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Chlorophyll a concentrations in the North Pacific: Does a latitudinal gradient exist?
Author(s) -
Dickson Mary-Lynn,
Wheeler Patricia A.
Publication year - 1993
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1993.38.8.1813
Subject(s) - picoplankton , transect , chlorophyll a , phytoplankton , chlorophyll , subtropics , chemistry , oceanography , environmental chemistry , biology , geology , nutrient , botany , ecology
Chlorophyll a concentrations were measured as a function of depth from 28 to 48°N along 152°W in March 1991 with Whatman GF/F and 0.2‐ µ m Nuclepore filters. Surface Chl a concentrations measured with 0.2‐ µ m Nuclepore filters were up to fourfold higher than those measured with Whatman GF/F filters. The largest difference between the two filter types was found in subtropical waters, where picoplankton were a major constituent of the phytoplankton assemblage. Chl a concentrations integrated from 0 to 175 m showed a threefold increase (9–26 mg Chl a m −22 ) between 28 and 48°N when Whatman GF/F filters were used. However, integrated Chl a concentrations based on measurements with 0.2‐ µ m Nuclepore filters were nearly constant (25–31 mg Chl a m −2 ) over the transect. These results lead us to question the existence of previously reported latitudinal gradients in integrated Chl a concentrations in the North Pacific Ocean.