The response of aquatic ecosystems to the interactive effects of stratospheric ozone depletion, UV radiation, and climate change

Abstract

Variations in stratospheric ozone and changes in the aquatic environment by climate change and human activity are modifying the exposure of aquatic ecosystems to UV radiation. These shifts in exposure have consequences for the distributions of species, biogeochemical cycles, and services provided by aquatic ecosystems. This Quadrennial Assessment presents the latest knowledge on the multi-faceted interactions between the effects of UV irradiation and climate change, and other anthropogenic activities, and how these conditions are changing aquatic ecosystems. Climate change results in variations in the depth of mixing, the thickness of ice cover, the duration of ice-free conditions and inputs of dissolved organic matter, all of which can either increase or decrease exposure to UV radiation. Anthropogenic activities release oil, UV filters in sunscreens, and microplastics into the aquatic environment that are then modified by UV radiation, frequently amplifying adverse effects on aquatic organisms and their environments. The impacts of these changes in combination with factors such as warming and ocean acidification are considered for aquatic micro-organisms, macroalgae, plants, and animals (floating, swimming, and attached). Minimising the disruptive consequences of these effects on critical services provided by the world’s rivers, lakes and oceans (freshwater supply, recreation, transport, and food security) will not only require continued adherence to the Montreal Protocol but also a wider inclusion of solar UV radiation and its effects in studies and/or models of aquatic ecosystems under conditions of the future global climate. Graphical abstract

Potential Environmental Impacts of Coastal Desalination Intake Structures: Urgent Data Gaps and Policy Needs

“…Though mechanical clearing of intake screens (e.g., via high pressure bursts of air in reverse of the intake flow) avoids potential ecotoxicological risks associated with the release of antifouling chemicals, it may adversely impact ecosystem health through other mechanisms. For example, the release of large pulses of colored organic matter (C-OM) from intakes can reduce the photosynthetic capacity of primary producers by compromising water clarity and decreasing penetration of sunlight into the water column. ,,,, Intake sites with long water residence times may experience a browning effect if high levels of C-OM are routinely cleared from intakes, potentially reducing the availability of sunlight for photosynthesizers. , Such effects on energy production can be important at highly biologically productive sites, due to impacts on the baseline level of energy available to support the entire food web …”

“…Changes in light penetration are also known to affect the behavioral ecology of early life stage (ELS) shrimp, crab, bivalves, and fish. ,,,, For example, planktonic blue crab ( Callinectes sapidus) and fiddler crab ( Uca longisignalis ) zoaea are positively phototactic estuarine-dependent species that vertically orient themselves toward the surface, thereby facilitating transport to seagrass beds in areas dominated by wind driven or stratified currents. − Thus, impacts on water clarity that interfere with this behavior may reduce the proportion of larvae that successfully reach target nursery habitats. Many juvenile or adult stage estuarine organisms also demonstrate habitat selection, vertical migration, hunting, and/or predator avoidance behaviors that are influenced by water clarity. ,,, As light availability drops and becomes less suited to the success of light-dependent species, habitats become more susceptible to invasives, which are often able to outcompete native species in degraded environments. , Over time, these factors may collectively contribute to changes in the composition of the aquatic community, with implications for food availability for aquatic-dependent ecological receptors (e.g., wading and shorebirds). ,, It should also be noted that the above impacts are expected to be more severe at sites that are already impacted by other stressors that commonly co-occur in environments where desalination is needed (e.g., marine heatwaves, stressed freshwater inflows, hypoxia, pollution). , …”

“…Notably, California’s regulations require that potential impacts on aquatic biota be evaluated individually and in combination with other historic, current, and anticipated future anthropogenic stressors resulting from other co-occurring/colocated activities, including other planned desalination facilities. , This is an essential component of the regulations, given that baseline assumptions used to conduct modeling and evaluate risk are expected to be altered in the near term, due to a combination of intensifying climate change, coastal development, and other factors. ,,,− As baseline assumptions evolve and marine environments become increasingly stressful, so too does the degree of ecological risk associated with construction and operation of SWRO facilities, particularly where entrainment is a major concern (e.g., essential fish habitat [EFH]) and/or nearby habitats are particularly valuable, productive, or sensitive (e.g., enclosed bays/estuaries, areas of special biological significance [ASBS], and marine protected areas [MPAs]). , …”

Environmental management cycles for chemicals and climate change, EMC4: A new conceptual framework contextualizing climate and chemical risk assessment and management

“…For example, increases in plant, animal, and human disease pressures will require increased use of pesticides, veterinary medicines, and pharmaceuticals (e.g., Boxall et al, 2009;Redshaw et al, 2013). Increasing dry and hot periods, which are predicted to increase under climate change (IPCC, 2021(IPCC, , 2023, may result in increased emissions and ecotoxicity of chemicals used in personal care products, such as chemical sunscreens interacting with higher-salinity water (Diffey, 2003;Neale et al, 2023). Additionally, the dilution of effluents and runoff will be reduced, thus increasing chemical concentrations, while increase of precipitation and/or intensity of rainfall events in some regions could provide higher nutrients loadings in certain catchment areas, which, together with an increase in temperature, could trigger eutrophication processes.…”

Monte Carlo Evaluation of Uncertainties of UV Spectra Measured With Brewer Spectroradiometers

“…Potential changes in solar UV irradiance are of great environmental concern as this radiation may have detrimental effects on humans (Bais et al., 2018; D’Orazio et al., 2013; Hart & Norval, 2018; Lumi et al., 2021), materials (Andrady et al., 2023; Wachter el al., 2021) as well as terrestrial and aquatic ecosystems (Barnes et al., 2023; García‐Corral et al., 2020; Neale et al., 2023). Since these harmful effects depend greatly on the wavelength, spectral UV measurements are needed to accurately appraise their risks.…”