Effects Of Ocean Acidification Research Articles

A Review: Mechanisms of Ocean Acidification in the Context of Global Warming

Global warming stems mainly from the accumulation of greenhouse gases, which leads to higher atmospheric and ocean temperatures and has far-reaching impacts on marine systems. This paper focuses on the impact of global warming on the El Nio phenomenon and ocean acidification. There are significant changes in the frequency and intensity of El Nio events in the context of global warming, but the exact trends are uncertain. At the same time, the increase in carbon dioxide has led to ocean acidification, which poses a threat to the growth of marine organisms and the stability of ecosystems. An in-depth understanding of the role of El Nio and ocean acidification in climate change is therefore essential for the protection of marine ecosystems. For future marine ecological conservation, a comprehensive analysis of the climatic effects of El Nio and ocean acidification is essential. Only an in-depth study of these factors can lead to a more effective response to the ecological challenges posed by global warming.

Rising tide of ocean acidification

This comprehensive review explores the escalating environmental crisis of ocean acidification, primarily driven by anthropogenic carbon dioxide molecules (CO2) emissions. In this study, we employed a systematic methodology to collect and analyze literature relevant to ocean acidification. Our research involved an exhaustive search of databases such as PubMed, Web of Science, Google Scholar, and Mendeley to gather pertinent studies published up until 2024. In addition, we consulted secondary sources, including expert panel reports, to enhance the depth of our analysis. Socio-economic ramifications are profound, particularly for fisheries, tourism, and coastal communities that rely heavily on marine resources. This research underscores the potential for substantial exacerbates in these sectors, emphasizing the need for targeted policies and management strategies to mitigate the adverse effects of ocean acidification. By addressing these critical areas, the study informs stakeholders and supports the development of adaptive measures that can sustain local economies and preserve biodiversity in affected regions. The economic consequences could be substantial, exacerbating global social and economic disparities. Speculative considerations highlight the potential for significant global impacts and the urgent need for proactive, coordinated action. This review emphasizes the importance of continued research and monitoring to develop effective mitigation and adaptation strategies, underscoring the critical role of global cooperation and innovation in environmental management. This review aims to serve as a call to action, highlighting the urgency to preserve marine ecosystems and their services to humanity in the face of this growing environmental challenge.

One Ocean – a New Regulatory Solution to Climate Change

Global heating is pushing ocean temperatures to new heights, fuelling more frequent and intense storms, rising sea levels, and the salinization of coastal lands and aquifers. Untreated sewerage and wastewater containing toxic chemicals and millions of tons of plastic waste are flooding into coastal ecosystems, killing, or injuring fish, sea turtles, seabirds, and marine mammals, and making their way into the food chain and ultimately being consumed by humans. More than 17 million metric tons of plastic entered the world’s ocean in 2021, making up 85 per cent of marine litter, and projections are expected to double or triple each year by 2040, according to the latest Sustainable Development Goals (SDG) report. According to UN estimates, by 2050, there could be more plastic in the sea than fish unless action is taken.2 An innovative governance approach to ocean management is needed that builds ecosystem resilience to tackle the adverse effects of climate change and ocean acidification, and maintains and restores ecosystem integrity, including carbon cycling services. This paper discusses such an approach. Keywords Climate change, pollution, carbon capture, oceanic biosphere, continental linkages, regulatory models, governance.

Symbiodiniaceae algal symbionts of Pocillopora damicornis larvae provide more carbon to their coral host under elevated levels of acidification and temperature

Climate change destabilizes the symbiosis between corals and Symbiodiniaceae. The effects of ocean acidification and warming on critical aspects of coral survical such as symbiotic interactions (i.e., carbon and nitrogen assimilation and exchange) during the planula larval stage remain understudied. By combining physiological and stable isotope techniques, here we show that photosynthesis and carbon and nitrogen assimilation (H13CO3− and 15NH4+) in Pocillopora damicornis coral larvae is enhanced under acidification (1000 µatm) and elevated temperature (32 °C). Larvae maintain high survival and settlement rates under these treatment conditions with no observed decline in symbiont densities or signs of bleaching. Acidification and elevated temperature both enhance the net and gross photosynthesis of Symbiodiniaceae. This enhances light respiration and elevates C:N ratios within the holobiont. The increased carbon availability is primarily reflected in the 13C enrichment of the host, indicating a greater contribution of the algal symbionts to the host metabolism. We propose that this enhanced mutualistic symbiotic nutrient cycling may bolster coral larvae’s resistance to future ocean conditions. This research broadens our understanding of the early life stages of corals by emphasizing the significance of symbiotic interactions beyond those of adult corals.

Long-term study of the combined effects of ocean acidification and warming on the mottled brittle star, Ophionereis fasciata.

The global ocean is rapidly changing, posing a substantial threat to the viability of marine populations due to the co-occurrence of multiple drivers, such as ocean warming (OW) and ocean acidification (OA). To persist, marine species must undergo some combination of acclimation and adaptation in response to these changes. Understanding such responses is essential to measure and project the magnitude and direction of current and future vulnerabilities in marine ecosystems. Echinoderms have been recognised as a model in studies of OW-OA effects on marine biota. However, despite their global diversity, vulnerability and ecological importance in most marine habitats, brittle stars (ophiuroids) are poorly studied. A long-term mesocosm experiment was conducted on adult mottled brittle star (Ophionereis fasciata) as a case study to investigate the physiological response and trade-offs of marine organisms to ocean acidification, ocean warming and the combined effect of these two drivers. Long-term exposure of O. fasciata to high temperature and low pH affected survival, respiration and regeneration rates, growth rate, calcification/dissolution and righting response. Higher temperatures increased stress and respiration, and decreased regeneration and growth rates as well as survival. Conversely, changes in pH had more subtle or no effect, affecting only respiration and calcification. Our results indicate that exposure to a combination of high temperature and low pH produces complex responses for respiration, righting response and calcification. We address the knowledge gap of the impact of a changing ocean on ophiuroids in the context of echinoderm studies, proposing this class as an ideal alternative echinoderm for future research.

Sustainable seaweed aquaculture and climate change in the North Atlantic: challenges and opportunities

Seaweed aquaculture is gaining traction globally as a solution to many climate issues. However, seaweeds themselves are also under threat of anthropogenically driven climate change. Here, we summarize climate-related challenges to the seaweed aquaculture industry, with a focus on the developing trade in the North Atlantic. Specifically, we summarize three main challenges: i) abiotic change; ii) extreme events; and iii) disease & herbivory. Abiotic change includes negative effects of ocean warming and acidification, as well as altered seasonality due to ocean warming. This can lower biomass yield and change biochemical composition of the seaweeds. Extreme events can cause considerable damage and loss to seaweed farms, particularly due to marine heatwaves, storms and freshwater inputs. Seaweed diseases have a higher chance of proliferating under environmentally stressful conditions such as ocean warming and decreased salinity. Herbivory causes loss of biomass but is not well researched in relation to seaweed aquaculture in the North Atlantic. Despite challenges, opportunities exist to improve resilience to climate change, summarized in three sections: i) future proof site selection; ii) advances in breeding and microbiome manipulation; and iii) restorative aquaculture. We present a case study where we use predictive modelling to illustrate suitable habitat for seaweed cultivation in the North Atlantic under future ocean warming. Notably, there was a large loss of suitable habitat for cultivating Alaria esculenta and Laminaria digitata. We show how selection and priming and microbe inoculates may be a cost-effective and scalable solution to improve disease- and thermal tolerance. Co-cultivation of seaweeds may increase both yield and biodiversity co-benefits. Finally, we show that aquaculture and restoration can benefit from collaborating on nursery techniques and push for improved legislation.

Energy budget as a tool to assess the effects of environmental stressors: a study on whiteleg shrimp (Penaeus vannamei) exposed to variations in salinity and ocean acidification

ABSTRACT Our goal was to use the energy budget as a tool to evaluate the effects of salinity (20, 25, 30, 35 or 40‰) and ocean acidification (pH 8.0 or 7.3) in Penaeus vannamei. We assessed the energy budget a range of physiological processes (ingestion, defecation, growth, metabolism, excretion, energy substrate, hepatosomatic index, and osmoregulation). In general, salinity had an accentuated effect than pH, as it altered nearly all physiological parameters, including the energy channeled into growth (up to −56%). Reduced pH also affected the energy budget: increased energy lost in feces (25 and 40‰: +21% and 13%, respectively), excretion (25‰: +55%), and metabolism (20‰: +58%). Furthermore, acidified pH increased oxygen consumption by 60%, which may be related to higher energy expenditure. In conclusion, the energy budget can be a valuable tool for assessing the impacts of environmental stressors and the salinity has an accentuated effect than the ocean acidification predicted.

Effects of ocean acidification on the interaction between calcifying oysters (Ostrea chilensis) and bioeroding sponges (Cliona sp.)

Ocean acidification can negatively affect a broad range of physiological processes in marine shelled molluscs. Marine bioeroding organisms could, in contrast, benefit from ocean acidification due to reduced energetic costs of bioerosion. Ocean acidification could thus exacerbate negative effects (e.g. reduced growth) of ocean acidification and shell borers on oysters. The aim of this study was to assess the impact of ocean acidification on the oyster Ostrea chilensis, the boring sponge Cliona sp., and their host-parasite relationship. We exposed three sets of organisms 1) O. chilensis, 2) Cliona sp., and 3) O. chilensis infested with Cliona sp. to pHT 8.03, 7.83, and 7.63. Reduced pH had no significant effect on calcification, respiration and clearance rate of uninfested O. chilensis. Low pH significantly reduced calcification leading to net dissolution of oyster shells at pHT 7.63 in sponge infested oysters. Net dissolution was likely caused by increased bioerosion by Cliona sp. at pHT 7.63. Additionally, declining pH and sponge infestation had a significant negative antagonistic effect (less negative than predicted additively) on clearance rate. This interaction suggests that sponge infested oysters increase clearance rates to cope with higher energy demand of increased shell repair resulting from higher boring activity of Cliona sp. at low seawater pH. O. chilensis body condition was unaffected by sponge infestation, pH, and the interaction of the two. The reduction in calcification rate suggests sponge infestation and ocean acidification together would exacerbate direct (reduced growth) and indirect (e.g., increased predation) negative effects on oyster health and survival. Our results indicate that ocean acidification by the end of the century could have severe consequences for marine molluscs with boring organisms.

Aquaculture and climate change: a data-driven analysis

Abstract As climate change increasingly impacts the aquaculture industry, it poses challenges to production quality, management, and sustainability. This study provides a scientometric analysis of 47 years of research on aquaculture and climate change, analysing 4,785 articles and 224,895 references through CiteSpace software. The study highlights enduring themes such as “ocean acidification” and “global warming,” alongside emerging concerns like “deforestation” and “nutrient runoff,” reflecting new research directions. Notably, “seasonal variations” persist as a key focus due to their significant impact on aquaculture practices. Fourteen research clusters were identified, revealing a diverse array of topics from environmental performance to the effects of blue food systems and ocean acidification on marine life. Clusters related to “carbon sequestration,” “seaweed farming,” and “integrated multi-trophic aquaculture (IMTA)” emphasise the shift toward innovative practices aimed at mitigating climate impacts and enhancing sustainability. The analysis shows a need for more collaborative research, particularly from leading contributors such as the USA, Europe and Australia with underrepresented regions like Southeast Asia and Africa, to develop resilient aquaculture systems capable of adapting to climatic challenges. It advocates for the integration of new technologies and the exploration of sustainable aquaculture practices that minimise environmental impacts while enhancing global food security. This approach sets a direction for future research to promote adaptive strategies and technological innovations in aquaculture.

Widespread scope for coral adaptation under combined ocean warming and acidification.

Reef-building coral populations are at serious risk of collapse due to the combined effects of ocean warming and acidification. Nonetheless, many corals show potential to adapt to the changing ocean conditions. Here we examine the broad sense heritability (H2) of coral calcification rates across an ecologically and phylogenetically diverse sampling of eight of the primary reef-building corals across the Indo-Pacific. We show that all eight species exhibit relatively high heritability of calcification rates under combined warming and acidification (0.23-0.56). Furthermore, tolerance to each factor is positively correlated and the two factors do not interact in most of the species, contrary to the idea of trade-offs between temperature and pH sensitivity, and all eight species can co-evolve tolerance to elevated temperature and reduced pH. Using these values together with historical data, we estimate potential increases in thermal tolerance of 1.0-1.7°C over the next 50 years, depending on species. None of these species are probably capable of keeping up with a high global change scenario and climate change mitigation is essential if reefs are to persist. Such estimates are critical for our understanding of how corals may respond to global change, accurately parametrizing modelled responses, and predicting rapid evolution.

An update of data compilation on the biological response to ocean acidification and overview of the OA-ICC data portal

Abstract. The number of studies investigating the effects of ocean acidification on marine organisms and communities increases every year. Results are not easily comparable since the carbonate chemistry and ancillary data are not always reported in similar units and scales and are not calculated using similar sets of constants. To facilitate data comparison, a data compilation hosted by the PANGAEA Data Publisher was initiated in 2008 and is updated on a regular basis (https://doi.org/10.1594/PANGAEA.962556; Ocean Acidification International Coordination Centre (OA-ICC), 2023). By November 2023, a total of 1501 datasets (over 25 million data points) from 1554 papers had been archived. To easily filter and access relevant biological response data from this compilation, a user-friendly portal (https://oa-icc.ipsl.fr, last access: 9 November 2023) was launched in 2018. Here, we present an update of this data compilation since its second description by Yang et al. (2016) and provide an overview of the OA-ICC portal for ocean acidification biological response data, launched in 2018. Most of the study sites from which data have been archived are in the North Atlantic Ocean, North Pacific Ocean, South Pacific Ocean, and Mediterranean Sea, while polar oceans are still relatively poorly represented. Mollusca and Cnidaria are still the best-represented taxonomic groups. The biological processes most reported in the datasets are growth and morphology. Other variables that can potentially be affected by ocean acidification and are often reported include calcification/dissolution, primary production/photosynthesis, and biomass/abundance. The majority of the compiled datasets have considered ocean acidification as a single stressor, but their relative contribution has decreased from 68 % before 2015 to 57 % today, showing a clear tendency towards more data archived from multifactorial studies.

Effects of Ocean Acidification and Temperature Coupling on Photosynthetic Activity and Physiological Properties of Ulva fasciata and Sargassum horneri.

To investigate the ecological impacts of macroalgae in the framework of shifting global CO2 concentrations, we conducted a study utilizing Ulva fasciata and Sargassum horneri specimens sourced from the Ma'an Archipelago in Zhejiang Province on how ocean acidification (OA) and temperature changes interact to affect the photosynthetic physiological responses of macroalgae. The results of the study showed that OA reduced the tolerance of U. fasciata to bright light at 20 °C, resulting in more pronounced photoinhibition, while 15 °C caused significant inhibition of U. fasciata, reducing its growth and photosynthetic activity, but OA alleviated the inhibition and promoted the growth of the alga to a certain extent. The tolerance of S. horneri to bright light was also reduced at 20 °C; the inhibition was relieved at 15 °C, and the OA further improved the algal growth. The Relative Growth Rate (RGR), photosynthetic pigment content, and the release of the dissolved organic carbon (DOC) of U. fasciata were mainly affected by the change in temperature; the growth of the alga and the synthesis of metabolites were more favored by 20 °C. A similar temperature dependence was observed for S. horneri, with faster growth and high metabolism at 15 °C. Our results suggest that OA reduces the tolerance of macroalgae to high light at suitable growth temperatures; however, at unsuitable growth temperatures, OA effectively mitigates this inhibitory effect and promotes algal growth.

Can niche plasticity mediate species persistence under ocean acidification?

Global change stressors can modify ecological niches of species, thereby altering ecological interactions within communities and food webs. Yet, some species might take advantage of a fast-changing environment, allowing species with high niche plasticity to thrive under climate change. We used natural CO2 vents to test the effects of ocean acidification on niche modifications of a temperate rocky reef fish assemblage. We quantified three ecological niche traits (overlap, shift and breadth) across three key niche dimensions (trophic, habitat and behavioural). Only one species increased its niche width along multiple niche dimensions (trophic and behavioural), shifted its niche in the remaining (habitat) was the only species to experience a highly increased density (i.e. doubling) at vents. The other three species that showed slightly increased or declining densities at vents only displayed a niche width increase in one (habitat niche) out of seven niche metrics considered. This niche modification was likely in response to habitat simplification (transition to a system dominated by turf algae) under ocean acidification. We further showed that, at the vents, the less abundant fishes had a negligible competitive impact on the most abundant and common species. This species appeared to expand its niche space, overlapping with other species, which likely led to lower abundances of the latter under elevated CO2. We conclude that niche plasticity across multiple dimensions could be a potential adaptation in fishes to benefit from a changing environment in a high-CO2 world.

Toward an ecologically realistic experimental system to investigate the multigenerational effects of ocean warming and acidification on benthic invertebrates

AbstractHuman activities over the past 150 yr have led to significant carbon dioxide (CO2) emissions, causing global warming and ocean acidification. Surface ocean temperature has risen by 0.93°C since 1850, with projections of an additional +1.42°C to 3.47°C by 2080–2099. Ocean acidification, driven by CO2 absorption, has already lowered seawater pH by 0.1 units, affecting calcifying organisms, including shelled mollusks. Long‐term multigenerational studies on mollusk responses to both ocean acidification and warming, under realistic environmental conditions, are scarce. To address this knowledge gap, two mobile experimental units that can be deployed at the vicinity of shellfish farming areas were developed within the framework of the CocoriCO2 project. The experimental systems were designed to manipulate temperature and pH as offsets from ambient conditions. The experimental units have shown their effectiveness in terms of controlling and maintaining pH and temperature to assess the multigenerational effects of ocean warming and acidification on benthic invertebrates. Finally, the developed experimental systems can be modified easily to provide an educated assessment of the impact of other relevant environmental changes such as deoxygenation and changes in salinity.

From Individual Calcifiers to Ecosystem Dynamics: Ocean Acidification Effects on Urchins and Abalone.

A central question in ecology is to what extent do trophic interactions govern the structure and function of communities? This question is becoming more pressing as trophic interactions shift with rapid climate change. Sea urchins and abalone are key invertebrates in the habitats where they reside. Sea urchins are critical members of exemplar trophic cascades in kelp forests due to their impact on kelp establishment and maintenance; yet their populations are controlled by predators, such as sea otters and sunflower sea stars. Abalone compete with urchins for macroalgal food resources and therefore can help regulate urchin populations in kelp forests. Given that both urchin tests and abalone shells used for predator defense are comprised of calcium carbonate, much research has been conducted on the impacts of ocean acidification (OA) on these calcified structures. A growing body of literature has shown that urchin tests are less calcified and break with less force under OA conditions. Less is known about abalone, but their shells also appear to respond negatively to OA. Using kelp forest communities as exemplar ecosystems, we discuss the morphological, biomechanical, and physiological responses to OA in urchins and abalone and consider how these individual level responses scale to trophic interactions and ultimately whole ecosystem processes. Although the impacts of OA on the calcified structures used for defense have been well studied, calcified mechanisms for food consumption, such as the Aristotle's lantern of urchins, are much less understood. Thus, examining both the feeding and defense sides of trophic interactions would greatly improve our understanding of OA responses across individual to ecosystem scales. More generally, measurements of morphological, biomechanical, and physiological responses to OA can be made in individuals to help predict higher level ecological responses, which would greatly contribute to broader predictions of whole ecosystem responses to OA.

The Science, Engineering, and Validation of Marine Carbon Dioxide Removal and Storage.

Scenarios to stabilize global climate and meet international climate agreements require rapid reductions in human carbon dioxide (CO2) emissions, often augmented by substantial carbon dioxide removal (CDR) from the atmosphere. While some ocean-based removal techniques show potential promise as part of a broader CDR and decarbonization portfolio, no marine approach is ready yet for deployment at scale because of gaps in both scientific and engineering knowledge. Marine CDR spans a wide range of biotic and abiotic methods, with both common and technique-specific limitations. Further targeted research is needed on CDR efficacy, permanence, and additionality as well as on robust validation methods-measurement, monitoring, reporting, and verification-that are essential to demonstrate the safe removal and long-term storage of CO2. Engineering studies are needed on constraints including scalability, costs, resource inputs, energy demands, and technical readiness. Research on possible co-benefits, ocean acidification effects, environmental and social impacts, and governance is also required.

A numerical model sheds new light on the effects of ocean acidification on an indicator species.

A Lagrangian Individual Based Model (IBM) offers new insights into the effects of ocean acidification on pteropods by providing detailed life histories of individuals. A thorough analysis of the results makes it possible to attribute the effects of ocean acidification to different mechanisms.

Impact of ocean acidification on microzooplankton grazing dynamics

This study examines the potential impacts of projected atmospheric carbon dioxide (pCO2) levels reaching 800 ppm by the end of the century, focusing on ocean acidification effects on marine ecosystems in the coastal areas of Bohai. We investigated how acidification affects the grazing patterns of microzooplankton using dilution techniques and ecophysiological methods. Our findings indicate that acidic conditions shift the phytoplankton community structure, changing dominant species. Elevated CO2 concentrations reduced grazing pressure on phytoplankton, with less steep declines in growth rates at 800 ppm CO2 (spring: 2.43 d−1 vs. 2.16 d−1, summer: −0.46 d−1 vs. −0.73 d−1, autumn: −0.45 d−1 vs. −0.90 d−1) and significant decreases in grazing pressure percentages (%Pp from 0.84 to 0.58 and %Pi from 0.64 to 0.46). Short-term acid exposure significantly increased superoxide dismutase activity in both microplankton (from 0.03 to 0.08 U mg−1, p<0.01) and nanoplankton (from 0.05 to 0.09 U mg−1, p<0.001), indicating an adaptive response to oxidative stress. These results highlight that elevated CO2 levels primarily boost phytoplankton growth by reducing microzooplankton grazing pressure, resulting in higher growth rates and a shift towards smaller-sized phytoplankton, reflecting complex short-term ecological responses to acidification. Further research is needed to understand the long-term effects of ocean acidification on microzooplankton and their role in marine secondary productivity.

Interactive effects of ocean acidification and nitrate on Ulva lactuca

Interactive effects of ocean acidification and nitrate on Ulva lactuca

Evaluating the time to detect biological effects of ocean acidification and warming: an example using simulations of purple sea urchin settlement

Ocean acidification (OA) and ocean warming driven by climate change are important stressors for marine species and systems, but documenting and detecting their long-term impacts on biological responses outside of laboratory settings are challenging due to natural variability caused by complex processes and interactions. We used settlement of purple sea urchins Strongylocentrotus purpuratus in the Southern California Bight (USA) over 6 yr as an example data set to parameterize a simulation model for exploring the time needed to detect environmental effects on a biological response. A generalized linear model was used to describe an index of urchin settlement as functions of pH, sea surface temperature (SST), sea surface salinity (SSS), and spatio-temporal factors, demonstrating that settlement was negatively associated with pH (i.e. lower settlement at higher pH) and positively associated with SST and SSS. Monte Carlo simulations were developed from this base model under a variety of alternative scenarios to estimate the time to detect: (1) annual trends in pH and SST time series, (2) pH and SST effects on urchin settlement, and (3) annual trends in urchin settlement. Time to detect pH and SST effects was predominantly influenced by the underlying strength of the relationships and the model uncertainty. Time to detect annual trends in settlement was more sensitive to the severity of long-term OA and warming trends, which had cumulative (at times opposing) effects. This study highlights the variable time scales (2-60+ yr) that may be necessary to detect biological responses to OA and ocean warming and the sensitivity to different assumptions of the study system.