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Distributions of chlorophyll and primary productivity in relation to water column structure in the eastern North Atlantic Ocean
Author(s) -
Frazel Denis W.,
Berberian G.
Publication year - 1990
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/gb004i003p00241
Subject(s) - oceanography , ocean gyre , water column , transect , productivity , latitude , pycnocline , chlorophyll a , subtropics , water mass , environmental science , geology , atmospheric sciences , ecology , biology , botany , macroeconomics , geodesy , economics
Latitudinal variations in the megascale (10 3 km) distribution of biological properties are described in relation to water column structure between 60° and 7°N in the eastern North Atlantic Ocean. Stations were occupied along a meridional transect of stations at 20°W in August‐September, 1988, during the third leg of the National Oceanic and Atmospheric Administration Global Change Expedition. An additional transect to the south (38°N to 7°N) was occupied to extend the total range of latitudinal observations. Chlorophyll a concentrations were highest in the northern latitudes (<2.51 mg m −3 ) , decreasing to >0.2 mg m −3 in the vicintiy of the subtropical gyre, south of 40°N. The nitracline was associated with a shoaling of the pycnocline in the northern latitudes. At 7°N, high chlorophyll concentrations (approximately 0.5 mg m −3 ), and enhanced primary productivity (375.5 mg C m −2 d −1 ) were associated with a lens of fresh Amazon River Water. Primary productivity rates were variable throughout the transect, ranging from 646.10 mg C m −2 d −1 to 138.26 mg C m −2 d −1 . Productivity maxima were located south of Iceland, at 46°N (646.10 mg C m −2 d −1 ) and in the vicinity of the Azores Front at 35°N (259.85 mg C m −2 d −1 ). Latitudinal distributions of primary productivity corresponded closely to a model of productivity along a transect at 40°N by Yentsch (1990).