Record Display for the EPA National Library Catalog


Main Title Iron Limitation of Phytoplankton Photosynthesis in the Equatorial Pacific Ocean.
Author Kolber, Z. S. ; Barber, R. T. ; Coale, K. H. ; Fitzwater, S. E. ; Greene, R. M. ;
CORP Author Brookhaven National Lab., Upton, NY. Oceanographic and Atmospheric Sciences Div. ;Duke Univ., Beaufort, NC. Marine Lab. ;Moss Landing Marine Labs., CA. ;Monterey Bay Aquarium Research Inst., Pacific Grove, CA.;Environmental Research Lab., Narragansett, RI.
Publisher c1994
Year Published 1994
Report Number EPA/600/J-94/505 ; ERLN-X228
Stock Number PB95-148672
Additional Subjects Phytoplankton ; Photosynthesis ; Ocean surface ; Iron ; Equatorial zone ; Pacific Ocean ; Nutrients ; Nitrates ; Phosphates ; Plant ecology ; Biomass ; Fluorescence ; Marine plants ; Plant nutrition ; Plant physiology ; Reprints ;
Library Call Number Additional Info Location Last
NTIS  PB95-148672 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 7p
The surface waters of the equatorial Pacific have unusually high nitrate and phosphate concentrations, but relatively low phytoplankton biomass. This 'high nitrate, low chlorophyll' (HNLC) phenomenon has been ascribed to 'top-down' grazing pressure by herbivores, which prevent the phytoplankton from fully utilizing the available nutrients. In the late 1980s, however, Martin and co-workers proposed that iron, which is delivered to the remote open ocean in aeolean dust, is the key factor limiting the standing crop of phytoplankton in HNLC areas. Using a sensitive fluorescence method, we have followed changes in photochemical energy conversion efficiency of the natural phytoplankton community both before and after artificial enrichment with iron of a small area (7.5 x 7.5 km) of the equatorial Pacific Ocean. Our results show that iron limits phytoplankton photosynthesis in all size classes in this region by impairing intrinsic photochemical energy conversion, thereby supporting the hypothesis of physiological ('bottom up') limitation by this element.