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Using a targeted metabolomic approach we investigated the effects of low seawater pH on energy metabolism in two late copepodite stages (CIV and CV) of the keystone Arctic copepod species Calanus glacialis. Exposure to decreasing seawater pH (from 8.0 to 7.0) caused increased ATP, ADP and NAD+ and decreased AMP concentrations in stage CIV, and increased ATP and phospho-L-arginine and decreased AMP concentrations in stage CV. Metabolic pathway enrichment analysis showed enrichment of the TCA cycle and a range of amino acid metabolic pathways in both stages. Concentrations of lactate, malate, fumarate and alpha-ketoglutarate (all involved in the TCA cycle) increased in stage CIV, whereas only alpha-ketoglutarate increased in stage CV. Based on the pattern of concentration changes in glucose, pyruvate, TCA cycle metabolites, and free amino acids, we hypothesise that ocean acidification will lead to a shift in energy production from carbohydrate metabolism in the glycolysis toward amino acid metabolism in the TCA cycle and oxidative phosphorylation in stage CIV. In stage CV, concentrations of most of the analysed free fatty acids increased, suggesting in particular that ocean acidification increases the metabolism of stored wax esters in this stage. Moreover, aminoacyl-tRNA biosynthesis was enriched in both stages indicating increased enzyme production to handle low pH stress. [ABSTRACT FROM AUTHOR]

Ongoing ocean acidification is expected to affect marine organisms and ecosystems. While sea urchins can tolerate a wide range of pH, this comes at a high energetic cost, and early life stages are particularly vulnerable. Information on how ocean acidification affects transitions between life-history stages is scarce. We evaluated the direct and indirect effects of pH (pHT 8.0, 7.6 and 7.2) on the development and transition between life-history stages of the sea urchin Strongylocentrotusdroebachiensis, from fertilization to early juvenile. Continuous exposure to low pH negatively affected larval mortality and growth. At pH 7.2, formation of the rudiment (the primordial juvenile) was delayed by two days. Larvae raised at pH 8.0 and transferred to 7.2 after competency had mortality rates five to six times lower than those kept at 8.0, indicating that pH also has a direct effect on older, competent larvae. Latent effects were visible on the larvae raised at pH 7.6: they were more successful in settling (45% at day 40 post-fertilization) and metamorphosing (30%) than larvae raised at 8.0 (17 and 1% respectively). These direct and indirect effects of ocean acidification on settlement and metamorphosis have important implications for population survival. [ABSTRACT FROM AUTHOR]

This study investigated the combined effects of seawater acidification and hypoxia on the antioxidant response in gonads of the thick shell mussel Mytilus coruscus. Mussels were collected along the Shengsi Island, East China Sea, where oxygen and pH fluctuations frequently occur in summer. Mussels were exposed to three pH (8.1, 7.7, and 7.3) and two dissolved oxygen (DO) levels (6 and 2 mg L−1) for 21 days followed by a 10-day recovery period (pH 8.1 and DO 6 mg L-1). Gonad surface area (GSA) and activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione (GSH), glutathione S-transferase (GST), and malondialdehyde (MDA) in gonad were measured at days 21 and 31. Complex and enzyme-specific responses were observed after the 21-day exposure period. Overall, PCA analysis revealed a stronger effect of pH than DO. Integrated biomarker response (IBR) analysis demonstrated that low pH and DO decreased mussel's antioxidant system and increased oxidative damage with potential consequences for gonad development. Mussels exposed to low pH and DO were only partly able to recover a normal enzymatic activity after 10-day recovery period. This suggests that mussels exposed to short-term pH and DO fluctuations event in the field may suffer lasting negative impacts. [ABSTRACT FROM AUTHOR]

The phenomenon of collective action and the origin of collective action problems have been extensively and systematically studied in the social sciences. Yet, while we have substantial knowledge about the factors promoting collective action at the local level, we know far less about how these insights travel to large-scale collective action problems. Such problems, however, are at the heart of humanity's most pressing challenges, including climate change, large-scale natural resource depletion, biodiversity loss, nuclear proliferation, antibiotic resistance due to overconsumption of antibiotics, and pollution. In this paper, we suggest an analytical framework that captures the theoretical understanding of preconditions for large-scale collective action. This analytical framework aims at supporting future empirical analyses of how to cope with and overcome larger-scale collective action problems. More specifically, we (i) define and describe the main characteristics of a large-scale collective action problem and (ii) explain why voluntary and, in particular, spontaneous large-scale collective action among individual actors becomes more improbable as the collective action problem becomes larger, thus demanding interventions by an external authority (a third party) for such action to be generated. Based on this, we (iii) outline an analytical framework that illustrates the connection between third-party interventions and large-scale collective action. We conclude by suggesting avenues for future research. [ABSTRACT FROM AUTHOR]

Thank you also to Rui Oliveira for the use of Observer software, António Roleira for assistance with the software, Sofia Aniceto for the assistance with R software, and Peter Mcgregor on the Advanced Course in Biology and Animal Behaviour (Scientific Writing). Thank you also to Rui Oliveira for the use of Observer software, António Roleira for assistance with the software, Sofia Aniceto for the assistance with R software, and Peter Mcgregor on the Advanced Course in Biology and Animal Behaviour (Scientific Writing). [Extracted from the article]

Ocean acidification is causing changes to the chemistry and biology of the marine environment, in ways that we are only just beginning to understand. Growing evidences demonstrate that ocean acidification can influence the survival, growth, development, and physiology of marine invertebrates. Here, we assessed the impact of ocean acidification on the sea urchin Paracentrotus lividus larval development (from embryos exposed to experimental conditions from the 24 h gastrula stage to 35 days) and settlement. Samples were collected from the Canary Islands (28°24′N, 16°18′W) in March 2012. Three pH treatments were tested: (1) pH 8.1, the present average pH; (2) pH 7.7, the average predicted for the year 2100, but already experienced in the natural environment during extremes of variability; and (3) pH 7.4, predicted extremes of natural variability by 2100. The mortality rate was significantly increased by 40 % at the lowest pH. Time required by larvae to achieve each developmental stage (from gastrula to competent stage) was decreased at pH 7.7 (larval development speed increased by 18 %), but larval morphology at a given size did not differ from the other pH treatments. Settlement was delayed by 8 days at pH 7.7 compared to pH 8.1, and no settlement was observed at pH 7.4. Overall, only sublethal effects were observed in larvae exposed to pH 7.7, while pH 7.4 induced both lethal and sublethal effects. Our results support the hypothesis that P. lividus is robust to survive in an environment with the present natural variation. However, the species is sensitive to extreme levels of pH that are predicted within the next 90 years. [ABSTRACT FROM AUTHOR]

Responses by marine species to ocean acidification (OA) have recently been shown to be modulated by external factors including temperature, food supply and salinity. However the role of a fundamental biological parameter relevant to all organisms, that of body size, in governing responses to multiple stressors has been almost entirely overlooked. Recent consensus suggests allometric scaling of metabolism with body size differs between species, the commonly cited 'universal' mass scaling exponent ( b) of ¾ representing an average of exponents that naturally vary. One model, the Metabolic-Level Boundaries hypothesis, provides a testable prediction: that b will decrease within species under increasing temperature. However, no previous studies have examined how metabolic scaling may be directly affected by OA. We acclimated a wide body-mass range of three common NE Atlantic echinoderms (the sea star Asterias rubens, the brittlestars Ophiothrix fragilis and Amphiura filiformis) to two levels of pCO and three temperatures, and metabolic rates were determined using closed-chamber respirometry. The results show that contrary to some models these echinoderm species possess a notable degree of stability in metabolic scaling under different abiotic conditions; the mass scaling exponent ( b) varied in value between species, but not within species under different conditions. Additionally, we found no effect of OA on metabolic rates in any species. These data suggest responses to abiotic stressors are not modulated by body size in these species, as reflected in the stability of the metabolic scaling relationship. Such equivalence in response across ontogenetic size ranges has important implications for the stability of ecological food webs. [ABSTRACT FROM AUTHOR]

Larval stages are considered as the weakest link when a species is exposed to challenging environmental changes. Reduced rates of growth and development in larval stages of calcifying invertebrates in response to ocean acidification might be caused by energetic limitations. So far no information exists on how ocean acidification affects digestive processes in marine larval stages. Here we reveal alkaline (∼pH 9.5) conditions in the stomach of sea urchin larvae. Larvae exposed to decreased seawater pH suffer from a drop in gastric pH, which directly translates into decreased digestive efficiencies and triggers compensatory feeding. These results suggest that larval digestion represents a critical process in the context of ocean acidification, which has been overlooked so far. [ABSTRACT FROM AUTHOR]

This special issue compiles 37 manuscripts investigating the biological impacts and societal relevance of ocean acidification. It includes important considerations regarding experimental design, new methods and how ocean acidification science can contribute to society through education and socioeconomic assessment. Altogether, this special issue constitutes a snapshot of recent ocean acidification research. This paper aims at summarizing the key findings and highlights future challenges and research priorities. [ABSTRACT FROM AUTHOR]

Ocean acidification (OA), the reduction of ocean pH due to hydration of atmospheric CO, is known to affect growth and survival of marine invertebrate larvae. Survival and transport of vulnerable planktonic larval stages play important roles in determining population dynamics and community structures in coastal ecosystems. Here, we show that larvae of the purple urchin, Strongylocentrotus purpuratus, underwent high-frequency budding (release of blastula-like particles) when exposed to elevated pCO level (>700 μatm). Budding was observed in >50 % of the population and was synchronized over short periods of time (~24 h), suggesting this phenomenon may be previously overlooked. Although budding can be a mechanism through which larval echinoids asexually reproduce, here, the released buds did not develop into viable clones. OA-induced budding and the associated reduction in larval size suggest new hypotheses regarding physiological and ecological tradeoffs between short-term benefits (e.g. metabolic savings and predation escape) and long-term costs (e.g. tissue loss and delayed development) in the face of climate change. [ABSTRACT FROM AUTHOR]

Ocean acidification is increasingly recognized as a component of global change that could have a wide range of impacts on marine organisms, the ecosystems they live in, and the goods and services they provide humankind. Assessment of these potential socio-economic impacts requires integrated efforts between biologists, chemists, oceanographers, economists and social scientists. But because ocean acidification is a new research area, significant knowledge gaps are preventing economists from estimating its welfare impacts. For instance, economic data on the impact of ocean acidification on significant markets such as fisheries, aquaculture and tourism are very limited (if not non-existent), and non-market valuation studies on this topic are not yet available. Our paper summarizes the current understanding of future OA impacts and sets out what further information is required for economists to assess socio-economic impacts of ocean acidification. Our aim is to provide clear directions for multidisciplinary collaborative research. [ABSTRACT FROM AUTHOR]

Increasing pCO is hypothesized to induce shifts in plankton communities toward smaller cells, reduced carbon export rates and increased roles of gelatinous zooplankton. Appendicularians, among the most numerous pan-global 'gelatinous' zooplankton, continuously produce filter-feeding houses, shortcutting marine food webs by ingesting submicron particles, and their discarded houses contribute significantly to carbon fluxes. We present a first mesocosm-scale study on the effects of temperature, pCO and bloom structures on the appendicularian, Oikopleura dioica. There were effects of temperature and nutrients on phytoplankton communities. No shifts in functional phytoplankton groups, nor changes in particle sizes/morphotypes, known to impact appendicularian feeding, were observed under manipulated pCO conditions. However, appendicularian abundance was positively correlated with increased pCO, temperature and nutrient levels, consistent with hypotheses concerning gelatinous zooplankton in future oceans. This suggests appendicularians will play more important roles in marine pelagic communities and vertical carbon transport under projected ocean acidification and elevated temperature scenarios. [ABSTRACT FROM AUTHOR]

Comparative features of the development of the larval nervous system of ophiuroids have the potential for resolving aspects of echinoderm evolution. In Amphiura filiformis serotonergic neural progenitors appear in the animal plate of late gastrulae. The serotonergic progenitors increase in number and become displaced to the aboral ectoderm side of the developing ciliary band. The ciliary band neurons appear as irregularly spaced neural progenitors on the oral side of the ciliary band lateral to the mouth. These cells extend neurites along the axis of the ciliary band, which meet at the center of the ventral transverse ciliary band. The larval nervous system begins as a U-shaped tract of axons that surrounds the oral field and tracts of axons and neurons in the ciliary bands of the larval arms are added. In addition, the larval nervous system has an extensive pre-oral neuropil, rings of nerves surrounding the anus and pyloric sphincters, and a plexus of axons that surround the esophagus. The nervous system of the juvenile develops beneath the oral ectoderm. The components of the adult nervous system: five segments of radial nerve, commissures that form the nerve ring, and podial nerves all appear as the juvenile develops. The larval nervous system begins to fragment and degenerate as the juvenile grows. The complete description of neural development of an ophiuroid reveals that the four classes so far investigated are consistent with phylogenies based on adult features and comparisons of neural organization help rationalize conflicting hypotheses of the evolution of larval forms in echinoderms. [ABSTRACT FROM AUTHOR]

Fish reproductive success is linked to the ability of couples to mate and produce clutches that successfully hatch. Environmental stressors like high temperature and low pH can jeopardize this energetically costly process. In this study, exposure to high temperature and low pH was tested on a marine temperate species, Gobiusculus flavescens, to evaluate effects on reproductive performance. Breeding pairs were assigned to different temperatures (+ 0 °C, + 3 °C relative to in situ temperature) and pH levels (8.0, 7.6), in a cross-factorial design for a 3-month period. Reproduction activity, success, and paternal investment were measured throughout the exposure period. Results show reproduction is impaired by elevated temperature, while low pH had little impact. Breeding pairs under high temperature had 3% to 10% hatching success, up to 30% less eggs and eggs up to 20% smaller. Although paternal investment was not affected by tested parameters, males of breeding pairs exposed to elevated temperature had smaller gonadosomatic indexes, which might indicate a lack of investment in the reproductive process. Overall, results show that elevated temperature, expected more frequently in the near future, as a consequence of global warming, may impair key processes like reproduction in temperate fish, with potential consequences for fitness and population replenishment. [ABSTRACT FROM AUTHOR]

Ocean warming (OW) and acidification (OA) are key features of global change and are predicted to have negative consequences for marine species and ecosystems. At a smaller scale increasing oil and gas activities at northern high latitudes could lead to greater risk of petroleum pollution, potentially exacerbating the effects of such global stressors. However, knowledge of combined effects is limited. This study employed a scenario-based, collapsed design to investigate the impact of one local acute stressor (North Sea crude oil) and two chronic global drivers (pH for OA and temperature for OW), alone or in combination on aspects of the biology of larval stages of two key invertebrates: the northern shrimp (Pandalus borealis) and the green sea urchin (Strongylocentrotus droebachiensis). Both local and global drivers had negative effects on survival, development and growth of the larval stages. These effects were species- and stage-dependent. No statistical interactions were observed between local and global drivers and the combined effects of the two drivers were approximately equal to the sum of their separate effects. This study highlights the importance of adjusting regulation associated with oil spill prevention to maximize the resilience of marine organisms to predicted future global conditions. [ABSTRACT FROM AUTHOR]

This corrects the article DOI: 10.1038/srep23728 [ABSTRACT FROM AUTHOR]

The uptake of anthropogenic CO2 emissions by oceans has started decreasing pH and carbonate ion concentrations of seawater, a process called ocean acidification (OA). Occurring over centuries and many generations, evolutionary adaptation and epigenetic transfer will change species responses to OA over time. Trans-generational responses, via genetic selection or trans-generational phenotypic plasticity, differ depending on species and exposure time as well as differences between individuals such as gender. Males and females differ in reproductive investment and egg producing females may have less energy available for OA stress responses. By crossing eggs and sperm from the calcareous tubeworm Hydroides elegans (Haswell, 1883) raised in ambient (8.1) and low (7.8) pH environments, we observed that paternal and maternal low pH experience had opposite and additive effects on offspring. For example, when compared to offspring with both parents from ambient pH, growth rates of offspring of fathers or mothers raised in low pH were higher or lower respectively, but there was no difference when both parents were from low pH. Gender differences may result in different selection pressures for each gender. This may result in overestimates of species tolerance and missed opportunities of potentially insightful comparisons between individuals of the same species. [ABSTRACT FROM AUTHOR]

Swimming behaviors of planktonic larvae impact dispersal and population dynamics of many benthic marine invertebrates. This key ecological function is modulated by larval development dynamics, biomechanics of the resulting morphology, and behavioral choices. Studies on ocean acidification effects on larval stages have yet to address this important interaction between development and swimming under environmentally-relevant flow conditions. Our video motion analysis revealed that pH covering present and future natural variability (pH 8.0, 7.6 and 7.2) did not affect age-specific swimming of larval green urchin Strongylocentrotus droebachiensis in still water nor in shear, despite acidified individuals being significantly smaller in size (reduced growth rate). This maintenance of speed and stability in shear was accompanied by an overall change in size-corrected shape, implying changes in swimming biomechanics. Our observations highlight strong evolutionary pressure to maintain swimming in a varying environment and the plasticity in larval responses to environmental change. [ABSTRACT FROM AUTHOR]

In this article, the authors focus on the issues regarding an increase in acidity of oceans by rising levels of carbon dioxide from the atmosphere. They mention that there has been an increase in acidity of surface ocean by 30 percent since 1850 due to the growing human population. They also focus on an initiative carried out by the Ocean Acidification International Coordination Centre to deal with the issue.

Global stressors, such as ocean acidification, constitute a rapidly emerging and significant problem for marine organisms, ecosystem functioning and services. The coastal ecosystems of the Humboldt Current System (HCS) off Chile harbour a broad physical-chemical latitudinal and temporal gradient with considerable patchiness in local oceanographic conditions. This heterogeneity may, in turn, modulate the specific tolerances of organisms to climate stress in species with populations distributed along this environmental gradient. Negative response ratios are observed in species models (mussels, gastropods and planktonic copepods) exposed to changes in the partial pressure of CO 2 (pCO2) far from the average and extreme pCO2 levels experienced in their native habitats. This variability in response between populations reveals the potential role of local adaptation and/or adaptive phenotypic plasticity in increasing resilience of species to environmental change. The growing use of standard ocean acidification scenarios and treatment levels in experimental protocols brings with it a danger that inter-population differences are confounded by the varying environmental conditions naturally experienced by different populations. Here, we propose the use of a simple index taking into account the natural pCO2 variability, for a better interpretation of the potential consequences of ocean acidification on species inhabiting variable coastal ecosystems. Using scenarios that take into account the natural variability will allow understanding of the limits to plasticity across organismal traits, populations and species.