Assessing Herbivorous Impacts of on the Green Tide in China.

An epiphytic gammarid species, , was abundant in the floating (), which forms large-scale green tides in the Yellow Sea (YSGT). Field observation and laboratory experiments were subsequently conducted to study the species identity, abundance, and grazing effects on the floating algal biomass. The abundance of showed great spatial variation and varied from 0.03 to 1.47 inds g in the YSGT. In average, each gram of body mass can consume 0.43 and 0.60 g algal mass of per day, and the grazing rates varied among the algae cultured with different nutritional seawaters. It was estimated that grazing of could efficiently reduce ~0.4 and 16.6% of the algal growth rates in Rudong and Qingdao, respectively. The fragments resulting from gnawing of had a higher growth rate and similar photosynthetic activities compared to the floating algae, indicating probably positive feedback on the floating algal biomass. This research corroborated the significant impact of on the floating algal mass of YSGT through the top-down control. However, further research is needed to understand the population dynamics of these primary predators and hence their correlation with the expansion or decline of YSGT, especially under the complex food webs in the southern Yellow Sea.