Effects of sediment and water column acidification on growth, survival, and burrowing behaviour of invertebrates
University of New Brunswick
In coastal regions, sediment-dwelling animals are exposed to a high degree of variability in ocean and sediment pH which is expected to increase in the future due to anthropogenic effects. The present study examined the impacts of a 6-week exposure to reduced-pH (acidified) water on length, weight, and mortality of 2 species of molluscs and 1 species of crustaceans that inhabit mudflats: juvenile soft-shell clams (Mya arenaria), adult mud snails (Tritia obsoleta), and adult mud shrimp (Corophium volutator), and subsequently investigated the interactive effects of this exposure and sediment acidification on burrowing behaviour of these species. The predator-prey relationship between mud snails and mud shrimp was also examined by investigating the effects of water column acidification on mud shrimp mortality in the presence of mud snails. Acidified water increased mortality of mud shrimp held alone but not of those in the presence of mud snails, decreased shell length of mud snails, and had no significant effect on soft-shell clams. Sediment acidification reduced mud shrimp burrowing, and prior exposure to acidified water reduced mud snail burrowing, but neither affected soft-shell clam burrowing. These results suggest taxonomic variation in species response to ocean and sediment acidification with respect to growth, mortality, and burrowing behaviour.