| Popis: |
Phytoplankton play a significant role in global biogeochemical cycles as they account for approximately 40% of annual carbon fixation, the conversion of inorganic carbon dioxide to organic compounds. Their ability to produce organic compounds provides food to marine organisms and, particularly in the case of the Red Sea, promotes biodiversity through its facilitation of coral growth. Satellite-derived concentrations of chlorophyll a, a pigment that is found in photoautotrophs, strongly correlate with the abundance of phytoplankton populations in ocean waters. The present study used satellite-derived chlorophyll a concentrations from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on board the NASA Aqua satellite, surface wind velocity data from NCEP-DOE Reanalysis 2 and sea surface temperature data from NOAA Optimal Interpolation (OI) v2 to explore the physical mechanisms driving seasonal variability of chlorophyll a in the southern Red Sea. The highest chlorophyll a concentrations in the region were seen along the southern Eritrea coast. Chlorophyll in this region reached a seasonal maximum during the late fall and winter. Our results suggest this phenomenon is caused by wind-driven coastal upwelling, and corresponded to advection from the Gulf of Aden as well as aeolian transport and deposition of sediment from the Sahara. The aforementioned mechanisms begin to explain the seasonal cycle of primary productivity in the southern Red Sea, which has broader implications for understanding marine biogeochemical cycling in this region, and will be examined further in a future numerical modeling study. |
