Structural and functional vulnerability to elevated pCO2 in marine benthic communities

• Main Authors: Christen, Nadja, Calosi, Piero, McNeill, C L, Widdicombe, Stephen
• Format: Dataset
• Language: English
• Published: PANGAEA 2013
• Subjects: Alkalinity; total; standard deviation; Aragonite saturation state; Benthos; Bicarbonate ion; Biomass; wet mass; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (<20 L); Calcification/Dissolution; Calcite saturation state; Calcium carbonate; mass; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Community composition and diversity; Description; Entire community; Evenness of species; EXP; Experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Identification; Laboratory experiment; Mount_Batten; Net calcification rate of calcium carbonate; North Atlantic; Number of calcareous individuals
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.823607; https://doi.org/10.1594/PANGAEA.823607

The effect of elevated pCO2/low pH on marine invertebrate benthic biodiversity, community structure and selected functional responses which underpin ecosystem services (such as community production and calcification) was tested in a medium-term (30 days) mesocosm experiment in June 2010. Standardised intertidal macrobenthic communities, collected (50.3567°N, 4.1277°W) using artificial substrate units (ASUs), were exposed to one of seven pH treatments (8.05, 7.8. 7.6, 7.4, 7.2, 6.8 and 6.0). Community net calcification/dissolution rates, as well as changes in biomass, community structure and diversity, were measured at the end of the experimental period. Communities showed significant changes in structure and reduced diversity in response to reduced pH: shifting from a community dominated by calcareous organisms to one dominated by non-calcareous organisms around either pH 7.2 (number of individuals and species) or pH 7.8 (biomass). These results were supported by a reduced total weight of CaCO3 structures in all major taxa at lowered pH and a switch from net calcification to net dissolution around pH 7.4 (Omega calc = 0.78, Omega ara = 0.5). Overall community soft tissue biomass did not change with pH and high mortality was observed only at pH 6.0, although molluscs and arthropods showed significant decreases in soft tissue. This study supports and refines previous findings on how elevated pCO2 can induce changes in marine biodiversity, underlined by differential vulnerability of different phyla. In addition, it shows significant elevated pCO2-/low pH-dependent changes in fundamental community functional responses underpinning changes in ecosystem services.