Nitrogen uptake by phytoplankton in the Atlantic sector of the Southern Ocean during late austral summer

As part of the Bonus-Good Hope (BGH) campaign, 15N-labelled nitrate, ammonium and urea uptake measurements were made along the BGH transect from Cape Town to ~ 60° S in late austral summer, 2008. Our results are categorised according to distinct hydrographic regions defined by oceanic fronts and ope...

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Bibliographic Details
Published in:Biogeosciences
Main Authors: Joubert, W R, Thomalla, S J, Waldron, H N, Lucas, M I, Boye, M, Le Moigne, F A C, Planchon, F, Speich, S
Format: Article in Journal/Newspaper
Language:English
Published: Department of Oceanography 2011
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Online Access:http://hdl.handle.net/11427/34227
Description
Summary:As part of the Bonus-Good Hope (BGH) campaign, 15N-labelled nitrate, ammonium and urea uptake measurements were made along the BGH transect from Cape Town to ~ 60° S in late austral summer, 2008. Our results are categorised according to distinct hydrographic regions defined by oceanic fronts and open ocean zones. Nitrogen uptake (ρN) in the oligotrophic Subtropical Zone (STZ) was dominated by ρ urea, which contributed up to 70 % of ρN. High regenerated ρN in the STZ resulted in low f-ratios (f = 0.2). Size fractionated chlorophyll data showed that the greatest contribution (>50 %) of picophytoplankton (