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Investigation into the impact of storms on sustaining summer primary productivity in the Sub‐Antarctic Ocean
Author(s) -
Nicholson SarahAnne,
Lévy Marina,
Llort Joan,
Swart Sebastiaan,
Monteiro Pedro M. S.
Publication year - 2016
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 - 10.1002/2016gl069973
Subject(s) - biogeochemical cycle , phytoplankton , entrainment (biomusicology) , mixed layer , environmental science , storm , mixing (physics) , oceanography , productivity , atmospheric sciences , winter storm , climatology , geology , nutrient , ecology , physics , biology , macroeconomics , quantum mechanics , rhythm , acoustics , economics
In the Sub‐Antarctic Ocean elevated phytoplankton biomass persists through summer at a time when productivity is expected to be low due to iron limitation. Biological iron recycling has been shown to support summer biomass. In addition, we investigate an iron supply mechanism previously unaccounted for in iron budget studies. Using a 1‐D biogeochemical model, we show how storm‐driven mixing provides relief from phytoplankton iron limitation through the entrainment of iron beneath the productive layer. This effect is significant when a mixing transition layer of strong diffusivities ( k z > 10 −4 m 2 s −1 ) is present beneath the surface‐mixing layer. Such subsurface mixing has been shown to arise from interactions between turbulent ocean dynamics and storm‐driven inertial motions. The addition of intraseasonal mixing yielded increases of up to 60% in summer primary production. These results stress the need to acquire observations of subsurface mixing and to develop the appropriate parameterizations of such phenomena for ocean‐biogeochemical models.