| 1. |
- Stoler, Aaron B., et al.
(författare)
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Combined Effects Of Road Salt And An Insecticide On Wetland Communities
- 2017
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Ingår i: Environmental Toxicology and Chemistry. - : John Wiley & Sons. - 0730-7268 .- 1552-8618. ; 36:3, s. 771-779
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Tidskriftsartikel (refereegranskat)abstract
- As the numbers of chemical contaminants in freshwater ecosystems increase, it is important to understand whether contaminants interact in ecologically important ways. The present study investigated the independent and interactive effects of 2 contaminants that frequently co-occur in freshwater environments among higher latitudes, including a commonly applied insecticide (carbaryl) and road salt (NaCl). The hypothesis was that the addition of either contaminant would result in a decline in zooplankton, an algal bloom, and the subsequent decline of both periphyton and periphyton consumers. Another hypothesis was that combining the contaminants would result in synergistic effects on community responses. Outdoor mesocosms were used with communities that included phytoplankton, periphyton, zooplankton, amphipods, clams, snails, and tadpoles. Communities were exposed to 4 environmentally relevant concentrations of salt (27 mg Cl- L-1, 77 mg Cl- L-1, 277 mg Cl- L-1, and 727 mg Cl- L-1) fully crossed with 4 carbaryl treatments (ethanol, 0 mu gL(-1), 5 mu g L-1, and 50 mu g L-1) over 57 d. Contaminants induced declines in rotifer and cladoceran zooplankton, but only carbaryl induced an algal bloom. Consumers exhibited both positive and negative responses to contaminants, which were likely the result of both indirect community interactions and direct toxicity. In contrast to the hypothesis, no synergistic effects were found, although copepod densities declined when high concentrations of both chemicals were combined. The results suggest that low concentrations of salt and carbaryl are likely to have mostly independent effects on aquatic communities. (C) 2016 SETAC
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| 2. |
- Stoler, A. B., et al.
(författare)
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Effects of a common insecticide on wetland communities with varying quality of leaf litter inputs
- 2017
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Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 226, s. 452-462
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Tidskriftsartikel (refereegranskat)abstract
- Chemical contamination of aquatic systems often co-occurs with dramatic changes in surrounding terrestrial vegetation. Plant leaf litter serves as a crucial resource input to many freshwater systems, and changes in litter species composition can alter the attributes of freshwater communities. However, little is known how variation in litter inputs interacts with chemical contaminants. We investigated the ecological effects resulting from changes in tree leaf litter inputs to freshwater communities, and how those changes might interact with the timing of insecticide contamination. Using the common insecticide malathion, we hypothesized that inputs of nutrient-rich and labile leaf litter (e.g., elm [Ulmus spp.] or maple [Acer spp.]) would reduce the negative effects of insecticides on wetland communities relative to inputs of recalcitrant litter (e.g., oak [Quercus spp.]). We exposed artificial wetland communities to a factorial combination of three litter species treatments (elm, maple, and oak) and four insecticide treatments (no insecticide, small weekly doses of 10 mu g L-1, and either early or late large doses of 50 mu g L-1). Communities consisted of microbes, algae, snails, amphipods, zooplankton, and two species of tadpoles. After two months, we found that maple and elm litter generally induced greater primary and secondary production. Insecticides induced a reduction in the abundance of amphipods and some zooplankton species, and increased phytoplanlcton. In addition, we found interactive effects of litter species and insecticide treatments on amphibian responses, although specific effects depended on application regime. Specifically, with the addition of insecticide, elm and maple litter induced a reduction in gray tree frog survival, oak and elm litter delayed tree frog metamorphosis, and oak and maple litter reduced green frog tadpole mass. Our results suggest that attention to local forest composition, as well as the timing of pesticide application might help ameliorate the harmful effects of pesticides observed in freshwater systems. (C) 2017 Elsevier Ltd. All rights reserved.
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| 3. |
- Hintz, William D., et al.
(författare)
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Salinization triggers a trophic cascade in experimental freshwater communities with varying food-chain length
- 2017
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Ingår i: Ecological Applications. - : John Wiley & Sons. - 1051-0761 .- 1939-5582. ; 27:3, s. 833-844
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Tidskriftsartikel (refereegranskat)abstract
- The application of road deicing salts in northern regions worldwide is changing the chemical environment of freshwater ecosystems. Chloride levels in many lakes, streams, and wetlands exceed the chronic and acute thresholds established by the United States and Canada for the protection of freshwater biota. Few studies have identified the impacts of deicing salts in stream and wetland communities and none have examined impacts in lake communities. We tested how relevant concentrations of road salt (15, 100, 250, 500, and 1000mgCl(-)/L) interacted with experimental communities containing two or three trophic levels (i.e., no fish vs. predatory fish). We hypothesized that road salt and fish would have a negative synergistic effect on zooplankton, which would then induce a trophic cascade. We tested this hypothesis in outdoor mesocosms containing filamentous algae, periphyton, phytoplankton, zooplankton, several macroinvertebrate species, and fish. We found that the presence of fish and high salt had a negative synergistic effect on the zooplankton community, which in turn caused an increase in phytoplankton. Contributing to the magnitude of this trophic cascade was a direct positive effect of high salinity on phytoplankton abundance. Cascading effects were limited with respect to impacts on the benthic food web. Periphyton and snail grazers were unaffected by the salt-induced trophic cascade, but the biomass of filamentous algae decreased as a result of competition with phytoplankton for light or nutrients. We also found direct negative effects of high salinity on the biomass of filamentous algae and amphipods (Hyalella azteca) and the mortality of banded mystery snails (Viviparus georgianus) and fingernail clams (Sphaerium simile). Clam mortality was dependent on the presence of fish, suggesting a non-consumptive interactive effect with salt. Our results indicate that globally increasing concentrations of road salt can alter community structure via both direct and indirect effects.
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| 4. |
- Jones, Devin K., et al.
(författare)
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Investigation of road salts and biotic stressors on freshwater wetland communities
- 2017
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Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 221, s. 159-167
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Tidskriftsartikel (refereegranskat)abstract
- The application of road deicing salts has led to the salinization of freshwater ecosystems in northern regions worldwide. Increased chloride concentrations in lakes, streams, ponds, and wetlands may negatively affect freshwater biota, potentially threatening ecosystem services. In an effort to reduce the effects of road salt, operators have increased the use of salt alternatives, yet we lack an understanding of how these deicers affect aquatic communities. We examined the direct and indirect effects of the most commonly used road salt (NaCl) and a proprietary salt mixture (NaCl, KCl, MgCl2), at three environmentally relevant concentrations (150, 470, and 780 mg Cl-/L) on freshwater wetland communities in combination with one of three biotic stressors (control, predator cues, and competitors). The communities contained periphyton, phytoplankton, zooplankton, and two tadpole species (American toads, Anaxyrus americanus; wood frogs, Lithobates sylvaticus). Overall, we found the two road salts did not interact with the natural stressors. Both salts decreased pH and reduced zooplankton abundance. The strong decrease in zooplankton abundance in the highest NaCl concentration caused a trophic cascade that resulted in increased phytoplankton abundance. The highest NaCl concentration also reduced toad activity. For the biotic stressors, predatory stress decreased whereas competitive stress increased the activity of both tadpole species. Wood frog survival, time to metamorphosis, and mass at metamorphosis all decreased under competitive stress whereas toad time to metamorphosis increased and mass at metamorphosis decreased. Road salts and biotic stressors can both affect freshwater communities, but their effects are not interactive. (C) 2016 Elsevier Ltd. All rights reserved.
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| 5. |
- Lind, Lovisa, et al.
(författare)
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Salty fertile lakes : how salinization and eutrophication alter the structure of freshwater communities
- 2018
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Ingår i: Ecosphere. - : John Wiley & Sons. - 2150-8925 .- 2150-8925. ; 9:9, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- The quality of freshwater ecosystems is decreasing worldwide because of anthropogenic activities. For example, nutrient over-enrichment associated with agricultural, urban, and industrial development has led to an acceleration of primary production, or eutrophication. Additionally, in northern areas, deicing salts that are an evolutionary novel stressor to freshwater ecosystems have caused chloride levels of many freshwaters to exceed thresholds established for environmental protection. Even if excess nutrients and road deicing salts often contaminate freshwaters at the same time, the combined effects of eutrophication and salinization on freshwater communities are unknown. Thus by using outdoor mesocosms, we investigated the potentially interactive effects of nutrient additions and road salt (NaCl) on experimental lake communities containing phytoplankton, periphyton, filamentous algae, zooplankton, two snail species (Physa acuta and Viviparus georgianus), and macrophytes (Nitella spp.). We exposed communities to a factorial combination of environmentally relevant concentrations of road salt (15, 250, and 1000 mg Cl-/L), nutrient additions (oligotrophic, eutrophic), and sunlight (low, medium, and high) for 80 d. We manipulated light intensity to parse out the direct effects of road salts or nutrients from the indirect effects via algal blooms that reduce light levels. We observed numerous direct and indirect effects of salt, nutrients, and light as well as interactive effects. Added nutrients caused increases in most producers and consumers. Increased salt (1000 mg Cl-/L) initially caused a decline in cladoceran and copepod abundance, leading to an increase in phytoplankton. Increased salt also reduced the biomass and chl a content of Nitella and reduced the abundance of filamentous algae. Added salt had no effect on the abundance of pond snails, but it caused a decline in banded mystery snails, which led to an increase in periphyton. Low light negatively affected all taxa (except Nitella) and light levels exhibited multiple interactions with road salt, but the combined effects of nutrients and salt were always additive. Collectively, our results indicate that eutrophication and salinization both have major effects on aquatic ecosystems and their combined effects (through different mechanisms) are expected to promote large blooms of phytoplankton and periphyton while causing declines in many species of invertebrates and macrophytes.
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| 6. |
- Schuler, Matthew S., et al.
(författare)
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How common road salts and organic additives alter freshwater food webs : in search of safer alternatives
- 2017
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Ingår i: Journal of Applied Ecology. - : John Wiley & Sons. - 0021-8901 .- 1365-2664. ; 54:5, s. 1353-1361
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Tidskriftsartikel (refereegranskat)abstract
- 1. The application of deicing road salts began in the 1940s and has increased drastically in regions where snow and ice removal is critical for transportation safety. The most commonly applied road salt is sodium chloride (NaCl). However, the increased costs of NaCl, its negative effects on human health, and the degradation of roadside habitats has driven transportation agencies to seek alternative road salts and organic additives to reduce the application rate of NaCl or increase its effectiveness. Few studies have examined the effects of NaCl in aquatic ecosystems, but none have explored the potential impacts of road salt alternatives or additives on aquatic food webs. 2. We assessed the effects of three road salts (NaCl, MgCl2 and ClearLane (TM)) and two road salts mixed with organic additives (GeoMelt (TM) and Magic Salt (TM)) on food webs in experimental aquatic communities, with environmentally relevant concentrations, standardized by chloride concentration. 3. We found that NaCl had few effects on aquatic communities. However, the microbial breakdown of organic additives initially reduced dissolved oxygen. Additionally, microbial activity likely transformed unusable phosphorus from the organic additives to usable phosphorus for algae, which increased algal growth. The increase in algal growth led to an increase in zooplankton abundance. Finally, MgCl2 - a common alternative to NaCl - reduced compositional differences of zooplankton, and at low concentrations increased the abundance of amphipods. 4. Synthesis and applications. Our results indicate that alternative road salts (to NaCl), and road salt additives can alter the abundance and composition of organisms in freshwater food webs at multiple trophic levels, even at low concentrations. Consequently, road salt alternatives and additives might alter ecosystem function and ecosystem services. Therefore, transportation agencies should use caution in applying road salt alternatives and additives. A comprehensive investigation of road salt alternatives and road salt additives should be conducted before wide-scale use is implemented. Further research is also needed to determine the impacts of salt additives and alternatives on higher trophic levels, such as amphibians and fish.
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| 7. |
- Sousa, Ronaldo, et al.
(författare)
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The role of anthropogenic habitats in freshwater mussel conservation
- 2021
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Ingår i: Global Change Biology. - : John Wiley & Sons. - 1354-1013 .- 1365-2486. ; 27, s. 2298-2314
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic freshwater habitats may provide undervalued prospects for long-term conservation as part of species conservation planning. This fundamental, but overlooked, issue requires attention considering the pace that humans have been altering natural freshwater ecosystems and the accelerated levels of biodiversity decline in recent decades. We compiled 709 records of freshwater mussels (Bivalvia, Unionida) inhabiting a broad variety of anthropogenic habitat types (from small ponds to large reservoirs and canals) and reviewed their importance as refuges for this faunal group. Most records came from Europe and North America, with a clear dominance of canals and reservoirs. The dataset covered 228 species, including 34 threatened species on the IUCN Red List. We discuss the conservation importance and provide guidance on how these anthropogenic habitats could be managed to provide optimal conservation value to freshwater mussels. This review also shows that some of these habitats may function as ecological traps owing to conflicting management practices or because they act as a sink for some populations. Therefore, anthropogenic habitats should not be seen as a panacea to resolve conservation problems. More information is necessary to better understand the trade-offs between human use and the conservation of freshwater mussels (and other biota) within anthropogenic habitats, given the low number of quantitative studies and the strong biogeographic knowledge bias that persists.
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| 8. |
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