Research Focus
‘Our work seeks to improve replication and natural realism in laboratory research, while also pushing experimental design to its limits. ‘
The research within the Coastal Eco-physiology Group generally has an overview on improving projection of the impacts of marine climate change. Within that broad topic, we tend to focus on the responses of seaweeds to global and local drivers of change, seaweed physiology, appropriately monitoring species’ abundances, the effects of climate variability, coral reef responses to drivers, carbonate budgets, and improving experimental design. Members of our group also have interest in coralline algal and coral geochemistry, scrutinising blue carbon pathways and geoengineering, future-proofed seaweed and coral restoration, and the responses of invertebrates to the impacts of climate change.
Seaweed and kelp forest responses to climate change
Our group uses a mixture of laboratory experiments, traditional seaweed physiology, field experiments and in collaboration with other groups we use novel geochemistry and molecular tools to answer our questions. Understanding the impacts of climate change on seaweed-based ecosystems is one of our core areas of focus. This work usually assesses the impacts of ocean acidification, ocean warming and marine heatwaves. It ranges from mechanistic assessments of complex physiological changes through to ecosystem and even global-level consequences.
In collaboration with other groups, we are currently using Raman Spectroscopy, boron isotopes and trace element proxies to better understand changes within the calcium carbonate precipitated by coralline algae. These proxies have been widely used in corals to better understand the “calcifying fluid” or site of precipitation of calcium carbonate, which reveals physiological traits in corals that enable select species to resist ocean acidification. As in corals, pH is elevated here in coralline algae. However, we are currently working to better understand other components of carbonate chemistry there that will result in us understand the degree to which coralline algae regulate Ca2+ and dissolved inorganic carbonate there.
We are also currently collaborating with other groups in Te Herenga Waka and abroad to better understanding molecular mechanisms of responses of both calcify and non-calcifying seaweeds to climate change and altered light regimes. This involves proteomics and transcriptomics to assess changes to calcification and photo-physiology related pathways.
Coral reefs
Although based in New Zealand, some of our research focuses on the physiology and ecology of species outside of New Zealand, particularly in the Mediterranean, at extreme locations with naturally occurring elevated CO2 or temperature across the globe, and coral reef ecosystems. We are especially interested in the role of calcifying seaweeds on coral reefs, focusing on the contribution of calcifying taxa to coral reef carbonate budgets and changes temporally or spatially that allow us to better understand how future reefs might function. Our group also focuses on projecting the impacts of climate change on corals, specifically with interests in geochemical responses, understanding traits that enable tolerance to climate change, changes to photo-physiology, and how these impacts will manifest to alter global carbonate production estimates.
Edges of Experimental Design
To maximise understanding of how changes in environmental variables influence species, we need appropriately designed tests that maximise inference. To do this, we must either use “natural laboratories” in the field, or appropriately simulate the natural environment in the laboratory. We use an array of field sites to test hypotheses regarding light, temperature, and CO2. However, for some variables, field equivalents either do not exist or are inappropriate to adequately test hypotheses. Our work seeks to improve replication and natural realism in laboratory research, while also pushing experimental design to its limits. For example, by teasing apart different components of carbonate chemistry responsible for the effects of ocean acidification, exploring how magnitudes, intensities and durations of changes in environmental conditions (e.g. pH, temperature and light) impact species’ responses to climate change, and exploring multigenerational responses of seaweeds to change.
Highlighted Publications
CEG members are listed in bold.
† = co-first author status of CEG member with first list author.
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Understanding coralline algal responses to ocean acidification: meta-analysis and synthesis.
Cornwall, C.E., Harvey, B.P., Comeau, S., Cornwall, D.L., Hall-Spencer, J.M., Peña, V., Wada, S., Porzio, L. Accepted 21st September 2021. DOI: 10.1111/gcb.15899
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Rapid multi-generational acclimation of coralline algal reproductive structures to ocean acidification.
Moore, B., Comeau, S., Bekaert, M., Cossais, A., Purdy, A., Larcombe, E., Puerzer, F., McCulloch, M.T., Cornwall, C.E. 2021. Proceedings of the Royal Society B.288. 20210130
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Global declines in coral reef calcium carbonate production under ocean acidification and warming.
Cornwall, C.E., Comeau, S., Kornder, K.A., Perry, C., Van Hooidonk, R., DeCarlo, T.M., Pratchett, M.S., Anderson, K.D., Browne, N., Carpenter, R., Diaz-Pulido, G., D’Olivo, J.P., Doo, S., Figueiredo, J., Fortunato, S.A.V., Kennedy, E., Lantz, C.A., McCulloch, M.T., González-Rivero, M., Schoepf, V., Smithers, S.G., Lowe, R. 2021. Proceedings of the National Academy of Sciences of USA. 118 (2): e2015265118
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A coralline alga gains tolerance to ocean acidification over multiple generations of exposure.
Cornwall, C.E., Comeau, S., DeCarlo, T.M., Larcombe, E., Moore, B., Giltrow, K., Puerzer, F., D’Alexis, Q., McCulloch, M.T. 2020. Nature Climate Change 10: 143–146.
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Flow-driven micro-scale pH variability affects the physiology of corals and coralline algae under ocean acidification.
Comeau, S., Cornwall, C.E. †, Pupier, C., DeCarlo, T.M., Alessi, C., Trehern, R., McCulloch, M.T. 2019. Scientific Reports.
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Resistance to ocean acidification in coral reef taxa is not gained by acclimatization.
Comeau, S., Cornwall, C.E., DeCarlo, T.M., Doo, S., Carpenter, R., McCulloch. M.T. 2019. Nature Climate Change
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Impacts of ocean warming on coralline algal calcification: meta-analysis, knowledge gaps and key recommendations for future research.
Cornwall, C.E., Diaz-Pulido, G., Comeau, S. 2019. Frontiers in Marine Science. DOI: 10.3389/fmars.2019.00186.
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Resistance to ocean acidification in corals and coralline algae under natural pH variability.
Cornwall, C.E., Comeau, S., DeCarlo, T.M., Moore, B., D’Alexis, Q, McCulloch, M.T. 2018. Proceedings of the Royal Society B, 20181168. Doi: http://dx.doi.org/10.1098/rspb.2018.1168.
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Similar controls on calcification under ocean acidification across unrelated coral reef taxa.
Comeau, S, Cornwall, C.E.†, DeCarlo, T.M., Krieger, E., McCulloch, M.T. 2018. Global Change Biology. 10.1111/gcb.14379.
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Coral resistance to ocean acidification linked to increased calcium at the site of calcification.
DeCarlo, T.M., Comeau, S., Cornwall, C.E., McCulloch, M.T. 2018. Proceedings of the Royal Society B, 285, 20180564.
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Coralline algae elevate pH at the site of calcification under ocean acidification.
Cornwall, C.E., Comeau, S., McCulloch, M.T. 2017. Global Change Biology 23 (10), 4245-4256. DOI 10.1111/gcb.13673.
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Inorganic carbon physiology underpins macroalgal responses to elevated CO2
Cornwall, C.E., Revill, A.T., Hall-Spencer, J., Milazzo, M., Raven, J.A., Hurd, C.L. 2017. Scientific Reports. 7:46297 | DOI: 10.1038/srep46297.
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Biological responses to environmental heterogeneity under future ocean conditions.
Boyd, P.W., Cornwall, C.E., Davidson, A., Doney, S., Fourquez, M., Hurd, C.L., Lima, S., McMinn, A. 2016. Global Change Biology 22: 2633 – 2650.
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Physiological responses of a Southern Ocean diatom to complex future ocean conditions
Boyd, P.W., Dillingham, P.W., McGraw, C., Armstrong, E., Cornwall, C.E., Feng, Y.-Y., Hurd, C.L., Roleda, M., Nunn, B., Timmins-Schiffman, E. 2016. Nature Climate Change. 6: 207-213.
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Experimental design in ocean acidification research: problems and solutions.
Cornwall, C.E., Hurd, C.L. 2015. ICES Journal of Marine Science. doi: 10.1093/icesjms/fsv118. Focus of a ‘highlight’ article in Nature.