U of T study
7. Changes to embryos can elicit change in adult fish
8. Changes in technique can reduce radiation dose in CT examination
9. Changes in community size affect the outcome of competition
10. Using satellite observations to study photosynthetic trends in northern circumpolar high latitudes
11. Warming most evident at high latitudes, but greatest impact will be in tropics