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

August 18, 2017 | Not Logged In (public login | local login)

§ Research Projects » Modeling

Improving Current Assessments and Future Predictions of Carbon Fluxes in the Southern Ocean as Mediated by the Dynamical Response of Ice-Ocean-Ecosystem Interactions to Climate Change (ROSES NASA 2007-2010) Principal Investigator: S. Stammerjohn, Columbia University. Co-Principal Investigators: L.B. Quetin and R.M. Ross, University of California Santa Barbara, C. Sweeney, National Oceanographic and Atmospheric Administration.
Funded by the National Aeronautics and Space Administration (NASA), Grant # NNX09AN14G, to Sharon Stammerjohn.

ABSTRACT: Our overall objective of the proposed research is to improve current assessments and future predictions of carbon fluxes in seasonal sea ice zones of the Southern Ocean by investigating the dynamic ice-ocean-ecosystem response to climate change. More specifically, we will investigate how air-sea fluxes of CO2 and export production respond to the seasonal cycle of ice-ocean-ecosystem interactions, and how in turn seasonal ice-ocean-ecosystem interactions respond to climate change. The area of study is the western Antarctic Peninsula (wAP) region, which is warming faster in winter than anywhere else on earth [Vaughan et al., 2003]. In short, we are investigating, through data synthesis and modeling, the effect of biological efficiency on carbon fluxes and the potential climate-carbon feedbacks, dynamic variables that have not been well resolved by existing ocean carbon estimates and modeling efforts [Friedlingstein et al., 2006; Le Quéré, 2006].

Key questions regarding ice-ocean-ecosystem interactions that can be tested with the proposed data synthesis and modeling effort are: (1) how different physical processes (e.g., timing of sea ice advance/retreat, latitudinal variations in day length, mixed layer depth variations) influence air-sea fluxes of CO2 as mediated by sea ice in winter and phytoplankton composition and bloom formation in spring-summer; (2) how different phytoplankton compositions and concentrations affect grazing efficiency and intensity, and (3) ultimately how different ice-ocean-ecosystem interactions, including climate-related changes, drive CO2 uptake/out-gassing versus export production. Two of the ecosystem processes that we will investigate that have not been well-studied in previous ecosystem data synthesis and modeling efforts include (1) the role of sea ice biota in enhancing spring phytoplankton concentrations and biogenic flux during sea ice melt, and (2) the role of macrozooplankton (e.g. the Antarctic krill Euphausia superba, the tunicate Salpa thompsonii) grazing in influencing phytoplankton community composition and export production. Observational data that will be used in achieving the synthesis include (1) 15+ years of physical, biological and chemical data collected from an oceanographic region (600 km alongshore, 200 km on-to-offshore) west of the Antarctic Peninsula, (2) 28+ years satellite sea ice data and 10+ years of ocean color, and (3) atmospheric forcing data consisting of numerical analyses and station observations.

Key results from the data synthesis and single column ice-ocean-ecosystem model will be compared and made available to other studies using coarser resolution regional/global models, including other NASA-funded projects at GISS and elsewhere. Such comparisons will enhance understanding of how regional changes in ocean biology are affecting global estimates of carbon fluxes. This proposed research is responsive to the NASA ROSES (Research Opportunities in Space and Earth Sciences) Southern Ocean Carbon Program - Data Synthesis, Assimilation and Modeling (Amendment No. 21), and its overall goal of improving future predictions of carbon fluxes in response to climate change and falls within the overall context of NASA's strategic goal 3, in the context of sub-goal 3.A.3: study earth from space to advance scientific understanding and meet societal needs, by contributing to progress in the quantification of marine productivity and in improvement of carbon cycle and ecosystem models.