Coastal hypoxia is a problem that is predicted to increase rapidly in the future. At the same time, we are facing rising atmospheric CO2 concentrations, which are increasing the pCO2 and acidity of coastal waters. These two drivers are well studied in isolation; however, the coupling of low O2 and pH is likely to provide a more significant respiratory challenge for slow moving and sessile invertebrates than is currently predicted. The Gullmar Fjord in Sweden is home to a range of habitats, such as sand and mud flats, seagrass beds, exposed and protected shorelines and rocky bottoms. Moreover, it has a history of both natural and anthropogenically enhanced hypoxia as well as North Sea upwelling, where salty water reaches the surface towards the end of summer and early autumn. A total of 11 species (Crustacean, Chordate, Echinoderm and Mollusc) of these ecosystems were exposed to four different treatments (high or low oxygen and low or high CO2; varying pCO2 of 450 and 1300ĝ€μatm and O2 concentrations of 2-3.5 and 9-10ĝ€mgĝ€Lĝ'1) and respiration measured after 3 and 6 days, respectively. This allowed us to evaluate respiration responses of species of contrasting habitats to single and multiple stressors. Results show that respiratory responses were highly species specific as we observed both synergetic as well as antagonistic responses, and neither phylum nor habitat explained trends in respiratory responses. Management plans should avoid the generalized assumption that combined stressors will result in multiplicative effects and focus attention on alleviating hypoxia in the region.
Bibliographical noteFunding Information:
Acknowledgements. This research was funded by the project ASSEMBLE (grant agreement no. 227799; under the EU Research Infrastructure Action FP7) and the Estres-X project funded by the Spanish Ministry of Economy and Competitiveness (CTM2012-32603). Aisling Fontanini was funded by the School of Plant Biology at the University of Western Australia (grant 10300374) and Alexandra Steckbauer was funded by a fellowship from the Government of the Balearic Islands (Department on Education, Culture and Universities) and the EU (European Social Fund) as well as King Abdullah University of Science and Technology. Sam Dupont is funded by the Linnaeus Centre for Marine evolutionary Biology at the University of Gothenburg and supported by a Linnaeus grant from the Swedish research Councils VR and For-mas. We thank Karen Chan, Pia Engström and Julia Dombrowski for their assistance.
© Author(s) 2018.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Earth-Surface Processes