Rising ocean acidity may deplete vital phytoplankton

Iron-poor oceans may cause populations of phytoplankton — a critical base of the marine food chain — to decline.

Rising acid levels in the world’s oceans appear to be robbing the tiny animals that form the bedrock of the marine food web of a vital nutrient. This shift in the ocean’s chemistry could reduce populations of phytoplankton, which could touch off a cascade of changes to ocean life.

Roughly one-third of the oceans contain phytoplankton that are limited in their growth by the amount of iron available to them. A study published today in Science, suggested that zone could grow.

“The concept of changes to ocean productivity and ecosystems due to acidification is a very important one to consider,” said Ken Buesseler of Woods Hole Oceanographic Institution in Woods Hole, Mass., who was not a part of the study. “If half of the photosynthesis on the planet is in the ocean and if you reduce that because of acidification, that is a big deal.”

Ocean acidification is a trickle-down effect of climate change. Higher levels of carbon dioxide in the atmosphere drive more CO2 to dissolve into the ocean, making it more acidic.

…

Jessica Marshall, DiscoveryNews, 14 January 2010. Full article.