Effect of continental shelf canyons on phytoplankton biomass and community composition along the western Antarctic Peninsula
Kavanaugh, Maria T.
Abdala, F. N.
Ducklow, Hugh W.
Glover, David M.
Fraser, William R.
Martinson, Douglas G.
Stammerjohn, Sharon E.
Schofield, Oscar M. E.
Doney, Scott C.
MetadataShow full item record
KeywordWestern Antarctic Peninsula; Canyons; Phytoplankton; Diatoms; Remote sensing; Adélie penguin habitat; Sea ice
The western Antarctic Peninsula is experiencing dramatic climate change as warm, wet conditions expand poleward and interact with local physics and topography, causing differential regional effects on the marine ecosystem. At local scales, deep troughs (or canyons) bisect the continental shelf and act as conduits for warm Upper Circumpolar Deep Water, with reduced seasonal sea ice coverage, and provide a reservoir of macro- and micronutrients. Shoreward of many canyon heads are Adélie penguin breeding colonies; it is hypothesized that these locations reflect improved or more predictable access to higher biological productivity overlying the canyons. To synoptically assess the potential impacts of regional bathymetry on the marine ecosystem, 4 major canyons were identified along a latitudinal gradient west of the Antarctic Peninsula using a high-resolution bathymetric database. Biological-physical dynamics above and adjacent to canyons were compared using in situ pigments and satellite-derived sea surface temperature, sea ice and ocean color variables, including chlorophyll a (chl a) and fucoxanthin derived semi-empirically from remote sensing reflectance. Canyons exhibited higher sea surface temperature and reduced sea ice coverage relative to adjacent shelf areas. In situ and satellite-derived pigment patterns indicated increased total phytoplankton and diatom biomass over the canyons (by up to 22 and 35%, respectively), as well as increases in diatom relative abundance (fucoxanthin:chl a). While regional heterogeneity is apparent, canyons appear to support a phytoplankton community that is conducive to both grazing by krill and enhanced vertical export, although it cannot compensate for decreased biomass and diatom relative abundance during low sea ice conditions.
© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Ecology Progress Series 524 (2015): 11-26, doi:10.3354/meps11189.
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
Penguin biogeography along the West Antarctic Peninsula : testing the canyon hypothesis with Palmer LTER observations Schofield, Oscar M. E.; Ducklow, Hugh W.; Bernard, Kim S.; Doney, Scott C.; Patterson-Fraser, Donna; Gorman, Kristen; Martinson, Douglas G.; Meredith, Michael P.; Saba, Grace; Stammerjohn, Sharon E.; Steinberg, Deborah K.; Fraser, William R. (The Oceanography Society, 2013-09)The West Antarctic Peninsula (WAP) is home to large breeding colonies of the ice-dependent Antarctic Adélie penguin (Pygoscelis adeliae). Although the entire inner continental shelf is highly productive, with abundant ...
Microbial diversity and community structure across environmental gradients in Bransfield Strait, Western Antarctic Peninsula Signori, Camila N.; Thomas, Francois; Enrich-Prast, Alex; Pollery, Ricardo C. G.; Sievert, Stefan M. (Frontiers Media, 2014-12-16)The Southern Ocean is currently subject to intense investigations, mainly related to its importance for global biogeochemical cycles and its alarming rate of warming in response to climate change. Microbes play an essential ...
Evidence of resource partitioning between humpback and minke whales around the western Antarctic Peninsula Friedlaender, Ari S.; Lawson, Gareth L.; Halpin, Patrick N. (2008-09-20)For closely related sympatric species to coexist, they must differ to some degree in their ecological requirements or niches (e.g., diets) to avoid inter-specific competition. Baleen whales in the Antarctic feed primarily ...