2006 Volume 1 Issue 2 Pages 109-116
We investigated the temporal changes of the environmental conditions of the sea floor and the abundance of marine nematode community in the sediment in the subtidal areas near a river mouth with tidal flats in Takamatsu, which faces Seto Inland Sea, Japan. We collected particulate organic matter sinking on the sea floor with a sediment trap and sediment samples with a core sampler bihourly from 11:00 on July 18 to 9:00 on July 19, 2001, and assessed the temporal changes of particulate organic carbon (POC) fluxes in the water column and the chemical characteristics of sediment. The Chl-a concentration and organic matter content of the sediment tended to increase in the surface layer of the sediment at both of the low tides during daytime and early morning, since the deposition of organic particulate containing Chl-a on the sea floor was concentrated at low tide. The organic particulates were produced and transported from the shore and tidal flats. The temporal increase of the density of the nematodes in the sediment up to 5 cm in depth just after the increase of the POC flux in the water column indicates the numerical response of the nematodes to utilize the organic matter deposited on the sea floor. It is likely that the nematodes rose to the surface layer of the sediment to feed the organic particulates and bacteria temporarily increased with them just after the intensive deposition of organic particulates at low tide.
