Abstract:

To understand the nutritional relationship among benthic organisms and the food web characteristics in seagrass beds, we collected macrobenthic organisms in intertidal zones of the Yellow River Delta of Dongying and the west coast of Yantai in August 2018. We used δ ¹³C and δ ¹⁵N stable isotopes determine trophic position. The range of organisms isotopic values in the Dongying seagrass bed were -21.99‰ to -12.13‰ for δ ¹³C and 5.23‰ to 11.05‰ for δ ¹⁵N; and -18.11‰ to -14.06‰ (δ ¹³C) and 6.60‰ to 10.22‰ (δ ¹⁵N) in the Yantai seagrass bed. In the Dongying seagrass bed, the trophic level of main organisms ranged from 2.00 to 3.85, while in the Yantai seagrass bed the trophic range was from 2.00 to 3.15. According to δ ¹⁵N value calculations, we found that the primary consumers in these two area’s seagrass bed were filter feeding bivalves and polychaetes; the secondary consumers were plant-eating or omnivorous crustaceans, carnivorous fish and gastropods. Compared to offshore habitats, the average trophic position of macrobenthic organisms in seagrass beds was relatively low.

Key words: stable isotope, seagrass bed, food web, trophic level, macrobenthos