“…1). The nearshore habitats of Lake Tahoe where SIP is low, are also where human use is high, and water intakes are located 36 , thus leading to potential increases in human exposure to pathogens.Figure 1Seasonal and interannual variation in SIP in a suite of temperate lakes. SIP is averaged over the top one m depth, and varies primarily as a function of differences in seasonally incident UV, water transparency to UV, and to a lesser extent elevation (Tahoe is 1,897 m above sea level, and Negra, 2,700 m).…”
Section: Modeling the Solar Inactivation Potential (Sip) In Naturementioning
Climate change is accelerating the release of dissolved organic matter (DOM) to inland and coastal waters through increases in precipitation, thawing of permafrost, and changes in vegetation. Our modeling approach suggests that the selective absorption of ultraviolet radiation (UV) by DOM decreases the valuable ecosystem service wherein sunlight inactivates waterborne pathogens. Here we highlight the sensitivity of waterborne pathogens of humans and wildlife to solar UV, and use the DNA action spectrum to model how differences in water transparency and incident sunlight alter the ability of UV to inactivate waterborne pathogens. A case study demonstrates how heavy precipitation events can reduce the solar inactivation potential in Lake Michigan, which provides drinking water to over 10 million people. These data suggest that widespread increases in DOM and consequent browning of surface waters reduce the potential for solar UV inactivation of pathogens, and increase exposure to infectious diseases in humans and wildlife.
“…1). The nearshore habitats of Lake Tahoe where SIP is low, are also where human use is high, and water intakes are located 36 , thus leading to potential increases in human exposure to pathogens.Figure 1Seasonal and interannual variation in SIP in a suite of temperate lakes. SIP is averaged over the top one m depth, and varies primarily as a function of differences in seasonally incident UV, water transparency to UV, and to a lesser extent elevation (Tahoe is 1,897 m above sea level, and Negra, 2,700 m).…”
Section: Modeling the Solar Inactivation Potential (Sip) In Naturementioning
Climate change is accelerating the release of dissolved organic matter (DOM) to inland and coastal waters through increases in precipitation, thawing of permafrost, and changes in vegetation. Our modeling approach suggests that the selective absorption of ultraviolet radiation (UV) by DOM decreases the valuable ecosystem service wherein sunlight inactivates waterborne pathogens. Here we highlight the sensitivity of waterborne pathogens of humans and wildlife to solar UV, and use the DNA action spectrum to model how differences in water transparency and incident sunlight alter the ability of UV to inactivate waterborne pathogens. A case study demonstrates how heavy precipitation events can reduce the solar inactivation potential in Lake Michigan, which provides drinking water to over 10 million people. These data suggest that widespread increases in DOM and consequent browning of surface waters reduce the potential for solar UV inactivation of pathogens, and increase exposure to infectious diseases in humans and wildlife.
“…To calculate the moving mean of the wind direction, the unit direction vector was decomposed into north‐south and east‐west components, the respective components were averaged over the smoothing window, and then the component averages were used to calculate back to mean cardinal direction using a four‐quadrant inverse tangent function (Berens, ). At each time step, wind fields were spatially interpolated from the six‐buoy data set using a Barnes interpolation scheme (Koch et al, ) following the approach of Hoyer et al () for three‐dimensional hydrodynamic modeling of Lake Tahoe. Interpolated VWF's were then iteratively fed to the model to generate hourly time series of wave height and bed‐shear for every node in the model domain for the three simulated months.…”
A steady-state spectral wave model, STWAVE, is evaluated as a tool for predicting wave-induced sediment resuspension in lake littoral zones. Steady-state wave height and bed-shear stress estimates are tested against 2 years of high-frequency wave height and turbidity data from six littoral measurement stations in Lake Tahoe. Average wave and sediment resuspension response to a broad range of wind conditions are well captured by the model. Despite steady-state assumptions, the model reproduces patterns in wave height and sediment resuspension under time-varying wind conditions at sites with different wave exposure. Model results are insensitive to the measurement location of wind data input among six offshore meteorological buoys. Uniform and variable wind field assumptions yield similar resuspension predictions. Results representing the steady-state response to spatially uniform wind speed-direction combinations enable output from a single set of model runs to serve as a reasonable static reference for hindcasting and predicting wave resuspension patterns. This obviates the need for repeated model runs, making STWAVE output an efficient tool for exploring long-term spatio-temporal patterns in nearshore wave forcing. Application of this tool is limited by wave height overprediction for short fetches and presumably by the validity of uniform wind field assumptions over very long fetches. Applied successfully at Lake Tahoe, we find that the north and east shores, exposed to the prevailing southwesterly winds, see resuspension conditions upward of 3,000 hr/year, while the south and west shores typically see less than 500. Location-specific resuspension hours can vary by upward of ±200 hr/year due to shifting interannual wind patterns.Plain Language Summary A tool that describes lake-wide wave conditions as a function of combinations of wind speeds and directions is tested using 2 years of wave height and water clarity data from six nearshore locations at Lake Tahoe. The data confirm the modeling tool's ability to predict wave-driven resuspension of lake bed sediments. An example application details seasonal and interannual variability in wind wave influence at the perimeter of Lake Tahoe. Due to the prevailing southwesterly winds, exposed sections of the north and east shores of the lake can see in excess of 3,000 hr of sediment resuspension-inducing wave conditions per year, while the south and west shores are comparatively calm. In representative year 2016, wave forcing was more prevalent in the fall and winter seasons.
Key Points:• A steady-state wind-wave model, with uniform-wind field forcing, accurately predicts littoral sediment resuspension in a deep lake • Model output for discrete wind speed-direction combinations enables reconstruction of resuspension patterns without repeated model runs • Wind waves drive resuspension conditions 30-40% of the fall and winter seasons on the wave-exposed north and east shores of Lake Tahoe
“…Shifts in precipitation patterns (intensity and location) is one of the climate change predictions for the future, and this will clearly impact both waterborne and foodborne transmissions of Cryptosporidium, and therefore, future human exposures may differ significantly from current patterns as the climate changes . Hydrodynamic modelling has been shown to represent a valid and cost‐effective support, for decision‐making and understanding of events . Quantitative microbial risk assessment (QMRA) is another widely used tool to estimate health impacts from exposure to Cryptosporidium and other pathogens and has been applied to climate change .…”
Section: Risk Managementmentioning
confidence: 99%
“…156 Hydrodynamic modelling has been shown to represent a valid and cost-effective support, for decision-making and understanding of events. 157 Quantitative microbial risk assessment (QMRA) is another widely used tool to estimate health impacts from exposure to Cryptosporidium and other pathogens 154 and has been applied to climate change. 158 Quantification and identification of Cryptosporidium in wildlife excreta is an essential starting point for estimating catchment loads.…”
SummaryCryptosporidium is a major cause of moderate-to-severe diarrhoea in humans worldwide, second only to rotavirus. Due to the wide host range and environmental persistence of this parasite, cryptosporidiosis can be zoonotic and associated with foodborne and waterborne outbreaks. Currently, 31 species are recognized as valid, and of these,
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