ORGANIC AGGREGATES IN SURFACE AND DEEP WATERS OF THE SARGASSO SEA1

Abstract

The quantities of organic aggregates and particulate organic carbon in surface waters of the Sargasso Sea were relatively small at all times but showed a slight seasonal variation, with highest values in winter and spring and lower ones in summer, in general agreement with observed seasonal variations in phytoplankton. Particulate matter decreased from the surface downward in the upper few hundred meters but was essentially constant from 500 m to more than 3,000 m. It is concluded that: a) There are bacteria and filter‐feeding animals in deep water which are potentially able to use this particulate matter. b) The particulate matter is large in total quantity but too thinly distributed to provide more than a minimal diet; hence the quantity of animals is small, and the turnover rate of organic matter is slow. c) Biological consumption in deep water should produce a decrease in organic matter with depth, unless this particulate matter is augmented by additional adsorption from the dissolved organic fraction. Preliminary experiments confirm the adsorption process as a possible explanation of observed distributions.