David Mountain and Maureen Taylor

Interannual Variability in Water Properties and Fluorescence in Georges Bank - Some Relationship?

Three years of hydrographic data from the Broad Scale surveys indicate considerable variability in the salinity of the water on the Bank. Combined with data from other sources the variability appears associated with changes in the relative contributions of Slope Water and Scotian Shelf water to the Gulf of Maine/Georges Bank system over a multi- year period. From high salinity in later 1994, indicating more Slope Water influence, the salinity decreased through 1995 and 1996, reaching a minimum in early 1997. The Bank averaged fluorescence appeared significantly lower in 1997 (at least through April) as compared to 1995. Two questions are raised - is the lower fluorescence an indication of lower productivity? And could a reduction in the supply of new nitrogen to the system due to a reduced amount of Slope Water (i.e., the lowering of salinity) have contributed to that lower productivity? (No real answers - but interesting to consider.)