Impact of elevated levels of CO2 on animal mediated ecosystem function: The modification of sediment nutrient fluxes by burrowing urchins

• Main Authors: Widdicombe, Stephen, Beesley, A, Berge, J A, Dashfield, S L, McNeill, C L, Needham, H R, Øxnevad, S
• Format: Dataset
• Language: English
• Published: PANGAEA 2013
• Subjects: Alkalinity; total; standard deviation; Ammonium; flux; Animalia; Aragonite saturation state; Behaviour; Benthic animals; Benthos; Bicarbonate ion; Bottles or small containers/Aquaria (<20 L); Brissopsis lyrifera; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Comment; Echinocardium cordatum; Echinodermata; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Laboratory experiment; Mass; Mortality/Survival; Nitrate; Nitrite; North Atlantic; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Phosphate; Potentiometric; Potentiometric titration; Salinity; Silicate; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.833188; https://doi.org/10.1594/PANGAEA.833188

A mesocosm experiment was conducted to quantify the relationships between the presence and body size of two burrowing heart urchins (Brissopsis lyrifera and Echinocardium cordatum) and rates of sediment nutrient flux. Furthermore, the impact of seawater acidification on these relationships was determined during this 40-day exposure experiment. Using carbon dioxide (CO2) gas, seawater was acidified to pHNBS 7.6, 7.2 or 6.8. Control treatments were maintained in natural seawater (pH = 8.0). Under normocapnic conditions, burrowing urchins were seen to reduce the sediment uptake of nitrite or nitrate whilst enhancing the release of silicate and phosphate. In acidified (hypercapnic) treatments, the biological control of biogeochemical cycles by urchins was significantly affected, probably through the combined impacts of high CO2 on nitrifying bacteria, benthic algae and urchin behaviour. This study highlights the importance of considering biological interactions when predicting the consequences of seawater acidification on ecosystem function.