Biology subjects

Beermann, J.

Publications and source records attributed to Beermann, J..

2 recordsLinked to original sources

bioRxiv2026

Benthic macrofauna and microbiota mediate bottom trawling impacts on long-term carbon storage in marine sediments

The seafloor is the largest organic carbon sink on Earth. Its benthic fauna and microbiota jointly regulate long-term carbon storage by assimilating and degrading sedimentary organic matter (SOM). Bottom trawling threatens the long-term storage of organic matter by physical disturbance of the seafloor and remobilization of SOM. Trawling also impacts faunal and microbial communities and their diversity, but the implications of these ecological consequences for long-term carbon storage dynamics are poorly understood. Here, we combined datasets of paired faunal and microbial communities from the North Sea and used structural equation modeling to disentangle direct and biotically mediated effects of bottom trawling on SOM. One third of trawling-induced SOM loss is indirect and mediated by shifts in benthic faunal and microbial communities. Microbial community structure directly affected SOM and represented a key link in this pathway. Microbial effects on SOM were strongly tied to changes in metabolic traits. SOM loss coincides with increased microbial aerobic respiration potential, whereas SOM increases correlated with microbial assimilation processes, including dark carbon fixation. Benthic fauna impact SOM indirectly by shaping benthic microbial communities. Faunal diversity and species traits related to bioturbation promoted shifts in benthic microbiota that favor OM storage, corroborating their indirect but essential role in seafloor carbon dynamics. This study reveals that bottom trawling alters seafloor carbon storage not only through physical disturbance but also by disrupting faunal-microbial interactions that regulate sediment carbon dynamics. Taxonomic and functional shifts in benthic microbiota are a key, but underestimated, component of the processes regulating the seafloor carbon sink and warrant better integration of benthic biodiversity and ecological processes into assessments of seafloor carbon storage under anthropogenic pressures.

ecology↗

bioRxiv2023

From microbial communities to regional biogeography: Unraveling patterns, determinants and the influence of bottom trawling in benthic microbiota

Microbial composition and diversity in marine sediments are shaped by environmental, biological, and anthropogenic processes that operate on different scales. However, our understanding of benthic microbial biogeography remains limited. Here, we study how benthic microbiota vary at a regional scale in the North Sea with sediment characteristics, temperature, organic matter content, shear bed stress and bottom trawling intensity, a prevalent industrial fishing practice which heavily impacts benthic ecosystems. Using 16S rDNA amplicon sequencing, we characterized benthic microbiota from the top centimeter of 349 sediment samples and used uni-and multivariate statistical models, accounting for spatial autocorrelation, to disentangle the effects of the different predictors. Fitted models demonstrate how the geographic interplay of different environmental anthropogenic drivers shapes the structure and functioning of benthic microbial communities. Sediment properties were the primary determinants, with diversity increasing with sediment permeability but at the same time increasing with mud content, highlighting different underlying processes. Alpha diversity also increased nonlinearly with total organic matter content and temperature and showed a more complex relationship with bottom shear stress but decreased with bottom trawling intensity. These trawling associated diversity changes were accompanied by shifts in functional groups related to energy metabolism. Specifically, with increasing trawling intensity, we observed a transition toward more aerobic heterotrophic and less denitrifying metabolism. Our findings provide first insights of benthic microbial biogeographic patterns on a large spatial scale and illustrate how anthropogenic activity such as bottom trawling may influence the distribution and abundances of microbes and overall benthic metabolism at macroecological scales.

ecology↗