The invasion of anthropogenic carbon into the global ocean poses an existential threat to calcifying marine organisms1–4. Observations indicate that conditions corrosive to aragonite shells, unprecedented in the surface ocean, are already occurring in mesoscale upwelling features of the North Pacific2,5,6 and Southern Ocean7, and modeling experiments indicate that large volumes of the global ocean8 including the polar ocean’s surface might become corrosive to aragonite by 20304,9–13. Such changes are expected to compress important marine habitats, but the pathways by which habitat compression manifests over global scales, and their sensitivity to mitigation, remain unexplored. Using a suite of large ensemble projections from an Earth system model14,15, we assess the effectiveness of climate mitigation for averting habitat loss at the ecologically-critical horizon of the base of the ocean’s euphotic zone. We find that without mitigation, 40-42% of this sensitive horizon experiences conditions corrosive to aragonite by 2100, with moderate mitigation this reduces to 16-19%, and with aggressive mitigation to 6-7%. Mitigation has a stronger effect on the eastern relative to western domains of the northern extratropical ocean with some of the greatest benefits in the ocean’s most productive Large Marine Ecosystems, including the California Current and Gulf of Alaska. This work reveals the significant impact that mitigation efforts compatible with the Paris Agreement target of 1.5°C could have upon preserving marine habitats that are vulnerable to ocean acidification.
The ocean is undergoing warming and acidification. Thermal tolerance is affected both by evolutionary adaptation and developmental plasticity. Yet, thermal tolerance in animals adapted to simultaneous warming and acidification is unknown. We experimentally evolved the ubiquitous copepod Acartia tonsa to future combined ocean warming and acidification conditions (OWA approx. 22°C, 2000 µatm CO2) and then compared its thermal tolerance relative to ambient conditions (AM approx. 18°C, 400 µatm CO2). The OWA and AM treatments were reciprocally transplanted after 65 generations to assess effects of developmental conditions on thermal tolerance and potential costs of adaptation. Treatments transplanted from OWA to AM conditions were assessed at the F1 and F9 generations following transplant. Adaptation to warming and acidification, paradoxically, reduces both thermal tolerance and phenotypic plasticity. These costs of adaptation to combined warming and acidification may limit future population resilience.
Elevated atmospheric carbon dioxide (CO2) is causing global ocean changes and drives changes in organism physiology, life-history traits, and population dynamics of natural marine resources. However, our knowledge of the mechanisms and consequences of ocean acidification (OA) – in combination with other climatic drivers (i.e., warming, deoxygenation) – on organisms and downstream effects on marine fisheries is limited. Here, we explored how the direct effects of multiple changes in ocean conditions on organism aerobic performance scales up to spatial impacts on fisheries catch of 210 commercially exploited marine invertebrates, known to be susceptible to OA. Under the highest CO2 trajectory, we show that global fisheries catch potential declines by as much as 12% by the year 2100 relative to present, of which 3.4% was attributed to OA. Moreover, OA effects are exacerbated in regions with greater changes in pH (e.g., West Arctic basin), but are reduced in tropical areas where the effects of ocean warming and deoxygenation are more pronounced (e.g., Indo-Pacific). Our results enhance our knowledge on multi-stressor effects on marine resources and how they can be scaled from physiology to population dynamics. Furthermore, it underscores variability of responses to OA and identifies vulnerable regions and species.
Rapid evolution may provide a buffer against extinction risk for some species threatened by climate change; however, the capacity to evolve rapidly enough to keep pace with changing environments is unknown for most taxa. The ecosystem-level consequences of climate adaptation are likely to be the largest in marine ecosystems, where short-lived phytoplankton with large effective population sizes make up the bulk of primary production. However, there are substantial challenges to predicting climate-driven evolution in marine systems, including multiple simultaneous axes of change and considerable heterogeneity in rates of change, as well as the biphasic life cycles of many marine metazoans, which expose different life stages to disparate sources of selection. A critical tool for addressing these challenges is experimental evolution, where populations of organisms are directly exposed to controlled sources of selection to test evolutionary responses. We review the use of experimental evolution to test the capacity to adapt to climate change stressors in marine species. The application of experimental evolution in this context has grown dramatically in the past decade, shedding light on the capacity for evolution, associated trade-offs, and the genetic architecture of stress-tolerance traits. Our goal is to highlight the utility of this approach for investigating potential responses to climate change and point a way forward for future studies.
Studying the local impacts of natural marine discharges can help in understanding the local impacts of large-scale restoration programs. This paper reviews studies of naturally occurring CO2 rich hydrothermal vents to understand how nature responds. Venting CO2 raises both total DIC, and the CO2 partial pressure by a factor of 10 or 20 times, lowering the pH and the saturation state of calcium carbonate, impeding calcification by calcifying organisms.
The ocean is a relatively stable environment and significant changes to water chemistry caused by high levels of CO2 input impacts marine organisms. Many algae are able to survive and photosynthesise at low pH levels, and some may actually benefit from an increase in dissolved CO2. However, coralline and calcareous algae that form carbonate skeletons are negatively impacted at low pH. Ecologically and economically valuable marine flora such as kelp, seagrass and certain seaweeds can benefit from increased DIC, exhibiting increases in photosynthetic and growth rates. Kelp and seagrass may also increase local pH levels, creating refuges for calcifying marine species.
The calcification rates of Many marine invertebrates decrease with increasing pCO2. At sites closer to vent openings, with lower pH, the abundance and diversity of invertebrates is significantly reduced. This can impact species valuable to the fishery and aquaculture industry by directly affecting recruitment, growth and survivorship of species such as mussels and oysters and indirectly through reduced abundance of invertebrate prey for herring and mackerel. Corals are also negatively impacted by declining pH and calcium carbonate saturation, yet not all hard corals respond evenly. More resilient genera such as Porites can survive pH drops to approximately 7.8, however below this value reef development is virtually absent and the habitat is dominated by algae and soft corals.
Naturally occurring low pH sites are relatively common in the marine environment and though they clearly alter species composition and abundance, the locally lower pH does not kill marine life, and beyond dispersion zones species are unaffected. Global ocean acidification is a serious problem, however the impacts of local releases of CO2 are relatively limited, resulting in community shifts towards low pH tolerant species. Reversal of global ocean acidification is essential, and restoration of the oceans will require huge carbon dioxide removal (CDR) processes.
The effects of ocean acidification on marine organisms are of increasing concern. Exopalaemon carinicauda is an important economic shrimp. However, little is known about the transcriptome data for shrimp in response to seawater acidification stress. In this study, the transcriptome of E. carinicauda in response to seawater acidification stress was recorded using the Illumina RNA-sequencing. A total of 59 990 unigenes from high-quality transcripts were generated. Of all annotated unigenes, 18 386 and 17 681 unigenes had significant matches with sequences in the NR, and GO databases, respectively. A total of 183 differentially expressed genes (DEGs) could be screened, of which 119 DEGs were up-regulated and 64 DEGs were down-regulated. KEGG enrichment analysis showed these DEGs were primarily enriched in the pathways of lysosome, carbohydrate digestion and absorption, apoptosis, and alpha-linolenic acid metabolism. These results indicate that seawater acidification stress leads to the activation of apoptosis and the activity of the energy metabolism system in order to resist the external environmental stress and ensure the continuity of the normal life metabolism, and thus the energy supply of the organism. These data will be helpful to further study the molecular mechanisms of shrimp resistance to seawater acidification stress.
- Ocean acidification (OA) under delta (∆) pH = – 0.3 (pH ~7.7), but not ∆pH = – 0.1 (pH ~ 7.9) relative to the present (~8.0 pH), reduced the survival, respiration and moulting of phyllosomas of T. australiensis.
- OA under pH ~7.7 adversely affected the attraction of T. australiensis phyllosomas to jellyfish cues.
- The majority of individual metabolites of phyllosomas were suppressed even in mild pH ~ 7.9.
- The interaction between phyllosoma and jellyfish may be impaired under pH ~7.7.
Ocean acidification (OA) can alter the behaviour and physiology of marine fauna and impair their ability to interact with other species, including those in symbiotic and predatory relationships. Phyllosoma larvae of lobsters are symbionts to many invertebrates and often ride and feed on jellyfish, however OA may threaten interactions between phyllosomas and jellyfish. Here, we tested whether OA predicted for surface mid-shelf waters of Great Barrier Reef, Australia, under ∆ pH = −0.1 (pH ~7.9) and ∆pH = −0.3 (pH ~7.7) relative to the present pH (~8.0) (P) impaired the survival, moulting, respiration, and metabolite profiles of phyllosoma larvae of the slipper lobster Thenus australiensis, and the ability of phyllosomas to detect chemical cues of fresh jellyfish tissue. We discovered that OA was detrimental to survival of phyllosomas with only 20% survival under ∆pH = −0.3 compared to 49.2 and 45.3% in the P and ∆pH = −0.1 treatments, respectively. The numbers of phyllosomas that moulted in the P and ∆pH = −0.1 treatments were 40% and 34% higher, respectively, than those in the ∆pH = −0.3 treatment. Respiration rates varied between pH treatments, but were not consistent through time. Respiration rates in the ∆pH = −0.3 and ∆pH = −0.1 treatments were initially 40% and 22% higher, respectively, than in the P treatment on Day 2 and then rates varied to become 26% lower (∆pH = −0.3) and 17% (∆pH = −0.1) higher towards the end of the experiment. Larvae were attracted to jellyfish tissue in treatments P and ∆pH = −0.1 but avoided jellyfish at ∆pH = −0.3. Moreover, OA conditions under ∆pH = −0.1 and ∆pH = −0.3 levels reduced the relative abundances of 22 of the 34 metabolites detected in phyllosomas via Nuclear Magnetic Resonance (NMR) spectroscopy. Our study demonstrates that the physiology and ability to detect jellyfish tissue by phyllosomas of the lobster T. australiensis may be impaired under ∆pH = −0.3 relative to the present conditions, with potential negative consequences for adult populations of this commercially important species.
- More simplified and modularized bacterial networks of rearing seawater under elevated pCO2.
- Changed abundances of CNPS cycling genes of seawater microbiome under elevated pCO2.
- Changed C, N, and P chemistry of rearing seawater under elevated pCO2.
- Seawater C, N, and P chemistry may be affected by future elevated pCO2 via seawater microbiome.
Mean oceanic CO2 values have already risen and are expected to rise further on a global scale. Elevated pCO2 (eCO2) changes the bacterial community in seawater. However, the ecological association of seawater microbiota and related geochemical functions are largely unknown. We provide the first evidence that eCO2 alters the interaction patterns and functional potentials of microbiota in rearing seawater of the swimming crab, Portunus trituberculatus. Network analysis showed that eCO2 induced a simpler and more modular bacterial network in rearing seawater, with increased negative associations and distinct keystone taxa. Using the quantitative microbial element cycling method, nitrogen (N) and phosphorus (P) cycling genes exhibited the highest increase after one week of eCO2 stress and were significantly associated with keystone taxa. However, the functional potential of seawater bacteria was decoupled from their taxonomic composition and strongly coupled with eCO2 levels. The changed functional potential of seawater bacteria contributed to seawater N and P chemistry, which was highlighted by markedly decreased NH3, NH4+-N, and PO43--P levels and increased NO2−-N and NO3−-N levels. This study suggests that eCO2 alters the interaction patterns and functional potentials of seawater microbiota, which lead to the changes of seawater chemical parameters. Our findings provide new insights into the mechanisms underlying the effects of eCO2 on marine animals from the microbial ecological perspective.
- Water acidification delays the oocyte maturation of Eriocheir sinensis.
- Water acidification induces significant changes in gills and ovaries at transcriptomic level.
- E. sinensis increased immune response to response in the water acidification.
Nowadays, due to increasing carbon dioxide released, water acidification poses a series of serious impacts on aquatic organisms. To evaluate the effects of water acidification on crustaceans, we focused on the Chinese mitten crab Eriocheir sinensis, which is a spawning migration and farmed species in China. Based on histological and oocyte transparent liquid observation, we found that the acidified environment significantly delayed the ovarian maturation of E. sinensis. Moreover, RNA-seq was applied to obtain gene expression profile from the crab’s gills and ovaries in response to acidified environment. Compared with control groups, a total of 5471 differentially expressed genes (DEGs) were identified in acidified gills and 485 DEGs were identified in acidified ovaries. Enrichment analysis indicated that some pathways also responded to the acidified environment, such as PI3K-Akt signaling pathway, Chemokine signaling pathway, apoptosis and toll-like receptor signaling pathway. Subsequently, some DEGs involved in immune response (ALF, Cathepsin A, HSP70, HSP90, and catalase) and ovarian maturation (Cyclin B, Fem-1a, Fem-1b, and Fem-1c) were selected to further validate the influence of water acidification on gene expression by qRT-PCR. The results showed that the expression level of immune-related genes was significantly increased to response to the water acidification, while the ovarian maturation-related genes were significantly decreased. Overall, our data suggested that E. sinensis was sensitive to the reduced pH. This comparative transcriptome also provides valuable molecular information on the mechanisms of the crustaceans responding to acidified environment.
Aim: The current study undertook manipulative experiments to observe changes in snapping shrimp sound signals in relation to temperature and pH changes.
Methodology: Sounds of intertidal snapping shrimp (Alpheus edwardsii) sequentially exposed to different temperature/pH treatments manipulation for a period of 2 week each, were recorded in the laboratory and analysed. The acoustic characteristics of snapping sound signal were examined to relate to the change in temperature, pH and combination of both parameters.
Results: Our results showed that there was a significant reduction in the frequency of peak amplitude of snapping sound wave following a two week exposure to a combination of temperature and pH treatments. The frequency of snapping shrimp sound decreased by approximately 30% when exposed to a 2°C increase in temperature and a 0.7 unit decrease in pH, however, elevated temperature alone caused no significant effect on the peak frequency of snapping shrimp sound.
Interpretation: The finding suggests that following the prediction values of temperature and pH changes due to climate change in the coming century may implicate the ambient noise at habitats where snapping shrimps dominate.
Ocean acidification (OA) is increasing predictably in the global ocean as rising levels of atmospheric carbon dioxide lead to higher oceanic concentrations of inorganic carbon. The Gulf of Maine (GOM) is a seasonally varying region of confluence for many processes that further affect the carbonate system including freshwater influences and high productivity, particularly near the coast where local processes impart a strong influence. Two main regions within the GOM currently experience carbonate conditions that are suboptimal for many organisms—the nearshore and subsurface deep shelf. OA trends over the past 15 years have been masked in the GOM by recent warming and changes to the regional circulation that locally supply more Gulf Stream waters. The region is home to many commercially important shellfish that are vulnerable to OA conditions, as well as to the human populations whose dependence on shellfish species in the fishery has continued to increase over the past decade. Through a review of the sensitivity of the regional marine ecosystem inhabitants, we identified a critical threshold of 1.5 for the aragonite saturation state (Ωa). A combination of regional high-resolution simulations that include coastal processes were used to project OA conditions for the GOM into 2050. By 2050, the Ωa declines everywhere in the GOM with most pronounced impacts near the coast, in subsurface waters, and associated with freshening. Under the RCP 8.5 projected climate scenario, the entire GOM will experience conditions below the critical Ωa threshold of 1.5 for most of the year by 2050. Despite these declines, the projected warming in the GOM imparts a partial compensatory effect to Ωa by elevating saturation states considerably above what would result from acidification alone and preserving some important fisheries locations, including much of Georges Bank, above the critical threshold.
Elemental ratios in biogenic marine calcium carbonates are widely used in geobiology, environmental science, and paleoenvironmental reconstructions. It is generally accepted that the elemental abundance of biogenic marine carbonates reflects a combination of the abundance of that ion in seawater, the physical properties of seawater, the mineralogy of the biomineral, and the pathways and mechanisms of biomineralization. Here we report measurements of a suite of nine elemental ratios (Li/Ca, B/Ca, Na/Ca, Mg/Ca, Zn/Ca, Sr/Ca, Cd/Ca, Ba/Ca, and U/Ca) in 18 species of benthic marine invertebrates spanning a range of biogenic carbonate polymorph mineralogies (low-Mg calcite, high-Mg calcite, aragonite, mixed mineralogy) and of phyla (including Mollusca, Echinodermata, Arthropoda, Annelida, Cnidaria, Chlorophyta, and Rhodophyta) cultured at a single temperature (25°C) and a range of pCO2 treatments (ca. 409, 606, 903, and 2856 ppm). This dataset was used to explore various controls over elemental partitioning in biogenic marine carbonates, including species-level and biomineralization-pathway-level controls, the influence of internal pH regulation compared to external pH changes, and biocalcification responses to changes in seawater carbonate chemistry. The dataset also enables exploration of broad scale phylogenetic patterns of elemental partitioning across calcifying species, exhibiting high phylogenetic signals estimated from both uni- and multivariate analyses of the elemental ratio data (univariate: λ = 0–0.889; multivariate: λ = 0.895–0.99). Comparing partial R2 values returned from non-phylogenetic and phylogenetic regression analyses echo the importance of and show that phylogeny explains the elemental ratio data 1.4–59 times better than mineralogy in five out of nine of the elements analyzed. Therefore, the strong associations between biomineral elemental chemistry and species relatedness suggests mechanistic controls over element incorporation rooted in the evolution of biomineralization mechanisms.
- Seawater acidification reduced the hatching, survival and growth of Artemia franciscana.
- Acidified seawater inhibited the biochemical constituents in A. franciscana.
- Franciscana showed oxidative and metabolic stress under acidified seawater.
Ocean acidification is becoming a potential threat to marine animals. The present study investigated the effect of seawater acidification on Artemia franciscana. A. franciscana cysts were allowed to hatch at different pH levels of pH 8.2 (control), 7.8, and 6.8. After 48 h incubation, the hatching percentage was significantly reduced in acidified seawater compared to that in control. Further, the hatched Artemia nauplii from each pH treatment were transferred to freshly acidified seawater for chronic study for 15 days. At the end of the experiment, survival, growth, and biochemical constituents were significantly decreased in Artemia at pH 7.8 and 6.8 compared to that in control, which indicates the adverse effects of acidified seawater on Artemia. The antioxidants, lipid peroxidation, and metabolic enzymes were significantly elevated in A. franciscana exposed to acidified seawater compared to that in control, which shows oxidative and metabolic stress on A. franciscana under acidified environment.
Zooplankton can serve as indicators of ecosystem health, water quality, food web structure, and environmental change, including those associated with climate change and ocean acidification (OA). Laboratory studies demonstrate that low pH and high pCO2 associated with OA can significantly affect the physiology and survival of zooplankton, with differential responses among taxa. While laboratory studies can be indicative of zooplankton response to OA, in situ responses will ultimately determine the fate of populations and ecosystems. In this perspective, we compare expectations from experimental studies with observations made in Puget Sound (Washington, United States), a highly dynamic estuary with known vulnerabilities to low pH and high pCO2. We found little association between empirical measures of in situ pH and the abundance of sensitive taxa as revealed by meta-analysis, calling into question the coherence between experimental studies and field observations. The apparent mismatch between laboratory and field studies has important ramifications for the design of long-term monitoring programs and interpretation and use of the data produced. Important work remains to be done to connect traits that are sensitive to OA with those that are ecologically relevant and reliably observable in the field.
Antarctic krill Euphausia superba is a key species in the Southern Ocean, where its habitat is projected to undergo continued warming and increases in pCO2. Experiments during 2 summer field seasons at Palmer Station, Antarctica, investigated the independent and interactive effects of elevated temperature and pCO2 (decreased pH) on feeding, growth, acid-base physiology, metabolic rate, and survival of adult Antarctic krill. Ingestion and clearance rates of chlorophyll were depressed under low pH (7.7) compared to ambient pH (8.1) after a 48 h acclimation period, but this difference disappeared after a 21 d acclimation. Growth rates were negligible and frequently negative, but were significantly more negative at high (3°C, -0.03 mm d-1) compared to ambient temperature (0°C, -0.01 mm d-1) with no effect of pH. Modest elevations in tissue total CO2 and tissue pH were apparent at low pH but were short-lived. Metabolic rate increased with temperature but was suppressed at low pH in smaller but not larger krill. Although effects of elevated temperature and/or decreased pH were mostly sublethal, mortality was higher at high temperature/low pH (58%) compared to ambient temperature/pH or ambient temperature/low pH (>90%). This study identified 3 dominant patterns: (1) shorter-term effects were primarily pH-dependent; (2) krill compensated for lower pH relatively quickly; and (3) longer-term effects on krill growth and survival were strongly driven by temperature with little to no pH effect.
- Elevated pCO2 influences growth and chemical composition of some intertidal algae.
- Herbivore preference is reinforced by resilience of preferred alga to pCO2 exposure.
- Preference is also influenced by changes in lesser-preferred algal species.
- Specialist and generalist feeding may be indirectly affected by ocean acidification.
Ocean acidification (OA) can induce changes in marine organisms and species interactions. We examined OA effects on intertidal macroalgal growth, palatability, and consumption by a specialist crab (Pugettia producta) and a generalist snail (Tegula funebralis) herbivore. Moderate increases in pCO2 increased algal growth in most species, but effects of pCO2 on C:N and phenolic content varied by species. Elevated pCO2 had no effect on algal acceptability to herbivores, but did affect their preference ranks. Under elevated pCO2, electivity for a preferred kelp (Egregia menziesii) and preference rankings among algal species strengthened for both P. producta and T. funebralis, attributable to resilience of E. menziesii in elevated pCO2 and to changes in palatability among less-preferred species. Preferred algae may therefore grow more under moderate pCO2 increases in the future, but their appeal to herbivores may be strengthened by associated shifts in nutritional quality and defensive compounds in other species.
- Copepods were subjected to OA and Hg pollution under multigenerational exposure.
- OA reduced Hg accumulation and its toxicity to the growth/reproduction in copepods.
- Copepod proteome enabled its physiological resilience to decreasing pH.
- Proteomics indicated many toxic events, ensuring Hg toxicity to the copepod’s traits.
- Proteome compensation was accounting for the alleviative effect of OA on Hg toxicity.
Here, we examined the combinational effect of ocean acidification (OA) and mercury (Hg) in the planktonic copepod Pseudodiaptomus annandalei in cross-factored response to different pCO2 (400, 800 μatm) and Hg (control, 1.0 and 2.5 μg/L) exposures for three generations (F0-F2), followed by single-generation recovery (F3) under clean condition. Several phenotypic traits and Hg accumulation were analyzed for F0-F3. Furthermore, shotgun-based quantitative proteomics was performed for F0 and F2. Our results showed that OA insignificantly influenced the traits. During F0-F2, combined exposure reduced Hg accumulation as compared with the counterpart Hg treatment, supporting the mitigating effect of OA on Hg toxicity in copepods. Proteomics analysis indicated that the copepods probably increased energy production/storage and stress response to ensure physiological resilience against OA. However, Hg induced many toxic events (e.g., energy depletion and degenerated organomorphogenesis/embryogenesis for F0; cell cycle arrest and detrimental stress-defense for F2), which were translated to the population-level adverse outcome, i.e., compromised growth/reproduction. Particularly, compensatory proteome response was identified (e.g., increased immune defense for F0; energetic compensation and enhanced embryogenesis for F2), accounting for a negative interaction between OA and Hg. Together, this study provides the molecular mechanisms behind the effects of OA and Hg pollution in marine copepods.
This study assessed the interactive effects of near-future coastal acidification in combination with varying sub lethal metal concentrations on the haemolymph osmolality of Dotilla fenestrata. Crabs were exposed to acute combination of near-future pH scenarios of estuarine systems (7.2, 7.4 and 7.6) by bubbling CO2 into holding tanks and metal concentrations (Cd = 0.50, 0.75, and 1.00 mg/l), (Pb = 6.50, 8.50 and 10.50 mg/l) and (Cd & Pb = 4.50, 5.75 and 7.00 mg/l) at 32 psu salinity and 18 °C for 96 h and compared with the control group that were acclimated in water medium (salinity 32 psu, temperature 18 °C and pH 8.1). Mean haemolymph osmolality of crabs exposed to a combination of varying pH and metal concentrations were not significantly different (ANOVA HSD: df 9; p > 0.05) from the crabs acclimated close to background water parameters. The study showed that near-future coastal pH has no significant effect on the haemolymph osmolality of the crab Dotilla exposed to sublethal concentrations of Cd and Pb at salinity level of 32 ppt.
The Arctic may be particularly vulnerable to the consequences of both ocean acidification (OA) and global warming, given the faster pace of warming and acidification. Here, we use the Atlantis ecosystem model to assess how the trophic network of marine fishes and invertebrates in the Icelandic waters is responding to the combined pressures of OA and warming. We develop an approach which allows us to focus on species of economic (catch-value), social (number of participants in fisheries), or ecological (keystone species) importance. We parameterize the model with literature-determined ranges of sensitivity to OA and warming for different species and functional groups in the Icelandic waters. We found divergent species responses to warming and acidification levels; (mainly) planktonic groups and forage fish benefited while (mainly) benthic groups and predatory fish decreased under warming and acidification scenarios. Assuming conservative harvest rates for the largest catch-value species, Atlantic cod, we see that the population is projected to remain stable under even the harshest acidification and warming scenario. Further, for the scenarios where the model projects reductions in biomass of Atlantic cod, other species in the ecosystem increase, likely due to a reduction in competition and predation. These results highlight the interdependencies of multiple global change drivers and their cascading effects on trophic organization, and the supply of an important species from a socio-economic perspective in the Icelandic fisheries.
- Elevated temperature accelerated early and late embryonic development.
- Reduced pH accelerated late embryonic development.
- Elevated temperature reduced survivorship in later stages.
- A negative synergetic effect between pH and temperature was evidenced in egg volume.
- > 70% of embryos well-developed under elevated temperature and reduced pH.
Predicted effects of anthropogenic climate change on estuarine and coastal organisms are complex, and early life history stages of calcified ectotherms are amongst the most sensitive groups. Despite the importance of understanding their vulnerability, we lack information on the effects of multiple stressors on the embryonic development of estuarine and burrowing organisms, mainly mangrove-associated species. Here, we determined the combined effects of elevated temperature and decreased pH on the embryonic development of the estuarine fiddler crab Leptuca thayeri. Initially, the microhabitat (burrow) of ovigerous (egg-bearing) females was measured for temperature, pH, and salinity, which provided control values in our laboratory experiment. Embryos at the early stage of development were subjected to cross-factored treatments of predicted temperature and pH and evaluated for development rate, survivorship, and volume until their later embryonic stage. Embryo development was faster at early and later stages of development, and survivorship was lower under elevated temperature. Embryos under reduced pH showed advanced embryonic stages at their late development stage. Higher egg volume was observed in a warmer and acidified environment, and lower volume in warmer and non-acidified conditions, indicating that embryo development is synergistically affected by warming and acidification. More than 70% of embryos developed until late stages under the multiple-stressors treatment, giving insights on the effects of a warm and acidified environment on burrowing estuarine organisms and their early stages of development.