CHLOROPHYLL SPECIFIC ABSORPTION COEFFICIENTS AND THE IMPACT OF PHYTOPLANKTON TAXONOMIC GROUP OF SURFACE WATERS IN THE NORTHEASTERN GULF OF MEXICO

Bisman Nababan

Abstract

The chlorophyll-specific absorption coefficient at 440 nm (a*
ph(440)) of surface water in the Northeastern Gulf of Mexico varied by a factor of 7 (0.02-0.15 m2 mg-1) with the of chlorophyll-a concentration of 0.06-12.25 mg m-3. In general, lower values of a*ph(440) (<0.06 m2 mg-1) were observed in the inshore particularly in the major river mouths. During summer, lower values of a*ph(440) were also observed offshore associated with low-salinity waters of the Mississippi River plume. Higher values of a*ph(440) (>0.1 m2 mg-1) were otherwise observed outside the river plumes in the outer
shelf and slope, where lower chlorophyll-a concentration occurred. Based on phytoplankton taxonomic groups, the average value of a*ph(440), of microphytoplankton group was significantly lower than that of nanophytoplankton and picophytoplantkon groups, suggesting that an increase in cell optical size (pigment packaging) resulted in decreasing a*
ph(440) values. The relationship between a*ph(440) and chlorophyll-a concentration was also not linear, indicating pigment composition played an important role in determining a*ph(440) variability.

Keywords: chlorophyll-specific absorption coefficient, microphytoplankton, nanophytoplankton,
picophytoplankton, Gulf of Mexico, pigment, packaging effect

Authors

Bisman Nababan
simson_naban@yahoo.com (Primary Contact)
NababanB. (2009). CHLOROPHYLL SPECIFIC ABSORPTION COEFFICIENTS AND THE IMPACT OF PHYTOPLANKTON TAXONOMIC GROUP OF SURFACE WATERS IN THE NORTHEASTERN GULF OF MEXICO. Jurnal Ilmu Dan Teknologi Kelautan Tropis, 1(1). https://doi.org/10.29244/jitkt.v1i1.7934

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