SeaWiFS satellite monitoring of oil spill impact on primary production in the Galapagos Marine Reserve

摘要

Near daily satellite monitoring of ocean colour using sea viewing wide angle of field viewing sensor (SeaWiFS) allowed the oceanic and near coastal chlorophyll-a distributions to be followed across the Galapagos Marine Reserve (GMR) from space. In the aftermath of the Jessica spill early indications suggested that, compared to the three preceding years 1998-2000, local chlorophyll concentrations over January 2001 were elevated across the Galapagos Marine Reserve [Biological Impacts of the Jessica Oil Spill on the Galapagos Environment: Preliminary Report. Charles Darwin Foundation, Puerto Ayora, Galapagos, Ecuador, 2001]. At the time of the spill the central and eastern extent of the archipelago was experiencing a spatially extensive moderate bloom event (0.5-2.5 mg m~(-3) chl-a) extending over the central islands, including the source of the spill and areas of known impact such as the islands of Santa Fe, eastern Santa Cruz and Floreana directly in the advection path. Further investigation shows that chlorophyll across the affected regions of western San Cristobal, Santa Fe, southeast Santa Cruz, eastern Floreana and eastern Isabela declined in the week directly following the spill event, yet rose in the successive month to levels analogous to preceding years. Although there may have been a localised effect of the spill upon near coast phytoplankton primary production in the short term, the observed variance in the weeks following the spill was not significant in comparison to the normal high variation between years and within the El Nino/Southern Oscillation signal.