CHLOROPHYLL SPECIFIC ABSORPTION COEFFICIENTS AND THE IMPACT OF PHYTOPLANKTON TAXONOMIC GROUP OF SURFACE WATERS IN THE NORTHEASTERN GULF OF MEXICO
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
The author submitting the manuscript must understand and agree that the copyright of the article manuscript must be submitted/transferred to the Jurnal Ilmu dan Teknologi Kelautan Tropis. This work is licensed under the Creative Commons Attribution-ShareAlike 4.0 (CC BY-SA) International License in which the Author and Reader can copy and redistribute the material in any media or format, and remix, modify and build material for any purpose, but they must provide appropriate credit (citing articles or content), provide a link to the license, and indicate whether there is a change. If you mix, change, or create material, you must distribute your contribution under the same license as the original.