Understanding the food web dynamics of Yellow Sea ecosystem: the role of Euphausia pacifica using multi-approaches

Abstract

Euphausia pacifica play a key role to transfer the energy to higher trophic level and maintain the function and structure of Yellow Sea ecosystem because of their abundance and high biomass. Although understanding their feeding ecology is necessary to accurately elucidate the structure and function of the Yellow Sea ecosystem, very limited information is available on their feeding ecology and behavior through the season. Therefore, we applied multiple approaches (in-situ feeding experiments, gut content analysis, trophic biomarkers, etc.) to track the source of nutrient and diets of E. pacifica during spring and summer in the Yellow Sea. According to the gut content and trophic biomarker analysis, diets of E. pacifica were seasonally shifted from algal-based particles (i.e., diatom) to microbial-based particles (i.e., detritus, protozoa) as season progress. However, the preliminary results of in-situ feeding experiments suggest that adult E. pacifica seems to preferentially feed on ciliates and heterotrophic dinoflagellates among natural diet assemblages during spring algal blooms even though a large amount of other food items (diatoms, autotrophic dinoflagellates, etc.) were available. Therefore, more careful approaches and further experiements will be required to better understand the role of E. pacifica in the Yellow Sea ecosystem.ecessary to accurately elucidate the structure and function of the Yellow Sea ecosystem, very limited information is available on their feeding ecology and behavior through the season. Therefore, we applied multiple approaches (in-situ feeding experiments, gut content analysis, trophic biomarkers, etc.) to track the source of nutrient and diets of E. pacifica during spring and summer in the Yellow Sea. According to the gut content and trophic biomarker analysis, diets of E. pacifica were seasonally shifted from algal-based particles (i.e., diatom) to microbial-based particles (i.e., detritus, protozoa) as season progress. However, the preliminary results of in-situ feeding experiments suggest that adult E. pacifica seems to preferentially feed on ciliates and heterotrophic dinoflagellates among natural diet assemblages during spring algal blooms even though a large amount of other food items (diatoms, autotrophic dinoflagellates, etc.) were available. Therefore, more careful approaches and further experiements will be required to better understand the role of E. pacifica in the Yellow Sea ecosystem.