| 1. |
- Hedgespeth, Melanie, et al.
(författare)
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Assessing potential vulnerability and response of fish to simulated avian predation after exposure to psychotropic pharmaceuticals
- 2016
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Ingår i: Toxics. - : MDPI AG. - 2305-6304. ; 4:9
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Tidskriftsartikel (refereegranskat)abstract
- Psychotropic pharmaceuticals present in the environment may impact organisms both directly and via interaction strengths with other organisms, including predators; therefore, this study examined the potential effects of pharmaceuticals on behavioral responses of fish to avian predators. Wild-caught juvenile perch (Perca fluviatilis) were assayed using a striking bird model after a seven-day exposure to psychotropic pharmaceuticals (the antidepressants fluoxetine or sertraline, or the -blocker propranolol) under the hypotheses that exposure would increase vulnerability to avian predation via increasing the probability of predator encounter as well as degrading evasive behaviors upon encounter. None of the substances significantly affected swimming activity of the fish, nor did they increase vulnerability by affecting encounter probability or evasive endpoints compared to control treatments. Counter to our expectations, fish exposed to 100 g/L fluoxetine (but no other concentrations or pharmaceuticals) were less likely to enter the open area of the arena, i.e., less likely to engage in risky behavior that could lead to predator encounters. Additionally, all fish exposed to environmentally relevant, low concentrations of sertraline (0.12 g/L) and propranolol (0.1 g/L) sought refuge after the simulated attack. Our unexpected results warrant further research as they have interesting implications on how these psychotropic pharmaceuticals may affect predator-prey interactions spanning the terrestrial-aquatic interface.
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| 2. |
- Hedgespeth, Melanie, et al.
(författare)
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Ecological implications of altered fish foraging after exposure to an antidepressant pharmaceutical.
- 2014
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 1879-1514 .- 0166-445X. ; 151:Online 17 December 2013, s. 84-87
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Tidskriftsartikel (refereegranskat)abstract
- Pharmaceutical residues are increasingly detected in environmental and biological samples, some at levels known to adversely affect non-target organisms; however, less is known of how these organism-level effects relate to the ecology of aquatic systems. Foraging processes may be used as behavioral endpoints that link effects on individuals to the population and community levels, enabling risk assessment of environmental contaminants at larger ecological scales. In this study, we performed feeding trials using juvenile Eurasian perch (Perca fluviatilis) exposed to the selective serotonin reuptake inhibitor (SSRI) sertraline to test the hypothesis that sertraline alters foraging ecology of the fish in terms of their functional response. We found an exposure-dependent decrease in feeding with increasing sertraline concentrations. Further experiments revealed that feeding rates decrease at both low and high prey densities, indicating effects on both attack rate and handling time, respectively. Because the functional response can shape consumer-resource dynamics, such effects may alter the stability of predator-prey systems and consequently, community structure.
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| 3. |
- Hedgespeth, Melanie Lea, et al.
(författare)
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Behaviour of freshwater snails (Radix balthica) exposed to the pharmaceutical sertraline under simulated predation risk
- 2018
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Ingår i: Ecotoxicology. - : Springer Science and Business Media LLC. - 0963-9292 .- 1573-3017. ; 27:2, s. 144-153
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Tidskriftsartikel (refereegranskat)abstract
- Due to their potential for affecting the modulation of behaviour, effects of selective serotonin reuptake inhibitors (SSRIs) in the environment are particularly interesting regarding interspecies interactions and non-consumptive effects (NCEs) induced by predator cues in prey organisms. We evaluated the effects of sertraline (0.4, 40 ng/L, 40 µg/L) over 8 days on activity and habitat choice in the freshwater snail Radix balthica, on snails’ boldness in response to mechanical stimulation (simulating predator attack), and their activity/habitat choice in response to chemical cues from predatory fish. We hypothesised that sertraline exposure would detrimentally impact NCEs elicited by predator cues, increasing predation risk. Although there were no effects of sertraline on NCEs, there were observed effects of chemical cue from predatory fish on snail behaviour independent of sertraline exposure. Snails reduced their activity in which the percentage of active snails decreased by almost 50% after exposure to fish cue. Additionally, snails changed their habitat use by moving away from open (exposed) areas. The general lack of effects of sertraline on snails’ activity and other behaviours in this study is interesting considering that other SSRIs have been shown to induce changes in gastropod behaviour. This raises questions on the modes of action of various SSRIs in gastropods, as well as the potential for a trophic “mismatch” of effects between fish predators and snail prey in aquatic systems.
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| 4. |
- Hedgespeth, Melanie
(författare)
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Psychotropic Pharmaceuticals in Aquatic Systems: An Ecological Perspective
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Psychotropic pharmaceuticals have been shown to exert a variety of sublethal effects on non-target organisms, even at low concentrations found in the environment (ng/L to µg/L); hence, the aim of my research has been to determine the individual-level effects of psychotropic pharmaceuticals (the selective serotonin reuptake inhibitors sertraline and fluoxetine, and the β-blocker propranolol) on behavioral and life history traits in freshwater organisms. Further, this research was directed towards assessing the potential large-scale impacts of these effects on population growth and predator-prey interactions (with community-level implications) via the application of traditional, ecological concepts and models. This work has therefore incorporated the exposure of organisms to key biotic stressors connected with predator-prey interactions (e.g. non-consumptive effects, variations in diet composition or prey density) that serve as vital links across levels of organization. The studies included in this thesis indicate that exposure to sertraline resulted in alterations in habitat choice of snails (Radix balthica), though this did not affect the predator-induced, non-consumptive effects in snail behavior. This suggests that sertraline may not increase risk for predation by fish. Also, fluoxetine exposure altered risk-taking behavior in fish (Perca fluviatilis) linked to decreased vulnerability to avian predation, but this was potentially at the cost of reduced food-intake. A separate study directly examined feeding in juvenile fish (Perca fluviatilis) for which those exposed to sertraline exhibited decreased feeding rates at both low and high zooplankton prey densities (Daphnia magna). When examining effects of sertraline on the zooplankton Daphnia magna, I also detected significant reductions in growth, fecundity, and capacity for population increase, especially when exposed to both sertraline and a toxic cyanobacterium, Microcystis aeruginosa, simultaneously, i.e. with synergistic effects due to exposure to the two stressors occurring at high sertraline concentrations. When employed within an ecological framework, scientific research on organism-level traits as endpoints of the short-term effects of chemical contaminant exposure can provide valuable information on the potential long-term outcomes of exposure in the environment. Not only are these effects of exposure interesting in themselves, but more importantly, the goal of this work has been to enable a holistic approach to ecotoxicology by determining how these behavioral and other trait-related effects impact the interactions among organisms, and the potential consequences thereof at higher levels of organization.
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| 5. |
- Liénart, Camilla, et al.
(författare)
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A sprinkling of gold dust : Pine pollen as a carbon source in Baltic Sea coastal food webs
- 2022
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Ingår i: Limnology and Oceanography. - : Wiley. - 0024-3590 .- 1939-5590. ; 67:1, s. 53-65
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Tidskriftsartikel (refereegranskat)abstract
- Allochthonous subsidies to marine ecosystems have mainly focused on biogeochemical cycles, but there has also been recent interest in how terrestrial carbon (C) influences marine food webs. In the Baltic Sea, pine (Pinus sylvestris) pollen is found in large amounts in shallow bays in early summer. Pollen is a significant C-source in freshwater ecosystems and may also be important in coastal food webs. We examined the consumption of pollen and autochthonous resources by benthic invertebrates in shallow bays of the Baltic Sea. We used stable isotopes to estimate diets and reconstructed consumer-resource networks (food webs) for grazers and particulate organic matter (POM)-feeders to compare how these different guilds used pollen. We found that P. sylvestris pollen was consumed in small amounts by a variety of animals and in some cases made up a sizeable proportion of invertebrates' diets. However, invertebrates generally depended less on pollen than other resources. The degree of pollen consumption was related to feeding traits, with generalist invertebrate grazers consuming more pollen (> 10% of diet) than the more specialist POM-feeders (< 5% of diet contributed by pollen). POM-feeders may consume additional microbially-degraded pollen which was not identifiable in our model. We suggest that pollen is a small but substantial allochthonous C-source in shallow bay food webs of the Baltic Sea, with the potential to affect the dynamics of these ecosystems.
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