American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article (file size: 319414 bytes)    Cited by

GEOPHYSICAL RESEARCH LETTERS, VOL. 32, L03606, doi:10.1029/2004GL021808, 2005

Recent trends in global ocean chlorophyll

Watson W. Gregg

Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA


Nancy W. Casey

Science Systems and Applications, Inc., Lanham, Maryland, USA


Charles R. McClain

Laboratory for Hydrospheric Processes, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA


Abstract

A 6-year time series of remotely-sensed global ocean chlorophyll was evaluated using linear regression analysis to assess recent trends. Global ocean chlorophyll has increased 4.1% (P < 0.05). Most of the increase has occurred in coastal regions, defined as bottom depth < 200 m, where an increase of 10.4% was observed. The main contributors to the increase were the Patagonian Shelf, Bering Sea, and the eastern Pacific, southwest African, and Somalian coasts. Although the global open ocean exhibited no significant change, 4 of the 5 mid-ocean gyres (Atlantic and Pacific) showed declines in chlorophyll over the 6 years. In all but the North Atlantic gyre, these were associated with significant increases in sea surface temperature in at least one season. These results suggest that changes are occurring in the biology of the global oceans.

Received 21 October 2004; accepted 12 January 2005; published 8 February 2005.

Index Terms: 4215 Oceanography: General: Climate and interannual variability (1616, 1635, 3305, 3309, 4513); 0480 Biogeosciences: Remote sensing; 1635 Global Change: Oceans (1616, 3305, 4215, 4513); 1616 Global Change: Climate variability (1635, 3305, 3309, 4215, 4513); 4855 Oceanography: Biological and Chemical: Phytoplankton.

Read Full Article (file size: 319414 bytes)    Cited by

Citation: Gregg, W. W., N. W. Casey, and C. R. McClain (2005), Recent trends in global ocean chlorophyll, Geophys. Res. Lett., 32, L03606, doi:10.1029/2004GL021808.