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Biogeochemical signatures of nitrogen fixation in the eastern North Atlantic
Author(s) -
Mahaffey Claire,
Williams Richard G.,
Wolff George A.,
Mahowald Natalie,
Anderson William,
Woodward Malcolm
Publication year - 2003
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl016542
Subject(s) - biogeochemical cycle , particulates , thermocline , nitrogen , environmental science , oceanography , phytoplankton , isotopes of nitrogen , nitrogen fixation , biogeochemistry , atmospheric sciences , geology , environmental chemistry , nutrient , ecology , chemistry , biology , organic chemistry
Stable nitrogen isotopic determination of particulate organic matter over the eastern North Atlantic in spring 2000 reveal a region of low natural abundance of 15 N relative to 14 N between 26°N and 32°N along 20°W. This light isotopic signal, together with phytopigment data and persistently elevated nitrate to phosphate ratios in the upper thermocline, suggest that nitrogen fixation provides a local dominant supply of nitrogen to phytoplankton over part of the eastern North Atlantic. These independent biogeochemical proxies are coincident with a region of enhanced atmospheric dust deposition, as suggested by an atmospheric transport model. Hence, the atmospheric dust events may spatially and temporally constrain the distribution of N 2 fixers.