Fish in the sea

Christina is our own Defender of the Deep

Dr Christina Roggatz is an interdisciplinary researcher who combines chemical analytical and computational methods with biological observations. Her work focuses on the hidden impacts of climate change, analysing the chemical effects of ocean acidification on key molecules. Christina wants to understand the impacts of pH and temperature on molecules and how they affect the molecules’ functioning in mediating interactions of marine organisms.

Ocean acidification, also dubbed the evil twin of climate change, is an invisible effect by which carbon dioxide reacts with water to form carbonic acid and makes the oceans more acidic. With many crucial interactions between marine organisms being mediated through chemicals, e.g. their sense of ‘smell’, chemical changes to the environment due to ocean acidification have the potential to cause significant disruption. It can affect key processes and interactions within ecosystems and impair marine animals’ ability to find food, mates and ideal living conditions and to avoid predators.

The video below explains this process in more detail.

Working closely with colleagues from Biology and Chemistry at the University of Hull, Christina showed for the first time that even the presumably small pH changes associated with ocean acidification have the potential to change molecules mimicking those used by shore crabs during brood care and by oyster and barnacle larvae during settlement. The findings, published in Global Change Biology, not only reveal substantial impacts on the structure, charge and shape of the molecules, but also an associated loss of their functionality for the crabs.

Christina also found similar impacts on molecules signalling food to fish, published in Frontiers in Physiology. She established with collaborators at the CCMAR (Portugal) - that the molecular changes, amongst other effects, contribute significantly to reduced ability of fish to detect smell and hence food in future ocean conditions.

Dr Christina Roggatz

Dr Christina Roggatz

Research Fellow

Besides these clearly negative impacts on some marine animals, Christina’s research also uncovered that some molecules will become more abundant and function more effectively. Two of these molecules are amongst the most potent biotoxins in our oceans: tetrodotoxin, also known as the pufferfish toxin, and saxitoxin, which is produced during harmful algae blooms. Published in Nature Climate Change in close collaboration with experts from the University of Hull and the US, her study revealed that acidified and warmer conditions in future oceans increase the amount of the toxic form of the molecules by up to 30%. This might be good news for the pufferfish who use tetrodotoxin as their chemical defence, but less positive for those animals and humans in regions affected by harmful algae blooms.

Christina is a Research Fellow in Marine Chemical Ecology at the Energy and Environment Institute, Associate Fellow of the Higher Education Academy, and a member of both the Royal Society of Chemistry and the International Society of Chemical Ecology.

Shore Crab with eggs and larvae UNI-4388 copy
These invisible but fundamental changes to message-bearing chemicals, which constitute the oldest language of life on Earth, could pose a considerable challenge for organisms in future oceans.

Dr Christina Roggatz

Research Fellow

What challenges are you addressing?

Climate change will inevitably affect our oceans and their inhabitants in the future, and in some instances does already. So far, the effects of climate change on key interactions and processes within complex ecosystems are only slowly uncovered as they happen. This allows little time to mitigate the impacts on, for example, livestock production and aquaculture. By using a cross-disciplinary approach to study and assess the sensitivity of biological systems at a fundamental chemical level, I aim to identify vulnerable chemically-mediated interactions and processes before they are affected.

How is this research different?

My research combines analytical and computational chemistry to assess the molecules’ sensitivity and changes to their chemical characteristics with pH and temperature. While this may seem trivial, most molecules to date are only studied from a bio-medical or physiological perspective or in the context of reactions or materials. The impact of climate change-relevant environmental factors on molecules used in the chemical communication of marine organisms is barely understood. But I also approach the questions from a bio-functional point of view and assess if the chemical changes observed and modelled actually translate into biological and ultimately ecological effects. This unique cross-disciplinary combination allows me to address fundamental key questions about climate change impacts on ecosystems.

What drives your passion for research?

Curiosity and the fascination that there are so many details we don’t know about our oceans and the organisms living in them. I was always intrigued by the fact that marine animals “talk” to each other mainly by means of chemistry, using an invisible language of molecules. Being able to link fundamental changes of this ‘language of life’ to important processes within ecosystems fascinates me. Big questions can never be answered by thinking in silos. I enjoy regularly stepping across the boundaries of different disciplines to link up the pieces related to a puzzling question to find an answer. Sharing my new, exciting and often unexpected findings with colleagues and the public is one of the aspects I enjoy most, especially if it helps to inspire the next generation of (female) scientists and critical interdisciplinary thinkers.

The Deep aquarium
You only protect what you know; understanding is key to inspire community-driven change.

Dr Christina Roggatz

Research Fellow

Community Impact

Alongside her research, Christina is a passionate science communicator. Making her findings accessible to the public and especially children matters to her.  She works closely with The Deep in Hull, one of the UK’s largest aquaria, as their Scientific Advisor and has recently co-curated their latest permanent exhibit  ‘Changing Seas’. Christina believes that clear, fact-based and engaging communication of climate change and its many impacts for different age groups remains a crucial factor in tackling future challenges. Together with her colleagues, she has also developed the Crabby's Reef game that allows everyone to experience how a crab might feel in future ocean conditions when its senses become more and more impaired. The game is featured at COP26 in Glasgow 2021. Christina has recently featured in @compoundchem’s Women in Chemistry card set, a list of 140 (and growing) inspirational profiles. During her regular engagement with primary and secondary school children, Christina inspires the next generation and acts as a female role model in STEM.


Book chapters:

Roggatz, C. C., Kenningham, N., & Bartels-Hardege, H. D. (2019). Taking Current Climate Change Research to the Classroom—The “Will Hermit Crabs Go Hungry in Future Oceans”? Project. In W. L. Filho, & S. L. Hemstock (Eds.), Climate Change and the Role of Education (255-277). Cham: Springer

Journal Article:

Porteus, C. S., Roggatz, C. C., Velez, Z., Hardege, J. D., & Hubbard, P. C. (2021). Acidification can directly affect olfaction in marine organisms 224(14)

Hardege, J. D., Schirrmacher, P., Roggatz, C. C., & Benoit, D. M. (in press). Ocean Acidification Amplifies the Olfactory Response to 2-Phenylethylamine: Altered Cue Reception as a Mechanistic Pathway? Journal of Chemical Ecology

Roggatz, C. C., Fletcher, N., Benoit, D. M., Algar, A. C., Doroff, A., Wright, B., …Hardege, J. D. (2019). Saxitoxin and tetrodotoxin bioavailability increases in future oceans Nature Climate Change, 9(11), 840-844

Velez, Z., Roggatz, C. C., Benoit, D. M., Hardege, J., & Hubbard, P. C. (2019). Short-and medium-term exposure to ocean acidification reduces olfactory sensitivity in gilthead seabream Frontiers in Physiology