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Research Fellows Directory

Cosima Porteus

Dr Cosima Porteus

Research Fellow


University of Exeter

Research summary

Atmospheric levels of carbon dioxide (CO2) are rising faster that any time in the last million years and the end of this century levels of CO2 are likely to have biologically significant impacts on fish populations and related socio-economics through rising temperatures (i.e. global warming). However, over a quarter of anthropogenic CO2 is absorbed by the oceans, which causes ocean acidification. Studies are already underway to understand how this higher CO2 marine environment may have minor effects on the growth and health of wild fish populations and those species grown in aquaculture. However, this approach to studying climate change impacts is ignoring perhaps a more ecologically important and potentially catastrophic influence of elevated CO2 on marine fish. This is based upon the recent and unexpected discovery that the offspring of tropical fish have decreased survival due to altered behaviour and sensory impairment caused by surprisingly small increases in CO2. Recently similar behavioural abnormalities have also been found in temperate fish indicating a widespread phenomenon. A brain-based mechanism has been proposed, but other causes remain untested. My research uses a multi-level approach, combining behavioural experiments, broad scale genetic screens and nerve recording, to determine the mechanisms behind this impairment in economically important European sea bass raised in high CO2 environments. Using electrophysiology, my recent work has shown that ocean acidification directly impairs the olfactory sensitivity of juvenile bass, uncovering a novel mechanism caused by ocean acidification on their sense of smell. Ultimately, it is becoming clear that high CO2 has a negative impact on the sense of smell of fish across a wide range of habitats and latitudes. Insights into the genetic mechanisms behind this impairment are crucial for determining the capacity these fish have to cope with such a rapid increase in CO2; I’m currently addressing this question.

Grants awarded

Physiological mechanisms behind ocean acidification-induced olfactory impairment in fish

Scheme: Newton International Fellowships

Dates: Jan 2013 - Jan 2015

Value: £99,323