Seawater carbonate chemistry and gene abundance and community composition in two contrasting coastal marine sediments

• Main Authors: Currie, Ashleigh R, Tait, Karen, Parry, Helen E, de Francisco-Mora, Beatriz, Hicks, Natalie, Osborn, A M, Widdicombe, Steve, Stahl, Henrik
• Format: Dataset
• Language: English
• Published: PANGAEA 2017
• Subjects: Alkalinity; total; standard deviation; Ammonium; Aragonite saturation state; Benthos; Bicarbonate ion; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Campaign; Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Community composition and diversity; Containers and aquaria (20-1000 L or < 1 m**2); Day of experiment; Depth; description; Eden_Estuary; Entire community; Evenness of species; Event label; EXP; Experiment; Experiment duration; Experiment week; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gene abundance; Identification; Laboratory experiment; Margelf index; Nitrate and Nitrite; North Atlantic; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.890872; https://doi.org/10.1594/PANGAEA.890872

Marine ecosystems are exposed to a range of human-induced climate stressors, in particular changing carbonate chemistry and elevated sea surface temperatures as a consequence of climate change. More research effort is needed to reduce uncertainties about the effects of global-scale warming and acidification for benthic microbial communities, which drive sedimentary biogeochemical cycles. In this research, mesocosm experiments were set up using muddy and sandy coastal sediments to investigate the independent and interactive effects of elevated carbon dioxide concentrations (750 ppm CO2) and elevated temperature (ambient + 4 °C) on the abundance of taxonomic and functional microbial genes. Specific q-PCR primers were used to target archaeal, bacterial and cyanobacterial/chloroplast 16S rRNA in both sediment types. Nitrogen cycling genes archaeal and bacterial ammonia monooxygenase (amoA) and bacterial nitrite reductase (nirS) were specifically targeted to identify changes in microbial gene abundance and potential impacts on nitrogen cycling. In muddy sediment, microbial gene abundance, including amoA and nirS genes, increased under elevated temperature and reduced under elevated CO2 after 28 days, accompanied by shifts in community composition. In contrast, the combined stressor treatment showed a non-additive effect with lower microbial gene abundance throughout the experiment. The response of microbial communities in the sandy sediment was less pronounced, with the most noticeable response seen in the archaeal gene abundances in response to environmental stressors over time. 16S rRNA genes (amoA and nirS) were lower in abundance in the combined stressor treatments in sandy sediments. Our results indicated that marine benthic microorganisms, especially in muddy sediments, are susceptible to changes in ocean carbonate chemistry and seawater temperature, which ultimately may have an impact upon key benthic biogeochemical cycles.