Biology subjects

Wrede, A.

Publications and source records attributed to Wrede, A..

3 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↗

bioRxiv2025

Single-cell Spatial Transcriptomics Reveals Disease-specificMicroenvironmental Niches in Neurodegeneration and COVID-19

Neurodegenerative diseases and infections can produce lasting effects on brain function, yet the spatial molecular mechanisms underlying these changes remain poorly understood. Here, we present high-resolution spatial transcriptomics of 40 postmortem brain samples from patients with Parkinsons disease, frontotemporal dementia, dementia with Lewy bodies, and severe COVID-19. Analyzing over 1.5 million spatially resolved cells across dorsolateral prefrontal cortex and anterior cingulate cortex revealed disease-specific transcriptional signatures with pronounced layer-and region-specificity. In Parkinsons disease, we identified stressed neurons creating distinctive microenvironmental gradients where metabolic and protein degradation pathways are elevated near stress epicenters, while regenerative processes increase with distance. COVID-19 brains displayed extensive peripheral immune cell infiltration, particularly in the subcortical white matter, accompanied by compromised blood-brain barrier and coordinated neuroinflammatory responses from microglia, astrocytes, and endothelial cells. Integration of miRNA sequencing with spatial transcriptomics uncovered layer-specific regulatory patterns, including neuroinflammation-associated miR-155. This atlas provides unprecedented insights into disease pathology and highlights the critical importance of spatial molecular context in understanding brain disorders. Key Messages[1] A high-resolution single-cell spatial transcriptomics atlas of the dorsolateral prefrontal cortex and anterior cingulate cortex across neurodegenerative conditions and severe COVID-19 [2] Region-and layer-specific transcriptional dysregulation across disease comparisons reveals disease-specific differential vulnerability [3] Metabolically stressed cells found selectively in the anterior cingulate cortex of Parkinsons disease patients but not in dementia with Lewy bodies, along with detailed characterization of their spatial microenvironment [4] Peripheral immune cell clusters identified in the white matter of the cerebral cortex of COVID-19 patients, with detailed characterization of their spatial microenvironment [5] Integration of bulk miRNA sequencing reveals cortical layer-specific miRNA regulatory patterns

neuroscience↗

bioRxiv2020

Simplicity in numbers: Implications of diversity for the community Bioturbation Potential (BPc)

The mobility of particles and solutes within aquatic sediment is substantially impacted by faunal bioturbation activities such as bioirrigation and sediment reworking. The non-quantitative community bioturbation potential (BPc) aims to estimate the potential of a given benthic community for bioturbation activities, based on the functional traits of the species within that community. We argue that in sufficiently diverse communities, the characteristics of individual species, expressed as traits scores, average each other out, and approach a universal constant. This enables to derive a simpler community bioturbation potential (BPs), which may be applied in cases when taxonomic expertise or trait data are not available. As a proof of concept, we evaluated a dataset of 84 benthos assemblages, and found a high degree of agreement of full BPc and simplified BPs.

ecology↗