Climate forcing for dynamics of dissolved inorganic nutrients at Palmer Station, Antarctica : an interdecadal (1993–2013) analysis
Doney, Scott C.
Iannuzzi, Richard A.
Meredith, Michael P.
Martinson, Douglas G.
Ducklow, Hugh W.
MetadataShow full item record
KeywordNutrient drawdown; Phytoplankton bloom; Climate variability; Western Antarctic Peninsula; Palmer LTER; Biogeochemistry
We analyzed 20 years (1993–2013) of observations of dissolved inorganic macronutrients (nitrate, N; phosphate, P; and silicate, Si) and chlorophyll a (Chl) at Palmer Station, Antarctica (64.8°S, 64.1°W) to elucidate how large-scale climate and local physical forcing affect the interannual variability in the seasonal phytoplankton bloom and associated drawdown of nutrients. The leading modes of nutrients (N, P, and Si empirical orthogonal functions 1, EOF1) represent overall negative anomalies throughout growing seasons, showing a mixed signal of variability in the initial levels and drawdown thereafter (low-frequency dynamics). The second most common seasonal patterns of nitrate and phosphate (N and P EOF2) capture prolonged drawdown events during December–March, which are correlated to Chl EOF1. Si EOF2 captures a drawdown event during November–December, which is correlated to Chl EOF2. These different drawdown patterns are shaped by different sets of physical and climate forcing mechanisms. N and P drawdown events during December–March are influenced by the winter and spring Southern Annular Mode (SAM) phase, where nutrient utilization is enhanced in a stabilized upper water column as a consequence of SAM-driven winter sea ice and spring wind dynamics. Si drawdown during November–December is influenced by early sea ice retreat, where ice breakup may induce abrupt water column stratification and a subsequent diatom bloom or release of diatom cells from within the sea ice. Our findings underscore that seasonal nutrient dynamics in the coastal WAP are coupled to large-scale climate forcing and related physics, understanding of which may enable improved projections of biogeochemical responses to climate change.
Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Biogeosciences 121 (2016): 2369–2389, doi:10.1002/2015JG003311.
Showing items related by title, author, creator and subject.
Constraining circulation changes through the last deglaciation with deep-sea coral radiocarbon and sedimentary 231Pa/230Th Burke, Andrea (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2012-02)Radioactive isotopes can be used in paleoceanography both for dating samples and as tracers of ocean processes. Here I use radiocarbon and uranium series isotopes to investigate the ocean’s role in climate change over ...
Moffat Varas, Carlos F. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-09)Observations of current velocity, temperature, salinity and pressure from a 2-year moored array deployment and four hydrographic cruises conducted by the United States Southern Ocean GLOBEC program on the western Antarctic ...
Sediment and nutrient delivery from thermokarst features in the foothills of the North Slope, Alaska : potential impacts on headwater stream ecosystems Bowden, W. B.; Gooseff, Michael N.; Balser, A.; Green, A.; Peterson, Bruce J.; Bradford, J. (American Geophysical Union, 2008-06-03)Permafrost is a defining characteristic of the Arctic environment. However, climate warming is thawing permafrost in many areas leading to failures in soil structure called thermokarst. An extensive survey of a 600 km2 ...