OS13A-2017
Taxonomy variability of phytoplankton and relationship with production of CDOM in the polynya of the Amundsen Sea, Antarctica
Abstract:
Taxonomic variability of phytoplankton and relationship with production of CDOM in the polynya of the Amundsen Sea, Antarctica
Yoon Chang Lee1, Mi Ok Park1, Jinyoung Jung2, Eun Jin Yang2, Sang Hoon Lee2
3
1Pukyong National University, Korea
2Korea Polar Research Institute, Incheon, Korea
ABSTRACT
We have examined the taxonomic variability of phytoplankton, nutrients and Chromophoric dissolved organic matter (CDOM) from two cruises ANA02C (Feb. 2012) and ANA04B (Jan. 2014) to find the relationship between the composition of phytoplankton and production of CDOM of the Amundsen Sea. The highest concentration of Chl a was found Amundsen Polynya (AP), during austral summer in 2014 and 2012. Average concentration of Chl a was 3.92μg/l in 2014, 1.56μg/l in 2012 at AP. The major phytoplankton groups were diatoms and prymnesiophytes and minor groups are cryptophytes, chlorophytes, dinophytes, and crysophytes. Variability in composition of phytoplankton at SIZ, AP and IS in the Amundsen Sea was distinct. The predominance of Phaeocystis antarctica (70-90%) at all station was found in austral summer in both 2012 and 2014, except at SIZ in 2012. The CDOM values are in the range of 0.07~0.98m-1 and were relatively high at the surface of the AP. The CDOM values at AP in mixed layer depth with 0.33m-1 in average was very higher than any other region of the Southern Ocean. The CDOM showed positive correlation with Chl a and no clear relation with salinity, which implies biological process is the main source of CDOM in the study area. The high CDOM related with P. antarctica in the AP suggest the potential heat absorbing factor and source of CO2 by photobleaching of the Amundsen Sea. The CDOM can be negative effect on the function of the biological pump by phytoplankton in the Southern Ocean. Variation of S value are great from 9μm-1 to 27μm-1, which indicates mixture or young and old CDOM at the surface layer, but higher in S value in AP below 100m depth reflects the high primary productivity in upper layer and the low S value shown the old refractory DOM at SIZ and IS.
Keywords : Chl a, CDOM, slope diatoms, Phaeocystis, polynya, Amundsen Sea