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
Email: mvernet@ucsd.edu

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§ Research Projects » Ice-Krill-Phytoplankton

PIIAK: Collaborative Research: U.S. SO GLOBEC Synthesis and Modeling: Timing is Everything: The Dynamic Coupling among Phytoplankton, Ice, Ice Algae and Krill (1 January 2006-31 December 2008) � Principal Investigator: Christopher Fritsen, Desert Research Institute; Co-Principal Investigators: Robin Ross and Langdon Quetin, University of California Santa Barbara.
Funded by the National Science Foundation, Grant # 0528728.

ABSTRACT: The annual advance and retreat of sea ice (from a summer minimum of approximately 4 million km2 to a winter maximum of 20 million km2 ) plays a dominant role in the Southern Ocean ecosystem, and has been called the largest seasonal process on Earth. The life history of Euphausia superba, the Antarctic krill and a key species in the food web of the Southern Ocean ecosystem, is intricately involved with seasonal sea ice dynamics. Recent results from the U.S. SO GLOBEC field program as well as historical information on sea ice dynamics and Antarctic krill recruitment suggest a shift in the paradigm that all pack ice is equally good habitat i.e., that sea ice varies in its habitat quality for larval krill.

The following hypotheses will be tested: -'Good' winter habitat for larval and juvenile krill can be defined as early forming ice with a high propensity for incorporation of autumn phytoplankton and a high degree of exposure to photosynthetically active radiation before the onset of winter darkness. -Ice cover from early fall and high phytoplankton entrainment is much more likely to contain high algal biomass and lead to higher ingestion and growth rates in larval Antarctic krill promoting higher growth rates associated with enhanced recruitment success of a year class. Through data synthesis and modeling, historical records of krill condition factor, larval growth and recruitment the work proposed will link the variability in sea ice dynamics via its coupling to phytoplankton incorporation and sea ice algal biomass. This project has two main goals: - development and refining diagnostic datasets and models of phytoplankton decreases in the fall, phytoplankton biomass incorporation into sea ice, sea ice growth dynamics, sea ice algal production and biomass accumulation, and larval krill energetics and condition models. The aim is to understand if climate change is likely to change the extent and/or location of 'good' winter habitat for larval Antarctic krill. In the WAP region the seasonal pattern of advance and retreat of the sea ice appears to be changing - with the timing of advance later and later. Thus the formation of the pack ice habitat is occurring under a changing light field due to changes in the latitude and timing of formation - hindcast the variability (spatially within a season as well as interannual) of the quality of the pack ice habitat west of the Antarctic Peninsula (WAP) from present back to 1979 by linking the mechanistic data sets and models in a two dimensional model. In this way, questions on the effects on the pack ice ecosystem of these changes can be addressed by the proposed synthesis and modeling efforts.

Broader Impacts: The development of synthesis data sets and integrated models serves the international community regarding the management of the life resources of the Southern Ocean. Thus the model integration, diagnostic and predicted results will be disseminated at national meetings, international meetings (specifically International GLOBEC and SCAR) as well as through the existing Antarctic Program and GLOBEC data dissemination repositories/Archives. In addition to presenting at these meeting the principals will propose to host/chair life resources and modeling sessions at AGU/TOS/ASLO and ESA meetings regarding modeling of the Antarctic Marine Ecosystems and Educational Outreach on how to make the Antarctic Marine Ecosystem and climate variations therein accessible to K-12. To reach out and share the excitement of discovery a web-based ecosystem interface model will be developed to allow users of varying abilities and backgrounds to download and run key components of these ecosystem models that will be created in a systems-analysis format - Stella. By creating subcomponents of the models in this format the Stella-based models will be shared through freeware (Isee software), and in essence a web-based exploratarium regarding ice growth, krill energetics, and marine systems behavior will be created. Workshops on the development of modeling interfaces will be run through the Access Grid Nodes (AGN) that will allow virtual computing and conferencing. Integration with other US SO GLOBEC modeling efforts will be solicited through synthesis workshops and through AGN meetings.

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