Seawater carbonate chemistry and benthic primary production and inorganic nitrogen fluxes in two coastal sediments, supplement to: Vopel, Kay; Del-Río, Vopel; Pilditch, Conrad A (2018): Effects of CO2 enrichment on benthic primary production and inorganic nitrogen fluxes in two coastal sediments. Scientific Reports, 8(1)

• Main Authors: Vopel, Kay, Del-Río, Vopel, Pilditch, Conrad A
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2018
• Subjects: Benthos; Coast and continental shelf; Containers and aquaria 20-1000 L or < 1 m**2; Entire community; Laboratory experiment; Other studied parameter or process; Soft-bottom community; South Pacific; Temperate; Event label; Type; Identification; Oxygen uptake, total; Difference; Ammonium, flux; Nitrite and nitrate, flux; Treatment; Time point, descriptive; Sediment type; Light mode; Salinity; Salinity, standard deviation; Temperature, water; Temperature, water, standard deviation; Partial pressure of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide, standard deviation; pH; pH, standard deviation; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Alkalinity, total; Alkalinity, total, standard deviation; Ammonium; Ammonium, standard deviation; Nitrate and Nitrite; Nitrate and Nitrite, standard deviation; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Aragonite saturation state; Calcite saturation state; Experiment; Calculated using CO2calc; Potentiometric; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Kay; Pacific; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.887792; https://doi.pangaea.de/10.1594/PANGAEA.887792

Ocean acidification may alter the cycling of nitrogen in coastal sediment and so the sediment-seawater nitrogen flux, an important driver of pelagic productivity. To investigate how this perturbation affects the fluxes of NOX- (nitrite/nitrate), NH4+ and O2, we incubated estuarine sand and subtidal silt in recirculating seawater with a CO2-adjusted pH of 8.1 and 7.9. During a 41-day incubation, the seawater kept at pH 8.1 lost 97% of its NOX- content but the seawater kept at pH 7.9 lost only 18%. Excess CO2 increased benthic photosynthesis. In the silt, this was accompanied by a reversal of the initial NOX- efflux into influx. The estuarine sand sustained its initial NOX- influx but, by the end of the incubation, released more NH4+ at pH 7.9 than at pH 8.1. We hypothesise that these effects share a common cause; excess CO2 increased the growth of benthic microalgae and so nutrient competition with ammonia oxidising bacteria (AOB). In the silt, diatoms likely outcompeted AOB for NH4+ and photosynthesis increased the dark/light fluctuations in the pore water oxygenation inhibiting nitrification and coupled nitrification/denitrification. If this is correct, then excess CO2 may lead to retention of inorganic nitrogen adding to the pressures of increasing coastal eutrophication. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2016) 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 by seacarb is 2018-03-28.