Is seafloor litter contributing to sea anemone blooms?

Increasing marine litter have become a global environmental disaster. The accumulation of seafloor litter (generally includes anthropogenic litter and natural debris) could change the habitat of benthic organisms and thereby affecting their population dynamics including spatial distribution. Metridium senile fimbriatum (i.e., M. senile), a fast-growing sea anemone, has become a dominant species of benthic community in the north Yellow Sea in recent years. In this study, we tested the hypothesis that the distribution of M. senile is positively correlated with that of seafloor litter, using data collected on seafloor litter and M. senile from three fisheries-independent bottom trawl surveys in the Yellow Sea in May, August and November 2019. Gradient Forest Model (GFM) was used to select appropriate response variables for characterizing the distribution of M. senile, and evaluate the influences of potential environmental factors on M. senile distribution. Surface area of anthropogenic litter (represented as 'Anthropogenic litter'), surface area of natural debris (represented as 'Natural debris') and latitude (Lat) were identified as themost significant variables influencing the distribution of M. senile. Furthermore, Generalized Additive Mixed Model (GAMM) was applied to model the abundance distribution of M. senile in terms of significant environmental variables, and evaluate its correlations with 'Anthropogenic litter' and 'Natural debris'. The best fitting GAMMshowed that the abundance ofM. senile has a significantly positive associationwith 'Anthropogenic litter' and 'Natural debris'. We therefore speculated that accumulation of seafloor litter might contribute to the bloomofM. senile, given that seafloor litter could serve as vectors for M. senile dispersal and providewith a preferable natural habitat for their settlement. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The distribution of Metridium senile fimbriatum (M. senile) is positively correlated with the distribution of seafloor litter, suggesting that accumulation of litter may contribute to the proliferation of M. senile.