Award: OCE-1736830

Climate change is threatening coastal marine ecosystems, particularly sedentary species and spatially constrained small-scale fisheries that are unable to keep up with shifts in ocean conditions and species distributions. The project addresses the overall question of whether and how local variability in oceanographic conditions provide refuges from adverse conditions associated with climate change and extremes. The project's specific objectives are to: Objective 1. Quantify the patterns and understand the drivers of local oceanographic variability that expose marine organisms to stressors and connect habitats with different stressor regimes, through integrated oceanographic-ecological field studies at multiple locations on the Baja California coast (Mexico). Objective 2. Assess the spatial and temporal variability of juvenile recruitment and performance (survival, growth and physiological condition) of pink and green abalone, and link these rates to local oceanographic conditions and stressor regimes through field studies and laboratory experiments. Objective 3. Scale up oceanographic and ecological variability, through population models, to project population dynamics and persistence under different current and future environmental and management scenarios. Through a combination of interdisciplinary field studies, controlled laboratory experiments, and population models, we found that, despite large-scale drivers and regional perturbations, local variability in physical conditions and biological responses are major drivers of the overall performance and vulnerability of coastal marine species to climate change. Climate refuges sheltering from adverse conditions associated with variability in oceanographic conditions and extremes can provide opportunities for fisheries management, conservation and restoration efforts in the face of global environmental change. Observations around headlands with contrasting kelp coverage illustrated the influence of living organisms on coastal hydrodynamics. Observations indicated flow attenuation within a kelp forest and demonstrated flow ducting through kelp forests. Flow ducting consists of mini-channels, ~10 to 30 m wide, of relatively enhanced flow through kelp forests. Additionally, flow ducting increases the effective radius of curvature around a headland and prevents headland upwelling. Flow ducting may enhance the creation of safe spaces, having wide-reaching ecological implications. Using results of this project, we developed an understanding of the effects of kelp forests on coastal flows. We were also able to examine the effects of kelp biomass on flows and were able to estimate bulk drag coefficients due to the presence of kelp, and to improve an ocean circulation model (COAWST) to allow for canopy flows. The novel kelp module reproduces observed flow ducting and biogeochemical variability (dissolved oxygen and pH in particular) that further suggests a biophysical link to local-scale climate refuges. Using giant kelp and marine benthic invertebrates ? primarily abalone, but also seastar, lobster and sea urchins ? as model species, we highlighted variable responses to the combination of multiple stressors ? from temperature variability and extremes, hypoxia, harmful algal blooms and disease - and the occurrence of both hotspots of vulnerability and refuges, influenced by both physical and biological drivers, including water flow characteristics and the abundance and configuration of kelp. Significant outputs and outcomes include the establishment of an oceanographic sensor networks spanning the southern California Current; an experimental control system at UABC in Ensenada, Mexico, for conducting lab experiments assessing marine organisms responses to multiple stressors; insights, models, and tools for identifying and harnessing climate refugia in fisheries management and conservation of kelp forest ecosystems in the California Current region; and training and education opportunities for postdocs, graduate, undergraduate and high school students, middle and high school teachers, and technical staff and partners in NGOs and coastal communities of Baja California. Last Modified: 05/04/2023 Submitted by: Fiorenza Micheli