Ocean's least productive waters are expanding

ResearchBlogging.orgYou read the title of this post, and the original paper, correctly. Brian H. sent this little gem of a paper to me today. Using SeaWiFS data from the last nine years, Polovina et al. show that in the North and South Pacific and Atlantic areas of low surface chlorophyll are in expanding by 0.8-4.3% per year. These areas have replaced higher surface chlorophyll with low surface area. The total expansion of these areas equals 6.6 million km2 (roughly 2/3 the size of the U.S.). The figure below shows a time series and regression line for the area with surface chlorophyll less than or equal to 0.07 chl/m3 in (a) quarter 4 in the North Pacific, (b) quarter 1 in the North Atlantic, and (c) quarter 3 in the South Pacific where you can clearly see the increase. A map is below the fold. The really, really bad news

The expansion of the low chlorophyll waters is consistent with global warming scenarios based on increased vertical stratification in the mid-latitudes, but the rates of expansion we observe already greatly exceed recent model predictions.

Apparently it is getting harder to find food in the deep.

Polovina, J.J., Howell, E.A., Abecassis, M. (2008). Ocean’s least productive waters are expanding. Geophysical Research Letters, 35(3) DOI: 10.1029/2007GL031745


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Dr. M (1801 Posts)

Craig McClain is the Executive Director of the Lousiana University Marine Consortium. He has conducted deep-sea research for 20 years and published over 50 papers in the area. He has participated in and led dozens of oceanographic expeditions taken him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses on how energy drives the biology of marine invertebrates from individuals to ecosystems, specifically, seeking to uncover how organisms are adapted to different levels of carbon availability, i.e. food, and how this determines the kinds and number of species in different parts of the oceans. Additionally, Craig is obsessed with the size of things. Sometimes this translated into actually scientific research. Craig’s research has been featured on National Public Radio, Discovery Channel, Fox News, National Geographic and ABC News. In addition to his scientific research, Craig also advocates the need for scientists to connect with the public and is the founder and chief editor of the acclaimed Deep-Sea News (http://deepseanews.com/), a popular ocean-themed blog that has won numerous awards. His writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.