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Influence of river discharge in the tropical and subtropical North Atlantic Ocean
Author(s) -
da Cunha Leticia Cotrim,
Croot Peter,
LaRoche Julie
Publication year - 2009
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.2009.54.2.0644
Subject(s) - subtropics , oceanography , geography , geology , biology , ecology
The recent article by Tovar-Sanchez et al. (2006; hereafter referred to as TS2006), presents a new comprehensive dataset of trace metal concentrations in Trichodesmium sp. populations and aerosol samples from the western tropical (MP01, MP03, and MP08 samples) and eastern subtropical (COCA2 samples) Atlantic Ocean. In TS2006, the authors considered the atmospheric deposition of Saharan dust as probably the main source of trace metals for the surface tropical Atlantic, together with the riverine input of trace metals to the coastal ocean. TS2006 determined the trace metal composition in aerosol samples and Trichodesmium sp. colonies in both the eastern and the western tropical Atlantic, and used additional published data for riverine upstream concentrations of dissolved and particulate trace metals. The riverine and aerosol metal ratios were used to infer the sources of these metals in Trichodesmium sp. colonies in the tropical and subtropical Atlantic Ocean. TS2006 found that trace metal ratios measured in some samples of Trichodesmium sp. colonies (Mn : Al and Fe : Al) were more similar to the dissolved riverine trace metal ratios than to the aerosol metal composition, and concluded that the Amazon and Niger Rivers are seasonally the most important sources of trace metals for Trichodesmium sp. Although the new data presented in TS2006 are relevant for the characterization of metal composition in aerosol and phytoplankton, we present here seven fundamental points explaining why we fundamentally disagree with their conclusions.