Marine suspended matters, sinking particles and surface sediments were collected for the amino acid analyses in the Harima-Nada, Seto Inland Sea, Japan. A cultured diatom, Skeletonema costatum, and a chloromonad, Chattonella marina, sampled from red tide, were also submitted. Amino acid concentrations varied in the range of 7.53 to 45.2 mg/g (n=7) for suspended matter, 12.7 to 92.3 mg/g (n=10) for sinking particle in sediment trap, 5.21 to 8.28 mg/g (n=4) for surface sediment on dry basis. A marked difference in the amino acid composition was observed between the suspended matter and the sinking particle. Sulfur and aromatic amino acid groups were depleted in the suspended matter compared to the phytoplankton and the sinking particle. Individual amino acid concentrations suggest that diagenetic reactions on the sinking particles and the surface sediments. The amino acid fluxes at 5 m above the sea bottom were estimated to be from 21 to 37% of primary pruductivity in surface water layers.

View full abstract

The author examined geochemical study of hot spring waters from Shinetsu • Hozu and Shimanto zone on the base of the first report. The derived conclusions are as follows. (1) The frequency distribution of boron is biased to a low content side as first report. In the first report, the most frequent range of boron contents is from 2.1 mg/l to 6.0 mg/l, while, it is from 4.1 mg/l to 12.0 mg/l, in the Shinetsu・Hozu and Shimanto zone. (2) Boron content has positive relationships with water temperature, evaporation residue, sodium, potassium, calcium, chloride ion contents. (3) Evaporation residue, boron, sodium, potassium, calcium, chloride ion contents of some hot spring waters from Shinetsu・Hozu and Shimanto zone are extremely greater than those of Hakusan and Japan North Alps. (4) Except for the hot spring waters fewer than 10 mg/l chloride ion content, minimum and maximum values of B/Cl ratios of the hot spring waters from Shinetsu・Hozu and Shimamto zone are 0.0025 and 0.2332, respectively and the mean value of those is 0.0597. These are greater than those of Hakusan and Japan North Alps. Except for Kashio hot spring, the sources of boron in hot spring waters of Shinetsu・Hozu and Shimanto zone are inferred to be the basement rocks. The sources of boron in Kashio hot spring waters are inferred to be the fossil sea waters.

View full abstract

An Overview
Chemical constituents discharged to river mouth area through river water,
Geochemical balance of chemical constituents in river mouth area,
Monitoring of chemical environment in river mouth area

View full abstract

To clarify the interrelationships of organisms in the estuarine environment under influences of human impacts, the extensive and careful studies were conducted around the estuarine region of the Ohta River. The methods used and the results gained are briefly explained.

View full abstract

In order to understand the behaviors of heavy metals at the confluence of the river and sea waters, the surface and vertical distributions of heavy metals such as Al, Ti, Mn, Fe, Co, Ni, Cu, Zn, and Y have been investigated at the Tama River estuary and Tokyo Bay. The gallium coprecipitation preconcentration-ICP (inductively coupled plasma) atomic emission spectrometric method was applied in the analysis, where the above mentioned elements were determined simultaneously. The sampling locations were 4 points between the Tama River estuary and the center of the Tokyo Bay. The concentrations of heavy metals showed characteristic changes for each element as the functions of location (distance from the river mouth) and depth. The concentrations of Fe, Ti, Mn, Co, and Y became lower at the deeper layer of sea water near the center of the bay, where the salinity was higher. On the other hand, those of Al, Cu, Ni and Zn were higher near the bottom layer. These experimental results may be important in the understanding of the distribution behaviors of trace heavy metals in the estuarine and coastal areas, which may be regulated by the exclusion and dissolution phenomena with suspended particles.

View full abstract

The stable isotope ratios of biogenic carbon and nitrogen were studied along the Otsuchi watershed with emphasis on the area drained by the Unosumai River. Plant remains collected from the mountain soil exhibited the lowest values (δ¹³C=-27.5±1.0‰, δ¹⁵N=-1.8±0.8‰) in the watershed. Both isotope ratios increase along the watershed from the upper reaches to the Otsuchi Bay but a dramatic change for the river and inner bay sediments near the river mouth. A biogeochemical framework for assessing the variation of the both isotope ratios is presented. The relationship between the size of particles in the sediments and isotope ratios was studied in detail. The plant remains and organo-silty-clay minerals were emphasized to be responsible for the land-derived refractory organic matters in the bay sediments. Carbon and nitrogen isotope ratios were shown to be useful to trace the behavior of organic matter along the watershed.

View full abstract