Phosphorus, Silicon, Carbon and Nitrogen Contents in Suspended Matter and Sediments from Tokyo Bay

Abstract

Bio-elements (C, N, P and Si) in suspended matter and sediments have been studied together with reactive silicate and phosphate in seawater from Tokyo Bay. The seasonal variation of reactive silicate exhibited higher amplitude than that of reactive phosphate. Organic-C and-N contents in the sediments were higher than those of the averaged oceanic sediments, but the phosphorus content was the same level with that of the oceanic sediment. The mean ratio of the bio-elements in suspended matter was calculated to be P:N:C:Si=1:18.8:137:22.6 (atoms). In the sediment it was P:N:C=1:7.6:73.6, but the ratios of N and C to the rest of the phosphorus, which was obtained by substracting the fractions combined with Ca, Al and Fe from the total amount of phosphorus, was found to approach to those of the suspended matter. During the period when stratification developed, about 80% of organic matter produced was estimated to be decomposed in the surface water. A considerable amount of suspended matter in winter season, was considered to be ascribed to the resuspension from the deposited sediment and/or to the debris of organic matter.