2022-2023 Executive Summary
Global climate change will fundamentally alter how aquatic systems are managed. As anthropogenic carbon dioxide emissions drive increasingly severe changes to weather, rainfall patterns, and ocean temperature and chemistry, water-quality managers will be tasked with developing long-term strategies and management responses. Although climate change drivers operate primarily at a global scale, the impacts will largely be managed at a local scale. To that end, managers must be prepared to confront the local impacts of climate change, including understanding how water bodies of all kinds are being altered by changing environmental conditions, and how the diverse plant and animal communities they support are impacted by these changes. SCCWRP is helping Southern California water-quality managers connect rapidly growing knowledge about the physical manifestations of climate change to aquatic ecosystem responses. SCCWRP’s end goal is to provide managers with viable, cost-effective strategies and tools for mitigating and offsetting climate change’s ecosystem impacts.
SCCWRP’s research is focused around four main areas: (1) Altered hydrological flow patterns, which encompasses how changing rainfall and runoff patterns, drought cycles, and changing water use and reuse practices are impacting efforts by California’s water resources management community to optimally protect the environmental flows that sustain aquatic ecosystems; (2) sea level rise, which encompasses how vulnerable animals and plants in coastal wetlands and other low-lying habitats will be impacted by rising sea levels in the coming decades, and how California’s coastal resources management community can use these insights to protect sensitive species and preserve maximum ecological functioning; (3) warming waters, which encompasses how toxic cyanobacterial blooms and other nuisance species – which are becoming more common as waters warm – threaten both public and ecosystem health, and how to design long-term management strategies and improved monitoring programs to combat this emerging threat; and (4) ocean acidification and hypoxia, which encompasses how corrosive coastal ocean conditions and low dissolved oxygen levels threaten the health of marine food webs, and how California’s water-quality management community can better control and manage human activities on land to mitigate ecological impacts at sea. Understanding climate change effects on our coastal resources requires quantifying the extent of biological effects through field studies and multiple co-related stressors experimental programs, coupled with process studies and models that link stressors mechanistically to ecological responses.
This year, SCCWRP will continue to focus on understanding biotic responses to the stressors of climate change. SCCWRP’s focus for 2022-2023 will be on:
- Evaluating climate change’s effects on in-stream beneficial uses: Given that climate change will affect rainfall patterns and temperature, which will, in turn, affect the ability of streams to support beneficial uses in the future, SCCWRP is coupling temperature response models with flow-ecology principles to evaluate the effects of climate change on aquatic life across Orange and San Diego County watersheds. SCCWRP is evaluating the effects of future changes in rainfall and water use patterns on stream flows and biological integrity, with a goal to inform flow management priorities. SCCWRP also is evaluating the linked effects of multiple stressors, including developing tools to relate climate change-induced flow and stream temperature changes to eutrophication and effects on biological communities. Finally, SCCWRP is evaluating hydrologic vulnerability on stream biological health in light of projected future changes in rainfall and land use.
- Assessing the biological effects of ocean acidification and hypoxia: SCCWRP is continuing to build unique capacity to assess biological trends and variability associated with coastal seawater chemistry conditions (temperature, oxygen, pH, productivity). SCCWRP is investigating how multiple biological communities, including HABs, kelp, seagrass, and pelagic and benthic organisms, are being affected by changing seawater chemistry and how these effects will intensify in the coming decades. SCCWRP’s focus areas include: (1) identifying the pathways of biological effects and the best indicators for measuring these effects; (2) identifying the seawater chemistry thresholds at which these biological effects occur; and (3) developing statistical and mechanistic numerical models characterizing the relative importance of these effects, both individually and at a population level. SCCWRP will continue facilitating ongoing efforts to build international consensus on the thresholds at which sentinel organisms can be expected to experience adverse impacts of ocean acidification and hypoxia (OAH). SCCWRP also will continue laboratory experiments, field experiments, and historical data analyses to better characterize how multiple stressors, including OAH, are affecting economically and ecologically important marine populations; this work will include partnering on West Coast-wide acidification surveys and linking them to the Southern California Bight Regional Monitoring Program, as well as conduct a status and trends assessment of kelp based on historical data sets. Finally, SCCWRP is helping to develop integrative indices that predict potential effects of climate change stressors on various habitats, and that then can be extended to population-level effects; these tools will be used both to disentangle the effects of climate change and local anthropogenic inputs when modeling coastal eutrophication (see Eutrophication research theme), as well as to support California’s climate change mitigation strategies.
- Evaluating regional strategies and solutions to climate change: SCCWRP is working not only to identify the adverse effects of climate change, but also to identify and quantify the efficacy of potential solutions to offset and mitigate these effects. The potential solutions that SCCWRP is investigating include: (1) how strategies such as augmenting accretion, management of mouth dynamics, and facilitating transgression could help reduce anticipated wetland losses associated with sea level rise; (2) how implementing “living shoreline” solutions could help biological communities in estuaries and similar ecologically fragile habitats adapt to sea level rise; (3) how aquatic plants (e.g., seagrass and macroalgae such as kelp) could fix carbon and remove nutrients that, via coastal eutrophication, exacerbate OAH and HABs, and (4) how regenerative kelp farming – either alone or in combination with bivalve culture – could be optimally sited to minimize environmental impacts and bolster coastal economies.