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Spatial and temporal variation of net community production and its regulating factors in the Amundsen Sea, Antarctica
Author(s) -
Hahm Doshik,
Rhee Tae Siek,
Kim HaeCheol,
Park Jisoo,
Kim YoungNam,
Shin Hyoung Chul,
Lee SangHoon
Publication year - 2014
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2013jc009762
Subject(s) - phytoplankton , bloom , oceanography , environmental science , algal bloom , sea surface temperature , chlorophyll a , mixed layer , atmospheric sciences , geology , nutrient , biology , ecology , botany
We observed ΔO 2 /Ar in the surface waters of the Amundsen Sea, Antarctica, during the austral summers in 2011 and 2012 to investigate the variability of net community production (NCP). Corresponding to the typical peak phytoplankton bloom period, the ΔO 2 /Ar of the Amundsen Sea Polynya (ASP) reached 30% in early January 2011 and had a strong positive correlation with the sea surface temperature (SST) and chlorophyll‐a (Chl‐ a ). In contrast, ΔO 2 /Ar decreased to −10% in the sea ice zone (SIZ), which was likely associated with either net O 2 consumption in the unlit area or the entrainment of deep water containing low dissolved oxygen. Near the terminal stage of the phytoplankton bloom in late February 2012, we observed the same contrasting ΔO 2 /Ar features between the ASP and SIZ. However, the ΔO 2 /Ar in the ASP was not >10%, which corresponded with the overall reduction in Chl‐ a , solar radiation, and SST compared with the corresponding values in 2011. The average net community production in the ASP was 119 ± 79 mmol O 2 m −2 d −1 in January 2011, and 23 ± 14 mmol O 2 m −2 d −1 in February 2012. The strong correlations of NCP with SST and mixed layer depth (MLD) indicate that the ASP phytoplankton bloom is likely initiated by a combination of increased light availability and SST in early summer. Low SST and variable fluorescence to maximum florescence ratio (Fv/Fm) in February indicate that decreased solar radiation and Fe availability are likely responsible for the phytoplankton bloom demise.