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Research Objectives:
This project will examine how climate change alters nutrient pools and cycling among plants, litter and soils in vascular-plant dominated communities, with the overall goal of predicting long-term climate change impacts on ecosystem productivity. The researchers' main approach is to manipulate temperature, water availability, and UV-B radiation exposure of tundra microcosms. These microcosms, or small patches or cores of plants and their associated soil, are in plots in an area adjacent to Palmer Station. The manipulations involve raising temperatures of some microcosms with overhead infrared lighting, adding water to some microcosms to simulate greater precipitation, and placing UV-B filters over some microcosms to remove UVB enhancements associated with stratospheric ozone depletion.
Investigators will assess how these manipulations influence plant growth and primary productivity, carbon and nitrogen fluxes and pools, litter decomposition, and soil microbial/arthropod communities. They will also examine the influence of snowpack and snowmelt date on plant survival, since winter snowpack may be increasing along the Peninsula. Early in the season, plants will be transplanted under snowbanks along a gradient in snowpack depth and snowmelt date. Plant survival, carbon storage status, and photosynthesis will be monitored as plants melt out from the snowbank over the growing season.
Project team members will also study the effects of penguin colonies on adjacent plant communities by measuring soil and plant nutrient concentrations and water availability, and atmospheric nutrient deposition along transects running from the edge of the colonies to adjacent plant communities. These transects should represent gradients of nutrient concentrations and water availability, and will be located on three or four islands or points near Palmer Station where plant communities are adjacent to penguin colonies. Soils and plants will be sampled for nutrient concentrations and moisture availability, and nutrient deposition collectors will allow investigators to quantify nutrient inputs. Lastly, project team members will continue surveying and censusing of young populations of vascular plant at several recently deglaciated sites near Palmer Station.
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