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Wednesday, June 29, 2022

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Student researchers study eelgrass habitats in shallow coastal regions. Student researchers study eelgrass habitats in shallow coastal regions.

Little Fish, Big Impact

Kevin Hovel and his team of student researchers are exploring the importance of biodiversity in marine ecosystems.
By Alyson Faucett

Under the sea lies a world of wonder that most people will never have the opportunity to explore. While our heads may be filled with images of sharks, whales or giant squid, Kevin Hovel and five student researchers have bigger fish to fry — so to speak.

Hovel, a biology professor at San Diego State University, is a co-principle investigator for an international research collaboration known as the Zostera Experimental Network. In 2011, ZEN set out to study the structure and function of eelgrass, the world’s most widespread marine plant.

Emphasis on eelgrass 

Eelgrass lives in shallow water on every coastline around the world and performs many ecosystem functions that both animals and people rely on. We count on eelgrass to buffer waves to prevent erosion, provide refuge and food for fish, lobsters, crabs and shrimp and to take in carbon dioxide, according to Hovel.

The valuable habitat that eelgrass creates is under threat from a process known as eutrophication, or the addition of nutrients to the water. In most cases, this is because of humans dumping fertilizers, sewage and other waste into lakes, rivers and oceans.

Algae and eelgrass thrive in similar environments and compete for the light and nutrients that are available. Because algae grow faster than eelgrass, adding nutrients promotes rapid growth of algae and the loss of eelgrass along with the habitat it provides. Eventually, what remains are unhealthy, smelly shallow water areas that once had the potential to support a variety of life.

Quality over quantity

The ZEN project found that a major factor in preventing these unwanted changes to marine systems is control of the algae population by ant-sized invertebrates referred to as “grazers” that live in eelgrass and feed on algae.

Diving even further, researchers discovered that the biodiversity of the grazers is much more important than their numbers. In other words, having many different types of grazers is more important to an ecosystem than simply having a lot of them.

“One of the major questions in ecology is: just how important is biodiversity for maintaining healthy ecosystems?” Hovel said. “A more diverse community of animals, like grazers, allow them to fill different niches; if different grazers prefer to eat different types of algae, many different species of grazers can control the algae and save the eelgrass.”

Global scale studies

The second phase of the study, ZEN2, is a global-scale research project that focuses on the role of biodiversity in regulating ecological processes. Funded by the National Science Foundation, Hovel and his graduate assistant, Erin Voigt, recruited five SDSU undergraduate students to participate in an international student exchange program.

“It’s nice to involve students and send them off to research in different places,” Hovel said. “It provides them with valuable research and cultural experiences and provides us with the help we need to achieve our research goals."

Because eelgrass grows all around the world, ZEN2 is working with 14 countries, 24 partner institutions and 40 individual sites. The student exchange program developed out of this global partnership, allowing Hovel’s team to be sent to the coasts of Europe, Asia, Mexico and the United States to assist with everything from field work to data entry. 

“We got to work in a place very different than back home,” said Christopher Bayne, one of Hovel’s student researchers who worked in Japan for this project. “This was really a good introduction into how variable things can sometimes be in science.”

Students in Japan

Bayne and his classmate Joshua Jaeger went overseas during the summer of this year to study eelgrass habitats in northern and southern regions of Japan. The research they conducted is being used to propel the ZEN2 project into its next phase, paving the way for future discoveries that might help scientists improve ecosystems around the world.

“After all the data has been entered and analyzed, it will be easier to see what can be answered and what new questions can be asked,” Bayne said.

For Jaeger, going to Japan was a lifelong dream that was made possible by Hovel’s program and an SDSU travel grant. As a senior marine biology student, this unique experience has served as his motivation for graduate school and beyond.

“Looking back at all I have accomplished, it’s still hard to grasp how lucky I was to have an opportunity like this,” Jaeger said.