Thermal Change and the Dynamics of Multi-Host Parasite Life Cycles in Aquatic Ecosystems

Abstract

Altered thermal regimes associated with climate change are impacting significantly on the physical, chemical, and biological characteristics of the Earth’s natural ecosystems, with important implications for the biology of aquatic organisms. As well as impacting the biology of individual species, changing thermal regimes have the capacity to mediate ecological interactions between species, and the potential for climate change to impact host–parasite interactions in aquatic ecosystems is now well recognized. Predicting what will happen to the prevalence and intensity of infection of parasites with multiple hosts in their life cycles is especially challenging because the addition of each additional host dramatically increases the potential permutations of response. In this short review, we provide an overview of the diverse routes by which altered thermal regimes can impact the dynamics of multi-host parasite life cycles in aquatic ecosystems. In addition, we examine how experimentally amenable host–parasite systems are being used to determine the consequences of changing environmental temperatures for these different types of mechanism. Our overarching aim is to examine the potential of changing thermal regimes to alter not only the biology of hosts and parasites, but also the biology of interactions between hosts and parasites. We also hope to illustrate the complexity that is likely to be involved in making predictions about the dynamics of infection by multi-host parasites in thermally challenged aquatic ecosystems.

Come rain or come shine: environmental effects on the infective stages of Sparicotyle chrysophrii, a key pathogen in Mediterranean aquaculture

“…Therefore, the wide salinity tolerance of gilthead sea bream (from 5 to 45 ppt [ 27 ]) makes unlikely that these species will be affected by the salinity increase projected. Despite of the fact that evolutionary potential and adaptability are predicted to be greater for parasites than for hosts [ 73 ], acclimation processes are likely to succeed for both organisms as changes are predicted to occur gradually enough [ 74 ]. Nevertheless, conditions in aquaculture facilities or in certain local microclimates might alter the stability of the relationship between gilthead sea bream and S. chrysophrii with unknown consequences.…”

Half the story: Thermal effects on within‐host infectious disease progression in a warming climate

“…In CBVs like the three‐spined stickleback, within‐host infection dynamics can thus be expected to respond appreciably to rapid year‐on‐year warming. Direct thermal effects may drive part of this response, which in turn contributes to population‐ (Barber, Berkhout, & Ismail, ; Mignatti, Boag, & Cattadori, ) and community‐level (Karvonen et al., ; Paull & Johnson, ) pathogen dynamics. But these higher level responses will also depend on other factors: on thermal responses of free‐living transmission stages and on indirect effects of temperature (on both within‐host and free‐living stages) mediated through changes in the environment.…”

Do Ecosystem Service Value Increase and Environmental Quality Improve due to Large–Scale Ecological Water Conveyance in an Arid Region of China?

“…Influencing factors of ecosystem service value, which varied with the change in natural and economic conditions, including climate, vegetation, market prices, and trade, etc. [61,62]. This study has solved two main problems.…”