U.S.
JGOFS
Synthesis & Modeling Project |
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Jim Christian
Ricardo Letelier |
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Modeling microbial processes and dissolved organic matter: a case study at the US-JGOFS time series Station ALOHA | ||
PROJECT DESCRIPTION: | he development of coupled physical-biological models
of ocean biogeochemistry
is hampered by several critical knowledge gaps. Plankton models have attempted
to incorporate the "microbial loop" and dissolved organic substances, but
have done so using formulations that are highly uncertain, do not take
into consideration a great deal of new information that has emerged over
the past decade, and have not been shown to have greater predictive power
than simple empirical formulations used in e.g. the Ocean Carbon Cycle
Model Intercomparison Project protocols. As these processes play a significant
role in biogeochemical cycling in the oceans, we consider development of
more realistic models of this component of the community to be critical
to development of global models that have a mechanistic basis for predicting
elemental budgets.
Of the JGOFS time-series study sites, the Hawaii Ocean Time-Series (HOT) has received the least attention from modelers. Observations at HOT deviate strongly from established paradigms of plankton ecology (seasonal convection, nitrate-based production, metazoan zooplankton as primary consumers) that are to some extent assumed in plankton models. The HOT data base provides an unprecedented opportunity to validate a more realistic model, as observations of dissolved organic substances have been made routinely throughout the HOT project, and significant interannual variability in these has been observed. Although there are significant uncertainties associated with one dimensional (depth-time) simulation, the high computational cost of three dimensional simulations makes extensive validation experiments with biological submodels impractical in such a context. In addition, the HOT data base is itself Eulerian, and significant interannual variability in ocean biogeochemistry has already been observed. To provide a meaningful simulation of such variability requires a mechanistic model not only of plankton population biology, but of the interface between biology and chemistry that is found in the decomposer loop. The HOT data base provides an excellent opportunity to develop and test such a model.
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DATA: | - no data submitted - | |
PUBLICATIONS: | - no publications listed - | |
RELATED PROJECTS: | Friedrichs; Hofmann "Regional
ecosystem model testbeds. A JGOFS synthesis and modeling project."
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INVESTIGATOR
INFORMATION: |
Jim Christian
Universities Space Research Association NASA Goddard Space Flight Ctr Code 970.2 Greenbelt, MD 20771 tel: 301-286-9911 fax: 301-286-0268 jrc@bluefin.gsfc.nasa.gov http://bluefin.gsfc.nasa.gov/~jrc/ Ricardo M. Letelier
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