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The world's fastest place : Bonneville land speed racing
Nowhere else have so many land speed records been set as at the Bonneville Salt Flats, Utah. Each year, devoted gearheads and adrenaline junkies around the world gather to add their names to the hall of fame with their hot rods, roadsters, motorcycles, and belly tankers. -- German photographer Alexandra Lier visited the famous Speed Week at Bonneville for the first time in 1999 and has returned annually ever since. In this book she documents the fanatically passionate culture of speed record chasers, the drivers, and their beautiful vehicles, set in the amazing landscape of the Utah salt flats.
Book
Intra-Lake Arcellinida (Testate Lobose Amoebae) Response to Winter De-icing Contamination in an Eastern Canada Road-Side “Salt Belt” Lake
Salt contamination of lakes, due to the application of winter de-icing salts on roads, presents a significant environmental challenge in the “salt belt” region of eastern North America. The research reported here presents the first deployment of a previously published proxy tool based on Arcellinida (testate lobose amoebae) for monitoring road salt contamination. The research was conducted at Silver Lake in Eastern Ontario, a 4-km-long lake with the heavily traveled Trans-Canada Highway (HWY 7) transiting the entire southern shore. The lake showed elevated conductivity (297–310 µS/cm) and sub-brackish conditions (0.14–0.15 ppt). Sodium levels were also elevated near the roadside (median Na = 1020 ppm). Cluster analysis and nonmetric multidimensional scaling results revealed four distinct Arcellinida assemblages: “Stressed Cool Water Assemblage (SCWA),” “Deep Cold Water Assemblage (DCWA),” both from below the 8-m thermocline, and the shallower water “Shallow Water Assemblage 1 (SWA-1)” and “Shallow Water Assemblage 2 (SWA-2)”. Redundancy analysis showed a minor response of Arcellinida to road salt contamination in shallower areas of the lake, with confounding variables significantly impacting assemblage distribution, particularly beneath the thermocline (e.g., water temperature, water depth, sediment runoff from catchment [Ti], sediment geochemistry [Ca, S]). The results of this study indicate that the trophic structure of the lake has to date only been modestly impacted by the cumulative nature of road salt contamination. Nonetheless, the Silver Lake results should be considered of concern and warrant continued arcellinidan biomonitoring to gauge the ongoing and long-term effects of road salt on its ecosystem.
Journal Article
Road Salt versus Urban Snow Effects on Lake Microbial Communities
Freshwater salinization is an ongoing concern for north temperate lakes; however, little is known about its impacts on microbial communities, particularly for bacteria. We tested the hypotheses that road de-icing salt induces changes in the microbial community structure of lake plankton, and that changes due to chloride would differ from those due to urban snowmelt because of additional chemicals in the snowmelt. In a laboratory incubator experiment, an overwintering plankton community in lake water was exposed for two weeks to either NaCl or municipal road snow with the same level of chloride. Microbial community structure as determined by 16S (prokaryotes) and 18S (eukaryotes) rRNA transcript analysis showed changes in response to the chloride-only enrichment, with some rare taxa becoming more prominent. Consistent with our hypothesis, the salt and the snow treatments induced different community changes. These results indicate that ecotoxicology assays based on a single salt addition may not reflect the in situ effects of salt-contaminated urban snow, and that the combined chemical effects of urban snowmelt require direct testing.
Journal Article
Environmental Impact of Chemical Deicers – A Review
Increased application of chemical deicers for winter maintenance has resulted in increased concentrations of deicer constituents in the environment. The runoffs from the deicing operation have a deteriorating effect on soil and water quality. But the degree of impact is localized and it depends on various climatic factors and can also be attributed to the type of salts used and their storage conditions. This paper presents a review of the environmental impact of deicing chemicals.
Journal Article
Effects of road salt on a free-living trematode infectious stage
Many temperate freshwater habitats are at risk for contamination by run-off associated with the application of road de-icing salts. Elevated salinity can have various detrimental effects on freshwater organisms, including greater susceptibility to infection by parasites and pathogens. However, to better understand the net effects of road salt exposure on host–parasite dynamics, it is necessary to consider the impacts on free-living parasite infectious stages, such as the motile aquatic cercariae of trematodes. Here, we examined the longevity and activity of cercariae from four different freshwater trematodes ( Ribeiroia ondatrae , Echinostoma sp., Cephalogonimus sp. and an unidentified strigeid-type) that were exposed to road salt at five different environmentally relevant concentrations (160, 360, 560, 760 and 960 mg/ml of sodium chloride). Exposure to road salt had minimal detrimental effects, with cercariae activity and survival often greatest at intermediate concentrations. Only the cercariae of Cephalogonimus sp. showed reduced longevity at the highest salt concentration, with those of both R. ondatrae and the unidentified strigeid-type exhibiting diminished activity, indicating interspecific variation in response. Importantly, cercariae seem to be relatively unaffected by salt concentrations known to increase infection susceptibility in some of their hosts. More studies will be needed to examine this potential dichotomy in road salt effects between hosts and trematodes, including influences on parasite infectivity.
Journal Article
Effects of Road Salts on Seasonal Wetlands: Poor Prey Performance May Compromise Growth of Predatory Salamanders
Road deicing agents that enter wetlands can affect amphibians both directly via their toxic effects and indirectly by altering food web interactions. We conducted experiments to determine whether larvae of the spotted salamander (
Ambystoma maculatum
) are more strongly influenced by direct versus indirect effects of salt concentration. Using outdoor mesocosms, we exposed salamanders and their prey to experimental salinities that were representative of values reported from salt contaminated breeding sites in North America. Increasing salinity depressed salamander growth but did not affect survival. Cladocerans were numerical dominants in samples taken 2 weeks after the experiment began, and markedly declined with increasing salinity. The number of cladocerans and total number of all invertebrates on this date were positively correlated with the mean mass of salamanders at the termination of the experiment. In a laboratory experiment where food was supplied in excess, increasing salinity did not affect the growth or survival of spotted salamanders that were chronically exposed to salinities that paralleled those in the mesocosm experiment. Our results suggest that spotted salamander larvae are more salt-tolerant than their prey, and that salamander growth may be compromised via indirect effects when breeding sites experience moderate salt contamination (i.e., < 1,000 mg L
−1
of salts).
Journal Article
Effect of Road Salt Application on Seasonal Chloride Concentrations and Toxicity in South-Central Indiana Streams
Contemporary information on road salt runoff is needed for management of water resources in regions experiencing urbanization and increased road density. We investigated seasonal Cl– concentrations among five streams in south-central Indiana that drained watersheds varying in degree of urbanization and ranging in size from 9.3 to 27 km2. We also conducted acute toxicity tests with Daphnia pulex to assess the potential effects of the observed Cl– concentrations on aquatic life. Periods of elevated Cl– concentrations were observed during the winters of 2007–08 and 2008–09 at all sites except the reference site. The highest Cl– concentration observed during the study was 2100 mg L–1 and occurred at the most urbanized site. The Cl– concentration at the reference site never exceeded 22 mg L–1. The application of road salt caused large increases in stream Cl– concentrations, but the elevated Cl– levels did not appear to be a significant threat to aquatic life based on our toxicity testing. Only the most urbanized site showed evidence of salt retention within the watershed, whereas the other sites exported the road salt relatively quickly after its application, suggesting storm drains and impervious surfaces minimized interaction between soils and salt-laden runoff. During winter at these sites, the response in stream Cl– concentrations appeared to be controlled by the timing and intensity of road salt application, the magnitude of precipitation, and the occurrence of air temperatures that caused snowmelt and generated runoff.
Journal Article
Calcium chloride pollution mitigates the negative effects of an invasive clam
Invasive bivalves can drastically alter freshwater ecosystems and affect ecosystem services, but they can be influenced by external factors including calcium concentrations. When a common road salt, calcium chloride (CaCl2), enters freshwater ecosystems, it may be toxic to organisms or facilitate bivalves by serving as a calcium source. Therefore, CaCl2 could benefit invasive mollusks tolerant to chloride that require calcium to grow. We used mesocosms to investigate the impacts of CaCl2 (35–187 mg Ca2+ L−1) and invasive bivalves (Asian clams, Corbicula fluminea; zebra mussels, Dreissena polymorpha) on a native lake food web. We hypothesized that invasive bivalves facilitate benthic algae because they reduce phytoplankton and excrete waste. These changes in primary producers would subsequently impact consumers. We also hypothesized that low to moderate CaCl2 concentrations promote the survival, growth, and reproduction of native and invasive mollusks, while causing few toxic effects. If so, we hypothesized that invaded communities exposed to CaCl2 experience stronger impacts from the invasive bivalves. We found that invasive bivalves decreased phytoplankton, which led to decreases in periphyton, zooplankton, and native clams. They caused increases in filamentous algae and isopods. While zebra mussels survived poorly in all treatments, moderate concentrations of CaCl2 substantially reduced Asian clams, which reduced their community effects. Our highest CaCl2 treatments also reduced zooplankton densities. Thus, while freshwater salinization from road salts poses a concern, we observed no indication that CaCl2 road salt will benefit Asian clams and zebra mussels. However, the community-wide consequences from Asian clams at low CaCl2 emphasize the extensive effects that invasive bivalves can have on freshwater communities and the immense concern surrounding their invasions.
Journal Article
Evolution to environmental contamination ablates the circadian clock of an aquatic sentinel species
Environmental contamination is a common cause of rapid evolution. Recent work has shown that Daphnia pulex, an important freshwater species, can rapidly evolve increased tolerance to a common contaminant, sodium chloride (NaCl) road salt. While such rapid evolution can benefit organisms, allowing them to adapt to new environmental conditions, it can also be associated with unforeseen tradeoffs. Given that exposure to environmental contaminants can cause circadian disruption, we investigated whether the circadian clock was affected by evolving a tolerance to high levels of road salt. By tracking the oscillations of a putative clock gene, period, we demonstrated that D. pulex express per mRNA with approximately 20‐hr oscillations under control conditions. This putative circadian rhythm was ablated in response to high levels of salinity; populations adapted to high NaCl concentrations exhibited an ablation of period oscillation. Moreover, we showed that while gene expression is increased in several other genes, including clock, actin, and Na+/K+‐ATPase, upon the adaptation to high levels of salinity, per expression is unique among the genes we tracked in that it is the only gene repressed in response to salt adaptation. These results suggest that rapid evolution of salt tolerance occurs with the tradeoff of suppressed circadian function. The resultant circadian disruption may have profound consequences to individuals, populations, and aquatic food webs by affecting species interactions. In addition, our research suggests that circadian clocks may also be disrupted by the adaptation to other environmental contaminants. Daphnia pulex has periodic oscillation in the core clock gene, period (per), suggesting that D. pulex maintain a molecular clock. The oscillation of per is ablated upon evolution to a common contaminant, road salt. This discovery reveals the unforeseen and potentially far‐reaching effects of environmental contamination on the circadian clock.
Journal Article
Salting our freshwater lakes
The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a strong predictor of chloride trends in Northeast and Midwest North American lakes. As little as 1% impervious land cover surrounding a lake increased the likelihood of long-term salinization. Considering that 27% of large lakes in the United States have >1% impervious land cover around their perimeters, the potential for steady and long-term salinization of these aquatic systems is high. This study predicts that many lakes will exceed the aquatic life threshold criterion for chronic chloride exposure (230 mg L−1), stipulated by the US Environmental Protection Agency (EPA), in the next 50 y if current trends continue.
Journal Article