Past Winner
2007 NSERC Howard Alper Postdoctoral Prize

Julia Baum

Biology

Dalhousie University

Julia Baum

Overexploitation and climate change are now widely understood to be stressing the world's ocean ecosystems. Despite this understanding, there is still relatively little known about the consequences of these human-induced changes and whether it is possible to restore and stabilize damaged marine environments.

Fortunately, some of the uncertainties about deteriorating ocean ecosystems could soon be resolved by Julia Baum, winner of NSERC's Howard Alper Postdoctoral Prize. Dr. Baum is currently on a postdoctoral fellowship (PDF) at the famed Scripps Institution of Oceanography in San Diego, a leading centre for marine sciences research. She is now engaged in a novel study comparing the ecosystems of pristine coral reefs with those of similar reefs that have been moderately to highly degraded by human activity.

Dr. Baum has already earned worldwide acclaim as a leading expert on declining populations of the ocean's top predators, the iconic sharks. Her master's and doctoral research at Dalhousie University, based on exhaustive analyses of massive data sets dating back to the 1950s, shows that populations of some species of large coastal sharks, including the tiger, scalloped hammerhead and bull, have plummeted more than 95 percent in the last 50 years.

As part of her PDF research, Dr. Baum plans to explore whether sharks, and other ocean predators, actually help make coral reef ecosystems better able to resist and recover from disturbances. "We know that predators can play important roles in terrestrial and near-shore temperate ecosystems. But their role on coral reefs is uncertain," she explains. One reason for this, she adds, is that most reefs that have been studied do not have top predators, because they have been fished out.

"Coral reef ecologists have been studying ‘broken' ecosystems and trying to determine how they function, but that approach is flawed. It's kind of like trying to study the rainforest after it has been chopped down."

By examining the few pristine environments that remain, Dr. Baum hopes to shed new light on precisely which characteristics are required to maintain resilient coral reefs. Much of her research will involve analyzing data from the National Marine Fisheries Service in Hawaii. That group has been monitoring coral reef ecosystems on more than 40 different islands in the equatorial Pacific Ocean.

Dr. Baum says that the removal of predators, through fishing, is usually one of the first human impacts on reefs. As stressors like overfishing, climate change and acidification mount on coral reefs over the coming decades, it will be critical to understand how those previous stressors might decrease the ability of coral reef ecosystems to withstand new stressors. "If reefs with top predators are more resilient to new disturbances, it would provide a strong argument for conserving and restoring them," she adds.