Hypoxia is common in marine environments and a major stressor for marine organisms inhabiting benthic and intertidal zones. Several studies have explored the responses of these organisms to hypoxic stress at the whole organism level with a focus on energy metabolism and mitochondrial response, but the instrinsic mitochondrial responses that support the organelle’s function under hypoxia and reoxygenation (H/R) stress are not w...

Microplastic particles have been found in all the world’s oceans. Since their surfaces are microbially colonised, research is currently determining whether microbes are able to degrade the synthetic polymers. We show that their contribution to the biodegradation of plastics seems to be extremely limited. Also, it is unlikely that microbes specialise in plastic degradation through evolutionary adaptation. This is not only due t...

Summary Microplastics in marine ecosystems are colonized by diverse prokaryotic and eukaryotic communities. How these communities and their functional profiles are shaped by the artificial surfaces remains broadly unknown. In order to close this knowledge gap, we set up an in situ experiment with pellets of the polyolefin polymer polyethylene (PE), the aromatic hydrocarbon polymer polystyrene (PS), and wooden beads along a coa...

Summary Marine sponges represent one of the few eukaryotic groups that frequently harbour symbiotic members of the Thaumarchaeota , which are important chemoautotrophic ammonia‐oxidizers in many environments. However, in most studies, direct demonstration of ammonia‐oxidation by these archaea within sponges is lacking, and little is known about sponge‐specific adaptations of ammonia‐oxidizing archaea (AOA). Here, we characteri...

Summary Metal‐sulfides are wide‐spread in marine benthic habitats. At deep‐sea hydrothermal vents, they occur as massive sulfide chimneys formed by mineral precipitation upon mixing of reduced vent fluids with cold oxygenated sea water. Although microorganisms inhabiting actively venting chimneys and utilizing compounds supplied by the venting fluids are well studied, only little is known about microorganisms inhabiting inacti...

Summary Chemoautotrophic bacteria belonging to the genus Sulfurimonas (class Campylobacteria ) were previously identified as key players in the turnover of zero‐valence sulfur, a central intermediate in the marine sulfur cycle. S. denitrificans was further shown to be able to oxidize cyclooctasulfur (S 8 ). However, at present the mechanism of activation and metabolism of cyclooctasulfur is not known. Here, we assessed the tra...

Summary Marine microscopic algae carry out about half of the global carbon dioxide fixation into organic matter. They provide organic substrates for marine microbes such as members of the Bacteroidetes that degrade algal polysaccharides using carbohydrate‐active enzymes (CAZymes). In Bacteroidetes genomes CAZyme encoding genes are mostly grouped in distinct regions termed polysaccharide utilization loci (PULs). While some stud...