Highlights
- Differences in copper accumulation and sensitivity were observed between coral species and between coral and zooxanthellae
- Increased CO2 did not influence copper accumulation
- Synergistic effects from combined CO2 and copper exposure were observed in corals
- Altered enzyme activity was observed in both coral exposed to copper or CO2
- A. cervicornis was more affected by copper and P. damicornis was more affected by increased CO2
Abstract
Acidification and land-based sources of pollution have been linked to widespread declines of coral cover in coastal reef ecosystems. In this study, two coral species, Acropora cervicornis and Pocillopora damicornis were exposed to increased copper at two CO2 levels for 96 h. Copper accumulation and anti-oxidant enzyme activities were measured. Copper accumulation only increased in A. cervicornis zooxanthellae and corresponded with photosynthetic toxicity. Enzyme activities in both coral species were affected; however, A. cervicornis was more sensitive than P. damicornis, and zooxanthellae were more affected than animal fractions of holobionts. Generally, activities of all anti-oxidant enzymes increased, with copper exposure in corals; whereas, activities of glutathione reductase and to some degree glutathione peroxidase were observed due to increasing CO2 exposure alone. Exposure to copper in combination with higher CO2 resulted in a synergistic response in some cases. These results provide insight into mechanisms of copper and CO2 impacts in corals.
Bielmyer-Fraser G. K., Patel P., Capo T. & Grosell M., 2018. Physiological responses of corals to ocean acidification and copper exposure. Marine Pollution Bulletin 133: 781-790. Article (subscription required).
