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Funded Research

Phytoplankton Community Organization by Cell Size, Optical Properties and Meso-scale Motions in an Eddy Resolving Ocean Model.

Follows, Michael (Mick): MIT (Project Lead)
Gregg, Watson: NASA GSFC (Institution Lead)

Project Funding: 2009 - 2013

NRA: 2008 NASA: Ocean Biology and Biogeochemistry   

Funded by NASA

Abstract:
We propose to examine how marine phytoplankton communities and biogeochemical cycles are regulated by (a) the spectral dependence of the absorption of short-wave radiation by phytoplankton and (b) meso-scale eddy structures of the physical circulation. We will do so in the context of an eddy-resolving model of ocean circulation, ecosystem and biogeochemical cycles, based on the physical models of the ECCO2 project. We will employ a "self-organizing" ecosystem which represents hundreds of potentially viable, stochastically generated, types of phytoplankton. Dominant community structure is selected according to the relative fitness of the initialized types. A backbone of physiological trade-offs will be implemented through generalized allometric constraints. We will implement an explicit wavelength-dependent, water-column radiative transfer model with size- and pigment-dependent phytoplankton absorption spectra. We will focus on decade-scale, regional, high-resolution simulations of the North Atlantic where remotely sensed ocean color products (SeaWiFS, MODIS) are augmented with extensive in situ observations (AMT, CPR, BATS) and expand to the global domain in the final year of the study. We will address the following questions: - To what extent are cell size and the spectral dependence of pigment properties significant in organizing phytoplankton community structure? - Can such a model capture regional and seasonal variations in the spectrum of water- leaving short wave radiation? - How does the explicit resolution of mesoscale eddies influence the organization of phytoplankton community structure, its radiative signatures, and its affect on surface ocean carbon cycling? Responsiveness to NASA OBB: We aim to improve understanding of the physical regulation of marine phytoplankton communities and nutrient cycles, interface directly with space-based ocean color observations through explicitly modeled, wavelength specific fluxes, improve the capability for dynamic modeling of marine ecosystems, and understand the influence of environmental variability on ocean ecosystems.


More details may be found in the following project profile(s):