Invasive macroalgae reduced P. oceanica seedling biomass and leaf development.
Macroalgal invasion depleted carbohydrate reserves in seedling roots and rhizomes.
Elevated CO2 increased rhizome starch but did not mitigate invasion impacts.
Root microbiome diversity declined markedly under macroalgal invasion.
Future CO2 enrichment unlikely to buffer invasion stress at recruitment stage.
Abstract
Seagrass seedlings are key to meadow recovery under global change, as they enable recolonization of degraded areas and provide genetic variability needed for adaptation. While invasive macroalgae increasingly threaten seagrass communities, elevated CO2 has been proposed to enhance seagrass performance and potentially buffer other stressors. Here, we conducted a mesocosm experiment to test the combined effects of two invasive macroalgae (Lophocladia trichoclados and Caulerpa cylindracea) and elevated CO2 on Posidonia oceanica seedlings. CO2 enrichment increased carbohydrate reserves in rhizomes and induced subtle shifts in root-associated microbiomes. In contrast, invasive macroalgae had consistently negative effects on seedling development and physiology and strongly altered both above- and belowground microbial communities. Despite its potential to stimulate seagrass productivity, elevated CO2 did not mitigate the detrimental impacts of invasive macroalgae. These findings indicate that future CO2 conditions may not offset invasion-driven stress at the recruitment stage, highlighting the need for targeted management efforts to limit macroalgal proliferation and support seagrass meadow regeneration.
Ocean acidification threatens coral reefs by reducing seawater pH and carbonate saturation state. Crustose coralline algae are particularly vulnerable because their high-magnesium calcite skeletons dissolve more readily than coral aragonite skeletons. However, this dissolution may increase alkalinity and buffer reef-water chemistry. Here we show, using repeated low-tide observations and in situ incubations in a shallow reef system in the southern Great Barrier Reef, that reef-water pH varies by more than one unit over the day (7.47 – 8.61), reaching levels comparable to those projected for the end of this century. Nighttime respiration promotes dissolution of high-magnesium calcite produced by crustose coralline algae, increasing alkalinity and helping maintain seawater supersaturated with respect to aragonite. At the same time, isolated coral incubations experience a greater decline in pH and aragonite saturation state in the absence of this buffering effect. These findings suggest that high-magnesium calcite-producing communities may help partially buffer reefs against future acidification.
More than a dozen Mendocino County schools will be hosting a new program providing students an opportunity to learn about their ocean environment as well as a unique art experience. The students will be dyeing fabric using purple sea urchin spines.
Workshop student, Sarah Burstein of Arcata, looks at live sea urchins in salt water, during a sea urchin natural dye workshop taught by Margaret Seelie, at Fibershed Learning Center in Pt. Reyes, Saturday, July 25, 2026. (Darryl Bush/For The Press Democrat)
The workshops, presented by Seelie Studio of Oakland, include an educational component that addresses the need to harvest vast numbers of the overblown populations of purple sea urchins because they are decimating the California kelp forests.
Bay Area artist Margaret Seelie is the founder and head dyer at Seelie Studio. She was introduced to natural dye through a fun wine and crafts evening.
Margaret Seelie, founder of Seelie Studio, looks at a purple sea urchin while wearing a light pink beanie dyed with sea urchin pigment, during her sea urchin natural dye workshop at Fibershed Learning Center in Pt. Reyes, Saturday, July 25, 2026. (Darryl Bush/For The Press Democrat)
“I went to a friend’s art studio one night for this, you know, like wine and crafts thing,” she said. “A woman brought indigo dye and I indigo dyed a pillowcase and that was the beginning of the end for me. I loved it. That’s when my infatuation with plant and nature-based dyes began.”
She said she began dyeing everything she could get her hands on using the indigo plant. “That just became my medium,” she said.
Live purple sea urchins are shown in front of a jar of liquid containing sea urchin pigment as Margaret Seelie, founder of Seelie Studio, teaches a sea urchin natural dye workshop at Fibershed Learning Center in Pt. Reyes, Saturday, July 25, 2026. (Darryl Bush/For The Press Democrat)
Discovering purple urchins
In 2022, Seelie learned that sea urchins had eaten around 95% of the kelp forest off the California coast. The urchin populations are so out of control from a lack of predators that a whole movement has been created around the need to harvest as many sea urchins as possible in order to bring down their populations and give the kelp beds a chance to revive. That stuck with her and informed her path toward a unique new business that help increase the harvesting of sea urchins while also educating the public to the problems their overpopulation poses.
A chance encounter inspired that new altruistic venture. She was doing natural dyeing for Santa Cruz surfer and shaper Ashley Lloyd’s line of beachwear called Unfurling. Through Lloyd she met Noyo Harbor Master Anna Neumann who was making dye from sea urchins.
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“I met Anna and I was just totally enamored of the fact that she was doing this work and then also her as a person,” Seelie said. “She’s a total badass, she’s a fisherwoman. Growing up on boats myself, I know it’s not the most glamorous place to be at times, so I just thought she was a great grace.”
Inspired by the colors Neumann was creating, Seelie decided to see if she could figure out how to coax color from these incredible creatures. “With my background as a natural dyer and environmentalist, I used my understanding of how a shift in Ph levels can create strong bonds between dye and fabric, but also how it can disrupt and break down calcium carbonate in marine animals.”
She was trying to figure out how to get the sea urchins to experiment with when she was left a gift by the sea. She had been surfing down south and a king tide left the sand covered with sea urchins. “I filled an empty water bottle with dried spines and urchin bits and I brought them back to San Francisco and made sea urchin dye in my kitchen,” she said.
That would inevitably be the start of a new direction for Seelie. Up to this point she had been doing production natural dye work for clients on the side while working a tech job. But in January of 2023 she was caught up in a large wave of layoffs. She decided to found Seelie Studio, based on her work with urchin dye.
Spines and shells from the purple sea urchins contained in a jar are later ground into powder to form the dye, are shown as Margaret Seelie, founder of Seelie Studio, teaches a sea urchin natural dye workshop at Fibershed Learning Center in Pt. Reyes, Saturday, July 25, 2026. (Darryl Bush/For The Press Democrat)
So far, all of the sea urchins she’s been using have been from kelp restoration projects, which helps to fund those projects. She said they haven’t needed that many for their educational workshops. But now she’s working on launching the world’s first urchin dye kits which will require a lot more sea urchins. She’s currently in talks with divers and organizations to determine who she will be using for urchins going forward.
Seelie said her goal from day one was to try and create incentive for people to want urchins and the infrastructure to make them available. “So it’s a really exciting moment to finally need a lot of urchins, because there’s a lot of them,” she said.
Once Seelie receives sea urchins, she takes them to her studio in Oakland to process them.
“They go from a live animal to a purple spines,” she said.
Teaching others
For the urchin dye workshops she hosts she includes an educational component about the overpopulation of sea urchins and the decimation of the kelp forests off the California coast. Seelie said the urchins provide an opportunity for many satellite lessons that are rich with material. She said the urchin dye itself is both a chemistry and an ecology lesson because the sea urchin dye is actually a version of ocean acidification.
“So it’s really exciting because you get to see this sort of accelerated breaking down process of the calcium carbonate,” she said. “Sea urchin shells and spines are made of calcium carbonate. When you create the dye with them, the calcium carbonate breaks down and releases the color.”
Seelie said it’s very similar to what happens when ocean acidification happens. “The pH of the ocean changes due to warming and the change in the pH of the ocean creates an inhospitable environment for animals with shells, and they basically can’t grow shells that are strong and hard enough to survive,” she said. “There’s a lot of lessons around the sea urchin dye, but to me, I think that is kind of the most magical and impactful because you’re seeing this happen.”
Global warming has caused a rise in ocean temperature and acidification, which collectively wreak havoc on marine animals. However, the combined ramifications of these stressors on energy metabolism, oxidative balance, and DNA integrity remain inadequately studied in teleosts. The present study aims to unravel the combined effects of warming (34°C) and acidification (pH 7.7) on energetic balance, antioxidant defense, and DNA stability in Mystus gulio at two intervals (15th and 45th day). Furthermore, the Effect Addition model was used to disentangle potential additive or non-additive effects of the combined stressors. Elevated temperature and acidification induced a marked energetic imbalance, as mirrored by suppressed ingestion and absorption rates, reduced scope for growth, and elevated excretion. Oxidative stress biomarkers revealed significant upregulation of SOD, CAT, and GST under combined treatment, which ultimately led to augmented lipid peroxidation. Genotoxic assessment delineated progressive upsurges in tail DNA (%) and olive tail moment, indicating compromised genomic stability. The integrated biomarker response consisted of six parameters, RR, ER, SOD, CAT, GST, and LPO, further corroborating that elevated temperature, alone and in combination with acidification, posed the highest cumulative physiological burden. Furthermore, the model assessment indicated that the interaction between warming and acidification varied among different biomarkers. Collectively, these findings corroborate that concurrent thermal and low pH perturbations destabilise physiological processes, oxidative instability, and DNA damage, which may undermine growth potential and jeopardise population structure and destabilise trophic relationships. The present study provides a mechanistic understanding of the impacts of multiple stressors and offers a robust integrative framework to predict fish vulnerability under future climate-driven oceanic vicissitudes.
Ocean warming and coastal acidification often co-occur in nearshore embayments, yet their joint associations with zooplankton remain difficult to characterize because responses are frequently nonlinear and spatially heterogeneous. In this study, we developed an integrated quantitative framework for characterizing joint warming-acidification exposure in Jiaozhou Bay. Based on six cruises conducted at nine stations in May (spring) and August (summer) from 2022 to 2024, we characterized zooplankton communities using abundance, biomass, Shannon-Wiener diversity (H′), and Pielou’s evenness (J). We further introduced a joint-exposure indicator, the Acid-Heat Vector Intensity Index (AHIvec), which summarizes joint temperature-pH departure based on standardized anomalies of temperature and pH. Generalized additive models (GAMs) were then applied to examine nonlinear response patterns and zone-specific associations between environmental gradients and zooplankton community attributes. Within the 2022–2024 observation window, sea surface temperature was generally higher in 2024 than in 2022, whereas surface pH was generally lower; however, these patterns should be interpreted as short-term observations rather than formal long-term trend estimates. Zooplankton also showed pronounced spring-summer and spatial variability. Notably, abundance showed pronounced temporal variation and generally increased with temperature, whereas biomass peaked at intermediate temperatures (∼20–22 °C) and declined thereafter, indicating a mismatch between abundance and biomass. Although pH-related associations were weaker than temperature-related associations, they became more evident at the lower end of the observed pH range (approximately 7.7–7.9). The AHIvec gradient was associated with contrasting zone-specific patterns in zooplankton community attributes. Overall, recent temperature-pH variations were associated with changes in zooplankton abundance, biomass, and diversity in Jiaozhou Bay. The AHIvec + GAM framework provides a monitoring-oriented complement to direct temperature-pH analyses for characterizing joint exposure in coastal ecosystems.
Genome-wide data revealed a mahimahi evolutionary history shaped by vicariance, ocean currents and local environments, needing models, functional genomics and selection tests for climate adaptation
This study examined the worldwide population structure of the cosmopolitan pelagic fish Coryphaena hippurus using a dataset of 8.7 million SNPs and complete mitochondrial genomes. The analyses reveal, for the first time, four genetically distinct populations corresponding to the major oceanic basins: the Atlantic, Pacific, Indian Ocean and Mediterranean Sea. Photo of Atlantic mahimahi by NOAA Fisheries.
The processes that generate and sustain marine biodiversity are still incompletely understood, especially in open-ocean systems where high dispersal potential is expected to prevent strong population differentiation. Understanding how evolutionary forces shape divergence or speciation in such environments requires detailed knowledge of a species’ life history and its interactions with key environmental variables.
In a study by Píndaro Díaz Jaimes and coworkers – at the Universidad Nacional Autónoma de México, the Tecnológico de Monterrey, and the Instituto Politécnico Nacional in Mexico; Universitat Pompeu Fabra in Spain, and the University of Palermo in Italy – the authors applied a genome-wide approach to examine the global population structure of the cosmopolitan pelagic dolphinfish or mahimahi (Coryphaena hippurus), an important commercial species. A comprehensive dataset comprising 8.7 million single-nucleotide polymorphisms together with complete mitochondrial genomes was generated during this research.
The analyses reveal, for the first time, four genetically distinct populations that correspond to the major oceanic basins: the Atlantic, Pacific, Indian Ocean and Mediterranean Sea. The Mediterranean population carries a unique genomic signature, most probably reflecting historical isolation and limited contemporary gene flow through the Strait of Gibraltar.
Despite this clear inter-basin structure, genome-wide data also retain extensive signals of historical connectivity. Results of various tests show significant excess allele sharing (meaning that two groups of individuals carry the same version or allele of a particular gene or DNA segment), particularly between the Indo-Pacific and Atlantic groups. In addition, phylogenetic network analyses (drawing evolutionary relationships that allows for mixing between groups, not just simple branching) show multiple migration events. These results underline the lasting influence of ancestral gene flow on present-day genetic patterns.
At finer geographic scales, modest but statistically significant structure was detected within both the Atlantic and Pacific basins. Seascape genomic analyses (how genetic differences in marine species are linked to the environment around them) further demonstrate that environmental gradients – including salinity, phosphate concentration, pH and others – are significantly associated with genomic variation, indicating that ecological factors play a role in shaping population differentiation across heterogeneous marine habitats.
Fig. 1: Graphical summary of the study. Adapted from the original.
Relevance of research findings to the industry
For fisheries managers and the fishing sectors, the discovery of four basin-scale genetic populations is important. Stocks that look continuous on a map may in fact be demographically independent. Management plans that treat all dolphinfish as a single global unit risk over-harvesting one basin while under-utilizing another.
Knowing that Mediterranean fish are particularly distinct and that Atlantic and Pacific populations also show internal structure gives managers a clearer basis for setting regional catch limits, seasonal closures or size regulations. The environmental associations also hint that climate-driven changes in salinity or nutrient levels could alter population boundaries in the future, which both industry and regulators should monitor.
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Perspectives
This research demonstrates that even highly dispersive oceanic species can maintain meaningful genetic structure. Future studies should combine these genomic results with ocean-circulation models to assess how currents move larvae and adults between basins. Functional genomic approaches and tests for loci under selection would help identify which genes allow each population to cope with local conditions and with rapid environmental change.
Expanding sample sizes, especially from under-represented regions of the Indian Ocean and southern Pacific, would refine the picture further. Overall, the four genetic groups identified in this study provide a solid starting point for designing management units that better match the true biology of the species.
Modeling ocean acidification and warming effects on Atlantic Sea scallop growth for adaptive management
Results of this study show that warming stress is stronger than previously recognized, especially in the southern Mid-Atlantic, while ocean acidification appears first in the north. Together these stressors shrink the optimal growth range of sea scallops, showing the value of the spatially coupled DEB model for adaptive fisheries management. Photo of a sea scallop (Placopecten magellanicus) – which has over 100 blue eyes along the edge of its mantle to sense light intensity – by Dann Blackwood, USGS (Public domain, via Wikimedia Commons).
Effective climate-ready fisheries management depends on robust predictions of how species will respond to environmental change across broad spatial scales. Bioenergetic approaches such as Dynamic Energy Budget (DEB) models link physiological processes to environmental conditions and can therefore forecast organismal growth under future climate scenarios.
In a recent study by Halle M. Berger and colleagues (University of Connecticut and NOAA Northeast Fisheries Science Center and Océanopolis in France) the scientists presented the first large-scale integration of a DEB model with downscaled regional oceanographic simulations. This coupling allows resolving spatiotemporal patterns and examine how climate stressors appear at biogeographic, economic and oceanographic scales that matter for management.
The researchers calibrated a DEB model for the Atlantic Sea scallop (Placopecten magellanicus) using output from a realistic oceanographic–biogeochemical model of the Northeast U.S. continental shelf. The model was used to project the combined effects of ocean acidification (OA) and warming on individual growth both historically and through the coming century. It successfully reproduced observed historical patterns in age at harvest size and maximum attainable size.
At mid-century (2035–2050), scallop growth was projected to increase across most of the region, with the exception of the southern Mid-Atlantic; OA effects remained confined to the deep Gulf of Maine. By the end of the century (2080–2095) under a high-emissions scenario, scallops were expected to grow more rapidly yet reach smaller maximum sizes. The results indicate that warming stress is more severe than previously recognized, especially in the southern Mid-Atlantic. Warming impacts appear first in the south, whereas OA stress precedes warming in the north.
Overall, together these stressors progressively shrink the geographic area that supports optimal growth, and the results of this study demonstrate the value of a spatially explicit, climate-forced DEB model as a practical tool for guiding adaptive fisheries management.
Fig. 5: Mean (± SD) dry flesh mass (top row) and shell height (bottom) of experimental juvenile scallops exposed to low (503 microatm – the microatmosphere is a unit of pressure equal to one-millionth of an atmosphere – black symbols), moderate (805 microatm, yellow symbols), or high (1168 microatm; red symbols) pCO2 (data from Pousse et al. 2023) used to calibrate the model. In ocean science (especially ocean acidification studies), a microatm is the standard unit used to express the partial pressure of carbon dioxide (pCO₂) in seawater. Typical surface ocean values today are around 400–450 microatm. Adapted from, and with additional information in the original publication.
Relevance of research findings to the industry
For the scallop fisheries industry, the most immediate value of the work is its ability to flag which fishing grounds are likely to become less productive and which may temporarily improve. Southern mid-Atlantic beds face the earliest risk of slower growth and smaller maximum size, while some northern areas may see short-term gains before acidification becomes limiting. Processors, vessel operators and managers can use these regional signals when planning long-term investments, lease decisions or rotational closures.
The finding that animals may grow faster yet end up smaller also has direct economic consequences: smaller scallops command lower prices and may require changes in gear or processing methods. Because the model is spatially explicit, it can be updated as new climate projections or survey data become available, giving the industry a living tool rather than a one-time snapshot.
Perspectives
Results of this study demonstrate that linking bioenergetic models to regional ocean forecasts is both feasible and useful for climate-ready management. Future work could refine the food-supply component of the model, incorporate density-dependent effects, and assess additional emission scenarios. Expanding the approach to other shellfish or finfish would allow multi-species comparisons and more integrated ecosystem planning.
Managers should consider that waiting until declines appear in the catch is no longer necessary. The spatial patterns of stress are already projected; adaptive measures – such as shifting effort northward, adjusting size limits, or protecting residual high-growth habitats – can be designed now. Overall, the model developed provides a practical bridge between climate science and the day-to-day decisions that will hopefully keep the Atlantic Sea scallop fishery viable through the coming decades.
Genetic connectivity varies within basins, revealing hidden substructure.
Abstract
The origin and maintenance of marine biodiversity remain poorly understood, particularly in highly connected oceanic environments where extensive dispersal is expected to limit population differentiation. Evolutionary processes driving population divergence or speciation frequently depend on a proper knowledge of species’ life history and its interaction with major environmental variables. Using a genome-wide approach, we investigated the global population structure of the cosmopolitan pelagic fish Coryphaena hippurus Linnaeus, 1758, generating a dataset of 8.7 million SNPs and complete mitochondrial genomes.
Our results reveal, for the first time, four genetically differentiated populations, corresponding to major oceanic basins: Atlantic, Pacific, Indian and Mediterranean Sea. The Mediterranean population exhibited a distinct genomic signature, likely resulting from historical isolation and restricted contemporary exchange through the strait of Gibraltar. Despite this structure, genome-wide analyses uncovered extensive signals of historical connectivity among basins. D-statistics and f4-ratio tests detected significant excess allele sharing, particularly between Indo-Pacific and Atlantic populations, while phylogenetic network reconstruction in TreeMix supported multiple migration events, highlighting the role of ancestral gene flow in shaping global genetic patterns.
At finer scales, a limited but significant intra-oceanic structure was detected within both Atlantic and Pacific basins. Seascape genomic analyses revealed that environmental gradients such as salinity, phosphate concentration, light availability (PAR, Kd), and pH are significantly associated with genomic variation, suggesting that ecological factors contribute to population differentiation across heterogeneous marine environments.
Seawater carbonate system measurements in the Mediterranean Sea are relatively scarce, especially in its eastern basin. This study describes the monthly variations of carbonate system parameters in the open sea and coastal water column of the eastern Mediterranean Sea during the period February 2018 to January 2019. Water samples were collected for analysis of Total Alkalinity and pHT at the shallow coastal THEMO1 and the deeper open-water THEMO2 (1,500 m bottom depth) stations off the Mediterranean coast of Israel. In the surface layer (<25 m), TA increased with salinity at a rate of +72 μmol·kg−1 and the pCO2(SW) was strongly and positively correlated with temperature. During summertime, surface waters were highly super-saturated with respect to atmospheric pCO2 (pCO2(SW) ∼ 600 μatm), while during winter they were only slightly super-saturated. The estimated net annual CO2 flux from the surface of the eastern Mediterranean Sea to the atmosphere during the study period was +2.8 Tg C·y−1, which is three times greater than a previous estimate made for this region (0.9 Tg C·y−1), and is attributed to the smaller volume of Atlantic water input in the present study compared to the previous one as well as the substantially shallower total dissolved inorganic carbon enriched core of the Levantine Intermediate Water in this study. Based on these results, it is still expected that future warming and salinization, reduced Atlantic Water influx to the eastern Mediterranean Sea, and increased stratification will increase the flux of CO2 to the atmosphere in this region.
Plain Language Summary
This study investigated annual variations in atmospheric CO2 flux from the surface of the eastern Mediterranean Sea based on monthly seawater sampling and carbon chemistry analyses conducted at two locations off the Mediterranean coast of Israel from February 2018 to January 2019. The results indicate that the southeastern Mediterranean Sea was a net source of CO2 to the atmosphere. This behavior was largely driven by seasonal changes in seawater temperature, which controls the saturation concentration of dissolved CO2 in seawater. During summer months, warm surface waters were a strong source of CO2 to the atmosphere, while during winter they were a weak sink. The study estimates that approximately 2.8 million tons of carbon were released annually from the sea to the atmosphere during the study period. This revised and more comprehensive estimate is ∼3 times higher than previous estimates reported for the same region. The increase is suggested to result from recent changes in regional circulation, particularly a reduced inflow of Atlantic Ocean waters into the eastern Mediterranean Sea. Based on these findings, continued warming, increasing salinity, and enhanced stratification of the eastern Mediterranean Sea are expected to further intensify CO2 release to the atmosphere in the future.
Low salinity linked to warming may intensify coastal pH reduction.
Low salinity reduced righting and emergence in the limpet Patelloida pygmaea.
Low salinity reduces Mg/Ca ratios in newly formed shell layers.
Low pH increases shell thickness and Mg/Ca ratios despite dissolution.
CHS2 upregulation suggests compensatory resistance to low pH.
Abstract
Rising anthropogenic carbon dioxide emissions have driven ongoing ocean warming and associated climate changes. In the Yellow Sea, this warming is associated with enhanced monsoonal rainfall, which increases freshwater inputs and lowers coastal salinity. Increased freshwater input can weaken seawater buffering capacity, thereby leading to lower pH conditions in coastal environments. Here, we examined the effects of low pH and low salinity on the intertidal limpet Patelloida pygmaea. Adult limpets were exposed for 31 days to four experimental artificial seawater conditions combining two pH levels (8.0 and 7.5) and two salinity levels (30 and 21 psu). Survival and condition factor were not influenced by pH or salinity. However, low salinity reduced righting and emergence behavior. In addition, the Mg/Ca ratio in the M + 1 layer was lower at 21 psu than at 30 psu. Low pH resulted in a thicker M + 2 layer with higher Mg/Ca ratios despite shell dissolution, potentially helping to maintain shell integrity. While there was no change in heat shock protein (HSP70) expression, these shell modifications were accompanied by an upregulation of chitin synthase (CHS2) genes under low pH. These findings suggest that P. pygmaea is negatively influenced by low pH and low salinity, but also demonstrate compensatory mechanisms that enhance resistance to low pH.
Talcott Mountain Academy | 7th grade | 12 years old
About the Idea
Meet Raji. Raji created an innovative coastal solution that uses algae and natural calcium buffers to lower ocean acidity and boost marine health
Why did you enter the 3M Young Scientist Challenge?
I entered the 3M Young Scientist Challenge because I wanted to do something real with my research. Studying ocean acidification in a classroom is one thing, but this competition gave me a reason to go further, to actually design an experiment, collect real data, and test whether my idea could hold up under scrutiny. I also entered because climate change feels urgent to me in a way that is hard to ignore. The oceans are absorbing carbon at a rate that is changing their chemistry, and that affects billions of people. I wanted to work on something that mattered, not just something that would earn a grade. The 3M Young Scientist Challenge specifically appealed to me because it is not just about having a good idea. It rewards students who communicate science clearly and think about real-world impact. That is exactly what I was trying to do with this project.
What is your favorite invention of the last 100 years, and why?
My favorite invention of the last 100 years is the autonomous underwater vehicle (AUV), such as those developed by organizations like Saildrone and the Woods Hole Oceanographic Institution. These AUVs (like Saildrone’s carbon-neutral ocean drones) allow scientists to collect real-time data on ocean chemistry, pH levels, and CO₂ absorption in remote and challenging environments—critical for understanding and addressing ocean acidification. Their ability to operate autonomously for months at a time makes them game-changers for monitoring the health of our oceans.
In 15 years I hope to be…
In 15 years, I hope to be a NASA aerospace engineer designing systems that monitor ocean health and climate change from space. My research taught me that the most significant climate breakthroughs happen when different fields work together, and I want to build the tools that make that possible.
The Faculty of Science and Technology at The University of the West Indies (The UWI), Mona, officially launched the Water, Analytics, Tracing and Environmental Research (W.A.T.E.R.) Laboratory on June 5, 2026, in the Department of Chemistry which coincides with World Environment Day. The establishment of the laboratory represents a significant investment in interdisciplinary research aimed at improving the understanding, monitoring and sustainable management of freshwater, coastal and marine environments in Jamaica and the wider Caribbean.
The W.A.T.E.R. Laboratory is headed by Dr. Debbie-Ann Gordon-Smith, Lecturer in the Department of Chemistry, who also serves as its Research Lead. Her grantsmanship, research leadership and development of strategic partnerships were instrumental in securing the resources and institutional support required to establish the facility. Dr. Gordon-Smith’s research interests include water chemistry and pollution, coral reefs, ocean acidification, groundwater–surface water interactions, the use of radioactive and stable isotope tracers, and climate change. These areas of expertise guide the laboratory’s scientific direction and its efforts to address some of the Caribbean’s most pressing water and environmental challenges.
Photo caption: Dr. Debbie-Ann Gordon Smith.
The launch was attended by senior University representatives, researchers and key external stakeholders, including Dr. Donna Minott Kates, (then) Head of the Department of Chemistry; Professor Michael Taylor, (then) Dean of the Faculty of Science and Technology; Professor Marvin Reid, Deputy Principal of The UWI Mona; and Mr. Geoffrey Marshall, Deputy Managing Director of the Water Resources Authority. Also in attendance was Dr. Anthony Greenaway, Dr. Gordon-Smith’s graduate research supervisor, whose research interests span environmental pollution and industrial chemistry. His presence highlighted the importance of academic mentorship and the contribution of established researchers to the development of the next generation of Caribbean scientists.
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Advancing Water and Ocean Sustainability
The mission of the W.A.T.E.R. Laboratory is to generate high-quality scientific knowledge that supports the sustainable management of aquatic environments across Jamaica and the Caribbean.
Its research places particular emphasis on understanding biogeochemical processes, ecosystem health and the ways in which freshwater, coastal and marine environments respond to natural and human-induced pressures. Through field-based observations, laboratory analyses and regional monitoring initiatives, the laboratory will strengthen scientific capacity, support evidence-based policy and management decisions, and contribute to regional and global discussions on water and ocean sustainability.
Interdisciplinary Research with Regional Impact
Water pollution chemistry is a core research area of the laboratory. Its work examines nutrient dynamics, isotopic tracers, climate impacts and other environmental drivers of change within aquatic ecosystems.
Researchers at the laboratory use radioactive and stable isotope techniques to trace biogeochemical pathways, identify sources of nutrients and pollution, and examine the connections among groundwater, rivers, estuaries and marine environments. Coastal research focuses on the effects of land-based pollution and other environmental pressures on Jamaica’s vulnerable coral reef and mangrove ecosystems. The laboratory also conducts analyses of marine sediments to investigate historical geochemical processes and the long-term effects of climate change. Ocean acidification is another key and expanding area of research. This work includes assessments of carbonate chemistry, the monitoring of ocean-observing capacity, and the evaluation of ecological and biogeochemical responses to changing ocean conditions.
The laboratory is also conducting detailed assessments of major freshwater systems, including the Rio Cobre, Rio Grande and Black River. These studies examine hydrology, water chemistry, pollution, land–water interactions and the movement of water between groundwater and surface-water systems.
Collectively, these research areas support a more integrated understanding of how Caribbean aquatic environments are being affected by pollution, climate change and other natural and human-induced pressures.
Laboratory Tour Highlights Research Capabilities
The official opening also included a guided tour of the W.A.T.E.R. Laboratory, facilitated by two of Dr. Gordon-Smith’s research students, Mr. Andrew Green and Ms. Pearl Bergan.
During the tour, guests were introduced to the laboratory’s research facilities, equipment and analytical capabilities. The students also provided insight into the scientific techniques used to examine water quality, environmental pollution, aquatic chemistry and the movement of chemical and isotopic tracers through freshwater, coastal and marine systems. The tour provided attendees with an opportunity to see firsthand how the laboratory will support field-based research, laboratory analyses, student training and collaborative environmental monitoring initiatives.
Building the Next Generation of Scientists
In addition to advancing scientific research, the W.A.T.E.R. Laboratory provides an important platform for graduate training, undergraduate research and international scientific engagement.
The laboratory currently supports three locally based postgraduate students—Ms. Pearl Bergan, Mr. Andrew Green and Mr. Kadane Coates—as well as undergraduate students and international researchers.
Students are actively involved in fieldwork, laboratory analyses, data interpretation and collaborative research projects. Their participation contributes to local and international scientific outputs while building the technical expertise needed to address emerging environmental challenges.
The involvement of Mr. Green and Ms. Bergan in facilitating the laboratory tour also demonstrated the central role students will play in the laboratory’s research, public engagement and knowledge-sharing activities.
Strengthening Partnerships and Research Capacity
The W.A.T.E.R. Laboratory maintains strong local, regional and international partnerships that expand its research capacity and scientific reach. Local collaborators include the Water Resources Authority, the National Irrigation Commission and several non-governmental organisations. International partners include The University of Texas at Austin and the Georgia Institute of Technology in the United States; the Leibniz Centre for Tropical Marine Research in Germany; and Liverpool John Moores University, University College London, and the Centre for Environment, Fisheries and Aquaculture Science in the United Kingdom. These partnerships support knowledge exchange, capacity building, student development, shared research methodologies and comparative studies across diverse aquatic environments.
Through its research, training and partnerships, the W.A.T.E.R. Laboratory is positioned to become an important centre for aquatic and environmental research in the Caribbean. Its establishment further strengthens the Department of Chemistry and the Faculty of Science and Technology’s contribution to addressing some of the region’s most urgent water, climate and environmental challenges.
We have an exciting opportunity for an experienced and motivated Project Manager (Research and Impact Services Officer – RISO) to join Plymouth Marine Laboratory (PML) on a 1-year fixed-term appointment. This is a chance to play a hands-on role in delivering ambitious international marine and environmental research projects, working alongside world-class scientists and partners to help turn excellent science into real-world impact.
The successful candidate will work across two exciting EU- funded projects, including SAFESEA, a major international initiative focused on helping society understand, manage and adapt to the growing threat of ocean acidification. This is a fantastic opportunity to support science that will inform policy, strengthen climate adaptation and help protect marine ecosystems and the services they provide.
You will be at the heart of project delivery, helping to coordinate activities, keep partners connected, support reporting and evidence gathering, and make sure outputs are delivered to a high standard. You will need to be confident managing competing priorities, working independently and bringing people together across scientific, policy and stakeholder communities.
By joining the Integrated Research, Impact and Support Services (IRISS) group at PML, you will become part of a small, collaborative and agile team that plays a vital role in supporting excellent research and maximising its influence beyond academia. As a RISO, you will act as a key link between scientists, funders, partners and stakeholders, helping projects stay on track, on budget and focused on outcomes that matter.
A scientific background is desirable but not essential. What matters most is proven project management experience, excellent communication and organisational skills, and the confidence to support complex, collaborative projects with enthusiasm and attention to detail.
Plymouth Marine Laboratory (PML) is a dynamic, innovative, and independent centre of excellence providing research and advice on coastal and ocean science, both globally and locally. As a registered charity and NERC Collaborative Centre, PML has been at the forefront of the UK’s strategic marine science capability for over 30 years, collaborating with universities and research institutes across the UK and around the world.Key Deliverables
Manage delivery of research projects where PML is lead partner or co-partner, ensuring activities, milestones, deliverables and reporting requirements are completed to a high standard and on time.
Monitor project schedules, work plans and budgets, including partner expenditure and financial records, to support effective delivery and compliance with funder requirements.
Act as a key point of contact between funders, steering committees, project partners, third parties and scientific management teams, ensuring information is shared clearly and promptly.
Support Principal Investigators by coordinating meetings, maintaining project documentation, preparing reports and recording accurate minutes and actions.
Lead the organisation of project meetings and external events, including those involving senior stakeholders, partners and policy audiences.
Support the generation, monitoring and evidencing of research impact, including impact pathways, case studies, award nominations and contributions to the PML Impact Strategy.
Contribute to IRISS through effective communication, knowledge sharing, process improvement and input to group strategy.
Work closely with internal PML teams, including Science Areas, Communications, Finance and Contracts, to ensure joined-up project delivery.
Develop and maintain stakeholder and contact databases, ensuring appropriate data management and adherence to GDPR.
Support innovative approaches to stakeholder and policy mapping, including tracking opportunities to maximise impact through government inquiries and consultations.
Support broader IRISS activities, including funding proposal development, research impact monitoring and reporting, stakeholder engagement, and continuous improvement of research support processes.
Skills Specification
Project management and delivery: Proven project management experience, preferably on European Commission-funded projects such as Horizon Europe, with the ability to manage several concurrent projects, respond to shifting priorities and meet deadlines under pressure.
Funding and reporting: Experience of working with major research funders such as ESA, Horizon Europe and UKRI, including project reporting and supporting proposal preparation.
Financial and administrative oversight: Proven ability to manage and work to budgets, and to handle different types of project information, including scientific, financial and legal material.
Communication and collaboration: Excellent written and verbal communication skills in English, with experience of working with overseas partners and drawing together diverse stakeholder groups.
Events and engagement: Experience organising conferences, events or large meetings, and supporting stakeholder engagement activity.
Research impact: Experience of research impact approaches, including generating, monitoring and evidencing impact.
Personal effectiveness: A proactive approach, strong initiative and the confidence to drive projects forward, encourage others and seek support when needed.
Travel: Willingness to travel internationally as required for project meetings and events.
Applicant Information
Interviews for this position will be on the 15th and 16th of September; as part of the interview, candidates will be asked to present for 5 minutes on “Managing Projects for Impact: Priorities, Evidence, and Partner Challenges”.
This is a 1 year fixed term appointment.
Our preference is to appoint a candidate on a full-time basis to provide continuity, consistency and maximise the impact of the role. We welcome applications from individuals seeking flexible working arrangements. We are committed to considering requests for alternative working patterns in line with business needs and applicable employment legislation, and encourage candidates to discuss any flexibility requirements with us.
You can find out more about working at PML here and view our company benefits here.
For more information about living and working in Plymouth please click here.
Please note that this position is a Hybrid role that will require at least 50% of the jobholder’s time to be spent in our Offices. We are not able to support fully remote working for this role.
If you have any questions about this position, please email careers@pml.ac.uk.
Information about using AI in job applications can be found here. Using AI outside of these boundaries may negatively affect your chances of progressing in the recruitment process
PML is a Disability Confident employer, and we have recently attained the Investors in Diversity Silver accreditation. We are committed to promoting a diverse and inclusive culture, where all can succeed based on merit, and will provide any reasonable adjustments required to enable this. To support staff from all backgrounds, we offer a range of family-friendly and inclusive employment policies, flexible working arrangements and staff engagement forums.
Ocean acidification, largely driven by the uptake of anthropogenic carbon dioxide, is reflected in a sustained decline in seawater pH. This paper examines the dynamics of surface-ocean pH at Station ALOHA over the period 1985–2024 using fractional integration methods, which allow for a flexible characterisation of persistence and trend behaviour. The differencing parameter is estimated under alternative assumptions concerning the error term, namely white-noise and autocorrelated Bloomfield disturbances, and recursive estimation is used to assess the evolution of the relevant parameters over time. The results show a negative and statistically significant time trend in both the original and logged pH series. The estimates of the differencing parameter are positive and significantly different from zero in all cases, providing evidence of long-memory behaviour. Under white-noise errors, the estimate of the differencing parameter is 0.89 and the unit-root hypothesis cannot be rejected, whereas allowing for autocorrelation yields an estimate of approximately 0.55, implying mean reversion with long-lasting but transitory effects of shocks. Recursive estimates further indicate that both persistence and the magnitude of the negative pH trend have increased over time. These findings suggest that pH dynamics at Station ALOHA are characterised by a persistent decline and slow adjustment following disturbances, highlighting the importance of long-term ocean monitoring and modelling approaches that account for fractional dependence. Nevertheless, the results should be interpreted with caution because the analysis is based on a single long-term record combining observational and reconstructed data.
Ocean acidification (OA), driven by atmospheric carbon dioxide (CO2) emissions, significantly impacts marine organism. This study investigated OA effects on retinal structure and function in marine medaka (Oryzias melastigma) across life stages under controlled CO2 exposures (450 × 10−6, 1 000 × 10−6, and 1 800 × 10−6). Quantitative analyses revealed concentration-dependent retinal pathology, with larval incidence rising from 16.7% (450 × 10−6) to 50.0% (1 800 × 10−6). Significant structural alterations include progressive pigment epithelium thickening and concurrent atrophy in inner plexiform and ganglion cell layers. Electrophysiological recording demonstrated severe neural hyperexcitability, with larval and adult fish showing 91.3% and 154.9% increased firing counts respectively at 1 800 × 10−6. Behavioral analyses revealed significant CO2-induced locomotor dysfunction with distinct light-dependent patterns. Under illumination, larvae exhibited hyperactivity at 1 800 × 10−6, while adults showed progressive impairment (high-performance swimmers declining from 60% to 37.5%). Conversely, dark conditions intensified activity across concentrations, with adults displaying dose-dependent increases in swimming speed (23.5% to 68.8%). These results demonstrated that OA induces significant visual disruption and behavioral changes. The differential responses across life stages and light conditions suggest complex neurophysiological impacts that may have cascading ecological consequences for marine fish in acidifying ocean.
ISER is delighted to welcome you to the International Conference on Ocean Acidification and Shellfish Biology (ICOASB-26) at Kranj, Slovenia on 26th – 27th November 2026, . This event will bring leading scientists, academicians, industry professionals, speakers, and experts of to one platform. The informative discussions will highlight solutions, achievements, trending issues, and future strategies.
ISER constantly aims to present techniques, skills, and the latest information in various fields like science, technology, medical sciences, environment, education, business, banking, finance, languages, history, and much more. It helps participants to explore speaking opportunities, present their unique ideas and create significant connections. You can participate in the groundbreaking discussion, which welcomes active participation and benefits the field and humankind. So, enhance your personal and professional journey by attending the upcoming event.
Submission Guidelines
Please follow these submission guidelines for a smooth procedure related to proffering papers.
The official language of all the conferences and papers is English. Therefore, the paper must be written in English, which must be straightforward and free of grammatical errors
Our Review Process
All the successfully submitted papers will be assessed by the Program Chair, who will initiate the peer review process. Then, the Program Chair will designate at least two suitable technical committee members (Reviewers) with ample field knowledge. After a thorough review, the comments will be submitted to the Program Chair personnel, who will make the final decision about submitting the paper.
Finally, the conference secretary will inform the concerned authors about the decision. The papers which are not accepted will be sent back for revision, and those that pass the second review will be accepted.
Note: Please check your email regularly during the review process.
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Peer Review Process
Empowering Education for a Resilient Future
ISER is dedicated to transforming education to meet the challenges of a rapidly changing world. By connecting researchers, educators, and institutions, ISER creates collaborative platforms that foster innovative solutions in education. The organization focuses on advancing inclusive learning, digital transformation, and sustainable educational practices. Through its work, ISER drives progress toward building resilient, equitable, and knowledge-driven communities, where education empowers future generations to thrive.
By advancing SDG 4: Quality Education, ISER ensures equitable access and improved learning outcomes for all. Its initiatives in digital transformation also support SDG 9: Industry, Innovation, and Infrastructure, enhancing the infrastructure for sustainable digital learning. ISER’s focus on inclusive education contributes to SDG 10: Reduced Inequality, promoting equal opportunities for marginalized communities. Through sustainable practices in education, ISER drives progress towards SDG 13: Climate Action
Ocean acidification may positively affect seagrasses, although the response of the early life stages remains generally unknown. This study investigated the effect of OA and seed origin on the viability, morphometry, and chemical content of Cymodocea nodosa seedlings, using a field experiment along a natural-low pH gradient created by submarine vents in Vulcano Island, Italy. After four months of exposure, seedlings under increased pCO2 showed a reduction in the viability but a higher development exhibiting a lower C leaf content, independently of their origin. Results indicate compensating responses which may favour the plant acclimation in early life stages to future acidification scenarios.
Spatial distribution of global surface ocean pH trends from 1985 to 2024 Credit: Earth-Science Reviews (2026). DOI: 10.1016/j.earscirev.2026.105623
When most people hear the phrase “ocean acidification,” they think of coral reefs, shellfish or declining fisheries. Those concerns are real. But while working on our recent research, I found myself asking a different question: What if ocean acidification is telling us something much bigger than the health of marine ecosystems?
The more we examined geological records, marine chemistry and Earth-system feedbacks, the more one idea became impossible to ignore. Ocean acidification is not simply a modern environmental problem. It is becoming a planetary-scale signal that records how human activities are altering Earth’s long-term carbon cycle.
Once we began viewing it from this perspective, the ocean no longer appeared as a passive victim of climate change. Instead, it emerged as an active archive that stores information about our civilization for thousands—perhaps even hundreds of thousands—of years. “That realization completely changed how we think about the future of our planet,” Dr. Das says. The research is published in the journal Earth-Science Reviews.
Most discussions focus on what happens near the ocean surface. Carbon dioxide released from burning fossil fuels dissolves into seawater, forming carbonic acid. Since the Industrial Revolution, average surface ocean pH has declined by about 0.1 units, representing roughly a 30% increase in hydrogen ion concentration. Although that numerical change seems small, it fundamentally alters marine carbonate chemistry and reduces the availability of carbonate ions needed by countless marine organisms to build shells and skeletons.
Ocean acidification as a planetary signal, showing how rapid atmospheric CO₂ forcing cascades through ocean chemistry, deep-ocean circulation, sedimentary buffering, and lithospheric feedbacks, imprinting long-lived Earth system memory far beyond human timescales. Credit: Earth-Science Reviews (2026). DOI: 10.1016/j.earscirev.2026.105623
Das says, “These biological consequences have been studied extensively. Yet they represent only the beginning of a much larger story.”
The ocean is not an isolated body of water. It is tightly connected to the atmosphere, deep-sea sediments and Earth’s crust through an intricate network of chemical exchanges that operates over vastly different timescales. Surface waters communicate with the deep ocean through global circulation. Sediments continuously exchange minerals with seawater. Continental rocks slowly weather and eventually replenish the ocean’s alkalinity. Together, these processes regulate Earth’s carbon cycle over thousands to millions of years.
“Our study argues that ocean acidification should be viewed within this entire Earth-system framework rather than solely as a biological stressor.”
One concept became particularly important throughout this work: Earth system memory. Unlike human memory, which exists in our brains, Earth stores information inside rocks, sediments, ice and chemical signatures. Every major disruption of the carbon cycle leaves traces that future geologists can detect long after the original event has disappeared.
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Marine sediments are among the most remarkable examples of this planetary memory.
As acidic waters penetrate deeper into the ocean, calcium carbonate begins dissolving from seafloor sediments. The boundary separating carbonate preservation from dissolution, known as the carbonate compensation depth, gradually shifts upward. Over time, this movement leaves behind distinctive layers that permanently record changes in ocean chemistry.
These sedimentary archives preserve evidence of carbon-cycle disturbances for tens of thousands—or even millions—of years.
In other words, today’s emissions are already beginning to write a geological chapter that future civilizations, if they exist, could eventually read.
This long-term perspective naturally led us to Earth’s geological past.
The Paleocene–Eocene Thermal Maximum, which occurred approximately 56 million years ago, is often regarded as one of the closest natural analogs to modern carbon release. During that event, thousands of petagrams of carbon entered the atmosphere and oceans, triggering global warming, widespread ocean acidification and extensive dissolution of deep-sea carbonates.
First ever reinterpretation of ocean acidification as a planetary-scale signal encoding Earth system disequilibrium.
Links rapid surface pH decline to deep-ocean, sedimentary, and lithospheric memory.
Reveals a rate mismatch that overwhelms geological buffering despite modest pH magnitude.
Identifies CCD shoaling as the key integrator of short-term forcing and deep-time response.
Synthesis elevates ocean acidification to a diagnostic of long-term carbon cycle stability.
Abstract
Ocean acidification (OA) is widely recognized as a defining chemical signature of the Anthropocene ocean, yet it is still predominantly framed as a near-surface ecological stressor. Here, we advance a planetary-scale reinterpretation of OA as an information-bearing signal that links rapid anthropogenic carbon forcing to deep-time lithosphere–ocean geochemical interactions and long-lived Earth system memory. Observations since the late 20th century document a persistent, spatially heterogeneous decline in global surface-ocean pH, corresponding to a ∼30–35% increase in hydrogen ion concentration, driven by sustained air–sea CO2 uptake. Projected pH declines of 0.3–0.4 units by 2100 under high-emission scenarios imply rates of change at least an order of magnitude faster than most natural variations recorded in the geological archive. We synthesize carbonate system thermodynamics, carbonate compensation depth dynamics, sedimentary proxy evidence, and Earth system modeling to demonstrate how small, rapid surface perturbations propagate vertically, trigger widespread carbonate undersaturation, and imprint durable stratigraphic and geochemical signatures through sediment dissolution, altered burial fluxes, and delayed alkalinity restoration. Comparison with hyperthermal events, particularly the Paleocene–Eocene Thermal Maximum, reveals that the uniqueness of modern OA lies not in magnitude alone but in an unprecedented rate mismatch that overwhelms geological buffering mechanisms. Furthermore, we identify critical knowledge gaps regarding irreversibility, sedimentary signal emergence, and threshold behavior under rapid forcing. Overall, this study reframes OA as a planetary-scale diagnostic of whole-Earth system disequilibrium, revealing its fundamental significance for evaluating long-term carbon cycle stability, Earth system resilience, and the enduring geological legacy of anthropogenic emissions beyond human timescales.
Marine fish survival is threatened by ocean acidification, but the hormonal mechanisms for pH compensation are not well understood, limiting mechanistic understanding of stress responses in marine fish. We examined isotocin signaling in marine medaka (Oryzias melastigma) exposed to year-2100 ocean acidification conditions (Pco2 ∼0.14 kPa, pH 7.6). Our analysis demonstrated that isotocin receptor b (ITRb) was selectively upregulated at 6 h postexposure in adult gills, though it showed only a nonsignificant trend at 5 days postfertilization (dpf) embryos, whereas adenylyl cyclase 5 (ADCY5) showed hypercapnia responsiveness primarily at hatching. Using immunofluorescence and confocal microscopy, we found that both ITRb and ADCY5 proteins localize to the basolateral membrane of Na+-K+-ATPase-positive ionocytes, partially separated from apical H+-secretion machinery. Knockdown experiments showed that ITRb-ADCY5 coupling is crucial for pH compensation, with individual knockdown moderately reducing H+ secretion and combined knockdown causing severe impairment (>70% reduction) and decreasing transcription of acid-secretion genes (nhe3, ca2, and rhcgb) by 44%–60%. Paradoxically, double knockdown triggered a twofold cAMP increase that failed to restore function, whereas wild-type embryos maintained stable cAMP levels across pH conditions, consistent with the hypothesis that ITRb-ADCY5 coupling may organize cAMP production within specific basolateral microdomains, though direct subcellular imaging would be required to validate this compartmentalization model. The developmental asynchrony between ITRb (5 dpf) and ADCY5 (hatching) responses indicates life-stage-specific vulnerabilities. Our findings reveal that basolateral ITRb-ADCY5 coupling represents a critical control point for pH compensation capacity.
NEW & NOTEWORTHY Isotocin signaling, through ITRb-ADCY5 coupling, enables marine fish to compensate for ocean acidification via compartmentalized rather than global cAMP production. Paradoxically, disrupting this pathway doubles cAMP levels yet abolishes H+ secretion, revealing that signal localization determines function. The developmental asynchrony between ITRb and ADCY5 responses suggests that pH-stress vulnerabilities are specific to each life stage and require further investigation.
Anthropogenic CO2 emissions and their continuous dissolution into seawater lead to seawater pCO2 rise and ocean acidification (OA). Phytoplankton groups are known to be differentially affected by carbonate chemistry changes associated with OA in different regions of contrasting physical and chemical features. To explore responses of phytoplankton to OA in the Chinese coastal waters, we conducted a mesocosm experiment in a eutrophic bay of the southern East China Sea under ambient (410 µatm, AC) and elevated (1000 µatm, HC) pCO2 levels. The HC condition stimulated phytoplankton growth and primary production during the initial nutrient-replete stage, while the community diversity and evenness in both pCO2 treatments were reduced during this stage due to the rapid nutrient consumption and diatom blooms, and the subsequent shift from diatoms to hetero-dinoflagellates led to a decline in primary production during the mid and later phases under nutrient depletion. HC treatment suppressed the diatom-to-dinoflagellate succession and enhanced the subsequent remineralization of organic matter, thereby facilitating smaller phytoplankton to dominant and sustaining primary production. Our findings indicate that, the impacts of OA on phytoplankton diversity in the coastal water of the southern East China Sea depend on availability of nutrients, with primary productivity and biodiversity of phytoplankton reduced in the eutrophicated coastal water.
