AB 15:73-86 (2012)  -  DOI: https://doi.org/10.3354/ab00408

ABSTRACT: There is an increasing need to predict the effects of global climate change on ecologically important marine organisms and a demand for proactive solutions to reduce CO₂ emissions. CO₂ sequestration is one such method. While this offers a practical solution, recognition should be given to the potential for considerable localised effects on marine organisms in the event of leakage. This laboratory study quantifies the impact of exposure to elevated pCO₂ conditions on the physiological and behavioural responses of a relatively tolerant marine organism. Burrowing shrimps Upogebia deltaura were exposed to CO₂-enriched seawater for 35 d to treatments of 1396 µatm (pH 7.64), 2707 µatm (pH 7.35) and 14110 µatm (pH 6.71). CO₂ levels represented scenarios which included coastal ocean acidification and extremely elevated CO₂ associated with geological CO₂ sequestration leaks. Results were compared with those from shrimps maintained in a control treatment (pH 7.99). U. deltaura appeared to be tolerant to elevated pCO₂ predicted to occur in the year 2100 (1396 µatm, pH 7.64). However, at 2707 µatm (pH 7.35) shrimps experienced extracellular acidosis, but no difference in haemolymph bicarbonate concentration, suggesting they have little or no buffering capacity, although there was no evidence of other physiological costs in terms of metabolism, osmotic regulation, shell mineralogy, growth and overall activity. At pH 6.71, before 100% mortality occurred, significant differences in activity were observed compared with shrimps in other pH treatments. Results suggest deleterious consequences for benthic ecosystems in the event of a CO₂ sequestration leakage.

KEY WORDS: Ocean acidification · Ecosystem engineer · Oygen consumption · Homeostasis · Haemolymph regulation · CO₂ sequestration · Carbon capture and storage · CCS · Upogebia deltaura · Upwelling