The United Nations Sustainable Development Goals (SDGs) represent a global call for action to sustain humans, the planet and prosperity. SDG14 (Sustaining Life below water) focuses on oceans, their conservation and sustainable use. Since committing to the 2030 Agenda for Sustainable Development, there have been several calls to take stock of progress and encourage decisive action to build a sustainable future. Here we evaluate progress against achieving each of the SDG14 goals using as an example Australia’s Torres Strait tropical rock lobster (TRL) Panulirus ornatus fishery because of the very strong dependence of Indigenous fishers and local communities on this resource. Our evaluation draws on 40 years of research, highlighting how changes have improved alignment or are on-track to meet the 2030 targets. We assessed that all targets were achieved to 2025 due to the small fishery ecological footprint, sound sustainable fishery and ecosystem management, science-based management plans, economic benefits derived though sustainable management, growth in research capacity as well as access for small-scale artisanal fishers to marine resources and markets. Our case-study therefore complements best practices examples in achieving SDG14 for a regionally important fishery. To meet 2030 aspirational goals, progress was assessed as on-track to address impacts of ocean acidification, enhanced transfer of marine technology and need to work with global partners to encourage market access for sustainable fisheries that are vital in supporting Indigenous and regional livelihoods. Overall, we calculated a conservative score of 3.5 reflecting very high achievement (~ 88%) towards future aspirational SDG targets.
Continue reading ‘SDG14 assessment of progress against sustaining life below water: a case study from Torres Strait’Posts Tagged 'South Pacific'
SDG14 assessment of progress against sustaining life below water: a case study from Torres Strait
Published 31 August 2026 Science Leave a CommentTags: crustaceans, fisheries, socio-economy, South Pacific
Giant kelp-associated variation in coastal seawater chemistry across contrasting sites in Chile and Tasmania
Published 13 August 2026 Science ClosedTags: algae, chemistry, field, Indian, South Pacific
Background and Aims
Widespread shifts in seawater chemistry are occurring across spatial and temporal scales, with important consequences for coastal ecosystems. Giant kelp (Macrocystis pyrifera) forests elevate seawater pH and dissolved oxygen (DO) through photosynthesis, potentially providing short-term refugia from ocean acidification and deoxygenation. However, whether these effects persist across contrasting environmental settings remains unclear. Here, we assess how biological and oceanographic conditions regulate giant kelp-mediated modification of seawater chemistry across multiple sites.
Methodology
Hourly measurements of seawater pH, DO and temperature were collected during spring–summer 2022–23 using paired deployments inside and outside giant kelp forests at one site in central Chile and four sites in Tasmania, Australia. The influence of giant kelp density was also evaluated at two sites in southern Chile and three sites in Tasmania. An upwelling index was calculated for the central Chile site to assess the influence of regional oceanographic forcing on kelp-associated seawater chemistry patterns.
Key Results
Hourly pH and DO were higher inside giant kelp forests than outside at the central Chile site and at one Tasmanian site. At these locations, stronger daytime pH–DO relationships indicated that photosynthetic carbon uptake exceeded night-time respiration, generating a net positive metabolic signal. In Tasmania, giant kelp density was positively associated with hourly pH and DO, whereas no such relationship was detected in southern Chile. At the central Chile site, kelp-associated effects intensified during a strong upwelling event, reducing the severity of low pH and DO conditions.
Conclusions
Giant kelp forests can locally buffer short-term fluctuations in seawater pH and DO, but this capacity is highly site-dependent and influenced by giant kelp density and environmental conditions. Overall, our findings suggest that continued loss of giant kelp forests in Tasmania may reduce their potential to provide short-term refugia, while in Chile the strength of kelp-mediated seawater chemistry modification is likely to remain strongly influenced by variability in upwelling and freshwater inputs.
Continue reading ‘Giant kelp-associated variation in coastal seawater chemistry across contrasting sites in Chile and Tasmania’Coastal phytoplankton response to acidification and warming under differing levels of nutrient availability
Published 12 June 2026 Science ClosedTags: biological response, community composition, mesocosms, multiple factors, nutrients, otherprocess, photosynthesis, phytoplankton, South Pacific
Ocean acidification and warming will alter phytoplankton biomass and composition, yet despite numerous studies, there are few consistent responses on which to base predictions. To determine the responses of chlorophyll-a and phytoplankton size and composition to predicted lower pH (−0.33 to −0.5) alone, and also combined with elevated temperature (+2.5–3.5 °C), two mesocosm experiments were carried out in austral spring and autumn in temperate New Zealand coastal waters. Lower pH alone had no effect on chlorophyll-a in either experiment and, as the treatment pH was lower than the pH minimum recorded in a parallel four-year time series, this lack of response in chlorophyll-a was not attributable to prior in situ exposure. Conversely, chlorophyll-a increased under lower pH and warming in both experiments, with the large (>20 µm) phytoplankton size fraction showing opposing responses under nutrient deplete and replete conditions. Diatom biomass also increased in both treatments when nutrient availability was maintained, with a dominant pennate species Cylindrotheca clostridium emerging. The results highlight the value of contextual time series for experimental interpretation, and also the importance of assessing warming and acidification together using regionally representative nutrient concentrations, for prediction of coastal phytoplankton response to climate change.
Continue reading ‘Coastal phytoplankton response to acidification and warming under differing levels of nutrient availability’Hydrodynamic control of coral metabolism: a coupled modeling approach linking flow, physiology, and reef-scale biogeochemistry
Published 2 June 2026 Science ClosedTags: biogeochemistry, biological response, chemistry, community composition, corals, individualmodeling, modeling, otherprocess, physiology, South Pacific
Tropical coral reefs exhibit high variability in coral metabolism, driven by complex interactions among physical, chemical, and biological processes. Understanding the spatiotemporal patterns of coral metabolism and their drivers is critical, as such variability may underpin corals’ adaptive capacity to withstand a warming and acidifying ocean. Here, we use a coupled hydrodynamic–biogeochemical–physiological model to investigate spatial and diel variations in coral metabolic processes (photosynthesis, respiration, and calcification) across Moorea’s north shore reef system under three prevailing wave regimes. We find that photosynthesis varies little across the reef, whereas respiration and calcification show pronounced spatial heterogeneity. These spatial patterns closely mirror the ones in seawater carbonate chemistry and depend strongly on wave-driven flow. Hydrodynamics regulate diffusive exchanges between coral tissues and surrounding seawater, and eventually generate distinct internal chemical environments (in the coelenteron and calcifying fluid) across the reef. Landward reef regions exhibit the greatest spatial and diel variability in coral metabolism. Low-wave, slow-flow conditions amplify metabolic fluctuations throughout the reef, but more strongly in the landward regions. Overall, our results highlight how interactions among transport processes, carbonate chemistry, and coral physiology produce strong day-night fluctuations and spatially heterogeneous but structured metabolic patterns across the reef, which vary systematically with wave conditions.
Continue reading ‘Hydrodynamic control of coral metabolism: a coupled modeling approach linking flow, physiology, and reef-scale biogeochemistry’Diel variability and decoupled pH-oxygen dynamics drive metabolic plasticity in kelp crabs from an upwelling seascape
Published 25 March 2026 Science ClosedTags: biological response, chemistry, crustaceans, laboratory, multiple factors, oxygen, physiology, respiration, South Pacific
Coastal upwelling zones, shaped by global change and human impacts, naturally impose hypoxia and acidification on marine species, creating selective pressures that influence physiological responses and drive phenotypic variability. Understanding these responses is crucial for predicting marine biodiversity dynamics in heterogeneous seascapes. We explored diel cycles of pH and dissolved oxygen (DO) and their influence on the metabolic performance of the kelp crab Taliepus dentatus, a species with limited larval dispersal. Kelp crabs from two environmentally contrasting sites along an upwelling seascape in central Chile—an upwelling shadow and an active upwelling zone—were studied using field sensor data and laboratory experiments. Active upwelling disrupted the regular diel pH cycle, resulting in persistently low pH (pHT ≈ 7.5) decoupled from oxygen dynamics. Experimental simulations of diel pH–DO fluctuations revealed that nocturnal low DO/low pH conditions (DO = 1 and 5 mg l⁻¹; pH = 7.5 and 7.8 for ‘upwelling’ and ‘downwelling’ conditions, respectively) reduced metabolic rates and respiratory quotient in crabs. Individuals from the active upwelling zone exhibited elevated metabolic rates, haemolymph pH and lactate accumulation under extremely low pH/low DO conditions compared with those from the upwelling shadow, suggesting site-specific physiological adjustments. These findings underscore the importance of incorporating natural variability into experimental designs and management frameworks aimed at predicting species resilience under climate change.
Continue reading ‘Diel variability and decoupled pH-oxygen dynamics drive metabolic plasticity in kelp crabs from an upwelling seascape’Long-term pH trends and spatiotemporal variability of the carbonate system in Jakarta Bay
Published 20 March 2026 Science ClosedTags: biogeochemistry, chemistry, field, South Pacific
Jakarta Bay, an industrialized and densely inhabited coastal area, presents considerable environmental issues as a result of excessive organic pollution and nutrient inflow. Understanding the spatiotemporal variability of the carbonate system in such an affected bay is critical for assessing marine ecosystem health. The spatiotemporal variability of the carbonate system, pH, partial pressure of carbon dioxide (pCO2), total alkalinity (TAlk), and dissolved inorganic carbon (DIC) was investigated in Jakarta Bay during the rainy and dry seasons of 2023. pH datasets from 2011 to 2023 were also collected from the Environmental Agency of DKI Jakarta (DLH DKI Jakarta) for trend analysis. The temporal analysis shows that during the SE monsoon, the lowest pH (mean: 8.06 ± 0.43); lowest TAlk (mean: 2099 ± 340 µmol kg-1); highest pCO2 (mean: 879 ± 1177 µatm); and highest DIC (mean: 2068 ± 806 µmol kg-1) were observed. The pH distribution gradually increased from the river outlet to the outer bay; inversely, pCO2, TAlk, and DIC gradually decreased. Furthermore, from 2011 to 2023, pH in Jakarta Bay showed a slight upward tendency that was statistically insignificant, reflecting high variability and the influence of local biogeochemical processes. The carbonate system variability reflects changes in biogeochemical (Chl-a, DO and nutrients) and physical (SST and Sal) parameters. In addition, the semi-enclosed hydrodynamic properties, together with the influence of human activities, including a continuous supply of nutrients and organic materials from the mainland through the incoming rivers, further affected the balance of the carbonate system in the bay.
Continue reading ‘Long-term pH trends and spatiotemporal variability of the carbonate system in Jakarta Bay’Fatoata’s NOAA Ocean Acidification Program empowers stewardship among educators and students
Published 19 March 2026 Media coverage ClosedTags: education, South Pacific
The remoteness of American Samoa is, for the most part, to our benefit when it comes to the health of our island’s ecosystems. Being in the middle of the ocean, away from everything, has its advantages. Our ocean waters are still relatively clean. Although we deal with marine debris, most of it is land-based and within our control (we just need to control it). We do not have major factories dumping toxins into our waters that kill off hundreds of species. We have even managed to stave off climate change’s evil twin, ocean acidification, and our goal is to keep it that way.
Like trees, the ocean also absorbs carbon dioxide. Carbon dioxide (CO2) is created by the burning of fossil fuels. Everyday activities that contribute to CO2 overload in the atmosphere include running your air conditioner all day and driving a car with low fuel mileage, as both require fossil fuels to operate. Increased CO2 in the ocean makes it harder for coral reefs and shell-forming organisms (like clams) to build their skeletons and shells. However, there are solutions too! One of the simplest things you can do with any environmental issue you are passionate about is to share what you know. That is exactly what Tafuna High School marine science educator, Ms. Roberta (Ertta) Laumoli, and her class did this school year.
Ms. Ertta took the first step in contributing to Ocean Stewardship this past summer by participating in Fatoata’s NOAA Ocean Acidification Program (OAP) Educator’s Workshop. The workshop provided educators with tools and resources to help them incorporate ocean acidification in their classrooms. As the school year began, the educators took what they learned about ocean acidification and shared it with their students. Ms.Ertta, Claire Bacus-Deewees and Mary Cheung-Fuk worked together and independently within their classrooms to highlight ocean acidification in their lesson plans. Their students conducted outreach, and got creative, through the development of public service announcements that shared what they learned about ocean acidification. In January, educators shared their teaching experience through photos and public service announcements. Ms. Ertta’s class excelled in all aspects of ocean acidification education, and her students’ public service announcement won first place.
Continue reading ‘Fatoata’s NOAA Ocean Acidification Program empowers stewardship among educators and students’A holistic approach to evaluating climate vulnerability of French Polynesia pearl oyster farming: bridging communities and scientific knowledge
Published 13 March 2026 Science ClosedTags: fisheries, socio-economy, South Pacific
Highlights
- A holistic assessment of climate vulnerability of black pearl aquaculture social-ecological system.
- Co-definition of adaptation strategies by scientific/institutional actors and local communities of French Polynesia.
- A list of scientifically robust and locally relevant vulnerability criteria potentially transferable to other Pacific pearl-producing countries.
- Interviewees consistently identify climate change as a factor that amplifies existing weaknesses in the pearl farming sector.
- COVID-19 exposed the sector’s dependence on global markets.
Abstract
While there is wide consensus about the reliance of climate projections at global scale, there is still uncertainty about changes at finer scale and even less on the effects of such fluctuations for local economies and societies. The vulnerability of social-ecological systems (SES) to climate change is a framework that takes into account the strong link between environment and local communities that depend on ecosystem services to ensure their livelihoods. This study explores the vulnerability of pearl farming SES to climate change, combining scientific insights with local knowledge from French Polynesian communities. A preliminary list of eighty-two criteria of exposure, sensitivity and adaptive capacity, identified through a targeted scoping review, was used to develop the interview guide that informed fifty-six face-to-face interviews and workshops conducted in 2020 and 2025. Using a combination of ranking questions and open-ended responses, the results highlight differences in the perceived exposure between scientific/institutional actors and local communities, which is reflected in the degree of sensitivity of the SES to climate drivers. Expectedly, the priorities given to adaptation measures were also different. The thematic analysis of the responses, however, shows that the two parties are aware of their own limitations in understanding the effects of climate change and recognise the need to fill mutual gaps through a collaborative production of knowledge. By integrating complementary forms of knowledge, this approach may help overcome the limitations of vulnerability assessments based exclusively on scientific expertise, and support the development of climate policies that are scientifically sound and socially accepted.
Continue reading ‘A holistic approach to evaluating climate vulnerability of French Polynesia pearl oyster farming: bridging communities and scientific knowledge’Physiology and survival of intertidal calcifiers in two contrasting upwelling systems
Published 27 February 2026 Science ClosedTags: adaptation, biological response, field, laboratory, mollusks, morphology, mortality, otherprocess, physiology, South Pacific
Climate change alters the oceans’ temperature, pH, and oxygen concentration. These changes are expected to increase globally over the coming decades, affecting a wide range of marine organisms. Coastal upwelling zones, characterized by their high environmental variability, serve as ideal natural laboratories to study the potential impacts on marine organisms and ecosystems of temperature change, acidification, and ocean deoxygenation. The estimation of survival using capture‐mark‐recapture (CMR) data has been commonly applied to vertebrates, and to date, very few studies have been done on marine invertebrate organisms. In this study, we combined field CMR data and laboratory measurements to assess the physiological responses (metabolic rate and heart rate) and survival probability of individuals in two populations of intertidal mollusks, Chiton granosus and Scurria zebrina, in contrasting upwelling environments (i.e., semi‐permanent vs. seasonal). We found that (1) there are no differences between the two studied populations for heart rate in both species, (2) the S. zebrina population subjected to seasonal upwelling has a higher metabolism, (3) there are no differences in the calcification rate between the two studied populations of both species, and (4) survival is significantly higher in the semi‐permanent upwelling location for both species. Our findings highlight species‐specific responses to contrasting upwelling regimes, suggesting that phenotypic plasticity and survival differences may influence resilience under ongoing climate change.
Continue reading ‘Physiology and survival of intertidal calcifiers in two contrasting upwelling systems’Assessing sponge resilience to ocean acidification in natural reef environments
Published 28 January 2026 Science ClosedTags: biological response, BRcommunity, community composition, field, otherprocess, photosynthesis, porifera, prokaryotes, respiration, South Pacific, vents
Highlights
- Sponges are key components of coral reefs globally providing a range of important functional roles.
- We used in situ incubation chambers to measure chlorophyll concentrations, oxygen fluxes and microbial communities for two common Indo-Pacific sponge species (Melophlus sarasinorum and Neopetrosia chaliniformis) at a natural CO2 vent (pHT 7.6–7.7) and control site in Papua New Guinea.
- We found little evidence for any physiological differences between vent and control sponges, and no differences in the overall microbial communities
- Overall, our results support the emerging evidence that heterotrophic sponges will likely be resilient to future ocean acidification.
Abstract
Sponges are key components of coral reefs globally providing a range of important functional roles. While sponges are under threat from the impacts of global climate change, there is an emerging picture of sponge tolerance to ocean acidification (OA). However, to date all physiological studies on sponge tolerance to OA have been under ex-situ experimental conditions and only for a limited number of sponge species. Instead, here we used in situ incubation chambers to measure chlorophyll concentrations and oxygen fluxes for two common Indo-Pacific sponge species (Melophlus sarasinorum and Neopetrosia chaliniformis) at a natural CO2 vent (pHT 7.6–7.7) and control site in Papua New Guinea. We also explored differences between the sponge microbial community composition between control and vent locations for N. chaliniformis. We found very low concentrations of chlorophyll in both species, compared to other sponges, suggesting these species are largely heterotrophic. We also found little evidence for any physiological differences between vent and control sponges, and no differences in the overall microbial communities, except some specific microbes. Overall, our results support the emerging evidence that heterotrophic sponges will likely be resilient to future ocean acidification.
Continue reading ‘Assessing sponge resilience to ocean acidification in natural reef environments’Core transcriptional plasticity pave the way for fish to succeed in a high-CO2 world
Published 26 January 2026 Science ClosedTags: biological response, BRcommunity, field, fish, molecular biology, performance, South Pacific, vents
Ocean acidification (OA) can alter the physiological and behavioural traits of marine fishes, raising concerns about how wild species will adapt to rising pCO2. Using natural volcanic CO2 vents at White Island, New Zealand, as analogues for future OA conditions, we quantified behaviours in situ and sequenced the brain transcriptomes of four highly site-attached fish species from two vents and a nearby control site with ambient pCO2, of which two species exhibit increased population densities at the vent. We found that two species showed changes in habitat preferences, and all four species with significant changes in gene expression related to circadian rhythm, visual perception, and energy metabolism at the vents. Strikingly, three differentially expressed genes, a heat shock protein (HS90A) and two immediate early genes (IEGs: JUN and FOS), were central regulators for transcriptional changes across all species at the vents. Within the circadian entrainment pathway, expression changes in opsins may act as a trigger, while core clock genes and IEGs function as downstream effectors, suggesting that elevated pCO2 may reset the circadian clock in these fishes. Notably, the two species with increased populations at the vents exhibited distinct transcriptional responses in genes involved in calcium signalling, reproduction, intracellular pH regulation and energy metabolism. Together with convergent evolution in a calcium signalling gene and an HS90 facilitator, these molecular features may confer their reproduction advantages and ability to cope with elevated pCO2. Our study provides novel insights into the molecular mechanisms underlying fish responses to OA and highlights key pathways that may support survival and ecological success under a naturally high-CO2 world.
Continue reading ‘Core transcriptional plasticity pave the way for fish to succeed in a high-CO2 world’Differing proteome responses to ocean acidification between two common pocilloporid corals
Published 24 December 2025 Science ClosedTags: adaptation, biological response, corals, laboratory, otherprocess, physiology, South Pacific
Ocean acidification threatens coral reef ecosystems by challenging calcification processes fundamental to reef accretion. Yet many corals continue to calcify under elevated pCO2, suggesting species-specific physiological plasticity and potential cellular compensations. Here, we use label-free quantitative proteomics to investigate proteomic responses of two common pocilloporid corals, Stylophora pistillata and Pocillopora damicornis, with known differential resistance to ocean acidification after two months at moderate (~ 940 ppm) and high (~ 2,800 ppm) pCO2 compared to the control (~ 480 ppm). S. pistillata exhibited extensive proteomic restructuring under high pCO2, marked by widespread declines of energy-generating pathways, yet selective increase of proteins involved in ion transport, cytoskeletal stability, and stress responses. This indicates a strategy of general metabolic suppression coupled with targeted investment into essential cellular functions, potentially sustaining calcification despite reduced overall metabolic capacity. In contrast, P. damicornis showed much less proteomic adjustment, primarily involving structural proteins and those potentially linked to cellular redox balance, signifying a moderate, targeted strategy for physiological stability. These divergent responses highlight contrasting modes of resistance (plasticity versus stability). Integrated with physiological data, our findings clarify cellular mechanisms controlling calcification, demonstrating the value of proteomics in coral ecophysiology and providing new insights into species-specific vulnerability under future ocean conditions.
Continue reading ‘Differing proteome responses to ocean acidification between two common pocilloporid corals’Developing scientific capacity to address ocean acidification in the Pacific Islands
Published 22 December 2025 Web sites and blogs ClosedTags: South Pacific
The Pacific Islands Ocean Acidification Centre hosted its second collective regional training on ocean acidification. The event not only enhanced the scientific skills of Pacific researchers but also strengthened a regional network dedicated to understanding and mitigating the growing impacts of ocean acidification across the Pacific.
The impact of ocean acidification on the balance of ocean ecosystems
The Intergovernmental Panel on Climate Change (IPCC) has said several times that ocean acidification is one of the most serious but often overlooked effects of growing levels of carbon dioxide (CO₂) in the air.
The IPCC’s Sixth Assessment Report (AR6) says that the ocean has absorbed over 30% of human-caused CO₂ emissions and more than 90% of the extra heat from global warming. Now, a new report from the Planetary Boundaries Science Lab reveals that seven out of nine planetary boundaries have been breached, with ocean acidification officially entering the danger zone.
The combined effects of warming and acidification are very harmful to marine species and to societies that depend on healthy ocean ecosystems. This is especially true in Small Island Developing States (SIDS) like those in the Pacific. Coral reefs that are deteriorating are harmful to fisheries and coastal protection, and the loss of marine biodiversity could jeopardise the tourist economy.
Understanding, monitoring, and responding to these changes is therefore not just a scientific need; it is a matter of survival for many island communities.
Continue reading ‘Developing scientific capacity to address ocean acidification in the Pacific Islands’Morphological adjustments enable sea urchins to sustain calcified structure function under ocean acidification
Published 10 December 2025 Science ClosedTags: biological response, echinoderms, field, morphology, South Pacific, vents
Ocean acidification can reduce the size of calcified structures produced by marine calcifiers, raising questions about their competitiveness and persistence in future oceans. Yet, size reduction in calcified structures may represent a plastic response to ocean acidification if these structures remain functional. To test this hypothesis and examine whether morphological plasticity can influence the functionality of calcified structures, we assessed the effects of ocean acidification on the morphological, mechanical and chemical properties of the calcified structures of a sea urchin species prevailing at natural CO2 vents. We found that the rigid shells covering sea urchins’ bodies (‘tests’) were thinner and that they had smaller teeth and lower spine density at vents, but the mechanical performance of these calcified structures (mechanical resilience, wear resistance and bending strength) was maintained, possibly mediated by the capacity of sea urchins to sustain acid-base balance for calcification (i.e. increased Na/Ca). Our findings suggest that such morphological shifts in calcified structures may enable sea urchins to maintain structural performance under ocean acidification. Since ocean acidification is a slow process relative to the life cycle of sea urchins, some sea urchin species may acclimate, or even adapt, to ocean acidification so that their populations and ecological functions can persist in a future high-CO2 world.
Continue reading ‘Morphological adjustments enable sea urchins to sustain calcified structure function under ocean acidification’Volcanic bubbles in Papua New Guinea a window into coral’s future
Published 9 December 2025 Press releases ClosedTags: corals, South Pacific, vents
By the end of this century, coral reefs in Australia and around the world could be slower to recover, structurally simpler, and increasingly dominated by fleshy algae as rising carbon dioxide reshapes ocean chemistry.
These are the predictions that new international research – published this week in Communications Biology – is warning against, as scientists present a volley of stark new findings about the current and long-term impact of a process known as ocean acidification.
As the oceans absorb more carbon dioxide from the atmosphere, they are becoming increasingly acidic – eroding the very calcium carbonate skeletons that build coral reefs. Yet despite decades of laboratory studies and ecosystem models, scientists have lacked real-world systems that reflect how entire reef communities respond to these long-term chemical shifts.
Researchers from the Australian Institute of Marine Science (AIMS) have now filled that gap by studying shallow-water reefs naturally bathed in volcanic CO₂. These reefs, located near remote submarine vents in Papua New Guinea’s Milne Bay Province, experience chronic exposure to elevated carbon dioxide, offering scientists a rare preview of the seascapes expected under future emissions scenarios.
Continue reading ‘Volcanic bubbles in Papua New Guinea a window into coral’s future’Impact of seawater acidification on the growth, nutritional composition, sensory profile, and antioxidant activity of Caulerpa racemosa in laboratory culture
Published 20 November 2025 Science ClosedTags: algae, biological response, growth, laboratory, morphology, physiology, South Pacific
Fluctuations in coastal water pH, driven by ocean acidification, can strongly influence photosynthetic marine species, including seaweeds. This study investigated the effects of seawater acidification on the growth, nutritional composition, sensory profile, and antioxidant activity of the green alga Caulerpa racemosa. Cultured under varying pH levels (8.25, 8.00, 7.75, and 7.50) adjusted using HCl, C. racemosa exhibited significant morphological and biochemical changes. Lower pH conditions caused bleaching and textural brittleness, with pH levels between 7.50 and 7.75 showing the most pronounced impacts. Conversely, pH 8.25 supported optimal growth, with superior morphometric performance (absolute growth of 138.30 ± 3.70 g; specific growth rate of 3.08 ± 0.04% day⁻1). Acidification decreased chlorophyll content but enhanced carotenoids, indicating reduced photosynthetic efficiency. Protein content declined under acidic conditions, while lipid and carbohydrate levels increased. Notably, antioxidant activity peaked under pH 7.50 (15.09 ± 0.04%; IC50 275.04 ± 0.85 ppm), suggesting an adaptive physiological response. Sensory evaluation revealed that C. racemosa cultured at pH 8.25 achieved the highest overall acceptability, supporting its potential for culinary and nutritional use. These findings highlight the capacity of C. racemosa to acclimate to acidified environments, providing insights into its adaptive mechanisms and applications in food, pharmaceuticals, and sustainable aquaculture.
Continue reading ‘Impact of seawater acidification on the growth, nutritional composition, sensory profile, and antioxidant activity of Caulerpa racemosa in laboratory culture’Environmental stressors interplay with top-down and bottom-up effects upon shell structure and function of an intertidal marine snail
Published 17 November 2025 Science ClosedTags: biological response, calcification, growth, laboratory, mesocosms, mollusks, morphology, multiple factors, physiology, predation, South Pacific, temperature
Highlights
- Environmental stressors affect shell properties varied across the trophic network.
- OA, OW and predator cues, reduced snail’s shell growth and calcification.
- OA and OW influenced shell structure and resistance more than predator risk.
- Food quality modulates periostracum organic content under OA and OW conditions.
- Biopolymer plasticity aids shell resistance, reducing climate stress vulnerability.
Abstract
Mollusc gastropods have evolved complex shells to protect their soft tissues from biotic and abiotic stress, but the impact of biological and environmental interactions on shell properties is not well understood. This study assessed how the individual and combined effects of increased temperature and pCO2 affect the structural and functional properties in shells of the intertidal snail Tegula atra, considering predator risk from the crab Homalaspis plana and changes in the nutritional quality of its food source, the brown kelp Lessonia spicata. Ocean acidification (OA) and ocean warming (OW) significantly affected growth rate and calcification of snails, with greater impacts under predator risk (top-down) than food quality (bottom-up) influences. FTIR-ATR analyses of the organic composition of shell periostracum indicated that OA conditions increased total organic matter, while polysaccharides, and carbonate content signals showed complex interactive effects under OA and OW conditions, with minor predator cue effects, while the nutritional value of the food source alters polysaccharides and lipids signals. Functional properties (resistance) of the shell material were affected by OA, OW, and predator cues but not by food quality source. These findings provides a novel understanding of how interacting climate stressors and trophic dynamics shape the structural (biomineralization) and functional (biomechanical) resilience of intertidal gastropods.
Continue reading ‘Environmental stressors interplay with top-down and bottom-up effects upon shell structure and function of an intertidal marine snail’Pacific Islands lead global push on ocean acidification
Published 14 November 2025 Media coverage ClosedTags: South Pacific
A Pacific Island researcher collects ocean samples from a coral reef to monitor changes in seawater chemistry — a scene from “Changing Waters: Time for Action on Ocean Acidification.” Image courtesy of the International Alliance to Combat Ocean Acidification (OA Alliance).
Pacific Island regional scientists and policy makers are featured in the upcoming short film, “Changing Waters: Time for Action on Ocean Acidification,” highlighting regional leadership on climate-ocean science and solutions.
Pacific Island nations are taking centre stage at the United Nations Framework Convention on Climate Change Meeting COP30 with the premiere of “Changing Waters: Time for Action on Ocean Acidification,” a short film that showcases how Fiji and the broader Pacific Island region are leading global efforts to address one of climate change’s invisible threats.
The short film “Changing Waters: Time for Action on Ocean Acidification,” produced by the International Alliance to Combat Ocean Acidification (OA Alliance) and LUMA Studio, will premiere at the Moana Blue Pacific Pavilion on November 17 at 5 pm, with a virtual screening available through the Virtual Ocean Pavilion on November 19 at 12 pm (Belém time).
Ocean acidification – caused by the ocean absorbing carbon dioxide from the atmosphere – may affect Pacific coral reefs, shellfish, fisheries, and the livelihoods of those who depend on healthy ocean ecosystems for food security, storm protection, and income.
Yet, as the film reveals, Pacific Island communities are not just witnessing these changes; they are pioneering solutions that combine local science with local practice.
Filmed in Fiji, Colombia, and Washington State, “Changing Waters: A Time for Action on Ocean Acidification” uses personal storytelling and on-the-ground projects to highlight ocean acidification science and policy leadership around the world.
The Fiji segment showcases how island nations are advancing local monitoring, ecosystem restoration, and policy advocacy — demonstrating how applied ocean acidification science can be integrated across broader climate policy.
“We in the Pacific contribute very little to carbon emissions, yet we are at the forefront of the impacts of climate change. Monitoring and research allow us to make informed decisions, now and for generations to come,” said Katy Soapi, Coordinator of Partnership and Engagement at the Pacific Community.
From traditional ecological knowledge to ocean monitoring networks, Pacific Island nations have become a model for integrating local expertise with scientific research and domestic policies.
Ocean acidification is a consequence of carbon emissions, and addressing it is central to global climate action, marine governance, and equity. Yet many regions around the world still lack scientific, policy, and financing support in responding to acidification at the local level.
Climate refugia could disappear from Australia’s marine protected areas by 2040
Published 3 November 2025 Science ClosedTags: chemistry, modeling, policy, regionalmodeling, South Pacific
Abstract
Climate change manifests in the ocean as chronic stressors, including warming, acidification and deoxygenation, and as acute stressors such as marine heatwaves. While marine protected areas (MPAs) are often designed to mitigate local stressors such as fishing and mining, their design seldom considers climate change. Using the Australian marine estate as a case study, we use projections from 11 CMIP6 Earth System Models to assess the climate exposure of Australian waters, and implications for the MPA network. We find that, under scenarios that exceed 1.8°C of global surface warming this century, ocean climate is projected to surpass recent variability (1995–2014) from mid-century. This results in the disappearance of climate analogs—where future ocean conditions remain within recent variability—and of climate refugia—regions with slowest rates of environmental change, most likely to retain biodiversity—by 2040. Australian MPAs and unprotected areas exhibit similar patterns of exposure to warming, acidification, deoxygenation, and marine heatwaves, suggesting that MPA placement with respect to future climate is no better than random. Despite potential re-emergence of climate refugia after 2060 under lower-emissions scenarios, continued emissions under current Nationally Determined Contributions (SSP2–4.5) risk ecosystem collapse from chronic and acute thermal stress across protected and unprotected waters. While cutting emissions can partially cap or delay climate impacts, even under lower-emissions scenarios, effective conservation requires adaptive strategies that protect biodiversity in place and on the move.
Plain Language Summary
Marine protected areas (MPAs) are designed to safeguard ocean biodiversity from threats like fishing, but their design rarely considers climate change impacts. We assessed the future exposure of Australia’s MPAs to climate change using projections of ocean climate. Our findings reveal that if global surface warming exceeds 1.8°C this century, Australian marine ecosystems will face entirely novel ocean conditions beyond recent historical variability (1995–2014) by mid-century. This results in the Australia-wide disappearance of regions with slowest rates of climate change—climate refugia—representing a substantial threat to marine biodiversity. Our results suggest that MPAs are no better off than unprotected areas, facing the same risks from warming, acidification, deoxygenation, and marine heatwaves as unprotected waters. We found that reducing emissions could facilitate the reappearance of some climate refugia after 2060, but continuing along current emissions trends risks ecosystem collapse from warming throughout Australia’s protected and unprotected waters. Effective marine conservation requires both emissions reductions and adaptive strategies to protect biodiversity as species respond to a changing ocean climate.
Key Points
- Ocean climate in Australia will reach a climate horizon by mid-century, representing novel conditions beyond recent variability (1995–2014)
- Under global warming scenarios exceeding 1.8°C this century, climate refugia are projected to disappear from Australian waters by 2040
- Existing MPAs and unprotected areas exhibit equivalent patterns of exposure to multiple ocean climate metrics, suggesting a lack of climate-smart design
