Impact of sub-seabed CO 2 leakage on macrobenthic community structure and diversity

Developments since 2005 in understanding potential environmental impacts of CO2 leakage from geological storage

“…There was considerable heterogeneity in chemical changes to both the water column and sediments with significant implications for detection, quantification and impact. Impact on benthic macrofauna, in terms of both number of species (biodiversity) and number of individuals (mortality and emigration) was significant towards the end of the 37 day injection period, but recovery of both chemical parameters and biological communities was rapid, within a few weeks Widdicombe et al, 2015). No impacts were seen on caged surface megafauna near the release site (Pratt et al, 2015) nor on the behaviour of mobile surface megafauna over the release site indicating some short term resilience in the selected species for this limited release.…”

“…The major benefit of this approach has been that the scale, longevity and nature of any exposure could be tightly controlled, and any confounding effects from other factors minimised. Unsurprisingly, therefore, the recognition of CCS as a potential environmental threat caused a rapid growth in such studies with new data produced describing the effect of CO 2 exposure on a range of marine species and hence the potential impacts of CCS leakage (see Widdicombe et al, 2015). However, unlike many toxicants, CO 2 is an element to which marine organisms are already exposed; many have strong physiological responses to CO 2 or to other, CO 2 -related, chemical changes (e.g.…”

“…temperature, hypoxia, food shortage, suspended matter) compounding the impact of any single environmental stress (such as CO 2 exposure from CCS leakage) and severely inhibiting the scope for physiological and behavioural adjustments to overcome that stress (Riedel et al, 2014;Queirós et al, 2015). It is unlikely therefore that hypercapnia will act as a single stressor, and caution is needed when assessing tolerances of species to environmental perturbations from studies that have only factored in one variable.…”

“…In post-injection surveys, observers should be looking, in particular, for changes in the community structure and diversity of infaunal organisms that have been shown to be sensitive to CO 2 impact (e.g. Widdicombe et al, 2015;). For CCS leakage, these changes could be a reduction in the presence of, juveniles of calcified taxa or a reduction in the occurrence of calcium carbonate structures (e.g.…”

No evidence for impacts to the molecular ecophysiology of ion or CO 2 regulation in tissues of selected surface-dwelling bivalves in the vicinity of a sub-seabed CO 2 release

“…Other papers within this issue have characterised the geological and geochemical impact of the CO 2 gas release at the Ardmucknish Bay experimental site, and perturbations in the sediment microstructure and in the geochemistry of sediment pore waters, as well as the overlying water column, have been reported already (Blackford et al, 2014). Localised and temporary impacts have been reported on the macro-and micro-infaunal community structure in response to CO 2 gas release (Widdicombe et al, 2015;Tait et al, 2015). These impacts were of a similar magnitude to the natural seasonal changes recorded at the other sites (Z2, Z3 and Z4), away from the immediate footprint of gas bubbles.…”