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Christopher Cornwall

2017: Dr Christopher Cornwall, Victoria University of Wellington, has been awarded a Rutherford Discovery Fellowship for research entitled: 'Physiological and environmental controls of coralline algal calcification under climate change'.

Biography

Dr Christopher Cornwall is a marine botanist who specialises in understanding the impacts of environmental variability and global change on organism calcification and photophysiology. He is originally from New Zealand and attained a PhD in Marine Botany from the University of Otago in 2013, during which he discovered that metabolic activity at the surface of temperate coralline algae could mediate their response to ocean acidification.

Following his PhD, Dr Cornwall accepted a postdoctoral fellowship at the Institute for Marine and Antarctic Studies (IMAS) at the University of Tasmania. From there, he moved to the School of Earth and Environment and ARC Centre of Excellence for Coral Reef Studies at the University of Western Australia, investigating how organism physiology and the environment will interact to influence the response of coralline algae to ocean acidification and warming.

Dr Cornwall has attained several early career awards and is an Associate Editor of the journal Frontiers in Marine Science. With this Rutherford Discovery Fellowship, Dr Cornwall will continue this important work at Victoria University of Wellington, New Zealand.

Research summary

The increasing acidification of the world’s oceans from the absorption of human-derived atmospheric CO2is known to negatively impact the growth and internal chemistry of many marine species. Because of their highly soluble calcium carbonate skeletons, reef-building algae are considered to be among the species most at risk from ocean acidification. However, Dr Cornwall challenges this idea, postulating that certain species or populations of calcifying algae may have the physiological machinery to cope with ocean acidification.

Dr Cornwall aims to investigate whether the greater tolerance observed in some populations of the New Zealand coralline algae is due to them having evolved in more variable pH environments. Coralline algae are ecologically important calcifying algae that create and bind together rocky reefs and act as nurseries for species important to fisheries in New Zealand and worldwide. New Zealand’s underwater kelp forests are a common habitat for coralline algae. Here, the algae are exposed to large daily shifts in pH as a result of fluctuating COconcentrations in the surrounding seawater. This fluctuation is created by the kelp taking up CO2 during daytime photosynthesis and releasing it at night during respiration. The variability in sea water pH in these forests can be extreme, with pH dropping at night to levels often lower than those estimated to occur by the end of this century due to ocean acidification.

Dr Cornwall will use cutting-edge geochemical techniques, in-depth physiological assessments, and multi-generational experiments to determine if and how physiological and environmental controls impart tolerance to ocean acidification in multiple coralline algae species. In addition, he aims to determine if any tolerance is maintained after successive generations in constant pH conditions. The findings from this research will greatly enhance our understanding of how climate change will impact coralline algae, and hence future rocky reefs. It will also enable us to understand if kelp forest habitats will protect resident organisms from ocean acidification, or harbour more tolerant populations. The outcomes of this research programme will aid in planning for shallow reef systems in the years to come.