Jenan Kharbush

Please note that this interview has been condensed and edited for length and clarity.  

To start, could you tell me a little bit about your current research?

Dr. Jenan Kharbush: “In my lab, we study any and all things nitrogen and any and all things microbial. We’re very interested in all of the amazing transformations that phytoplankton and bacteria make, and everything they do to change nitrogen into different usable forms. One of the main tools we use is natural abundance isotopes, so N15 to trace processes in the nitrogen cycle. The most charismatic area of focus right now is probably the harmful algal blooms that occur in Lake Erie every year. In my group, we’re specifically trying to understand, what’s the role of nitrogen in the progression and toxin production, how long the bloom lasts, and what nitrogen recycling processes are going on that make the bloom last for so long. They last sometimes until October or even November. So thinking about harmful algal blooms, that’s where a lot of thinking about sustainability and climate change comes into my work. But I also have a graduate student who’s very interested in past environments. So there’s a portion of our work that also looks back in time at the history of primary productivity in the Great Lakes and other places on early Earth.”

Could you talk a little bit more about the research on past environments?

Dr. Kharbush: “This is the work of my graduate student on records from ancient lakes and how 15N isotopes preserved in the rock record may trace the evolution of the N cycle in lakes. Last summer, she also went on a cruise and they collected sediment cores from all of the Great Lakes. We would like to use these to look back at the primary productivity history of the Great Lakes as deglaciation happened and afterward when there were cold periods and warm periods, and the lake levels went up and down. That was a period with a lot of change and we don’t have enough information about how that affected primary productivity, which is important because now things are really changing again. The Great Lakes support about $8 billion in the fishery sector, so it is important to be able to predict future changes in productivity that might affect food webs, and we would like to know if there is any historical precedent that might help with that.”

What is something that you wish people understood a little bit better about your research?

Dr. Kharbush: “I think a lot of people don’t think about how important tiny things are. A lot of what we study is very tiny or even invisible. We’re studying invisible worlds, it’s either things that are too tiny to see, like microbes, or ancient worlds that don’t exist anymore. So you have to use a lot of imagination and data from the rock record, to imagine what that was like. Then the other thing I hope to show people with my work is the importance of the nitrogen cycle. I think people know we use too much fertilizer on our lawns and that causes pollution and the dead zone in the Gulf of Mexico. I think people understand that, but not so much that it’s a global problem where as a whole we’ve added so much nitrogen to ecosystems worldwide that even if we stopped now, it might take a long time for it to stabilize again.”

Given their sometimes “invisible” nature, how do you make sense of the scale of impact that microbes have on climate change?

Dr. Kharbush: “Microbes are tiny but collectively they are mighty. A good example of this is that tiny plants called cyanobacteria were responsible for the oxygenation of the entire planet; their collective photosynthetic activity produced enough oxygen 2.4 billion years ago to irreversibly change atmospheric and ocean chemistry and pave the way for the evolution of eukaryotes and higher life forms like dinosaurs- and eventually humans. An example from modern times is that the oceans are full of billions of tiny algae that each year fix the same amount of carbon as all the forests and plants on land. Again, collectively their impact is disproportionate to their size.”

What is your advice to other educators? 

Dr. Kharbush: “Something that I’ve recently been thinking about is how climate science, earth science, and environmental science are actually connected to other issues, like geopolitical issues. There are a lot of ways for us to incorporate some of this in our teaching. Right now, I think that climate science and earth science are a little bit too divorced from those things. Like, ‘emissions are going up this much. That’s bad. They’re projected to go up this much more. That’s bad.’ Without really addressing which countries are driving those trends and/or what nations are most impacted by climate change, even though they’re not contributing to the problem. I think thinking about resources is especially relevant, considering the role of developed nations in the overconsumption and exploitation of resources. For example, I had a guest lecturer come to my ocean biogeochemistry class last year – he’s an anthropologist, and he studies piracy (and maritime policy, and economics in general). The class is about processes in the ocean, nitrogen cycling, sulfur cycling, carbon cycling, but also human impacts, and the human connection with the ocean and its resources. His lecture was perfect for that because he talked about how piracy has evolved over time. The way it started is that people couldn’t make a living the way that they had always made a living because of resource issues and conflicts with more powerful countries. So they turned to piracy to support their families, instead of fishing which was the traditional way of doing things. Now it’s become very elaborate, the pirates have different levels and there are different jobs, they have a structure for ransoming captive ships and people, it’s become very complex. But it started as primarily a resource conflict, and in the context of the ocean many people and nations have to share the ocean as a resource, but that can lead to a lot of exploitation and lawlessness. We also talk about how there’s a big connection between wars and the environment, wars and emissions. So I think we all need to take a broader view; I’ve been trying to encourage students in our department to take classes for their social science and humanities electives that illuminate some of the underlying issues of sustainability and resource acquisition.”