Seasonal dynamics response mechanism of benthic microbial community to artificial reef habitats

Artificial reefs (ARs) have been globally deployed to enhance and restore coastal resource and ecosystems. Microorganisms play an essential role in marine ecosystems, while the knowledge regarding the impact of ARs on microecology is still limited, particularly data concerning the response of benthic microbial community to AR habitats. In this study, the seasonal dynamics of benthic microbial community in AR and adjacent non-artificial reef (NAR) areas surrounding Xiaoshi Island were investigated with high-throughput sequencing technology. The results revealed that the diversity and structure of microbial community between AR and NAR both displayed pronounced seasonal dynamics. There was a greater influence of season factors on microbial communities than that of habitat type. The microbial communities in AR and NAR habitats were characterized by a limited number of abundant taxa (ranging from 5 to 12 ASVs) with high relative abundance (8.35-25.53%) and numerous rare taxa (from 5994 to 12412 ASVs) with low relative abundance (11.91%-24.91%). Proteobacteria, Bacteroidota and Desulfobacterota were the common predominant phyla, with the relative abundances ranging from 50.94% to 76.76%. A total of 52 biomarkers were discovered, with 15, 4, 6, and 27 biomarkers identified in spring, summer, autumn and winter, respectively. Co-occurrence network analysis indicated that AR displayed a more complex interaction pattern and higher susceptibility to external disturbances. Furthermore, the neutral model and βNTI analyses revealed that the assembly of microbial communities in both AR and NAR is significantly influenced by stochastic processes. This study could provide valuable insights into the impact of ARs construction on the benthic ecosystems and would greatly facilitate the development and implementation of the future AR projects.

Response mechanism of meiofaunal communities to multi-type of artificial reef habitats from the perspective of high-throughput sequencing technology

Multiple types of artificial reefs have been widely deployed in the coast of northern Yellow Sea, which can enhance fishery resources, restore coastal habitats and improve the marine environment. Meiofauna plays important ecological roles in marine ecosystem, but the response mechanism of meiofaunal community to different types of artificial reef is still poorly understood. In this study, we characterized the meiofaunal communities of concrete artificial reef habitat (CAR), rocky artificial reef habitat (RAR), ship artificial reef habitat (SAR) and adjacent natural habitat (NH) using 18S rRNA gene high-throughput sequencing technology, and explored the relationship of community-environment. The results showed that the diversity and community structure of meiofauna differed significantly on both spatial and temporal scales. Spatial differences were mainly contributed to the flow field effects and biological effects generated by artificial habitats, while temporal differences were driven by temperature (T) and dissolved oxygen (DO). The dominant taxa of meiofauna included arthropods, annelids, platyhelminths and nematodes. Platyhelminths were mainly positively influenced by artificial habitats but annelids were the opposite. Co-occurrence network analysis revealed that NH was more sensitive to environmental change than artificial habitat, while the performance of CAR and SAR were more stable. These results indicated that meiofauna can respond accordingly to different types of artificial habitats, and could be superimposed over the normal seasonal effects. The current study could provide fundamental data for understanding the response mechanism of meiofaunal community to different types of artificial habitats and a reference for assessments of the impact of artificial reefs on the marine environment.

Evaluation of artificial reef habitats as reconstruction or enhancement tools of benthic fish communities in northern Yellow Sea

Artificial reefs have been widely deployed in the northern Yellow Sea. However, the differences in the ecological benefits on different types of artificial reef habitats are still poorly understood. In this study, the temporal and spatial differences on benthic fish communities were evaluated among concrete artificial reef habitat (CAR), rocky artificial reef habitat (RAR), ship artificial reef habitat (SAR) around Xiaoshi Island in northern Yellow Sea. The results indicated that all three types of artificial reef habitats can enhance the diversity variables of benthic fish communities, and fish abundance, species richness and Shannon-Wiener index of CAR were generally better than the other two. CAR and RAR hosted similar community composition of benthic fish, and all types of habitats showed significant differences in community composition between winter-spring and summer-autumn. Environmental factors, especially water temperature, can also affect the community composition by affecting the migration of temperature-preferred species. Overall, the enhancement effects of artificial habitats on fisheries productivity varied with fish species and reef types. This study will help to understand the ecological effects of different types of artificial reefs in northern Yellow Sea, and then could give an insight for scientific construction of artificial reefs in this region.