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ESS Ph.D. Dissertation Defense - Virginia Selz: Controls On Polar Ice Algal Communities And Their Linkage To The Phytoplankton Community During The Spring Season
This talk comprises the public portion of the PhD dissertation defense from approximately 1:00-2:00 PM.
Department: Earth System Science
Graduate Student: Virginia Selz
Advisor: Dr. Kevin Arrigo
Title: Controls On Polar Ice Algal Communities And Their Linkage To The Phytoplankton Community During The Spring Season
Abstract: Sea ice algae, primary producers inhabiting sea ice, are a vital food source for upper trophic levels in spring prior to the development of summer phytoplankton blooms. As ice algae melt out of the sea ice they are eaten by zooplankton, exported to the benthos, or hypothesized to remain in the water column and seed phytoplankton blooms. Over the last few decades, ice conditions have dramatically changed in the Arctic and Antarctic. This dissertation work seeks to understand how these drastic environmental changes impact early spring primary producers. Even though ice algal measurements have increased in recent years, they are still relatively scarce given the hostile nature of polar regions. Using a combination of modeling and fieldwork, I expand ice algal measurements in the Chukchi Sea pack ice and provide the first quantitative estimates of coupling between ice algae and phytoplankton (Chapter 1) and changes in ice algal production over the 1980 to 2015 record (Chapter 2). Examining similar questions in Antarctica, I provide the first measurements of spring ice algae along the West Antarctic Peninsula (Chapter 3), while advancing our understanding of the linkages between ice algal and phytoplankton communities. Comparison of the ice algal communities and the linkages between ice algae and phytoplankton communities of the Arctic and Southern Oceans shows lower trophic level responses to environmental change in polar marine ecosystems are diverse and dependent on the system in question. Understanding how physical and biological drivers impact lower trophic levels is important to advance our knowledge on how continued climatic change will impact regional foodweb processes as well as broader global biogeochemical cycles.