Santa Barbara, California
Kelp forests are highly productive coastal ecosystems that support fisheries, protect shorelines, and sustain marine biodiversity along the California coast. In recent years, widespread kelp loss driven by marine heatwaves, long-term warming, and intense sea urchin grazing has raised urgent questions about how these ecosystems recover and how organizations can make restoration efforts more effective.
Kelp Forest Hydrodynamics in Santa Barbara
Kelp recovery depends on the dispersal and settlement of microscopic spores, which are transported by ocean currents before attaching to the seafloor and growing into mature kelp. However, we need a better understanding of the hydrodynamic processes that control kelp spore dispersal, since the water flow within kelp forests is complex: dense kelp canopies slow currents, redirect circulation, and alter mixing in ways that are still poorly understood. These physical processes play a central role in determining where spores travel, where they settle, and whether they successfully recruit into new kelp plants.
Understanding these transport processes also has broader ecological implications. For example, the same currents that move spores could influence how kelp-derived carbon is retained within forests or exported to the surrounding ocean. Motivated by this and other reasons, we study kelp forest hydrodynamics to identify the physical controls on transport and to better understand the processes that shape kelp connectivity and recovery.
In July 2024, we conducted three submarine dye-release experiments using Rhodamine-WT to directly observe water transport within and around a kelp forest near Santa Barbara. We measured dye concentrations using moored fluorometers and transects from boats, kayaks, and surfboards. At the same time, we deployed instruments to measure currents, temperature, salinity, and pressure both inside and outside the kelp forest.
Ideally, we would use these observations to develop and validate high-resolution models of spore transport and retention within kelp beds, providing insights for restoration practitioners, resource managers, and tribal governments working to restore kelp forests in a changing coastal ocean. However, we are currently focusing only on the observations themselves and what they reveal about the complex hydrodynamics around kelp forests.
The primary student leading this work at UCLA is Eber Reyes López. This project is a collaborative effort involving partners from UC Santa Barbara, the Woods Hole Oceanographic Institution (WHOI), and UNC Wilmington.
