- Related Research Areas
- Carbon Cycle & Ecosystems
Among ocean ecosystems globally those in polar regions are expected to experience the most acute transformations due to climate change. Ongoing reductions of seasonal sea ice cover are well documented over most of the Arctic, representing a severe loss of habitat for Arctic species at many trophic levels. Primary producers at the base of the food web are especially impacted by this loss of sea ice, particularly the ice algal communities that currently generate a large fraction of the primary production in seasonally ice-covered waters. In the current ecosystem seasonal ice loss replaces ice-algal communities with pelagic phytoplankton assemblages, but long-term loss of sea ice will not necessarily result in permanent phytoplankton assemblages that are similar to those that now occur seasonally. Climate-driven changes in the Arctic, especially the lengthening of the boreal growing season and changes in ocean circulation, water mass properties, and nutrient distributions, may create new habitats for phytoplankton in the Chukchi and Beaufort Seas that are materially different than those that now occur each year following the seasonal retreat of sea ice. To provide the necessary baseline data against which such shifts in habitat and algal taxonomy will be measured, our research will directly measure the current taxonomic composition and habitats of ice-algal and phytoplankton assemblages in the Beaufort and Chukchi Seas to a) learn how they vary in time and space, b) examine how physical oceanographic conditions structure their distributions, and c) assess how taxonomic variability may affect ocean color products for chlorophyll, phytoplankton functional types (PFTs), and primary production in the Arctic Ocean. A proven approach will be used to determine algal taxonomic composition, the Imaging FlowCytobot. Two such instruments will be modified for automated, unattended use on ships-of-opportunity in the Beaufort and Chukchi in 2010 and 2011: a small coastal research vessel operating in the inner shelf between Prudhoe Bay and Point Barrow, and the NASA-sponsored icebreaker operating between Nome and the Beaufort Sea. These ships will survey different regions of the Beaufort and Chukchi at different times and thus provide a more comprehensive taxonomic assessment of algal distributions than what would otherwise be accomplished by the icebreaker alone. Use of this coastal vessel is leveraged from ongoing oceanographic research along the inner shelf. Radiometry will be also measured on these surveys to examine the ocean color signatures of these waters, to learn how assemblage composition affects water-leaving radiance and therefore remotely sensed ocean color products. A comprehensive remote sensing analysis of sea surface temperature, wind speed, sea ice properties, and surface roughness will also be conducted over the study region to learn how physical factors establish the algal biogeographies that are observed in these waters. This multisensor, multiplatform effort represents a new approach for examining Arctic ocean biology beyond chlorophyll or ocean color alone. The combined findings from these investigations will provide substantive new knowledge and insights into taxonomic and bio-optical variability on the western Beaufort and eastern Chukchi shelves, its forcing by physical mechanisms, and its potential disturbance by climate-related processes. This research address several NASA priorities for Arctic research in 2009 because it a) examines the distribution and community composition of microbial communities in the Arctic Ocean, b) assesses the relationship between sea ice conditions and radiation on Arctic phytoplankton assemblage structure, and c) investigates how the taxonomic composition of algal assemblages in the Arctic affect ocean color and its use in remote sensing products for chlorophyll, primary production, and PFTs.
Project PI: Samuel Laney/Woods Hole Oceanographic Institution
Biology Department MS #34, Redfield 138 Woods Hole, MA 02543
Phone: (508) 289-3647
Fax: (508) 457-2134
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