Algal blooms are natural coastal events that occur when ocean conditions favor the rapid growth of marine algae. Most algal blooms are not harmful. But a small number of algal species produce toxic chemicals; if these species proliferate in large quantities, their blooms can negatively affect marine animals and pose significant human health risks. Such events are known as Harmful Algal Blooms (HABs).
The frequency and severity of HAB events along Southern California’s coast has been increasing in recent decades. But the exact conditions that trigger HABs remain unclear. What environmental circumstances lead to an algal bloom? Which species of algae will flourish, and why? And when a toxic species blooms, what then triggers it to release its toxins?
Dr. David Caron and collaborators with the USC Wrigley Institute have spent the last decade monitoring California’s coastal waters, trying to identify the conditions that elicit HABs. Using a diverse array of technology including stationary sensors, underwater gliders and traditional boat collections, Dr. Caron’s team has surveyed much of southern California’s coastline. Their data provide a growing picture of our region’s marine environment before and during HAB events. The information provides a critical backdrop for understanding HABs as they occur, and possibly predicting or managing such events in the future.
Dr. Caron and colleagues in northern California are also doing comparative studies of algal blooms at different HAB “hotspots” across the state. Certain locations are more susceptible to algal blooms than others. By identifying traits that are similar or different across these sites, Dr. Caron’s project will continue to shed light on the natural and human-sourced factors that lead to California’s harmful blooms.
The dynamics of HABs are important to understand since humans can both influence and be influenced by these phenomena. Urban runoff and wastewater may contribute to creating HAB conditions; meanwhile, access to important resources such as seafood, recreation and water can be temporarily compromised when blooms occur. Dr. Caron’s research helps to explore these connections, and his findings have significant implications for the sustainable management of our coastal waters. Such research epitomizes the USC Wrigley Institute’s emphasis on understanding complex relationships between coastal oceans and society.