PRJNA540961
Meiofauna communities from seagrass beds Raw sequence reads
Assessing how anthropogenic pressures affect sediment biodiversity underpins our knowledge of how ecological interactions between aquatic plants and sediment communities shape the structure and function of natural systems. At present, we do not understand how seagrass habitat degradation impacts benthic biodiversity, particularly in regard to meiobenthic belowground communities. Here, we evaluated potential indirect effects of disturbance of seagrass meadows on meiobenthic community composition, with a five-month in situ experiment in a tropical seagrass meadow (Thalassia hemprichii). We disturbed these meadows by reducing light availability for plants with two levels of shading and by continuously harvesting above-ground biomass to mimic grazing events (also two levels) and assessed impacts on meiobenthic beta-diversity using Ilumina MiSeq sequencing of environmental 18S rRNA amplicons. Both shading levels (High-HS and low-LS) and the lowest simulated grazing level (LC) had a significant effect on meiobenthic community structure which were mediated by seagrass-associated biotic drivers (changes in rhizome carbon content and plant nitrogen content) and sediment abiotic parameters (sediment C:N ration). Additionally, shading significantly altered the trophic structure and life-history characteristics of the nematode community. The relative abundance of nematode epistrate feeders decreased while the abundance of selective deposit feeders increased in the HS treatment. Shifts in trophic modes were accompanied by changes in the proportion of colonizer vs persistent nematode genera. Our findings show that environmental degradation of seagrass meadows can significantly alter benthic community beta-diversity and structure in coastal areas. This might in turn impact important ecosystem functions mediated by meiofauna in marine sediments.