Spring 2007 Update: Fall Conditions on the Northeast Shelf Ecosystem
If we consider only the time trend of SST during the fall season then a different pattern emerges from the annual trend in SST for the entire shelf system. Whereas the annual mean suggests surface waters have cooled during the past few years, the fall SST data indicate a continuation of the warming trend that began in the 1990s. Fall chlorophyll levels are slightly higher than the annual mean reflecting the seasonally of fall blooms in some areas. The fall bloom pattern appears to be in synchrony with the overall time series pattern of chlorophyll levels on the shelf. Fall zooplankton biomass suggests a different pattern of decline and increase in zooplankton communities; the decline in zooplankton biomass of the mid 1980s appears to be a more localized event. The recent increase in annual zooplankton abundance is also not seen in the fall, indicating important seasonal dynamics affecting the annual pattern.