Vernet Lab

The Ecology of

Polar Phytoplankton

Dr. Maria Vernet
Integrative Oceanography Division
Room 2123, Sverdrup Hall
Phone: (858) 534-5322
Fax: (858) 822-0562

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§ Research Projects » LARISSA

Collaborative Research in IPY: Abrupt Environmental Change in the Larsen Ice Shelf System, A Multidisciplinary Approach - Marine Ecosystems (15 August 2007 - 15 March 2011) - Co-Principal Investigators: Cindy van Dover, Duke University; Michael McCormick, Hamilton College; Craig Smith, University of Hawaii.
Funded by the National Science Foundataion, Grant # 0732983.

ABSTRACT: INTELLECTUAL MERIT: We propose an integrated, multi-disciplinary field program to address the rapid and fundamental changes occurring in the Antarctic Peninsula region as a consequence of the abrupt collapse of the Larsen B Ice Shelf in the fall of 2002. Given the broad scope of the project, three separate but interrelated proposals have been prepared: this proposal addresses Marine Ecosystems. A profound transformation in ecosystem structure and function is occurring in coastal waters of the western Weddell Sea. This transformation appears to be yielding a redistribution of energy flow between chemoautotrophic and photosynthetic production, and to be causing the rapid demise of the extraordinary seep ecosystem discovered beneath the ice shelf, providing an ideal opportunity to test fundamental paradigms in ecosystem evolution. We propose to test the following hypotheses to elucidate the transformations occurring in marine ecosystems as a consequence of the Larsen B collapse:

  1. Cold Seeps: The biogeographic isolation and sub-ice shelf setting of the Larsen B seep has led to novel habitat characteristics, chemoautotrophically dependent taxa and functional adaptations.
  2. Background (Non-Seep) Benthos: Benthic communities beneath the former Larsen B ice shelf are fundamentally different from assemblages at similar depths in the Weddell sea-ice zone, and resemble oligotrophic deep-sea communities. Larsen B assemblages are undergoing rapid change.
  3. Phytoplankton communities: The previously dark, oligotrophic waters of the Larsen B embayment now support a thriving phototrophic community, with production rates and phytoplankton composition similar to other productive areas of the Weddell Sea.

To test these hypotheses, and to document rapid changes occurring in the Larsen B ecosystem, we will use a remotely operated vehicle, shipboard samplers, and moored sediment traps to:

  • Sample and characterize microbial, macrofaunal and megafaunal components of the seep community,
  • Evaluate patterns of surface productivity, export flux, and mega- and macrofaunal composition in areas previously covered by the ice shelf and compare them to the open sea-ice zone,
  • Place ecosystem changes within the geological, glaciological and climatological context that led to ice-shelf retreat,
  • Predict the likely consequences on marine ecosystems of ice-shelf collapse in other regions of Antarctica vulnerable to climate change.

These activities will be conducted during a cruise in Jan-Feb 2010 to the Larsen B region, with sediment-trap recoveries occurring 12 and 24 months later. Our efforts will significantly advance understanding of linkages among the earth's systems in polar regions and are proposed in the true spirit of IPY. The project is tightly linked to companion proposals addressing Marine & Quaternary Geosciences and Cryosphere & Oceans, topics, and to international collaborators from Argentina, Belgium, Canada, Germany, Spain and the United Kingdom.

BROADER IMPACTS: Our outreach efforts are planned to share the excitements of polar environmental discoveries in real time by: (1) participation of a science writer (Kevin Krajick) during our field season who will contribute short articles to popular science publications, (2) broadcast of science segments by members of the Jim Lehrer News Hour (Public Broadcasting System), (3) summer courses for undergraduates on environmental change in the Larsen B region organized around the principles and concepts developed in this project and emphasizing cryosphere-atmosphere-ocean connections, (4) education and mentoring of graduate students and postdoctoral fellow, (5) project web pages at each of our participating institutions as a venue for outreach and data availability, and (6) showcasing scientific activities and findings to students and public through vodcasts.

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