The 1991 coccolithophore bloom in the central North Atlantic, II. Relating optics to coccolith concentration. Limnology and Oceanography 41

This study summarizes the relationships between various biological and optical properties of a mesoscale coccolithophore bloom observed in the North Atlantic during June 1991. Backscattering and coccolith concentration were positively correlated. Backscattering and concentration of suspended calcite...

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Bibliographic Details
Main Authors: William M. Balch, Katherine A. Kilpatrick, Patrick Holligan, Derek Harbour, Emilio Fernandez
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Published: 1996
Subjects:
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.553.1324
http://www.aslo.org/lo/toc/vol_41/issue_8/1684.pdf
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Summary:This study summarizes the relationships between various biological and optical properties of a mesoscale coccolithophore bloom observed in the North Atlantic during June 1991. Backscattering and coccolith concentration were positively correlated. Backscattering and concentration of suspended calcite were even better correlated because atomic absorption analyses of calcite calcium were equally accurate whether calcite was attached or detached from cells, whereas it was difficult to enumerate the numbers of coccoliths attached to cells by means of microscopy. As the bloom aged, the ratio of detached coccoliths to plated cells increased. Dilution experiments provided the most precise relationships between coccolith backscattering and coccolith abundance. The calcite-specific scattering coefficient was estimated from measurements of beam attenuation, absorption, and calcite concentration. The contribution of coccolith backscattering to total scattering was modeled as a function of coccolith concentration and chlorophyll concentration. Even outside the cocco-lithophore bloom, coccoliths were responsible for 5-30 % of the total backscattering. Anomalous diffraction theory was used to show that calcite-specific scattering is the highest for I-3-pm spheres, which correspond to the diameters of Emiliania huxleyi coccoliths (this prediction was close to the observed values). The calcite-specific scattering coefficients of larger calcite particles (e.g. plated coccolithophore cells, foraminifera