Global warming may change ocean biology

Jorge Sarmiento: We don’t know yet what will happen, but one of the speculations is that global warming is going to tend to push the ocean towards new directions.

That’s Jorge Sarmiento, professor of geosciences at Princeton, talking about a major shift in ocean life. He spoke of a 10-year satellite record of ocean color used to study microscopic sea plants called phytoplankton.

Jorge Sarmiento: And we’ve been examining this record trying to look for patterns in it that could help us to understand how the biology in the ocean – as the world warms – might respond to this global warming, to the changes that will occur.

Phytoplankton live on the ocean surface, where fewer nutrients are available as water warms according to research by Sarmiento conducted in the tropics. He said that climate models indicate slightly less phytoplankton in the ocean overall by the year 2100. But because the tiny plants form the base of the ocean food chain, even a small change can have a big impact on ocean life.

Jorge Sarmiento: I suspect that the kinds of ecosystem changes or ocean biology changes that are going to have the biggest impact on human beings are going to be more like things that happen on the west coast, for example, the huge change in salmon fisheries that occurs, shifting between the Northwest United States and up farther north in Canada and Alaska where one fishery can go up while the other goes down.

Satellite data on ocean color data were used to estimate chlorophyll-a, a pigment contained in phytoplankton. The depth of the mixed layer was determined from an ocean-atmosphere model. Sarmiento and colleagues intend to keep studying how year-to-year changes in climate affect ocean biology.

Our thanks today to NOAA, the National Oceanic and Atmospheric Administration.

Our thanks to:
Jorge Sarmiento
Professor of Geosciences
Director, Atmospheric and Oceanic Sciences Program
Princeton University