NIU biologist dives into coral reef mystery with NSF-funded research

DEKALB, IL - When long-spined sea urchins across the Caribbean began dying by the thousands in 2022, marine scientists feared a repeat of an ecological disaster that struck coral reefs four decades earlier.

Now, an NIU researcher is part of a major, multi-institutional effort to understand why it happened and how to stop it from happening again.

Just two years after joining NIU's Department of Biological Sciences, Assistant Professor Michael Henson has received a share of a $1.3 million National Science Foundation grant to study the environmental and biological factors behind the mysterious die-offs of Diadema antillarum, a sea urchin species critical to reef health.

More than $275,000 of the award will support Dr. Henson's Aquatic Microbiology lab, funding graduate and undergraduate research. NIU students will gain opportunities for hands-on training and collaboration at leading marine research institutions.

"Being able to collaborate with world-class institutions while giving our students access to those same networks and resources is huge," Henson said. "For an early-career lab at a landlocked university like NIU, this kind of cross-training and field experience is incredibly valuable."

The project brings together scientists from the University of the Virgin Islands, Cornell University, the University of South Florida and the U.S. Geological Survey.

The team's work will combine field studies in the U.S. Virgin Islands with controlled aquarium experiments to uncover how ocean conditions, microbial communities and a microscopic parasite interact to drive mass urchin mortality.

"These urchins play a crucial role in coral reef ecosystems by grazing on algae and keeping reefs healthy," Henson said. "When they die off, reefs can quickly become overgrown and start to collapse. Understanding what's driving these outbreaks is key to protecting coral reefs around the world."

Early work is already underway, with baseline data collection conducted this fall as researchers, including Henson, snorkeled off the coast of St. Thomas.

The 2022 die-off was traced to a single-celled parasite, its closest relative being Philaster apodigitiformis, part of the Diadema scuticociliatosis Philaster clade. The discovery was made using techniques Henson teaches in NIU's introductory microbiology course (BIO 313). The pathogen has since been detected in the Mediterranean, Red Sea, Arabian Gulf and Indian Ocean, raising alarms about what could be a global marine pandemic.

Despite identifying the culprit, Henson said, these key questions remain: What environmental conditions trigger outbreaks? Where does the pathogen persist between events? And why do some sea urchin populations survive while others collapse?

"In comes our current grant," he said.

Henson's team will explore those questions through a combination of field sampling, laboratory experiments and microbiome analysis.

Beyond the scientific impact, the project offers unique training opportunities for NIU students, not to mention "amazing trips to the U.S. Virgin Islands," Henson said. Participants will gain experience in microbiology, molecular ecology and marine science.

"It's exciting science with real implications for the future of coral reefs," he said.

Media Contact: Jami Kunzer

About NIU

Northern Illinois University is a student-centered, nationally recognized public research university, with expertise that benefits its region and spans the globe in a wide variety of fields, including the sciences, humanities, arts, business, engineering, education, health and law. The Wall Street Journal and CollegeNET recognize NIU as a leading institution for social mobility, or helping its students climb the socioeconomic ladder. Through its main campus in DeKalb, Illinois, and education centers for students and working professionals in Chicago, Naperville and Rockford, NIU offers more than 100 areas of study while serving a diverse and international student body.