Balch, W. M.. Bigelow Laboratory for Ocean Sciences, ddrapeau@bigelow.org
Drapeau, D. M.. Bigelow Laboratory for Ocean Sciences, ddrapeau@bigelow.org
Bowler, B. C.. Bigelow Laboratory for Ocean Sciences, bbowler@bigelow.org
Ashe, A. L.. Bigelow Laboratory for Ocean Sciences, bbalch@bigelow.org
Vaillancourt, R. D.. Bigelow Laboratory for Ocean Sciences, bbalch@bigelow.org

 
BACKSCATTERING PROBABILITY AND CALCITE-DEPENDENT BACKSCATTERING IN THE GULF OF MAINE
 
For the past several years, we have measured inherent optical properties (absorption (a), scattering (b), attenuation (c), and backscattering (bb)), along with biological and hydrographical parameters (fluorescence, particle abundance, temperature and salinity) in the Gulf of Maine. We derived backscattering probability (=bb/b), important for understanding remote sensing reflectance. Traditionally bb/b has been modeled as a function of chlorophyll, but in the Gulf of Maine, the situation is clearly more complicated. We also measured acid-labile backscattering, which is related to suspended calcium carbonate (primarily from coccolithophores). CaCO3-dependent backscattering is generally highest in the central basins of the Gulf of Maine, common sites of mesoscale coccolithophore blooms. Surprisingly, in non-bloom situations, coccolith-dependent backscattering was inversely correlated to b/a. This unexpected result was due to the well known preference of coccolithophores for low productivity, stratified waters, such as in the Wilkinson or Jordan Basin. In non-bloom periods these waters have low b/a. High b/a values were observed in well mixed coastal waters containing high turbidity, and low calcite. Such high b/a values were found in the coastal plume emanating from the Bay of Fundy where the phytoplankton population was dominated by diatoms, not coccolithophores.
 
Day: Thursday, Feb. 4
Time: 03:30 - 03:45pm
Location: Eldorado Hotel
 
Code: CS61TH0330E