Document Detail

Controls on tropical Pacific Ocean productivity revealed through nutrient stress diagnostics.
MedLine Citation:
PMID:  16943835     Owner:  NLM     Status:  MEDLINE    
In situ enrichment experiments have shown that the growth of bloom-forming diatoms in the major high-nitrate low-chlorophyll (HNLC) regions of the world's oceans is limited by the availability of iron. Yet even the largest of these manipulative experiments represents only a small fraction of an ocean basin, and the responses observed are strongly influenced by the proliferation of rare species rather than the growth of naturally dominant populations. Here we link unique fluorescence attributes of phytoplankton to specific physiological responses to nutrient stress, and use these relationships to evaluate the factors that constrain phytoplankton growth in the tropical Pacific Ocean on an unprecedented spatial scale. On the basis of fluorescence measurements taken over 12 years, we delineate three major ecophysiological regimes in this region. We find that iron has a key function in regulating phytoplankton growth in both HNLC and oligotrophic waters near the Equator and further south, whereas nitrogen and zooplankton grazing are the primary factors that regulate biomass production in the north. Application of our findings to the interpretation of satellite chlorophyll fields shows that productivity in the tropical Pacific basin may be 1.2-2.5 Pg C yr(-1) lower than previous estimates have suggested, a difference that is comparable to the global change in ocean production that accompanied the largest El Niño to La Niña transition on record.
Michael J Behrenfeld; Kirby Worthington; Robert M Sherrell; Francisco P Chavez; Peter Strutton; Michael McPhaden; Donald M Shea
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Nature     Volume:  442     ISSN:  1476-4687     ISO Abbreviation:  Nature     Publication Date:  2006 Aug 
Date Detail:
Created Date:  2006-08-31     Completed Date:  2006-10-02     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0410462     Medline TA:  Nature     Country:  England    
Other Details:
Languages:  eng     Pagination:  1025-8     Citation Subset:  IM    
Department of Botany and Plant Pathology, Cordley Hall 2082, Oregon State University, Corvallis, Oregon 97331-2902, USA.
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MeSH Terms
Carbon Dioxide / metabolism
Chlorophyll / metabolism
Iron / metabolism
Nitrogen / metabolism
Oxygen / metabolism
Pacific Ocean
Phytoplankton / metabolism*
Seawater / chemistry*
Tropical Climate*
Zooplankton / metabolism
Reg. No./Substance:
124-38-9/Carbon Dioxide; 1406-65-1/Chlorophyll; 7439-89-6/Iron; 7727-37-9/Nitrogen; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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