Utilizing benthic foraminifera to explore the environmental condition of the Laizhou Bay (Bohai Sea, China).

Through the analysis of benthic foraminifera in the soft bottom sediments of the Laizhou Bay - Yellow River Delta system, this study characterized the foraminiferal biotopes and explored the possibility of obtaining an index of ecological quality comparable with other estuarine and coastal environments of the world. Five foraminiferal biotopes have been identified and their distribution patterns highlight the ecological stress from the marine-fluvial water mixing and pollution. The foraminiferal species were analyzed as a function of organic carbon gradients, and the main species were assigned to four ecological groups based on their sensitivity/tolerance towards an increasing stress gradient. Finally, the relative proportions of the species assigned to the four different ecological groups were used for the definition of a marine biotic index based on foraminifera, i.e. the Foram-AMBI, and thus the assessment of the ecological quality status of marine soft-bottom habitats.