Principal Investigator: Heidi M. Sosik
Sponsoring Agency: National Aeronautics & Space Administration
Understanding the magnitude and distribution of marine phytoplankton
biomass and production is a fundamental problem in biological oceanography
which may be solved in part through interpretation of satellite-based ocean
color. The research project aims to contribute to improved methods
for interpretation of ocean color through a multidisciplinary, collaborative
research effort using several sampling platforms including research ships,
oceanographic moorings and satellites. We have taken advantage of
a field experiment on the mid-Atlantic continental shelf, which is part
of the Office of Naval Research's Coastal Mixing and Optics (CMO) Accelerated
Research Initiative. This collaborative effort between optical and
physical oceanographers represents an unique opportunity to gain fundamental
insights into the sources of variability in surface ocean reflectance and
its relationship to phytoplankton pigment concentration and the rate of
primary production.
Our work, aimed at improved interpretation of SeaWiFS data, includes
the application of some recent advances in optical tools and the development
of approaches for incorporating information from moorings to estimate primary
production. We are exploring relationships between ocean reflectance
and variability in the distributions of particle optical properties; his
is being accomplished through use of shipboard laser-based flow cytometry
and both in situ and remote determinations of ocean color. Plans
for combining mooring- and satellite-based measurements to obtain accurate
estimates of seasonal primary production on the mid-Atlantic shelf originally
includes addition of a Fast Repetition Rate (FRR) fluorometer to the CMO
optical mooring, but delays in instrument production precluded this.
Current work includes evaluation of the FRR instruments capability to provide
quantitative information about phytoplankton optical and photosynthetic
properties which can not be assessed based on passive remote sensing, but
which are critical determinants of the rate of production. Future
plans include the mooring of the FRR on Georges Bank.