Bloggence, Cunning, Exile

Fish Species Halved since 1955.

"The variety of species in the world's oceans has dropped by as much as 50 percent in the past 50 years, according to a paper published today in the journal Science.

A combination of overfishing, habitat destruction and climate change has narrowed the range of fish across the globe, wrote biologists Boris Worm and Ransom A. Myers of Dalhousie University in Nova Scotia and three other scientists." {article continues at the Washington Post at link above...}

The cause of this decimation of fish species in the world's oceans is said to be mainly over-fishing, with global warming thrown in as a secondary factor. Meanwhile, in related science news, the oceans' acidic level is rising:

Acid Buildup in Oceans Threatens Species Diversity
Industrial and auto pollution could turn Earth's oceans so acidic by the end of this century that the entire marine world will be threatened, a new report warns.

The study, issued today by the Royal Society in the U.K., documents the rise of carbon dioxide, or C02, which occurs naturally and is also emitted in the burning of fossil fuels like coal and gasoline.

"If CO2 from human activities continues to rise, the oceans will become so acidic by 2100 it could threaten marine life in ways we can't anticipate," said Ken Caldeira, co-author of the report.

"This report should sound the alarm bells around the world," said Chris Field, director of the Carnegie Department of Global Ecology. "It provides compelling evidence for the need for a thorough understanding of the implications of ocean acidification. It also strengthens the case for rapid progress on reducing CO2 emissions."

Caldeira is a staff scientist at the Carnegie Institution's Department of Global Ecology in Stanford, Calif. He did the research while at the federal government's Lawrence Livermore National Laboratory.

Marine plants soak up carbon dioxide and convert it to food during photosynthesis. The CO2 is also used to make skeletons and shells, which ultimately become sediment on the sea floor. In that way, the oceans act as a giant carbon sink.

Some scientists estimate that more than a third of all human-produced C02 has been absorbed by the oceans.....

{ see rest of this at http://www.livescience.com/environment/050630_oceans_acid.html

posted by E. Heroux @ 6:13 PM