Premium
Fe and Nutrients in Coastal Antarctic Streams: Implications for Primary Production in the Ross Sea
Author(s) -
Olund Sydney,
Lyons W. Berry,
Welch Susan A.,
Welch Kathy A.
Publication year - 2018
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2017jg004352
Subject(s) - biogeochemistry , biogeochemical cycle , streams , oceanography , phytoplankton , nutrient , environmental science , flux (metallurgy) , plankton , environmental chemistry , hydrology (agriculture) , geology , chemistry , ecology , biology , computer network , geotechnical engineering , organic chemistry , computer science
The Southern Ocean (SO) has been an area of biogeochemical interest due to the presence of macronutrients (N, P, and Si) but lack of the expected primary production response, which is thought to be primarily due to Fe limitation. Because primary production is associated with increased drawdown of atmospheric CO 2 , it is important to quantify the fluxes of Fe and other nutrients into the SO. Here we present data from subaerial streams that flow into the Ross Sea, a sector of the coastal SO. Water samples were collected in the McMurdo Dry Valleys, Antarctica, and analyzed for macronutrients and Fe to determine the potential impact of terrestrial water input on the biogeochemistry of coastal oceanic waters. The physiochemical forms of Fe were investigated through analysis of three operationally defined forms: acid‐dissolvable Fe (no filtration), filterable Fe (<0.4 μm), and dissolved Fe (<0.2 μm). The combined average flux from two McMurdo Dry Valley streams was approximately 240 moles of filterable Fe per year. The dissolved fraction of Fe made up 18%–27% of the filterable Fe. The stream data yield an average filterable stoichiometry of N 3 P 1 Si 100 Fe 0.8 , which is substantially different from the planktonic composition and suggests that these streams are a potential source of Fe and P, relative to N and Si, to coastal phytoplankton communities. While the Fe flux from these streams is orders of magnitude less than estimated eolian and iceberg sources, terrestrial streams are expected to become a more significant source of Fe to the Ross Sea in the future.