Distribution and ecological characteristics of seagrass in Shuangdao Bay, Weihai

Abstract:

The seagrass bed ecosystem is one of the most productive ecosystems on earth with important ecological functions and ecological service values. In August 2016, the seagrass resources and ecological characteristics were investigated and analyzed in Shuangdao Bay sea area of Weihai city, Shandong Province. Seagrass beds of Zostera marina and Phyllospadix iwatensis covering approximately 442.19 hm2 were discovered. Z. marina was distributed over 434.46 hm2, which is approximately 98.3% of the total seagrass area. These Z. marina plants mostly grow in the eastern part of Shuangdao Bay and in the farming ponds of Stichopus japonicus. The average shoot density and biomass of Z. marina were (174.2±9.2) shoots/m2 and (337.7±17.5) g DW/m2, respectively. The distribution area of P. iwatensis was 7.73 hm2 and was approximately equivalent to 1.7% of the total seagrass area. These P. iwatensis plants mostly grow on rocky coasts and displayed an obvious band-like distribution. The average shoot density and biomass of P. iwatensis were (889.1±17.1) shoots/m2 and (605.9±18.1) g DW/m2, respectively. The average water depth of seagrass beds was about 1.6 m and the farming ponds growing Z. marina had a hard substrate with an average particle size of (4.3± 0.2) mm. The investigation showed that the seagrass habitats are being seriously threatened by human activities, such as pollution discharge from the land, culling, and fishing. Suggestions for the protection of the seagrass beds in Shuangdao Bay have been proposed to provide supplementary data on China’s seagrass resources and their conservation.