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On the vertical phytoplankton response to an ice‐free Arctic Ocean
Author(s) -
Lawrence J.,
Popova E.,
Yool A.,
Srokosz M.
Publication year - 2015
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2015jc011180
Subject(s) - phytoplankton , arctic , oceanography , sea ice , environmental science , ocean gyre , new production , photic zone , arctic ice pack , arctic geoengineering , nitrate , atmospheric sciences , geology , nutrient , drift ice , ecology , biology , subtropics
Rapidly retreating sea ice is expected to influence future phytoplankton production in the Arctic Ocean by perturbing nutrient and light fields, but poor understanding of present phytoplankton distributions and governing mechanisms make projected changes highly uncertain. Here we use a simulation that reproduces observed seasonal phytoplankton chlorophyll distributions and annual nitrate to hypothesize that surface nitrate limitation in the Arctic Ocean deepens vertical production distributions where light‐dependent growth rates are lower. We extend this to interpret depth‐integrated production changes projected by the simulation for an ice‐free Arctic Ocean. Future spatial changes correspond to patterns of reduced surface nitrate and increased light. Surface nitrate inventory reductions in the Beaufort Gyre and Atlantic inflow waters drive colocated production distributions deeper to where light is lower, offsetting increases in light over the water column due to reduced ice cover and thickness. Modest production increases arise, 10% in a seasonally ice‐free Arctic Ocean and increasing to 30% by the end of the century, occurring at depth.