Thermal tolerance and potential impacts of climate change on coastal and estuarine organisms (original) (raw)
Related papers
Effect of warming rate on the critical thermal maxima of crabs, shrimp and fish
Journal of Thermal Biology, 2015
The threat of global warming has prompted numerous recent studies on the thermal tolerance of marine species. A widely used method to determine the upper thermal limit has been the Critical Thermal Maximum (CTMax), a dynamic method, meaning that temperature is increased gradually until a critical point is reached. This method presents several advantages over static methods, however, there is one main issue that hinders interpretation and comparison of CTMax results: the rate at which the temperature is increased. This rate varies widely among published protocols. The aim of the present work was to determine the effect of warming rate on CTMax values, using different animal groups. The influence of the thermal niche occupied by each species (intertidal vs subtidal) and habitat (intertidal vs subtidal) was also investigated. CTMax were estimated at three different rates: 1°C min À 1 , 1°C 30 min À 1 and 1°C h À 1 , in two species of crab, Eurypanopeus abbreviatus and Menippe nodifrons, shrimp Palaemon northropi and Hippolyte obliquimanus and fish Bathygobius soporator and Parablennius marmoreus. While there were significant differences in the effect of warming rates for some species, for other species warming rate produced no significant differences (H. obliquimanus and B. soporator). While in some species slower warming rates lead to lower CTMax values (P. northropi and P. marmoreus) in other species the opposite occurred (E. abbreviatus and M. nodifrons). Biological group has a significant effect with crabs' CTMax increasing at slower warming rates, which did not happen for shrimp and fish. Subtidal species presented lower CTMax, at all warming rates tested. This study highlights the importance of estimating CTMax values at realistic rates that species encounter in their environment and thus have an ecological value.
Naturwissenschaften, 2012
In the global warming context, we compared the thermal tolerance of several populations of the crustacean Gammarus pulex (Amphipoda: Gammaridae) along a latitudinal thermal gradient in the Rhône Valley. To disentangle the effect of regional (North vs. South) and local (site-specific) factors, the ecophysiological responses of populations were investigated at two levels of biological organisation: whole organism level considering body size [critical thermal maximum (CTmax), mean speed of locomotion (MS), time mobile (TM)] and organelle function level [mitochondrial respiratory control ratios (RCRs)]. CTmax and RCRs, but not MS and TM, revealed a significantly higher thermal tolerance in southern populations compared to northern ones. Nevertheless, temperatures≥ 30°C were deleterious for all populations, suggesting that populations located in the warmer limit of the species distribution will be more threatened by climate change as they live closer to their upper thermal limits. The strong differences observed between populations indicate that the species-level thermal tolerance used in predictive models may not be informative enough to study the impact of global warming on species distributions. This work also reveals that an appropriate choice of indicators is essential to study the consequences of global warming since the response of organisms at the whole body level can be influenced by local conditions.
Temperature tolerances of North American freshwater fishes exposed to dynamic changes in temperature
Traditionally lower and upper temperature tolerances of fishes have been quantified in the laboratory via three different experimental approaches: the Fry or incipient lethal temperature (ILT), critical thermal (CTM) and chronic lethal (CLM) methodologies. Although these three experimental laboratory approaches generate endpoints which are quantitatively expressed as a temperature, are determined experimentally with random samples of fish acclimated to specific temperatures, and involve both time and temperature as major test variables, they do not quantify the same response. All three approaches generate valuable, albeit different, information concerning the temperature tolerance of a species. In this review we have summarized published research concerning the tolerance of North American freshwater fishes to dynamic changes in temperature, i.e., tolerance is tested by methods that gradually change temperatures until biological stress is observed. We found more than 450 individual temperature tolerances listed in 80 publications which present original dynamic temperature tolerance data for 116 species, 7 subspecies and 7 hybrids from 19 families of North American freshwater fishes. This total represents about 1/3 of the families and 1/6 of the known North American freshwater species. Temperature tolerance data were partitioned by experimental approach, i.e., critical thermal method (CTM) and chronic lethal method (CLM), and direction of temperature change. Although both CTM and CLM expose fish to dynamic changes in water temperature, these two methods differ in temperature change rates and test endpoints, and hence measure different aspects of thermal stress. A majority of the 80 studies employed CTM to assess temperature tolerance, in particular determination of CTmaxima. One or more CTmaxima has been reported for 108 fishes. Twenty-two fishes have reported highest CTmaxima of 40 • C or higher. Several species in the family Cyprinodontidae have generated some of the highest CTmaxima reported for any ectothermic vertebrate. For a variety of reasons, data concerning tolerance of low temperatures are less plentiful. Low temperature tolerance quantified as either CTminima or CLminima were found for a total of 37 fishes. Acclimation temperature exerts a major effect on the temperature tolerance of most North American fish species and it is usually strongly linearly related to both CTmaxima and CTminima. Although we uncovered dynamic temperature tolerance data for 130 fishes, only a single dynamic, temperature tolerance polygon has been published, that for the sheepshead minnow, Cyprinodon variegatus.
In hot water: sustained ocean warming reduces survival of a low-latitude coral reef fish
Marine Biology, 2018
Tropical species are predicted to be particularly vulnerable to the impacts of climate change given the relatively narrow thermal range they naturally experience. Within the tropics, average temperature and thermal variation can differ among populations and consequently low-latitude populations may respond differently to increased temperatures than higher latitude tropical populations. In this study, we investigate the long-term effects of climate change relevant temperature increases on commonly measured condition metrics for a low-latitude population of damselfish (Acanthochromis polyacanthus). Adult fish were randomly assigned to one of the three seasonally cycling treatments: (1) current average ocean temperatures for the collection locations, (2) 1.5 °C, or (3) 3 °C higher than current average temperatures. Treatments were maintained for approximately 10 months. At the end of the experimental period, Fulton's K and hepatosomatic index were calculated for fish from each treatment group and critical thermal limit (CT Max) was measured for a subset of fish at control temperatures. Fish mortality was recorded throughout the experimental period, as well as at the end of the experimental period after the introduction of a secondary exercise stressor. No significant effect of temperature was observed on fish condition (Fulton's K and hepatosomatic index); however, significant mortality was observed for fish maintained at 3 °C higher than current average temperatures. When a secondary exercise stressor was introduced, significant mortality was also observed at 1.5 °C higher than current average temperatures. Acute exposure to higher temperatures (CT Max) suggested a much higher thermal tolerance for this population than long-term mortality, producing a thermal limit of 37.1 °C compared with a chronic thermal limit of 33 °C. Our results show that some basic measures of fish condition may not be capable of detecting lethal and sublethal effects of increased temperature. The results of this study are consistent with the hypothesis that low-latitude species are already living close to their thermal maximum.
Critical thermal maxima of common rocky intertidal fish and shrimps – a preliminary assessment.
Rocky shore ecosystems are considered sentinels of climate warming because they are in close contact with the atmosphere and their shallow waters present low thermal inertia. Concerns on the vulnerability of rocky shore species subject to climate warming make the investigation of their thermal tolerance an urgent topic. The aim of this study was to determine the upper thermal limits of species that are common in tidal pools of rocky shore ecosystems of the Northeast Atlantic. The method used was the Critical Thermal Maximum (CTMax), which allowed the ranking of species in terms of their upper thermal limits as follows: Coryphoblennius galerita (32.0°C), Palaemon serratus (33.0°C), Gobius paganellus (33.1°C), Palaemon elegans (33.4°C), Lipophrys pholis (33.9°C) and Paralipophrys trigloides (35.0°C). Intraspecific variability was always lower than 2%.
Ecological forecasting on the likely impacts of climate warming is crucial at a time when several ecosystems seem to be responding to this environmental threat. Among the most important questions are: which are the most vulnerable organisms to climate warming and where are they? Recently, there has been debate on whether the tropics or temperate zones are more vulnerable to warming. Vulnerability toward higher temperatures will depend on the organisms' thermal limits and also on their acclimation capacity, which remains largely unknown for most species. The aim of the present work was to estimate (1) the upper thermal limits (Critical Thermal Maximum (CTMax)), (2) the warming tolerance (CTMax – Maximum Habitat Temperature) and (3) the acclimation capacity of tropical and temperate rocky shore organisms. Differences in biological groups (decapod crustaceans vs fish) were investigated and the effect of region (tropical vs temperate) and habitat (intertidal vs subtidal) was tested. Overall, 35 species were tested. For the assessment of the acclimation capacity, tropical-temperate pairs of closely related species of shrimp, crab and fish were selected. Warming tolerance was higher for temperate species than for tropical species and higher for subtidal species than for intertidal species, confirming that species with the highest thermal limits have the lowest warming tolerance. All species tested presented some accli-mation capacity (CTMax Trial − CTMax Control), with the exception of gobiid fish, which was not observed to acclimate. The tropical species tested showed a lower acclimation capacity than their temperate counterparts. Given that tropical rocky shore organisms are already living very close to their thermal limits and that their acclimation capacity is limited, it is likely that the impacts of global warming will be evident sooner in the tropics than in the temperate zone.
Climate change effects on fishes and fisheries: towards a cause-and-effect understanding
Journal of Fish Biology, 2010
Ongoing climate change is predicted to affect individual organisms during all life stages, thereby affecting populations of a species, communities and the functioning of ecosystems. These effects of climate change can be direct, through changing water temperatures and associated phenologies, the lengths and frequency of hypoxia events, through ongoing ocean acidification trends or through shifts in hydrodynamics and in sea level. In some cases, climate interactions with a species will also, or mostly, be indirect and mediated through direct effects on key prey species which change the composition and dynamic coupling of food webs. Thus, the implications of climate change for marine fish populations can be seen to result from phenomena at four interlinked levels of biological organization: (1) organismal-level physiological changes will occur in response to changing environmental variables such as temperature, dissolved oxygen and ocean carbon dioxide levels. An integrated view of relevant effects, adaptation processes and tolerance limits is provided by the concept of oxygen and capacity-limited thermal tolerance (OCLT). (2) Individual-level behavioural changes may occur such as the avoidance of unfavourable conditions and, if possible, movement into suitable areas. (3) Population-level changes may be observed via changes in the balance between rates of mortality, growth and reproduction. This includes changes in the retention or dispersion of early life stages by ocean currents, which lead to the establishment of new populations in new areas or abandonment of traditional habitats. (4) Ecosystem-level changes in productivity and food web interactions will result from differing physiological responses by organisms at different levels of the food web. The shifts in biogeography and warming-induced biodiversity will affect species productivity and may, thus, explain changes in fisheries economies. This paper tries to establish links between various levels of biological organization by means of addressing the effective physiological principles at the cellular, tissue and whole organism levels.
Fish heating tolerance scales similarly across individual physiology and populations
Communications Biology, 2021
Extrapolating patterns from individuals to populations informs climate vulnerability models, yet biological responses to warming are uncertain at both levels. Here we contrast data on the heating tolerances of fishes from laboratory experiments with abundance patterns of wild populations. We find that heating tolerances in terms of individual physiologies in the lab and abundance in the wild decline with increasing temperature at the same rate. However, at a given acclimation temperature or optimum temperature, tropical individuals and populations have broader heating tolerances than temperate ones. These congruent relationships implicate a tight coupling between physiological and demographic processes underpinning macroecological patterns, and identify vulnerability in both temperate and tropical species.
Critical thermal tolerance polygons of tropical marine fishes from Sulawesi, Indonesia
Journal of Thermal Biology, 2009
a b s t r a c t 1. Replicate thermal tolerance polygons were created using critical thermal methodology (CTM) and statistically compared. 2. Reef-associated damselfish and cardinalfish displayed the smallest total and intrinsic polygon zones and equal upper and lower acquired tolerance zones within species. 3. Two gobiids and a mullet species (resident and transient to tidepools, respectively) showed greater total and intrinsic tolerance zones than reef-associated species. 4. These CTM-polygons assess the thermal biology of fishes in habitats sensitive to global climate change and suggest that tropical Indo-Pacific fishes are likely to be affected by indirect consequences of global climate change, rather than by direct temperature mortality.
Tropical organisms are predicted to be among the most impacted by increasing sea surface temperatures, particularly those from intertidal habitats. In this study, a complete thermal biology assessment was conducted for two widespread tropical Atlantic shallow reef fish: Abudefduf saxatilis (damselfish) and Scartella cristata (blenny), which make extensive use of tide pools. The main objectives were to measure the time-course changes during one month in i) thermal and oxidative stress biomarkers (in gills, muscle and skin), ii) upper thermal limits, acclimation capacity and thermal safety margins and iii) body size, condition and energy reserves (total protein and lipid contents), under two temperature treatments (control – mean summer temperature, and elevated temperature −+ 3 °C, as projected by climate warming scenarios for the end of this century). Results from biomarker analyses suggest that under increased temperature, both species displayed a typical response of physiological stress characterized by the activation of molecular chaperones and antioxidant protection. Both species presented a significant acclimation potential in the long term, as shown by increased critical thermal maxima values at higher temperature. However, these species may already be at risk during summer heat waves, as thermal safety margins for both species were low. Additionally, despite acclimation, some energetic tradeoffs may exist, since specimens from both species showed smaller body sizes at higher temperature (even though maintaining body condition). Finally, temperature treatments had a significant influence not only in the total amount of energy reserves (lipid contents) but also in their rate of deposition or depletion (total proteins and lipid contents). This is the first multi-end-point holistic approach to assess the impact of warming in shallow tropical water fish and it highlights the high risk that intertidal organisms are facing in both present and future sea surface temperature conditions.