Beyond troubled waters: the influence of eutrophication on host–parasite interactions

Abstract

Summary1. Recent research in biomedicine and in ecology has linked disease emergence and resurgence with human-induced environmental change. Water bodies, in particular, have dramatically changed during the past century due to artificial enrichment of nutrients from diverse sources (e.g. agriculture, forestry, waste discharges). A growing number of studies, reviewed in this synthesis, highlights how these alterations are tightly linked to changes in host-parasite interactions and impact wildlife health. 2. Direct responses of aquatic ecosystems to the disturbance include changes in the community of primary producers and cause indirect responses such as turbidity, oxygen depletion and foodweb alteration; a phenomenon known as anthropogenic eutrophication. Ultimately, eutrophication causes a wide range of effects on host-parasite interactions which should all be considered to predict infection probability and outcome in disturbed areas. 3. Future research should encompass a more fundamental and holistic view of eutrophication, considering altogether the multitude of environmental changes encountered in eutrophied sites. Stronger collaborations among disease biologists and aquatic ecologists are necessary to better understand and manage wildlife health at impacted water bodies.

Allometric and trait‐based patterns in parasite stoichiometry

“…First, ecological stoichiometry provides a mechanistic framework to study the importance of parasitism to ecosystem processes, a poorly understood topic (Ostfeld et al 2008). While describing pools of biomass for both free‐living and parasitic consumers serves as one method to address this issue (Paseka ), stoichiometry provides a more mechanistic approach to measure the flux of energy and nutrients through host–parasite interactions. Second, while the response of parasites to changes in ecosystem‐level nutrient cycling has received ample attention (Smith 2007, McKenzie and Townsend 2007, Budria ), few studies have employed a stoichiometric framework to address this topic for animal parasites.…”

“…However, our measurements of parasite stoichiometry may have been influenced by plastic responses particular to the ecosystems or hosts (in the case of generalist parasites) from which we sampled. The importance of bottom–up nutrient availability to infection patterns is of great importance to parasite ecology (Smith 2007, McKenzie and Townsend 2007, Budria ), but it is unknown whether parasites exhibit stoichiometric homeostasis or plasticity in response to variation in dietary resources. An ideal study would sample a diverse parasite assemblage from a single ecosystem to control for potential effects of ecosystem identity, but both the distribution of parasite species across our study system and our need for relatively high sample mass necessitated that we sample from many ecosystems to address our questions.…”

“…While describing pools of biomass for both free-living and parasitic consumers serves as one method to address this issue (Paseka 2017), stoichiometry provides a more mechanistic approach to measure the flux of energy and nutrients through host-parasite interactions. Second, while the response of parasites to changes in ecosystem-level nutrient cycling has received ample attention (Smith 2007, McKenzie and Townsend 2007, Budria 2017, few studies have employed a stoichiometric framework to address this topic for animal parasites. Data from snail-trematode and zooplanktonbacteria systems demonstrate shifts in parasite production in response to environmental nutrient ratios (Frost et al 2008, Bernot 2013.…”

How Temperature, Pond-Drying, and Nutrients Influence Parasite Infection and Pathology

“…Environmental changes involving temperature, drought, and nutrient-loading are altering aquatic environments in ways that influence pathogen transmission (Johnson et al 2010; Altizer et al 2013; Budria 2017), but the relative importance and cumulative effects of these abiotic factors can be challenging to assess. A wide variety of laboratory and mesocosm studies have examined the effects of isolated or paired drivers such as temperature or nutrient addition on disease systems, providing valuable mechanistic understanding (Paull et al 2012; Decaestecker et al 2015; Buck et al 2016; Penttinen et al 2016; Laverty et al 2017).…”

Monitoring fish, benthic invertebrates, and physicochemical properties of surface water for evaluating nonpoint source pollution control in coastal agricultural watersheds

“…Similarly, agricultural watersheds can manifest spatial variation in water quality impairment due to differences in land use types, soils, nutrient inputs, and agricultural activities across the landscape (Demcheck et al 2004;Mueller-Warrant et al 2012;Poudel et al 2013). The impairment of physical and chemical properties of surface waters can negatively impact biological communities due to, for example, hypoxia and harmful algal blooms (Zhou et al 2008;Broussard and Turner 2009;Riseng et al 2011;Budria 2017;Breitburg et al 2018), increased levels of fecal bacteria (Brendel and Soupir 2017), elevated levels of suspended sediment (Basnyat et al 1999;Riseng et al 2011), or the presence of pesticides (Echeverría-Sáenz et al 2012;Anderson et al 2014Anderson et al , 2018.…”