Abstract
The distributions of particulate amino acids (PAA) and other organic components : carbon (POC), nitrogen (PON) and chlorophyll pigments (chl. a) in the northwestern part of Tokyo Bay and Tamagawa Estuary were investigated in 1990. The particulate organic matter was fractionated to three size fractions of 0.3-1.2μm., 1.2-63μm and >63μm. The total concentrations of PAA in the three fractions ranged from 194μg•l-1 to 3044μg•l-1 and averaged 1218μg•l-1. The fraction of 1.2-63μm was a constantly predominant portion of PAA, which accounted for 69-76% of the total, as well as other particurate componets. The source of PAA could be estimated from a correlation observed between PAA and Chl. a concentrations in the fraction of 1.2-63μm. The percentages of PAA derived from phytoplankton origin were calculated to be 71±20% at the St. 8 in the estuary of Arakawa River, 61±23% at the St. 25 off Haneda and 95±4% at the St. 35 near the center of the bay. It was also found that sedimentary organic matter was characterized by high percentage of glycine and low ratio of PAA-C/POC compared to suspended particles directly generated from phytoplankton, indicating that these parameters might be useful to estimate the microbial decomposition process of particulate organic matter.
