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Seasonal iron depletion in temperate shelf seas
Author(s) -
Birchill Antony J.,
Milne Angela,
Woodward E. Malcolm S.,
Harris Carolyn,
Annett Amber,
Rusiecka Dagmara,
Achterberg Eric P.,
Gledhill Martha,
Ussher Simon J.,
Worsfold Paul J.,
Geibert Walter,
Lohan Maeve C.
Publication year - 2017
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 - 10.1002/2017gl073881
Subject(s) - oceanography , particulates , spring bloom , thermocline , phytoplankton , bloom , environmental science , temperate climate , stratification (seeds) , polar front , mixed layer , seasonality , seawater , spring (device) , environmental chemistry , geology , chemistry , nutrient , ecology , biology , seed dormancy , germination , botany , organic chemistry , dormancy , engineering , mechanical engineering
Our study followed the seasonal cycling of soluble (SFe), colloidal (CFe), dissolved (DFe), total dissolvable (TDFe), labile particulate (LPFe), and total particulate (TPFe) iron in the Celtic Sea (NE Atlantic Ocean). Preferential uptake of SFe occurred during the spring bloom, preceding the removal of CFe. Uptake and export of Fe during the spring bloom, coupled with a reduction in vertical exchange, led to Fe deplete surface waters (<0.2 nM DFe; 0.11 nM LPFe, 0.45 nM TDFe, and 1.84 nM TPFe) during summer stratification. Below the seasonal thermocline, DFe concentrations increased from spring to autumn, mirroring NO 3 − and consistent with supply from remineralized sinking organic material, and cycled independently of particulate Fe over seasonal timescales. These results demonstrate that summer Fe availability is comparable to the seasonally Fe limited Ross Sea shelf and therefore is likely low enough to affect phytoplankton growth and species composition.