Empirical Evidence Reveals Seasonally Dependent Reduction in Nitrification in Coastal Sediments Subjected to Near Future Ocean Acidification

• Main Authors: Braeckman, Ulrike, Van Colen, Carl, Guilini, Katja, Van Gansbeke, D, Soetaert, Karline, Vincx, Magda, Vanaverbeke, Jan, Vopel, Kay
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2014
• Subjects: Abra alba; Bathyporeia elegans; Benthos; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria <20 L; Coast and continental shelf; Community composition and diversity; Entire community; Glycera alba; Laboratory experiment; Macoma balthica; Magelona johnstoni; Magelona mirabilis; Nephtys cirrosa; Nephtys hombergii; North Atlantic; Oligochaeta sp.; Other metabolic rates; Respiration; Scoloplos armiger; Sigalion mathildae; Soft-bottom community; Spionida sp.; Tellina fabula; Temperate; Urothoe brevicornis; Event label; Sample ID; Experiment; Date; Date/time start; Date/time end; Community, oxygen consumption; Ammonium, flux; Nitrate, flux; Nitrification, oxygen consumption; Nitrogen mineralization; Chlorophyll a; Replicate; Treatment; Diameter; Genus; Species; Individuals; Biomass, wet mass; Abundance per area; pH; pH, standard error; Temperature, water; Temperature, water, standard error; Salinity; Salinity, standard error; Oxygen; Oxygen, standard error; Alkalinity, total; Alkalinity, total, standard error; Partial pressure of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide water at sea surface temperature wet air, standard error; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard error; Aragonite saturation state; Aragonite saturation state, standard error; Calcite saturation state; Calcite saturation state, standard error; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Estimated from mass budget; Potentiometric; Potentiometric titration; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.840479; https://doi.pangaea.de/10.1594/PANGAEA.840479

Research so far has provided little evidence that benthic biogeochemical cycling is affected by ocean acidification under realistic climate change scenarios. We measured nutrient exchange and sediment community oxygen consumption (SCOC) rates to estimate nitrification in natural coastal permeable and fine sandy sediments under pre-phytoplankton bloom and bloom conditions. Ocean acidification, as mimicked in the laboratory by a realistic pH decrease of 0.3, significantly reduced SCOC on average by 60% and benthic nitrification rates on average by 94% in both sediment types in February (pre-bloom period), but not in April (bloom period). No changes in macrofauna functional community (density, structural and functional diversity) were observed between ambient and acidified conditions, suggesting that changes in benthic biogeochemical cycling were predominantly mediated by changes in the activity of the microbial community during the short-term incubations (14 days), rather than by changes in engineering effects of bioturbating and bio-irrigating macrofauna. As benthic nitrification makes up the gross of ocean nitrification, a slowdown of this nitrogen cycling pathway in both permeable and fine sediments in winter, could therefore have global impacts on coupled nitrification-denitrification and hence eventually on pelagic nutrient availability. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne et al, 2014) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation is 2014-12-04.