Relationships between benthic animals and detritus deposits in estuarine tidal flats.

在仙台湾名取河口的Gamo潮滩和名取河口的Idoura潮滩两个河口潮滩上，对沉积物捕捉器采集的大型动物、沉积物和沉积颗粒物进行了季节性调查。在Gamo和Idoura潮滩中检测到的大型底栖动物非常相似，可能是因为盐度范围相似，但优势物种不同。Gamo潮间带的生物量主要集中在Neanths Japan和Notomastus latericeus，而在Idoura潮间带，蟹类和双壳类Macoma Conculata的生物量占了绝大部分。Gamo滩涂大型底栖动物的总生物量较高，优势种的寿命较短，可能预示着底栖动物的产量较高。结果还表明，营养价值较高的颗粒有机物(POM)的沉积较大，导致Gamo滩涂的大型底栖动物产量高于Idoura滩涂。沉积物圈闭样品和滩涂表层沉积物的C/N比表明，Gamo滩涂的沉积有机质来源于浮游植物，而Idoura滩涂的沉积有机质更多地来自陆源。底泥捕获器捕获的POM量与生物量之间呈负相关，说明Gamo潮间带底栖大型底栖动物的生产量不受食物限制。结果表明，低Eh(缺氧)和硫化物胁迫导致Gamo潮滩内侧大型底栖动物生物量较低，这是由于POM分解不稳定的微生物活性较高、暴露时间较长以及上覆水中氧浓度的降低所致。

Seasonal investigations of macrofauna, sediment, and deposited particulate matter collected by sediment trap were conducted on two estuarine tidel flats, the Gamo tidal flat at the mouth of the Nanakita River and the ldoura tidal flat at the mouth of the Natori River, Sendai Bay. The macrobenthos detected were very similar between the Gamo and the ldoura tidal flats, probably because of similar salinity ranges, but the dominant species were different. In the Gamo tidal flat, Neanthes japonica and Notomastus latericeus were quantitatively abundant, while in the ldoura tidal flat, the crab Macrophthalmus japonicus and the bivalve Macoma contabulata comprised the most part of the biomass. The higher total biomass of macrofauna, and the shorter lifespan of the dominant species in the Gamo tidal flat may indicate a higher production of benthic macrofauna. The results also suggested that the greater sedimentation of POM (particulate organic matter) of higher nutritional value resulted in a higher production of macrobenthos in the Gamo tidal flat than in the ldoura tidal flat. The C/N ratios of sediment trap samples and surface sediment of tidal flats showed that the sedimentary organic matter of the Gamo tidal flat was derived from phytoplankton, while that of the ldoura tidal flat was of more terrestrial origin. The negative correlation between the biomass and the amount of POM caught in the sediment traps indicated that the benthic macrofaunal production was not food limited in the Gamo tidal flat. It was suggested that severe low Eh (anoxic) and sulfide stresses caused by higher microbial activity of labile POM decomposition combined with long exposure time and a decrease in oxygen concentration in the overlying water resulted in a lower macrofaunal biomass at the inner part of the Gamo tidal flat.