Variability of Chlorophyll a off Southwestern Nova Scotia in Late Fall and Its Relationship to Water Column Stability

Publisher Website
Google Scholar
Abstract
Chlorophyll a, nitrate, and physical variables collected during December 1978 and November 1979 off southwest Nova Scotia show two distinct patterns in phytoplankton abundance. In December 1978, conditions were similar to those expected in late fall over temperate North American shelves. The water was well mixed and chlorophyll was at background level (~0.5 mg/m3). By contrast, in November 1979, both inshore and offshore regions were stratified, and chlorophyll levels were, in some places, 5 times above background. Two explanations are offered for this bimodal chlorophyll distribution. Offshore, temporary stratification resulted from the intrusion of warm saline water from either the slope or the Gulf of Maine. This may be a temporary condition that eventually deteriorates with seasonal cooling and convective mixing. Inshore, stratification results from the influx of a shallow layer of relatively low-salinity water carried by the Nova Scotia current. The onset and seasonal vagaries of this current help to explain differences observed in 1978 and 1979.

This publication has 12 references indexed in Scilit: