In the wake of passing what many scientists deemed a global warming milestone, where levels of carbon dioxide in the atmosphere exceeded 400 ppm, Dr. Chris Junium from the Department of Earth Sciences at Syracuse University presented at EMPOWER’s weekly Water-Energy seminar on how we could use the geologic past to predict the future effects of our current climate crisis on the environment. As global temperatures rise, oxygen concentrations in the oceans are expected to decrease. In fact, it is predicted by 2100, most of the world’s oceans will be experiencing a significant decrease in oxygen levels. This phenomenon, known as ocean anoxia, is believed to be responsible for the mass extinction of many aquatic organisms such as fish, shellfish, coral and plants,that rely on dissolved oxygen in the ocean to survive.

Geological evidence suggests that oceanic anoxic events (OAE) have occurred millions of years ago. Junium, a sedimentary, organic, geochemist, uses this geological evidence collected from ground sediments around the world to better understand these past OAEs and their effect on the environment. In his presentation, titled “Oceanic Anoxic Events in the Geologic Past,” Junium discussed how he uses carbon and nitrogen isotopes found in sediments taken from areas that experienced OAE in the past to examine how various biogeochemical cycles, such as carbon, nitrogen and phosphorous cycling, were affected by these events. Nitrogen and phosphorous are essential nutrients for aquatic life and it is clear that the way they were cycled was drastically different during OAEs than most of Earth’s history. Therefore, Junium’s research provides insight into how marine food webs and marine ecology respond to OAEs. Since we are on a trajectory for more widespread OAEs, better understanding of how ecosystems were affected by these events in the past will help predict how ecosystems will be affected in the future. For more information about Junium’s research, visit http://paleoclimate.syr.edu/

Story written by Laura DeMott, Caitlin Eger, Kristina Gutchess, Changcheng Pu, and Alexa Stathis