Publication Date:
2024-03-15
Description:
Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in sub-tropical regions. The present study investigates the effects of ocean acidification on sediment composition, processes and sediment-water fluxes in an Arctic coastal system. Undisturbed sediment cores, exempt of large dwelling organisms, were collected, incubated for a period of 14 days, and subject to a gradient of pCO2 covering the range of values projected for the end of the century. On five occasions during the experimental period, the sediment cores were isolated for flux measurements (oxygen, alkalinity, dissolved inorganic carbon, ammonium, nitrate, nitrite, phosphate and silicate). At the end of the experimental period, denitrification rates were measured and sediment samples were taken at several depth intervals for solid-phase analyses. Most of the parameters and processes (i.e. mineralization, denitrification) investigated showed no relationship with the overlying seawater pH, suggesting that ocean acidification will have limited impacts on the microbial activity and associated sediment-water fluxes on Arctic shelves, in the absence of active bio-irrigating organisms. Only following a pH decrease of 1 pH unit, not foreseen in the coming 300 years, significant enhancements of calcium carbonate dissolution and anammox rates were observed. Longer-term experiments on different sediment types are still required to confirm the limited impact of ocean acidification on shallow Arctic sediment processes as observed in this study.
Keywords:
Alkalinity, total; Alkalinity, total, flux; Ammonium; Ammonium, flux; Aragonite saturation state; Arctic; Benthos; beta-Carotene, beta,beta-Carotene per unit sediment mass; Bicarbonate ion; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (〈20 L); Calcite saturation state; Calculated using seacarb; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, flux; Carbon, organic, total; Carbon, total; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chlorophyll a + pheophorbides per unit sediment mass; Chlorophyll a per unit sediment mass; Chlorophyll b per unit sediment mass; Chlorophyll c per unit sediment mass; Coast and continental shelf; Core; DATE/TIME; Date/time end; Date/time start; Density, mass density; DEPTH, sediment/rock; Depth water equivalent; Deviation; Diadinoxanthin per unit sediment mass; Diatoxanthin per unit sediment mass; Entire community; EPOCA; European Project on Ocean Acidification; Fucoxanthin per unit sediment mass; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Identification; Laboratory experiment; Median, grain size; Neoxanthin per unit sediment mass; Nitrate; Nitrate, flux; Nitrate and Nitrite; Nitrite; Nitrite, flux; Nitrite and nitrate, flux; Nitrogen, inorganic, dissolved, flux; Nitrogen, total; OA-ICC; Ocean Acidification International Coordination Centre; Oxygen; Oxygen, flux, sediment oxygen demand; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Peak area; Percentile 10; Percentile 90; Peridinin per unit sediment mass; pH; Phaeophorbide a per unit sediment mass; Phaeophytin a + allomer and isomer per unit sediment mass; Phaeophytin a per unit sediment mass; Phosphate; Phosphate, flux; Polar; Potentiometric; Potentiometric titration; Salinity; Sample volume; Silicon; Silicon, particulate, flux; Size fraction 〈 0.002 mm, clay; Size fraction 〈 0.004 mm, clay; Size fraction 〈 0.008 mm, clay; Size fraction 〈 0.016 mm; Size fraction 〈 0.032 mm; Size fraction 〈 0.050 mm; Size fraction 〈 0.063 mm, mud, silt+clay; Size fraction 0.250-0.125 mm, 2.0-3.0 phi, fine sand; Size fraction 1.000-0.500 mm, 0.0-1.0 phi, coarse sand; Soft-bottom community; Spectrophotometric; Temperature, water; Violaxanthin per unit sediment mass; Zeaxanthin per unit sediment mass; δ13C, particulate organic carbon; δ13C, total particulate carbon; δ15N, particulate organic nitrogen
Type:
Dataset
Format:
text/tab-separated-values, 11348 data points
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