RESUMEN
Ocean acidification and warming are key stressors for many marine organisms. Some organisms display physiological acclimatization or plasticity, but this may vary across species ranges, especially if populations are adapted to local climatic conditions. Understanding how acclimatization potential varies among populations is therefore important in predicting species responses to climate change. We carried out a common garden experiment to investigate how different populations of the economically important great scallop (Pecten maximus) from France and Norway responded to variation in temperature and PCO2 concentration. After acclimation, post-larval scallops (spat) were reared for 31â days at one of two temperatures (13°C or 19°C) under either ambient or elevated PCO2 (pH 8.0 and pH 7.7). We combined measures of proteomic, metabolic and phenotypic traits to produce an integrative picture of how physiological plasticity varies between the populations. The proteome of French spat showed significant sensitivity to environmental variation, with 12 metabolic, structural and stress-response proteins responding to temperature and/or PCO2. Principal component analysis revealed seven energy metabolism proteins in French spat that were consistent with countering ROS stress under elevated temperature. Oxygen uptake in French spat did not change under elevated temperature but increased under elevated PCO2. In contrast, Norwegian spat reduced oxygen uptake under both elevated temperature and PCO2. Metabolic plasticity allows French scallops to maintain greater energy availability for growth compared with Norwegian spat. However, increased physiological plasticity and growth in French spat may come at a cost, as they showed reduced survival compared with Norwegian scallops under elevated temperature.
Asunto(s)
Pecten , Pectinidae , Animales , Pecten/metabolismo , Concentración de Iones de Hidrógeno , Agua de Mar , Larva , Proteómica , Acidificación de los Océanos , Temperatura , Oxígeno/metabolismo , Dióxido de Carbono/metabolismoRESUMEN
Biological burrowing behavior is an important driver shaping ecosystems that is being threatened by CO2-induced ocean acidification; however, the effects of ocean acidification on burrowing behavior and its neurological mechanism remain unclear. This study showed that elevated pCO2 significantly affected the burrowing behaviors of the Manila clam Ruditapes philippinarum, such as increased foot contraction, burrowing time, and intrabottom movement and decreased burrowing depth. Delving deeper into the mechanism, exposure to elevated pCO2 significantly decreased extracellular pH and increased [HCO3-]. Moreover, an indicator GABAA receptor, a neuroinhibitor for movement, was found to be closely associated with behavioral changes. In situ hybridization confirmed that the GABAA receptor was widely distributed in ganglia and foot muscles, and elevated pCO2 significantly increased the mRNA level and GABA concentration. However, the increase in GABAA receptor and its ligand did not suppress the foot movement, but rather sent "excitatory" signals for foot contraction. The destabilization of acid-base homeostasis was demonstrated to induce an increase in the reversal potential for GABAA receptor and an alteration in GABAA receptor function under elevated pCO2. This study revealed that elevated pCO2 affects the burrowing behavior of Manila clams by altering GABAA receptor function from inhibitory to excitatory.
Asunto(s)
Bivalvos , Agua de Mar , Animales , Dióxido de Carbono , Receptores de GABA-A , Concentración de Iones de Hidrógeno , Ecosistema , Acidificación de los Océanos , Bivalvos/fisiologíaRESUMEN
Climate change is leading to alterations in salinity and carbonate chemistry in arctic/sub-arctic marine ecosystems. We examined three nominal populations of the circumpolar arctic/subarctic amphipod, Gammarus setosus, along a salinity gradient in the Kongsfjorden-Krossfjorden area of Svalbard. Field and laboratory experiments assessed physiological (haemolymph osmolality and gill Na+/K+-ATPase activity, NKA) and energetic responses (metabolic rates, MO2, and Cellular Energy Allocation, CEA). In the field, all populations had similar osmregulatory capacities and MO2, but lower-salinity populations had lower CEA. Reduced salinity (S = 23) and elevated pCO2 (~1000 µatm) in the laboratory for one month increased gill NKA activities and reduced CEA in all populations, but increased MO2 in the higher-salinity population. Elevated pCO2 did not interact with salinity and had no effect on NKA activities or CEA, but reduced MO2 in all populations. Reduced CEA in lower-rather than higher-salinity populations may have longer term effects on other energy demanding processes (growth and reproduction).
Asunto(s)
Anfípodos , Salinidad , Animales , Regiones Árticas , Ecosistema , Branquias , Concentración de Iones de Hidrógeno , Agua de Mar , SvalbardRESUMEN
Regulation of extracellular acid-base balance, while maintaining energy metabolism, is recognised as an important aspect when defining an organism's sensitivity to environmental changes. This study investigated the haemolymph buffering capacity and energy metabolism (oxygen consumption, haemolymph [l-lactate] and [protein]) in early benthic juveniles (carapace length <40â mm) of the European lobster, Homarus gammarus, exposed to elevated temperature and PCO2 At 13°C, H. gammarus juveniles were able to fully compensate for acid-base disturbances caused by the exposure to elevated seawater PCO2 at levels associated with ocean acidification and carbon dioxide capture and storage (CCS) leakage scenarios, via haemolymph [HCO3-] regulation. However, metabolic rate remained constant and food consumption decreased under elevated PCO2 , indicating reduced energy availability. Juveniles at 17°C showed no ability to actively compensate haemolymph pH, resulting in decreased haemolymph pH particularly under CCS conditions. Early benthic juvenile lobsters at 17°C were not able to increase energy intake to offset increased energy demand and therefore appear to be unable to respond to acid-base disturbances due to increased PCO2 at elevated temperature. Analysis of haemolymph metabolites suggests that, even under control conditions, juveniles were energetically limited. They exhibited high haemolymph [l-lactate], indicating recourse to anaerobic metabolism. Low haemolymph [protein] was linked to minimal non-bicarbonate buffering and reduced oxygen transport capacity. We discuss these results in the context of potential impacts of ongoing ocean change and CCS leakage scenarios on the development of juvenile H. gammarus and future lobster populations and stocks.
Asunto(s)
Dióxido de Carbono , Nephropidae , Equilibrio Ácido-Base , Animales , Concentración de Iones de Hidrógeno , Agua de Mar , TemperaturaRESUMEN
Rising atmospheric carbon dioxide (CO2), primarily from anthropogenic emissions, are resulting in increasing absorption of CO2 by the oceans, leading to a decline in oceanic pH in a process known as ocean acidification (OA). There is a growing body of evidence demonstrating the potential effect of OA on the energetics/physiology and consequently life-history traits of commensally important marine organisms. However, despite this little is known of how fundamental metabolic pathways that underpin changes in organismal physiology are affected by OA. Consequently, a gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) based metabolic profiling approach was applied to examine the metabolic responses of Crassostrea gigas to elevated pCO2 levels, under otherwise natural field conditions. Oysters were exposed natural environmental pCO2 (~625.40⯵atm) and elevated pCO2 (~1432.94⯵atm) levels for 30â¯days. Results indicated that 36 differential metabolites were identified. Differential metabolites were mapped in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database to search for the related metabolic pathways. Pathway enrichment analysis indicates that alanine, aspartate and glutamate metabolism and glycine, serine and threonine metabolism were the most statistically enriched pathways. Further analysis suggested that elevated pCO2 disturb the TCA cycle via succinate accumulation and C. gigas most likely adjust their energy metabolic via alanine and GABA accumulation accordingly to cope with elevated pCO2. These findings provide an understanding of the molecular mechanisms involved in modulating C. gigas metabolism under elevated pCO2.
Asunto(s)
Dióxido de Carbono/metabolismo , Crassostrea/metabolismo , Cromatografía de Gases y Espectrometría de Masas/métodos , Branquias/metabolismo , Metabolómica , Aminoácidos/metabolismo , AnimalesRESUMEN
Ocean acidification may have far-reaching consequences for marine community and ecosystem dynamics, but its full impacts remain poorly understood due to the difficulty of manipulating pCO2 at the ecosystem level to mimic realistic fluctuations that occur on a number of different timescales. It is especially unclear how quickly communities at various stages of development respond to intermediate-scale pCO2 change and, if high pCO2 is relieved mid-succession, whether past acidification effects persist, are reversed by alleviation of pCO2 stress, or are worsened by departures from prior high pCO2 conditions to which organisms had acclimatized. Here, we used reciprocal transplant experiments along a shallow water volcanic pCO2 gradient to assess the importance of the timing and duration of high pCO2 exposure (i.e., discrete events at different stages of successional development vs. continuous exposure) on patterns of colonization and succession in a benthic fouling community. We show that succession at the acidified site was initially delayed (less community change by 8 weeks) but then caught up over the next 4 weeks. These changes in succession led to homogenization of communities maintained in or transplanted to acidified conditions, and altered community structure in ways that reflected both short- and longer-term acidification history. These community shifts are likely a result of interspecific variability in response to increased pCO2 and changes in species interactions. High pCO2 altered biofilm development, allowing serpulids to do best at the acidified site by the end of the experiment, although early (pretransplant) negative effects of pCO2 on recruitment of these worms were still detectable. The ascidians Diplosoma sp. and Botryllus sp. settled later and were more tolerant to acidification. Overall, transient and persistent acidification-driven changes in the biofouling community, via both past and more recent exposure, could have important implications for ecosystem function and food web dynamics.
Asunto(s)
Incrustaciones Biológicas , Agua de Mar/química , Ácidos , Animales , Dióxido de Carbono/química , Ecosistema , Cadena Alimentaria , Concentración de Iones de Hidrógeno , Urocordados/fisiologíaRESUMEN
Ocean acidification is predicted to have detrimental effects on many marine organisms and ecological processes. Despite growing evidence for direct impacts on specific species, few studies have simultaneously considered the effects of ocean acidification on individuals (e.g. consequences for energy budgets and resource partitioning) and population level demographic processes. Here we show that ocean acidification increases energetic demands on gastropods resulting in altered energy allocation, i.e. reduced shell size but increased body mass. When scaled up to the population level, long-term exposure to ocean acidification altered population demography, with evidence of a reduction in the proportion of females in the population and genetic signatures of increased variance in reproductive success among individuals. Such increased variance enhances levels of short-term genetic drift which is predicted to inhibit adaptation. Our study indicates that even against a background of high gene flow, ocean acidification is driving individual- and population-level changes that will impact eco-evolutionary trajectories.
Asunto(s)
Organismos Acuáticos , Modelos Biológicos , Océanos y Mares , Dinámica Poblacional , Animales , Femenino , MasculinoRESUMEN
Understanding long-term, ecosystem-level impacts of climate change is challenging because experimental research frequently focuses on short-term, individual-level impacts in isolation. We address this shortcoming first through an interdisciplinary ensemble of novel experimental techniques to investigate the impacts of 14-month exposure to ocean acidification and warming (OAW) on the physiology, activity, predatory behaviour and susceptibility to predation of an important marine gastropod (Nucella lapillus). We simultaneously estimated the potential impacts of these global drivers on N. lapillus population dynamics and dispersal parameters. We then used these data to parameterize a dynamic bioclimatic envelope model, to investigate the consequences of OAW on the distribution of the species in the wider NE Atlantic region by 2100. The model accounts also for changes in the distribution of resources, suitable habitat and environment simulated by finely resolved biogeochemical models, under three IPCC global emissions scenarios. The experiments showed that temperature had the greatest impact on individual-level responses, while acidification had a similarly important role in the mediation of predatory behaviour and susceptibility to predators. Changes in Nucella predatory behaviour appeared to serve as a strategy to mitigate individual-level impacts of acidification, but the development of this response may be limited in the presence of predators. The model projected significant large-scale changes in the distribution of Nucella by the year 2100 that were exacerbated by rising greenhouse gas emissions. These changes were spatially heterogeneous, as the degree of impact of OAW on the combination of responses considered by the model varied depending on local-environmental conditions and resource availability. Such changes in macro-scale distributions cannot be predicted by investigating individual-level impacts in isolation, or by considering climate stressors separately. Scaling up the results of experimental climate change research requires approaches that account for long-term, multiscale responses to multiple stressors, in an ecosystem context.
Asunto(s)
Ecosistema , Gastrópodos/fisiología , Calor , Concentración de Iones de Hidrógeno , Dinámica Poblacional , Conducta Predatoria/fisiología , Agua de Mar/química , Distribución Animal/fisiología , Animales , Océano Atlántico , Calentamiento Global , Modelos TeóricosRESUMEN
Metabolic rate determines the physiological and life-history performances of ectotherms. Thus, the extent to which such rates are sensitive and plastic to environmental perturbation is central to an organism's ability to function in a changing environment. Little is known of long-term metabolic plasticity and potential for metabolic adaptation in marine ectotherms exposed to elevated pCO2. Consequently, we carried out a series of in situ transplant experiments using a number of tolerant and sensitive polychaete species living around a natural CO2 vent system. Here, we show that a marine metazoan (i.e. Platynereis dumerilii) was able to adapt to chronic and elevated levels of pCO2. The vent population of P. dumerilii was physiologically and genetically different from nearby populations that experience low pCO2, as well as smaller in body size. By contrast, different populations of Amphiglena mediterranea showed marked physiological plasticity indicating that adaptation or acclimatization are both viable strategies for the successful colonization of elevated pCO2 environments. In addition, sensitive species showed either a reduced or increased metabolism when exposed acutely to elevated pCO2. Our findings may help explain, from a metabolic perspective, the occurrence of past mass extinction, as well as shed light on alternative pathways of resilience in species facing ongoing ocean acidification.
Asunto(s)
Aclimatación/fisiología , Adaptación Biológica/fisiología , Dióxido de Carbono/análisis , Ambiente , Poliquetos/fisiología , Agua de Mar/química , Animales , Concentración de Iones de Hidrógeno , Modelos Lineales , Mar Mediterráneo , Poliquetos/metabolismo , Especificidad de la EspecieRESUMEN
Although temperature is known to have an important effect on protein synthesis rates and growth in aquatic ectotherms held in the laboratory, little is known about the effects of thermal gradients on natural populations in the field. To address this issue we determined whole-animal fractional rates of protein synthesis (ks ) in four dominant species of gammarid amphipods with different distributions along the coasts of Western Europe from arctic to temperate latitudes. Up to three populations of each species were collected in the summer and ks measured within 48 h. Summer ks values were relatively high in the temperate species, Gammarus locusta, from Portugal (48°N) and Wales (53°N) and were maintained across latitudes by the conservation of translational efficiency. In sharp contrast, summer ks remained remarkably low in the boreal/temperate species G. duebeni from Wales, Scotland (58°N) and Tromsø (70°N), probably as a temporary energy saving strategy to ensure survival in rapidly fluctuating environments of the high intertidal. Values for ks increased in acclimated G. duebeni from Scotland and Tromsø showing a lack of compensation with latitude. In the subarctic/boreal species, G. oceanicus, summer ks remained unchanged in Scotland and Tromsø but fell significantly in Svalbard (79°N) at 5°C, despite a slight increase in RNA content. At 79°N, mean ks was 4.5 times higher in the circumpolar species G. setosus than in G. oceanicus due to a doubling in RNA content. The relationship between whole-animal protein synthesis rates and natural thermal gradients is complex, varies between species and appears to be associated with local temperatures and their variability, as well as changes in other environmental factors.