Description: The alterations in environmental parameters anticipated during global climate change are predicted to intensify physiological stress to marine ectotherms and impose selective regimes on their stress-tolerance capacities. The limits to which the effects on ecosystems will be buffered by phenotypic plasticity and adaptation of populations appear unpre- dictable. One of the most universal reactions to environmental stress is the classic heat shock response, and its evaluation in intertidal invertebrates, which experience extreme fluctuations in stress levels, may be useful to advance in the mechanistic understanding of future regime shifts. Using real-time RT-qPCR, I quantified the heat shock response in limpets of the genus Nacella that had been subjected to tidal emersion under natural conditions in field experiments at two locations in Chile. In a subpolar limpet population from Punta Arenas in the Strait of Magellan, high-intertidal limpets showed delayed stress responses, including markedly lower expression of the hsp70A gene, in comparison to their subtidal congeners. Low-intertidal limpets from a warmer acclimatized population sampled at Puerto Montt (Central Chile) exhibited the highest stress response to tidal emersion, presumably due to higher temperatures affecting air exposed animals in a cold-temperate as compared to a subpolar environment. On the genomic level, the subtidal and intertidal subpopulations display a conspicuous divergence in two distinct hsp70A allele groups, as evidenced by a discrepancy in F’st estimates in comparison to neutral genetic markers. My work indicates that Patagonian limpets show a graded heat shock response, increasing from South to North on a latitudinal gradient and from low to high on a tidal stress gradient. It provides indication for adaptive divergence of the hsp70A gene in these South American limpets, which might be explained by the selective effect of environmental stress caused by tidal emersion. Furthermore, it illustrates the great explanatory potential, but also conceptual difficulties of the heat shock response as an integrative biomarker for environmental stress. Stability assessment of reference genes is an integral part of quantification of the response, as stress conditions can cause down-regulation of constitutive genes and lead to overestimation of stress response levels. The quantification of response levels has to be performed against a thoroughly assessed background of inter-individual variation, population dynamic history and potential sequence adaptation.

Description: Global climate change affects marine fish through drivers such as ocean warming, acidification and oxygen depletion, causing changes in marine ecosystems and socioeconomic impacts. While experimental and observational results can inform about anticipated effects of different drivers, linking between these results and ecosystem-level changes requires quantitative integration of physiological and ecological processes into models to advance research and inform management. We give an overview of important physiological and ecological processes affected by environmental drivers. We then provide a review of available modelling approaches for marine fish, analysing their capacities for process-based integration of environmental drivers. Building on this, we propose approaches to advance important research questions. Examples of integration of environmental drivers exist for each model class. Recent extensions of modelling frameworks increase the potential for including detailed mechanisms and improving model projections. Experimental results on energy allocation, behaviour and physiological limitations will advance the understanding of organism-level trade-offs and thresholds in response to multiple drivers. More explicit representation of life cycles and biological traits can improve description of population dynamics and adaptation, and data on food web topology and feeding interactions help to detail the conditions for possible regime shifts. Identification of relevant processes will also benefit the coupling of different models to investigate spatial–temporal changes in stock productivity and integrated responses of social–ecological systems. Thus, a more process-informed foundation for models will promote the integration of experimental and observational results and increase the potential for model-based extrapolations into a future under changing environmental conditions.

Description: Rising temperatures and other environmental factors influenced by global climate change can cause increased physiological stress for many species and lead to range shifts or regional population extinctions. To advance the understanding of species’ response to change and establish links between individual and ecosystem adaptations, physiological reactions have to be compared between populations living in different environments. Although changes in expression of stress genes are relatively easy to quantify, methods for reliable comparison of the data remain a contentious issue. Using normalization algorithms and further methodological considerations, we compare cellular stress response gene expression levels measured by RT-qPCR after air exposure experiments among different subpopulations of three species of the intertidal limpet Nacella. Results: Reference gene assessment algorithms reveal that stable reference genes can differ among investigated populations and / or treatment groups. Normalized expression values point to differential defence strategies to air exposure in the investigated populations, which either employ a pronounced cellular stress response in the inducible Hsp70 forms, or exhibit a comparatively high constitutive expression of Hsps (heat shock proteins) while showing only little response in terms of Hsp induction. Conclusions: This study serves as a case study to explore the methodological prerequisites of physiological stress response comparisons among ecologically and phylogenetically different organisms. To improve the reliability of gene expression data and compare the stress responses of subpopulations under potential genetic divergence, reference gene stability algorithms are valuable and necessary tools. As the Hsp70 isoforms have been shown to play different roles in the acute stress responses and increased constitutive defences of populations in their different habitats, these comparative studies can yield insight into physiological strategies of adaptation to environmental stress and pr 47 ovide hints for the prudent use of the cellular stress response as a biomarker to study environmental stress and stress adaptation of populations under changing environmental conditions.

Description: Background: Rising temperatures and other environmental factors influenced by global climate change can cause increased physiological stress for many species and lead to range shifts or regional population extinctions. To advance the understanding of species’ response to change and establish links between individual and ecosystem adaptations, physiological reactions have to be compared between populations living in different environments. Although changes in expression of stress genes are relatively easy to quantify, methods for reliable comparison of the data remain a contentious issue. Using normalization algorithms and further methodological considerations, we compare cellular stress response gene expression levels measured by RT-qPCR after air exposure experiments among different subpopulations of three species of the intertidal limpet Nacella. Results: Reference gene assessment algorithms reveal that stable reference genes can differ among investigated populations and / or treatment groups. Normalized expression values point to differential defense strategies to air exposure in the investigated populations, which either employ a pronounced cellular stress response in the inducible Hsp70 forms, or exhibit a comparatively high constitutive expression of Hsps (heat shock proteins) while showing only little response in terms of Hsp induction. Conclusions: This study serves as a case study to explore the methodological prerequisites of physiological stress response comparisons among ecologically and phylogenetically different organisms. To improve the reliability of gene expression data and compare the stress responses of subpopulations under potential genetic divergence, reference gene stability algorithms are valuable and necessary tools. As the Hsp70 isoforms have been shown to play different roles in the acute stress responses and increased constitutive defenses of populations in their different habitats, these comparative studies can yield insight into physiological strategies of adaptation to environmental stress and provide hints for the prudent use of the cellular stress response as a biomarker to study environmental stress and stress adaptation of populations under changing environmental conditions.

Description: This report synthesizes the results about the impacts of climate change and ocean acidification on marine ecosystems and ecosystem services in Norway, from interviews and a workshop with stakeholders in 2013.

Description: Background Rising temperatures and other environmental factors influenced by global climate change can cause increased physiological stress for many species and lead to range shifts or regional population extinctions. To advance the understanding of species’ response to change and establish links between individual and ecosystem adaptations, physiological reactions have to be compared between populations living in different environments. Although changes in expression of stress genes are relatively easy to quantify, methods for reliable comparison of the data remain a contentious issue. Using normalization algorithms and further methodological considerations, we compare cellular stress response gene expression levels measured by RT-qPCR after air exposure experiments among different subpopulations of three species of the intertidal limpet Nacella. Results Reference gene assessment algorithms reveal that stable reference genes can differ among investigated populations and / or treatment groups. Normalized expression values point to differential defense strategies to air exposure in the investigated populations, which either employ a pronounced cellular stress response in the inducible Hsp70 forms, or exhibit a comparatively high constitutive expression of Hsps (heat shock proteins) while showing only little response in terms of Hsp induction. Conclusions This study serves as a case study to explore the methodological prerequisites of physiological stress response comparisons among ecologically and phylogenetically different organisms. To improve the reliability of gene expression data and compare the stress responses of subpopulations under potential genetic divergence, reference gene stability algorithms are valuable and necessary tools. As the Hsp70 isoforms have been shown to play different roles in the acute stress responses and increased constitutive defenses of populations in their different habitats, these comparative studies can yield insight into physiological strategies of adaptation to environmental stress and provide hints for the prudent use of the cellular stress response as a biomarker to study environmental stress and stress adaptation of populations under changing environmental conditions. Keywords: Ecological physiology; Cellular stress response; Hsp70; RT-qPCR; Gene expression; Normalization; Intertidal; Nacella