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The deep pelagic ocean is increasingly subjected to human-induced environmental change. While pelagic animals provide important ecosystem functions including climate regulation, species-specific responses to stressors remain poorly documented. Here, we investigate the effects of simulated ocean warming and sediment plumes on the cosmopolitan deep-sea jellyfish Periphylla periphylla, combining insights gained from physiology, gene expression and changes in associated microbiota. Metabolic demand was elevated following a 4 °C rise in temperature, promoting genes related to innate immunity but suppressing aerobic respiration. Suspended sediment plumes provoked the most acute and energetically costly response through the production of excess mucus (at ≥17 mg L -1 ), while inducing genes related to aerobic respiration and wound repair (at ≥167 mg L -1 ). Microbial symbionts appeared to be unaffected by both stressors, with mucus production maintaining microbial community composition. If these responses are representative for other gelatinous fauna, an abundant component of pelagic ecosystems, the effects of planned exploitation of seafloor resources may impair deep pelagic biodiversity and ecosystem functioning., (© 2023. The Author(s).)

Anaerobic oxidation of ammonium (anammox) in oxygen minimum zones (OMZs) is a major pathway of oceanic nitrogen loss. Ammonium released from sinking particles has been suggested to fuel this process. During cruises to the Peruvian OMZ in April-June 2017 we found that anammox rates are strongly correlated with the volume of small particles (128-512 µm), even though anammox bacteria were not directly associated with particles. This suggests that the relationship between anammox rates and particles is related to the ammonium released from particles by remineralization. To investigate this, ammonium release from particles was modelled and theoretical encounters of free-living anammox bacteria with ammonium in the particle boundary layer were calculated. These results indicated that small sinking particles could be responsible for ~75% of ammonium release in anoxic waters and that free-living anammox bacteria frequently encounter ammonium in the vicinity of smaller particles. This indicates a so far underestimated role of abundant, slow-sinking small particles in controlling oceanic nutrient budgets, and furthermore implies that observations of the volume of small particles could be used to estimate N-loss across large areas.

Colorectal cancer (CRC) incidence increases with age, and early onset of the disease is an indication of genetic predisposition, estimated to cause up to 30% of all cases. To identify genes associated with early-onset CRC, we investigated gene expression levels within a series of young patients with CRCs who are not known to carry any hereditary syndromes (n=24; mean 43 years at diagnosis), and compared this with a series of CRCs from patients diagnosed at an older age (n=17; mean 79 years). Two individual genes were found to be differentially expressed between the two groups, with statistical significance; CLC was higher and IFNAR1 was less expressed in early-onset CRCs. Furthermore, genes located at chromosome band 19q13 were found to be enriched significantly among the genes with higher expression in the early-onset samples, including CLC. An elevated immune content within the early-onset group was observed from the differentially expressed genes. By application of outlier statistics, H3F3A was identified as a top candidate gene for a subset of the early-onset CRCs. In conclusion, CLC and IFNAR1 were identified to be overall differentially expressed between early- and late-onset CRC, and are important in the development of early-onset CRC.