An Interview with Dr. Travis Courtney – Marine Chemist and PLOS Author

Here, we chat with Dr. Travis Courtney about his newest publication in PLOS ONE, his exciting research on coral reefs, and his thoughts on equity and openness in science.

Travis Courtney (he/him/his) grew up in the coastal city of Wilmington, North Carolina, USA where he gained an intense appreciation for coastal ecosystems. He completed his BS in Geological and Environmental Sciences at the University of North Carolina at Chapel Hill while conducting research on the effects of ocean warming and acidification on a tropical sea urchin. Courtney later attended Scripps Institution of Oceanography for his PhD and postdoctoral research on quantifying the rates and drivers of coral and coral reef calcification. He is currently an assistant professor of marine chemistry in the Department of Marine Sciences at the University of Puerto Rico Mayagüez.

PLOS: You currently head the Biogeochemistry and Ecology Research Group (BERG) at the University of Puerto Rico Mayagüez. Tell us all about your research.

My previous research has largely focused on understanding the drivers of the growth and maintenance of coral reef structures under environmental change. While I plan to continue this research here in Puerto Rico, the BERG lab is also looking to broaden our research goals to include research themes that will be most beneficial to Puerto Rico through conversations with local governmental and non-profit agencies. Climate change, coral diseases, land-use change, fishing practices, and degrading water quality are all potentially important research themes impacting the health and functioning of coastal marine ecosystems here in Puerto Rico. By understanding how these driving forces are influencing coastal ecosystems, we can also work with local agencies and community groups to develop and implement evidence-based conservation, restoration, and remediation efforts.

PLOS: Your research has ranged from fieldwork-centric studies (in Bermuda, Belize, etc.) to more data and/or mesocosm-based approaches. Tell us why both types of approaches are needed to create a comprehensive understanding of environmental impacts on coral reefs?

There’s always a trade-off between working in the field vs working in controlled laboratory settings such as mesocosms. On one hand, field-based studies allow us to directly quantify how coral reefs are changing but attributing these changes to individual environmental drivers can be difficult. There are often so many co-varying environmental factors impacting reefs, which makes it challenging to determine the direct and indirect effects of any single variable in the field. On the other hand, mesocosm-based studies allow us to precisely test how selected environmental variables influence coral reefs while keeping all other variables constant. However, controlling for so many variables means that these types of mesocosm studies may not necessarily mimic the true responses of coral reefs occurring in the field. By combining the data and insights gained from these field and mesocosm-based approaches, we can test hypotheses in a controlled setting (mesocosms) and see if those hypotheses are supported in the real world (fieldwork) to increase our understanding for how environmental change impacts coral reef systems.

PLOS: As many researchers know, community-wide adherence to protocols and standards can be critical for temporal research and the intercomparison of results. This is especially true for ocean and atmospheric measurements, where the lack of a uniform approach can impede the identification of long-term trends. In your recent paper, published in PLOS ONE, you discuss the implications of total alkalinity data with respect to salinity. You simulated the potential uncertainties associated with salinity normalization of coral reef total alkalinity data and propose a series of recommendations to reduce these uncertainties in future studies. What was your motivation for pursuing this research, and how do you think it will influence the research community’s approaches to salinity normalization of total alkalinity data on coral reefs?

The original motivation for this study was to develop user friendly tools to rapidly assess coral reef calcification tipping points under climate change as part of a project funded by NOAA’s Ocean Acidification Program. For example, our first ecology-based tool estimates coral reef calcification from coral reef images in CoralNet. When developing the chemistry-based tool, we found a lack of clear guidelines in the literature describing the various assumptions and resulting uncertainties associated with normalizing coral reef total alkalinity data to a common reference salinity. Salinity normalization is an important step that is used to isolate the effects of coral reef calcification on total alkalinity from other processes such as freshwater dilution, evaporation, and mixing. Repeated measurements of coral reef calcification through time are one tool we have as researchers to quantify the impacts of environmental change on the growth of coral reefs so increasing the precision of these measurements is important for detecting any changes in coral reef calcification through time.

The primary goal of this study was to test how the salinity normalization process potentially influences measurements of coral reef calcification derived from seawater total alkalinity data. I hope that by providing a discussion of the uncertainties associated with salinity normalized total alkalinity data and suggestions to reduce these uncertainties, this study will increase our capacity as a research community to reliably detect any potential changes in coral reef calcification under ongoing environmental change.

PLOS: There is a close link between coral reef research and a better understanding of global climate change – how have your findings on reefs contributed to our knowledge of Earth’s rapidly changing climate?

Coral reefs are often called the canaries in the coal mine, owing to the widespread observed declines in global coral cover associated with climate change and other local factors. They can provide unique insights into our knowledge of Earth’s changing climate by quantifying the impacts of climate change on present-day coral reefs as well as historical coral reefs preserved in the geologic record. Additionally, geochemical analysis of calcium carbonate from reef environments can generate useful reconstructions of historical climate change.

For example, my first experiment as an undergraduate researcher cultured sea urchins under various ocean warming and acidification conditions. We quantified changes in growth rates to see how ocean warming and acidification might influence the growth of sea urchins under climate change. Additionally, we quantified how sea urchin skeletal geochemistry was influenced by ocean warming and ocean acidification. This allowed us to develop proxies that could be used to estimate historical seawater temperatures and carbonate chemistry from the skeletal geochemistry of sea urchin spines preserved in the rock record. I’m currently involved in a range of other projects quantifying the impacts of climate change on coral reef calcification and reconstructing historical seawater temperatures from coral skeletons. I hope these ongoing projects will continue to increase our collective understanding for how the Earth’s climate has changed and how these changes influence coral reef structures and the ecosystem services they provide to humanity.

PLOS: Some people have expressed the belief that the ocean will simply uptake and offset increased carbon emissions, providing a natural solution to the problem of elevated atmospheric CO₂ concentrations. Some have even posited that the dissolution of corals and other calcium-rich organisms could create a negative feedback loop, increasing ocean pH and offsetting ocean acidification. Can you discuss the limitations to these theories and why we cannot rely on the ocean to sequester CO₂ without making changes to emissions?

While there are a range of feedback mechanisms in the Earth’s climate system that can mitigate climate change, there are also feedback mechanisms capable of accelerating climate change. In the context of global climate change, the current input of CO₂ to the atmosphere is more rapid than the rates of CO₂ uptake by these naturally occurring CO₂ uptake mechanisms. As a result, atmospheric and oceanic CO₂ concentrations are currently increasing, and we are experiencing unprecedented ocean warming, acidification, and deoxygenation in response to greenhouse gas emissions. Current estimates suggest we’ve lost approximately 50% of global coral cover in recent decades, and widespread coral bleaching events are expected to continue to intensify in the coming decades and drive further declines in coral reefs. While researchers continue to explore various natural and artificial climate regulatory mechanisms further, the best way to mitigate climate change, and the negative impacts for coral reefs and people around the world, is to reduce emissions of CO₂ to the atmosphere as soon as possible. Project Drawdown has many resources for further details on addressing the global climate crisis.

PLOS: The BERG lab’s website has a section titled “We believe” which outlines your support of equity and inclusivity in science (and other realms). Can you talk here in a bit more depth about your views on equity in science and research and how your lab supports efforts to promote this?

I witnessed the “leaky pipeline” throughout my studies with decreasingly diverse classrooms and academic environments as I progressed from high school to undergraduate, graduate, and postgraduate work. How can we, as a research community, promote the importance of diversity for improving success of ecological communities and fail to do the same to promote success within our own research communities? I believe we must do better to promote a more just, equitable, diverse, and inclusive research community.

Maintaining a commitment to these principles of inclusion and equity is an important part of developing a supportive lab environment that actively promotes the success of students to the next stage of their careers. I’m also working on developing relationships with local governmental and non-governmental organizations to identify research needs where our work in the BERG lab can be most beneficial to the coastal ecosystems and people of Puerto Rico. Outside of the lab, I teach a class on ethics that focuses on principles of justice, equity, diversity, and inclusion, where we discuss some of latest scientific literature on these issues within academic science and debate how we can work to improve academic culture.

PLOS: As you may know, PLOS is dedicated to advancing not just Open Access, but Open Science, which includes transparency and equitable access to data, code, protocols, preprints, etc. What are your thoughts on Open Science and how does this ethos fit in with your research?

I believe science should be freely accessible to everyone. Especially since so much research currently remains behind internet paywalls, I think we as a scientific community really need to ask ourselves who this paywalled research benefits and explore Open Science options to share the knowledge and resources we produce. Much of this science is also funded by taxpayer dollars, so I believe publicly funded researchers owe it to those taxpayers to make our research outputs accessible to the people who paid for it. Moreover, the data and code we produce for any given publication or project can often be incredibly useful to other scientific research projects and monitoring efforts for community, non-profit, and governmental organizations so having that data openly available can help to accelerate new discoveries and improve policies. Open science also increases transparency and trust in the scientific process by making everything freely available for review to ensure that any conclusions in the published papers are adequately supported by the data and analyses. Overall, I think that the increased accessibility provided by the Open Science movement has been an incredible step forward in the scientific process and making science more accessible, and I look forward to continuing to educate myself and the students here at UPRM on the latest Open Science best practices.

Citation: Courtney TA, Cyronak T, Griffin AJ, Andersson AJ (2021) Implications of salinity normalization of seawater total alkalinity in coral reef metabolism studies. PLoS ONE 16(12): e0261210. https://doi.org/10.1371/journal.pone.0261210