Description: Physicochemical parameters and relative abundance of selected nutrient cycling genes were measured in sediment and pore water samples taken from a fish farming area (Site S3 16◦23.097 N, 119◦55.551 E, depth 12.6m) and a control site (Site S1 16◦22.960 N, 119◦54.723 E, depth 15m) not influenced by fish farming. From each site, five pairs of cores representing five biological replicates were collected. One core from each pair was used for physicochemical analysis while the other cores were used for microbial community analysis. Samples from S1 were collected on 2017-06-10 and samples from S3 were collected the following day. This dataset presents grain size distribution.

Description: Global warming poses new threats to marine ecosystems since rising seawater temperature potentially induces cascading effects in biogeochemical cycles and food webs. Heterotrophic bacteria are the main producers of CO2 in the ocean, thereby counteracting the biological drawdown of CO2 by primary production. In Antarctic marine systems, low seawater temperature, and the low availability of labile organic matter are major environmental constraints on bacterial growth and degradation activity. However, temperature and the availability of resources for heterotrophic bacteria undergo considerable change induced by climate warming combined with subsequent ice melt and changes in primary productivity. This project aims to test single and combined effects of temperature and organic matter availability on Antarctic marine bacterioplankton. This data set includes measurements on bacterial biomass production at 0°C and 3°C measured alongside the CTD casts during the Polarstern cruise PS111 to the Weddell Sea. Samples were collected in the upper 100 m of the water column at the Eastern Weddell Sea Shelf and at the Filchner-Ronne ice shelf.

Description: Milkfish (Chanos chanos) is one of the most important aquaculture species in Asian countries. These teleost fish are traditionally cultured in outdoor-based systems and therefore have to cope with daily and/or seasonally changing environmental conditions. Temperature changes beyond the optimal range of a fish species are known to induce an endocrine stress response resulting in the release of cortisol via the hypothalamic-pituitary-interrenal axis. Moreover, (thermal) stress induces glucocorticoid-mediated changes in the fish's energy metabolism to cope with the stressor(s) and regain homeostasis. Long-term elevations of cortisol are known to be detrimental for fish performance. In this study, we investigated the stress response of juvenile milkfish, which were exposed to a gradual temperature increase of 1°C per day over 7 days in the range from 26°C to 33°C, followed by an exposure to constant 33°C for 21 days. We quantified ontogenetic (OG) and regenerated (RG) scale cortisol to evaluate chronic stress. To investigate metabolic implications and oxidative stress response, activity levels of key enzymes involved in metabolic (isocitrate dehydrogenase - IDH, lactate dehydrogenase - LDH, electron transfer system - ETS) and antioxidant (superoxide dismutase - SOD, catalase - CAT) related pathways were quantified. Furthermore, we measured available energy resources (protein, carbohydrates, lipids) and potential cellular damage due to oxidative stress (lipid peroxidation - LPO). Finally, changes in the gut microbiome of the milkfish related to the temperature stress were analyzed to elucidate their role in the stress response and interactions with physiological parameters. This study is part of the ACUTE project (AquaCUlture practice in Tropical coastal Ecosystems - Understanding ecological and socio-economic consequences) funded by the Leibniz Association grant SAW-2015-ZMT-4. It is associated with the following publications: Hanke et al., 2019 (doi:10.1016/j.aquaculture.2018.09.016) and Hassenrück et al., 2020 (doi:10.3390/microorganisms9010005). The final OTU table and statistical analysis scripts for Hassenrück et al., 2020 are supplied as further details to this data set.

Description: This data collection comprises environmental data and taxonomic parameters of the investigated biocrusts of sampling sites in coastal and inland sand dunes in northern Germany. Sampling took place in spring 2020 and winter 2021. Biocrusts and uppermost sediment samples were collected along dune successional gradients and sequenced by LGC Genomics Ltd. Corresponding sequence data of biocrust organisms are archived at the European Nucleotide Archive.