Early Career Insights: How life flows in a river

In poetry we often find the metaphor that our lives are like rivers, but how is the life of a river – inside a river? John Gardner is trying to understand this better by analyzing how its components evolve and change during the course of the river, moving with its flow.

He is currently doing his PhD at the Nicholas School of the Environment at Duke University. His research group is devoted to the study of natural waters, and his work is focused on the role of water columns in rivers, where he seeks the connection between the shape of rivers and streams and ecosystem functions. Moreover, his research is part of a broader multidisciplinary program for Wireless Intelligent Sensor Networks (WISeNet), joining research groups from different fields of environmental, computer, and engineering science, which are collaborating in the study of a more general topic, sensing: how we perceive and sense the environment surrounding us.

In his research, John Gardner observes rivers from different reference frames (moving and stationary) and examines how water and matter move through river channels. For this purpose, he uses sensors developed in collaboration with his research group (called HydroSpheres) which allow him to mimic a particle moving and evolving along the river. These detectors, similar to sensors already used in oceanography, provide hydrodynamic information by taking data of different physical and chemical properties such as oxygen, pH or velocity, in order to understand the evolution of a column of water.

All in all, John Gardner is studying how life flows in a river and knows that, as the Greek philosopher said, rivers are in constant change.

John Gardner about to release in a river one of the sensors used in his research.

John Gardner about to release in a river one of the sensors used in his research.

You have recently started your PhD in Environmental Science, after your former studies in Environmental Science and Geography. How did you choose this field and its application to rivers? 

Originally I started my studies in biochemistry as an undergraduate student. I really liked the work I was doing in the lab, and I became more interested in doing the same kind of studies where I would analyze biochemical processes that involved hydrology and soil sciences, but in larger scales. During my Masters in Environmental Science, I focused my studies on a stream’s ecology. I realized there were less studies and less people doing this kind of analysis in rivers and that there was still a lot to understand in a river’s ecology, which I find simply fascinating – as it’s an ecosystem always changing, always in movement.

What would you say makes the ecosystem of a river so special? And why do you like “thinking longitudinally about rivers”?

Rivers are alive, dynamic and the continental veins that connect land and ocean. Life in these systems must adapt to constantly changing conditions, extreme events and the linear tree-like structure of river networks. Comparing rivers with other bodies of water, smaller streams and even lakes, is something I am very interested in. We know a lot about small streams and lakes because they are ideal for identifying processes and conducting experimental manipulations. But we don’t know what we can or cannot extrapolate to larger systems such as a river. Therefore, I think there is a lot of space to ask very simple questions about large river ecosystems. For example: where along a river, from a tiny stream to the ocean, does the biological activity of the water column exceed that of the river bed?

How is a working day in the field (in the river) for you?

The field work now basically consists of getting information by using the sensors. First we spend some hours calibrating them in the lab, getting them ready, and then we go to the river where we want to do our study, we put them in the water, leave them there to move with the river and recover them in one or two days. During this time we follow them and observe them from a boat for some time, then we let them free over night and recover them the next day. They have a GPS and GSM system to track their location so we can check if they get stuck for some reason and go back and move them. With these sensors we are basically sampling some chemical and physical parameters as they are moving, to have a better idea of how a particle on the surface of the river evolves.

You visit different places with interesting rivers. How do you select them?

We select the rivers where we want to do our field study based on their morphology: we are interested in large and complex systems, with lots of channels and complicated shapes. For instance, next summer we will be doing field work at the Mississippi river.

This summer you have been collaborating with a research group in Venice. How was this experience? Did you find many differences with respect to your group’s approaches?

Yes, I spent some months this summer in Venice and it was undoubtedly a great experience. I certainly find this kind of international collaborations very enriching and valuable during a PhD. In my case, on the basis of the broad research program I am part of, the group I joined in Venice was not working in something directly related to my research. The exchange was the following: I taught them about the sensors we use in my group, doing mainly a river engineering research which is more empirical and data driven, and I learned from them the models they use as they have a much more theoretical approach. Now I would like to incorporate their models in the studies I am doing at the moment, and will also use these models in my field work next summer.

Do you combine your research with other educational activities to protect the environment?

Personally I am not involved in many activities like this at the moment, but it is something my group does. For instance, with undergraduate students: sometimes we take a group of Master students and go for a hike with them, explain different water systems we find along our way and do simple experiments like using a dye in the water as an example of dispersion in a stream. In any case, I would like to dedicate more time to these activities in the future. I was more involved in them as a Master student. At that time I was working in a marine lab, and explaining twice per week our work to the public, using for instance a pool for fish when we had schools visiting, so that the kids could “touch the fish”.

I read that your group organizes something called “River Retreats” with the aim of reading thoroughly a selection of papers around a topic and during a weekend. Have you participated in these retreats?

Yes, these are retreats organized every year for PhD students, with about 15-17 PhD students involved, and I participated last year. There is usually a person outside the group invited to the retreat to give a different perspective. Sometimes it is a researcher working on the topic of that year’s retreat, sometimes it’s a person working in something totally different, such as an environmental lawyer. We try to combine different aspects in this way: ecology, society, behaviour. All together with fresh air, a short hike and moderate discussion, makes it a really enjoyable and productive experience, useful to have a broader image of your field.

Have you already participated in any publication as author? If so, how has been your first impression of the publishing process? Did you have any kind of training to help you to understand its different stages?  

We are currently waiting to receive the first comments about the review of the first manuscript I have co-authored. In general, from what I have seen so far and also from colleagues’ experiences, it seems to be quite a slow process. And no, I never heard about any training, but I think it would be useful to have some kind of workshops, specially targeting students, about how to navigate the publishing world.

How do you see the years coming? 

Looking ahead, the next years will be the most exciting and difficult ones. I think that the key lies in developing the right questions now. If you find the right questions, it will lead to more fulfilling and insightful research.

We wish you the best luck with your upcoming research projects!

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