Arctic Nitrogen

Does competition for nitrogen between autotrophs and heterotrophs control carbon fluxes in the western coastal Arctic?

Funded by NSF: ARC. September 2009 - September 2013.
Bronk, Co-PI. Bronk part $382,339. Patricia Yager (Lead PI, UGA), Marc Frischer (Co-PI, Skidaway)

Abstract

Reductions in sea ice and increases in terrestrial inputs to the coastal Arctic have profound implications for productivity, ecosystem structure, and carbon fluxes in this region. For the Arctic coastal region in particular, ecosystem shifts could be considerable if sea-ice changes lead to increased water-column production and reduced benthic production. Such a restructuring would ultimately alter the pathways and magnitude of energy transfer to upper trophic levels such as fish, sea birds and marine mammals, and impact the people dependant on those resources. Our challenge today is to transform such generalizations with mechanistic and detailed understanding of specific
ecosystems and their components to allow assessment of past, present, and future variation. One important component lacking detailed understanding is the role of microorganisms in Arctic marine ecosystems. The importance of microbes to the productivity and carbon fluxes of low latitude marine ecosystems has been established. In contrast to the extensive research in temperate marine systems, much less is known about marine microorganisms in the Arctic. We do know that bioavailable nitrogen is key to the productivity of the coastal Arctic, yet how it gets partitioned to microbial autotrophs and heterotrophs is entirely undetermined. Such unknowns prevent us from
predicting with any confidence the impact of climate change on food webs and basic biogeochemical processes in the coastal Arctic.