ABSTRACT
The flux of total particulates, POC, carbonate, silica, and even aluminum collected in sediment traps at 3200 m in the Sargasso Sea displayed clear seasonal patterns, with maxima in early spring and minima in summer or fall. Dissolved carbohydrates and amino acid concentrations were also maximum during the wet season in the Huanghe River, China, but dissolved carbohydrates showed no clear seasonal pattern in the lower Elorn River, France. As in the steep-drainage basin Alaskan rivers, there was also no discernible seasonal pattern in DOC levels. In Lake Superior, whole-lake average POC:PON ratios from the upper 20 m showed clear seasonal patterns with May and October minima and a July-August maximum, probably because of phytoplankton nutrient deprivation due to seasonal thermal stratification. The patterns of particulate carbohydrate and lipid were quite similar, with a much less evident seasonal pattern than for protein.
