東京湾で採集さけた底棲生物の糞粒からの燐酸と珪酸の再生いついて

抄録

The fecal pellets collected from water-sediment interface by pumping were identified microscopically to be composed of a mixture of phytoplankton detritus and minerals, and then submitted for a study of the regeneration rates of phosphate and silica under laboratory conditions. Under aerobic proceeding, inorganic phsophate regenerated from the detritus was sorbed exclusively on the pellets until the sorption capacity was aturated by phosphate; while with development of anaerobic conditions the phosphate sorption capacity was reduced and the desorption of inorganic phsphate started instantaneously. The fecal pellets thus appeared to act as an important phosphate buffer. The aerobic regeneration rate of phosphate (K_p, day^-1) can be predicted as a function of temperature (t°C); log K_p=2.61×10_-2t-2.05, and the dissolution rate of biogenic silica in the pellets (K_si, day_-1); log k_si=4.53×10_-2t-3.15. The study strongly supports the assumption that phosphate and silica regenerated from the fecal pellets supply a significant fraction of nutrients required by primary producers in the water column during summer months when anoxic conditions are spreading in the water-sediment interfce.