Regional ocean models enable generation of computationally-affordable and regionally-tailored \ ensembles of near-term forecasts and long-term projections of sufficient resolution to serve marine resource management. Climate change, however, has created marine resource challenges, such as shifting stock distributions, that cut across domestic and international management boundaries and have pushed regional modeling efforts toward “coastwide” approaches. Here we present and evaluate a multidecadal hindcast with a Northeast Pacific (NEP) regional implementation of the Modular Ocean Model version 6 with sea ice and biogeochemistry that extends from the Chukchi Sea to the Baja California Peninsula at 10-km horizontal resolution (MOM6-COBALT-NEP10k, or “NEP10k”). This domain includes an Arctic-adjacent system with a broad shallow shelf seasonally covered by sea ice (the Eastern Bering Sea, EBS), a sub-Arctic system with upwelling in the Alaska Gyre and predominant downwelling winds and large freshwater forcing along the coast (the Gulf of Alaska, GoA), and a temperate, eastern boundary upwelling ecosystem (the California Current Ecosystem, CCE). The coastwide model was able to recreate seasonal and cross-ecosystem contrasts in numerous ecosystem-critical properties including temperature, salinity, inorganic nutrients, oxygen, carbonate saturation states, and chlorophyll. Spatial consistency between modeled quantities and observations generally extended to plankton ecosystems, though small to moderate biases were also apparent. Fidelity with observed zooplankton biomass, for example, was limited to first-order seasonal and cross-system contrasts. Temporally, simulated monthly surface and bottom temperature anomalies in coastal regions (< 500m deep) closely matched estimates from data-assimilative ocean reanalyses. Performance, however, was reduced in some nearshore regions coarsely resolved by the model’s 10-km resolution grid, and the time series of satellite-based chlorophyll anomaly estimates proved more difficult to match than temperature. System-specific ecosystem indicators were also assessed. In the EBS, NEP10k robustly matched observed variations, including recent large declines, in the area of the summer bottom water “cold pool” (< 2 °C) which exerts a profound influence on EBS fisheries. In the GoA, the simulation captured patterns of sea surface height variability and variations in thermal, oxygen and acidification risk associated with local modes of inter-annual to decadal climate variability. In the CCE, the simulation robustly captured variations in upwelling indices and coastal water masses, though discrepancies in the latter were evident in the Southern California Bight. Enhanced model resolution may reduce such discrepancies, but any benefits must be carefully weighed against computational costs given the intended use of this system for ensemble predictions and projections. Meanwhile, the demonstrated NEP10k skill level herein, particularly in recreating cross-ecosystem contrasts and the time variation of ecosystem indicators over multiple decades, suggests considerable immediate utility for coastwide retrospective and predictive applications.
Continue reading ‘A regional physical-biogeochemical ocean model for marine resource applications in the Northeast Pacific (MOM6-COBALT-NEP10k v1.0)’Archive Page 54
A regional physical-biogeochemical ocean model for marine resource applications in the Northeast Pacific (MOM6-COBALT-NEP10k v1.0)
Published 25 December 2024 Science ClosedTags: Arctic, biogeochemistry, biological response, field, modeling, North Pacific, regionalmodeling, zooplankton
Marine biological responses to abrupt climate change in deep time
Published 24 December 2024 Science ClosedTags: biological response, paleo, review
Non-technical Summary
Paleobiology can offer diverse insights into how climate change has affected past species and ecosystems. Timely and important areas of research focus on the potential of paleobiology to contribute to solutions for climate impacts on natural ecosystems. But how far can past responses to abrupt climate change be generalized to derive predictions for the modern and future worlds? The long timescales over which biological responses are observed in the deep time past hamper the applicability of paleontological observations, but by how much? To address these questions, we review paleontological evidence for the impacts of geologically rapid climatic change. Fruitful avenues for future research lie in (1) characterizing the relationship between the magnitude of warming and extinction toll, (2) using physiology to bridge timescales, and (3) assessing the role of long-term climate history to predict the impact of short-term climate change. Identifying how consistent and robust paleontological signals are across timescales will help to make deep-time observations more useful for the modern world.
Abstract
Ancient changes in the biosphere, from organismic traits to wholesale ecosystem changes, can be aligned with climate forcing across the Phanerozoic. Clear examples of abrupt climate warming causing biodiversity crises are primarily found between the Permian and Paleogene periods. During these times, catastrophic events occurred, resembling the extreme climate scenarios projected for the near future. The paleobiologic literature around these events generally supports the hypothesis that abrupt climate change was a dominant trigger of extinction and/or ecological crisis. When climate change and climate history are considered, virtually all post-Paleozoic global biotic events can be confidently attributed to climatic change, with abrupt warming (hyperthermal events) leaving the most consistent fingerprint. The combined stress of deoxygenation and warming are sufficient to explain marine extinction patterns across most hyperthermal events. Although ocean acidification may have contributed, the direct role of pH on the extinction toll of organisms is not consistently demonstrated. Future research can enhance the correspondence between the magnitudes of climatic changes and their biological impacts, even though observed rates of change cannot currently be compared across different timescales. Mimicking multi-scale approaches in modern ecology, paleontological approaches to climate impact research will benefit from specifically targeting scaling relationships
How does the interaction between the stress status of bivalves (Mytilus galloprovincialis) and marine environmental factors unfold through a principal component analysis approach?
Published 24 December 2024 Science ClosedTags: biological response, field, mollusks, North Atlantic, physiology
The Bay of Agadir, located in Morocco, is of significant economic and ecological value, yet it has faced persistent pollution challenges due to industrial, port, and tourism activities. Despite recent improvements following the implementation of wastewater treatment plants, particularly in the Anza-Imouran sector, knowledge gaps remain regarding the interactions between marine environmental factors and pollution biomarkers in marine organisms. This study examines the influence of environmental factors on the biomarker responses of Mytilus galloprovincialis across three sites (Anza, Aourir, and Imouran) in Agadir Bay, covering the period from January 2017 to December 2018. Principal Component Analysis (PCA) was employed to explore the relationships between four key biomarkers (Catalase (CAT), Glutathione S-transferase (GST), Malondialdehyde (MDA), and Acetylcholinesterase (AChE)), and seven marine environmental factors (water temperature, air temperature, salinity, pH, dissolved oxygen, electrical conductivity, and precipitation). At Anza, Aourir, and Imouran, the first two principal components explained a significant portion of the total variance (80.19%, 78.63%, and 88.60%, respectively). Notable findings include a negative correlation between GST and water temperature (r = − 0.57) at Anza. In Aourir, CAT exhibited a positive correlation with rainfall and dissolved oxygen (r = 0.78 and r = 0.41, respectively) but a negative correlation with pH and salinity (r = − 0.58 and r = − 0.44, respectively). Additionally, GST was positively correlated with rainfall (r = 0.52), while showing a negative relationship with pH and water temperature (r = − 0.40 and r = − 0.53, respectively). MDA was negatively correlated with salinity (r = − 0.59), and AChE was inversely associated with electrical conductivity (r = − 0.41). In Imouran, CAT was positively correlated with rainfall (r = 0.70), while exhibiting negative correlations with pH, salinity, and electrical conductivity (r = − 0.73, r = − 0.60, and r = − 0.61, respectively). GST showed a positive correlation with electrical conductivity and salinity (r = 0.55 and r = 0.48), but a negative correlation with water temperature (r = − 0.47). MDA was positively correlated with rainfall (r = 0.66) and negatively with pH, electrical conductivity, and salinity (r = − 0.74, r = − 0.58, and r = − 0.67, respectively). These findings highlight the intricate relationship between marine environmental factors and biomarker variability in M. galloprovincialis, emphasizing the importance of further understanding their impact on marine organism health amid ongoing environmental changes.
Continue reading ‘How does the interaction between the stress status of bivalves (Mytilus galloprovincialis) and marine environmental factors unfold through a principal component analysis approach?’Divergent responses of an armored and an unarmored dinoflagellate to ocean acidification
Published 24 December 2024 Science ClosedTags: biological response, growth, laboratory, molecular biology, physiology, phytoplankton
Highlights
- An armored and an unarmored dinoflagellate exhibited divergent responses to OA.
- The unarmored species presented a higher ability to withstand OA stress.
- Cell wall structure may play essential roles in response to OA stress.
- Unarmored dinoflagellates may have significant advantages in acidic oceans.
Abstract
Dinoflagellates, both armored and unarmored, with distinct cell wall difference, are being affected by elevated CO2-induced ocean acidification (OA). However, their specific responses to OA are not well understood. In this study, we investigated the physiological and molecular response of the armored species Prorocentrum obtusidens and the unarmored species Karenia mikimotoi to OA over a 28-day period. The results show that the two species responded differently to OA. Cell growth rate, particulate organic carbon (POC) content, and the activities of C4 pathway enzymes decreased in P. obtusidens under future acidified ocean condition (pH 7.8, 1000 μatm pCO2), but the activities of carbonic anhydrase (CA), ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), and superoxide dismutase (SOD) increased. Whereas cell growth rate, contents of Chl a and PON, and SOD activity altered insignificantly in K. mikimotoi, but contents of POC and total carbohydrate, and the activity of RubisCO increased while the activities of CA and C4 pathway enzymes decreased. Transcriptomic analysis indicates that genes associated with antioxidative response, heat shock protein, proteasome, signal transduction, ribosome, and pH regulation were up-regulated in P. obtusidens but down-regulated in K. mikimotoi. Notably, the synthesis of soluble organic matter (i.e., spermidine and trehalose) was enhanced in K. mikimotoi, thereby regulating intracellular pH and improving stress resistance. This study highlights the divergent response of the armored and unarmored dinoflagellates to OA, with the unarmored dinoflagellate exhibiting a higher ability to withstand this stressor. Therefore, caution should be exercised when predicting the behavior and the eventual fate of dinoflagellates in the future acidified ocean.
Continue reading ‘Divergent responses of an armored and an unarmored dinoflagellate to ocean acidification’Will climate change alter the swimming behavior of larval stone crabs?: a guided-inquiry lesson
Published 23 December 2024 Science ClosedTags: biological response, crustaceans, education, multiple factors, performance, reproduction, temperature
The ocean has absorbed ~one third of the excess atmospheric carbon dioxide (CO2) released since the Industrial Revolution. When the ocean absorbs excess CO2, a series of chemical reactions occur that result in a reduction in seawater pH, a process called ocean acidification. The excess atmospheric CO2 is also resulting in warmer seawater temperatures. These stressors pose a threat to marine organisms, especially during earlier life stages (i.e., larvae). The larvae of species like the Florida stone crab (Menippe mercenaria) are free swimming, allowing a population to disperse and recruit into new habitats. After release, stone crab larvae undergo vertical swimming excursions in response to abiotic stimuli (gravity, light, pressure) allowing them to control their depth. Typically, newly hatched larvae respond to abiotic cues that would promote a shallower depth distribution, where surface currents can transport them offshore to complete development. As larvae develop offshore, they become less sensitive to certain abiotic stimuli, which promotes a deeper depth distribution that may expose them to variable current speeds, thus influencing the direction of advection (horizontal movement). Environmental stressors like ocean acidification and elevated seawater temperatures may also impact the larvae’s natural response to these abiotic stimuli throughout ontogeny (development). Changes in their natural swimming behavior due to climate stressors could, therefore, influence the transport and dispersal of the species. This guided-inquiry lesson challenges introductory marine biology and oceanography students to determine how future ocean pH and temperature projections could impact the swimming behavior of Florida stone crab larvae.
Continue reading ‘Will climate change alter the swimming behavior of larval stone crabs?: a guided-inquiry lesson’Contrasting responses of commercially important Northwest Atlantic bivalve species to ocean acidification and temperature conditions
Published 23 December 2024 Science ClosedTags: biological response, laboratory, mollusks, morphology, mortality, multiple factors, North Atlantic, temperature
Modern calcifying marine organisms face numerous environmental stressors, including overfishing, deoxygenation, increasing ocean temperatures, and ocean acidification (OA). Coastal marine settings are predicted to become warmer and more acidic in coming decades, heightening the risks of extreme events such as marine heat waves. Given these threats, it is important to understand the vulnerabilities of marine organisms that construct their shells from calcium carbonate, which are particularly susceptible to warming and decreasing pH levels. To investigate the response of four commercially relevant bivalve species to OA and differing temperatures, juvenile Mercenaria mercenaria (hard shell clams), juvenile Mya arenaria (soft shell clams), adult and juvenile Arctica islandica (ocean quahog), and juvenile Placopecten magellanicus (Atlantic sea scallops) were grown in varying pH and temperature conditions. Species were exposed to four controlled pH conditions (7.4, 7.6, 7.8, and ambient/8.0) and three controlled temperature conditions (6, 9, and 12°C) for 20.5 weeks and then shell growth and coloration were analyzed. This research marks the first direct comparison of these species’ biological responses to both temperature and OA conditions within the same experiment. The four species exhibited varying responses to temperature and OA conditions. Mortality rates were not significantly associated with pH or temperature conditions for any of the species studied. Growth (measured as change in maximum shell height) was observed to be higher in warmer tanks for all species and was not significantly impacted by pH. Two groups (juvenile M. arenaria and juvenile M. mercenaria) exhibited lightening in the color of their shells at lower pH levels at all temperatures, attributed to a loss of shell periostracum. The variable responses of the studied bivalve species, despite belonging to the same phylogenetic class and geographic region, highlights the need for further study into implications for health and management of bivalves in the face of variable stressors.
Continue reading ‘Contrasting responses of commercially important Northwest Atlantic bivalve species to ocean acidification and temperature conditions’Sea-Bird Scientific introduces deep SeapHOx V2 moored system
Published 23 December 2024 Educational Materials , Resources , Web sites and blogs ClosedTags: resource, sensor
Sea-Bird Scientific has introduced the Deep SeapHOx™ V2. Designed for long-term deployments in diverse environments, from shallow regions to the deep ocean, this state-of-the-art multiparameter moored system integrates the Deep SeaFET™ V2 pH sensor with the tried-and-true SBE 37 SMP-ODO MicroCAT CTD+DO sensor. The result? A powerful tool for monitoring ocean acidification and other critical physical and biological processes.
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Applications and Case Studies
The Deep SeapHOx V2 is designed to support a wide range of oceanographic research and monitoring applications:
- Carbon cycle analysis – track the movement and storage of carbon in the ocean to better understand the global carbon cycle.
- Climate science – collect data on ocean temperature and salinity to contribute to climate models and predict future climate change scenarios.
- Coral reef monitoring – investigate the conditions that support deep-sea coral ecosystems and assess their vulnerability to environmental changes.
- Deoxygenation and hypoxia monitoring – measure dissolved oxygen levels to identify and study hypoxic zones, which can have significant impacts on marine life.
- Fisheries and aquaculture – early warning and monitoring for critical marine resources that are sensitive to changing pH.
- Case study – Experimental kelp farming with Saccharina latissima
- Food web studies – analyze the interactions between different species in the marine food web and how they are affected by environmental factors.
- Marine biology – Study the health and behavior of marine organisms in response to changing environmental conditions.
- Ocean acidification – monitor changes in ocean pH levels to understand the impacts of increased carbon dioxide on marine ecosystems.
- Case study – Inductive modem technology for use in measuring pH
Ocean acidification trends and carbonate system dynamics across the North Atlantic subpolar gyre water masses during 2009–2019 (Update)
Published 20 December 2024 Science ClosedTags: chemistry, laboratory, methods, North Atlantic
Key points
- During the 2010s, the subpolar North Atlantic experienced a 50 %–86 % increase in anthropogenic CO2, accelerating by 7 %–10 % the acidification.
- Anthropogenic CO2 contributed to acidification by 53 %–68 % in upper layers and > 82 % in the interior ocean.
- The acidification trends (0.0006 and 0.0032 units yr−1) declined the ΩCa and ΩArag by 0.004–0.021 and 0.003–0.0013 units yr−1, respectively.
Abstract
The CO2–carbonate system dynamics in the North Atlantic subpolar gyre (NASPG) were evaluated between 2009 and 2019. Data were collected aboard eight summer cruises through the Climate and Ocean: Variability, Predictability and Change (CLIVAR) 59.5° N section. The ocean acidification (OA) patterns and the reduction in the saturation state of calcite (ΩCa) and aragonite (ΩArag) in response to the increasing anthropogenic CO2 (Cant) were assessed within the Irminger, Iceland, and Rockall basins during a poorly assessed decade in which the physical patterns reversed in comparison with previous well-known periods. The observed cooling, freshening, and enhanced ventilation increased the interannual rate of accumulation of Cant in the interior ocean by 50 %–86 % and the OA rates by close to 10 %. The OA trends were 0.0013–0.0032 units yr−1 in the Irminger and Iceland basins and 0.0006–0.0024 units yr−1 in the Rockall Trough, causing a decline in ΩCa and ΩArag of 0.004–0.021 and 0.003–0.0013 units yr−1, respectively. The Cant-driven rise in total inorganic carbon (CT) was the main driver of the OA (contributed by 53 %–68 % in upper layers and > 82 % toward the interior ocean) and the reduction in ΩCa and ΩArag (> 64 %). The transient decrease in temperature, salinity, and AT collectively counteracts the CT-driven acidification by 45 %–85 % in the upper layers and in the shallow Rockall Trough and by < 10 % in the interior ocean. The present investigation reports the acceleration of the OA within the NASPG and expands knowledge about the future state of the ocean.
Continue reading ‘Ocean acidification trends and carbonate system dynamics across the North Atlantic subpolar gyre water masses during 2009–2019 (Update)’New York State climate impacts assessment chapter 05: ecosystems
Published 20 December 2024 Newsletters and reports , Science ClosedTags: North Atlantic, review
The people of New York have long benefited from the state’s diversity of ecosystems, which range from coastal shorelines and wetlands to extensive forests and mountaintop alpine habitat, and from lakes and rivers to greenspaces in heavily populated urban areas. These ecosystems provide key services such as food, water, forest products, flood prevention, carbon storage, climate moderation, recreational opportunities, and other cultural services. This chapter examines how changes in climatic conditions across the state are affecting different types of ecosystems and the services they provide, and considers likely future impacts of projected climate change. The chapter emphasizes how climate change is increasing the vulnerability of ecosystems to existing stressors, such as habitat fragmentation and invasive species, and highlights opportunities for New Yorkers to adapt and build resilience.
Continue reading ‘New York State climate impacts assessment chapter 05: ecosystems’Coexisting mangrove-coral habitats: trends in seawater chemistry and coral diversity
Published 20 December 2024 Science ClosedTags: biological response, BRcommunity, chemistry, corals, field, morphology, phanerogams, South Pacific
Coral reefs face unprecedented threats from climate change, with rising temperatures, ocean acidification, and other stressors endangering their survival. Coexisting mangrove-coral (CMC) habitats provide a natural laboratory to study coral resilience under extreme conditions. However, these habitats are rare and understudied, leaving gaps in understanding their biogeochemical and ecological dynamics. This thesis examines how mangrove proximity influences seawater chemistry, coral diversity, and morphology. A global review identified differences in seawater chemistry between habitat types and regions, driven by biogeochemical processes and freshwater inputs. Edge habitats, particularly in the Great Barrier Reef (GBR), were identified as understudied. An empirical study at Pioneer Bay, GBR, revealed significant spatial and temporal variations in seawater chemistry along a gradient from mangroves to open reefs. Corals near mangroves experienced greater fluctuations in pH, temperature, and oxygen, stabilizing with distance. Tidal flushing mitigated extremes, fostering coral resilience. Mangrove proximity significantly influenced benthic communities, coral morphology, and biodiversity. Extreme conditions near mangroves favored resilient corals like *Porites*, while intermediate sites supported the highest diversity due to nutrient influx and moderate disturbances. Farther sites were dominated by complex coral communities. Edge CMC habitats play a vital role in supporting coral adaptation to climate change. However, intensifying stressors threaten even resilient systems, underscoring the need for long-term monitoring and adaptive management to protect these critical biodiversity hotspots.
Continue reading ‘Coexisting mangrove-coral habitats: trends in seawater chemistry and coral diversity’Evaluating the cumulative impacts of multiple stressors on marine and coastal ecosystems in China’s marine waters
Published 20 December 2024 Science ClosedTags: North Pacific, review
Highlights
- Cumulative stressor impact on China’s coastal waters has increased significantly.
- Salt marshes, mangroves and coasts are at the highest risk of stress in China’s marine waters.
- Cumulative stressor impact in the southern coasts of Shandong increased significantly.
- Climate change has emerged as a primary driver of ecosystem alterations in China’s marine waters.
- The most significant threat to China’s marine ecosystem is the rise in sea surface temperatures.
Abstract
Understanding the spatial patterns of human activities and the consequences of stressors on marine and coastal environments is critical for mitigating marine ecological risks and maintaining healthy ecosystems. However, there is limited understanding of the spatial variations, locations, and drivers of the most significant changes in the cumulative impacts, causing significant challenges for the conservation and restoration of marine habitats. Here, we estimated the spatial intensity of 14 stressors (land-based, sea-based, and climate change-related) and their potential impacts on 9 marine and coastal ecosystems during three five-year periods (2006–2010, 2011–2015, and 2016–2020) at an ∼1 km resolution as well as the spatiotemporal changes in the cumulative impacts on China’s marine waters. In addition, we generated maps of the cumulative exposure occurring in each pixel, that is, the sum of their intensities without considering ecosystem vulnerability. We found that nearly all eastern provinces of China experienced significantly increasing cumulative impacts on marine waters, as did all marine and coastal ecosystems from 2006 to 2020, with salt marshes, mangroves, and coasts at the greatest risk. However, notably, in recent years, the cumulative impacts in most coastal waters, except for the southern coast of Shandong, have decreased significantly. Furthermore, the increasing areas of the cumulative effects gradually shifted from coastal regions to areas beyond the shelf, indicating that the threats related to climate change have gradually emerged as the primary drivers of most significant change. The ranking of the stressor impacts on coastal and marine ecosystems for the entire study region suggested that the five stressors with the greatest impact were sea surface temperature (29.42 %), coastal ports (21.81 %), sea level rise (17.97 %), commercial shipping (14.95 %), and ocean acidification (7.73 %).
Continue reading ‘Evaluating the cumulative impacts of multiple stressors on marine and coastal ecosystems in China’s marine waters’Antarctica’s tipping points threaten global climate stability
Published 19 December 2024 Press releases Closed
Antarctica is approaching a series of cascading tipping points that could reshape ecosystems and intensify global climate disruptions, according to a new study by an international team of scientists, including researchers from the University of Tasmania.
The study identifies eight potential tipping points spanning physical, biological, chemical, and governance systems. The research is published in the journal Ambio.
These include collapsing ice sheets, invasive species, ocean acidification, and pressures on the Antarctic Treaty System (ATS), which oversees human activity in the region.
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The study warns that these tipping points are interconnected, creating a risk of cascading effects.
Melting ice sheets, for example, not only contribute to sea-level rise but also disrupt ocean circulation, which is crucial for transporting heat, carbon, and nutrients around the globe. Such disruptions threaten marine ecosystems, global fisheries, and food security.
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At the same time, the Southern Ocean’s ability to absorb carbon dioxide—a crucial buffer against global warming—is diminishing.
“The interconnected nature of these systems means small failures can quickly escalate,” Professor King said. “Without decisive action, we risk triggering a chain reaction with far-reaching and irreversible consequences.”
The researchers call for stronger international cooperation, urgent climate policies, and greater investment in Antarctic science. Their findings frame Antarctica not as a remote and isolated region, but as a critical player in the Earth’s environmental systems.
Continue reading ‘Antarctica’s tipping points threaten global climate stability’Cascading tipping points of Antarctica and the Southern Ocean
Published 19 December 2024 Science ClosedTags: Antarctic, review
Antarctica and the Southern Ocean are key elements in the physical and biological Earth system. Human-induced climate change, and other human activities in the region, are leading to several potential interacting tipping points with major and irreversible consequences. Here, we examine eight potential physical, biological, chemical, and social Antarctic tipping points. These include ice sheets, ocean acidification, ocean circulation, species redistribution, invasive species, permafrost melting, local pollution, and the Antarctic Treaty System. We discuss the nature of each potential tipping point, its control variables, thresholds, timescales, and impacts, and focus on the potential for cumulative and cascading effects as a result of their interactions. The analysis provides substantial evidence of the need for more concerted and rapid action to limit climate change and to minimise the impacts of local human activities to avoid these cascading tipping points.
Continue reading ‘Cascading tipping points of Antarctica and the Southern Ocean’Impact of ocean acidification on marker enzymes in Asian seabass Lates calcarifer
Published 19 December 2024 Science ClosedTags: biological response, fish, laboratory, physiology
Backgrounds: The influence of ocean acidification (OA) is particularly significant on calcifying organisms in marine environment. A possible explanation for acidification-induced changes in fish behaviour is that acidification interferes with marker enzymes in the liver, muscle and brain. Under a range of severe environmental circumstances, marine organisms can be susceptible to oxidative stress and results in the changes in the biochemical components which can be assessed to know the health status of organisms.
Aim of the Works: The aim of this study is to observe the impact of ocean acidification in Asian seabass Lates calcarifer and to employ a large number of biomarker to discover distinct and unique patterns. For this the fingerlings of L. calcarifer were exposed to OA, in order to understand the changes in marker enzymes in liver, muscle and brain of L. calcarifer.
Methodology: Fish fingerlings were exposed to OA condition with two different pH (7.8 and 7.5) for a period of 9 weeks in order to assess changes in biomarker. Acid phosphatase (ACP) and alkaline phosphatase (ALP), alanine transaminase (ALT), and aspartate transaminase activity (AST) were examined in the liver, brain and muscles of fish.
Results: The Liver has considerably higher in ACP and ALP enzymes after 3 weeks of OA exposure. AST and ALT marker enzymes were induced in the brain at greater levels and in most cases, the entire marker enzymes in the liver, muscle and brain were concentration dependent and also the exposure period. The observed changes in marker enzymes which detected in the brain and liver tissues of L. calcarifer were statistically significant.
Conclusions: The present study showed a significant association between the entire biomarkers tested in fish exposed to OA. Overall, the results indicate that brain and liver is the most vulnerable component to OA exposure when compared to muscles and brain it may be employed as a bioindicator of OA exposure.
Continue reading ‘Impact of ocean acidification on marker enzymes in Asian seabass Lates calcarifer’Advanced deep learning technique for estimating global surface ocean calcium carbonate saturation (Ωcal)
Published 18 December 2024 Science ClosedTags: chemistry, globalmodeling, methods, modeling
Highlights
- The study employed FFNN, RF, and TabNet ML models to estimate Ωcal using in-situ measurements and satellite-derived data.
- The TabNet model outperformed with significantly low errors (RMSE=0.39, MNB=0.0058, MRE=0.019) and high accuracy (R2=0.96).
- SST strongly correlated with Ωcal (r=0.98), SSS moderately (r=0.49), and Chla showed a weak negative correlation (r=-0.27).
- The study observed seasonal Ωcal variability, with higher values in summer months, notably in temperate and polar regions.
- Emphasized a declining trend of Ωcal from 2012 to 2022, likely influenced by changing oceanic and atmospheric conditions.
Abstract
The accurate estimation of surface ocean calcium carbonate saturation (Ωcal) is crucial for understanding the impacts of ocean acidification (OA) on marine ecosystems, particularly for calcifying organisms. This study investigates the estimation of global surface ocean Ωcal using machine learning (ML) models and satellite-derived data. Three ML models such as feed-forward neural networks (FFNN), random forests (RF), and Tabularnet (TabNet) were employed to estimate Ωcal, utilizing in-situ and satellite measurements of sea surface temperature (SST), sea surface salinity (SSS), and Chlorophyll-a concentration (Chla). Among these, the TabNet model exhibited superior performance, with a root-mean-square error (RMSE) of 0.39, mean relative error (MRE) of 0.019, mean normalized bias (MNB) of 0.0058 and coefficient of determination (R2) of 0.96. SST showed a strong positive correlation with Ωcal (r = 0.95), while SSS and Chla exhibited moderate positive (r = 0.49) and weak negative (r = −0.27) correlations, respectively. The study revealed significant spatiotemporal variability in Ωcal, driven by seasonal changes and ocean circulation patterns. Sensitivity analysis highlighted the robustness of the TabNet model, maintaining high predictive capability despite variations in SST, SSS, and Chla. The TabNet model high accuracy provides a valuable tool for monitoring and forecasting changes in ocean chemistry, informing conservation efforts and policy-making. This study emphasizes the importance of advanced ML models in marine science and their potential for enhancing our understanding of global oceanic processes.
Continue reading ‘Advanced deep learning technique for estimating global surface ocean calcium carbonate saturation (Ωcal)’Sensitivity of pteropod calcification to multi stressor variability in coastal habitats
Published 18 December 2024 Science , Uncategorized ClosedTags: biological response, field, modeling, mollusks, morphology, multiple factors, North Pacific, regionalmodeling, temperature, zooplankton
Highlights
- Pteropod calcification under coastal multiple stressors was investigated.
- Shell morphometrics and high-resolution model outputs was combined.
- Saturation state, temperature and food are drivers of calcification.
- Different calcification modes are dependent on the type of environment.
- Stable vs dynamic conditions induce different calcification strategy.
Abstract
Comprehensive understanding of environmental multiple stressors on calcification in marine calcifiers remains an important topic of study, especially under ocean global change associated with multiple stressors. We explore the impact of multiple stressor variability on pteropod calcification in the southern Salish Sea (Washington, U.S.), a coastal estuarine system that exhibits a high degree of spatial and temporal variability in multiple environmental parameters across sampling locations. We hypothesized that such variability is associated with differences in pteropod calcification. Shell thickness and shell density across pteropod life history stages was compared with high-resolution outputs from a realistic model of regional circulation and biogeochemistry to explore how the mean and variability of multiple stressors (aragonite saturation state (Ωar), temperature, food availability) influence calcification. We found that both the mean and variability in multiple stressors play a major role in calcification in pteropods, with a generalized linear model explaining more than 60% of the variance in calcification. We suggest two different modes of shell building: stable conditions of lower mean Ωar trigger the loss of shell thickness and density. In the more variable habitats, i.e., where the variability occurs over diel and seasonal scales, shell thickness increases at higher Ωar variability and greater food availability, which might partially compensate for the loss of shell density. This plastic response appears to be consistent across life stages and could represent a response mechanism that allows some compensatory calcification under less favourable conditions. However, compensation is very limited, as evident by lower shell growth resulting in lower shell sizes comparable to early life stages. These results substantially improve the understanding of the variability in multiple stressors on the calcification process under multiple stressors and provide a foundation for the development of two new proxies for calcification monitoring, and with implications for marine carbon dioxide removal strategies.
Continue reading ‘Sensitivity of pteropod calcification to multi stressor variability in coastal habitats’Buffer properties in the Guadalquivir Estuary (SW Iberian Peninsula)
Published 18 December 2024 Science ClosedTags: chemistry, field, North Atlantic
Highlights
- The inorganic carbon system is mainly regulated by river flow and tidal conditions.
- The estuary is well buffered, being more sensitive in the innermost area.
- The estuary exports inorganic carbon to the coastal zone.
Abstract
The Guadalquivir Estuary (main source of continental waters to the Gulf of Cadiz) has a carbonate basin, which enables the transport of inorganic carbon to adjacent coastal areas. Therefore, in order to study the dynamic of the carbonate system and its buffer capacity, a total of 12 samplings were carried out from 2017 to 2022. Samplings included longitudinal transects and tidal cycles in different seasonal and tidal conditions. Total alkalinity (TA) and dissolved inorganic carbon (DIC) showed increased values upstream, while calcium (Ca2+) presented the highest values in most of the marine samples. The ranges values obtained for these three variables were of 2180–5140 μmol kg−1, 430–3950 μmol kg−1 and 1295–10,855 μmol kg−1 for TA, DIC and Ca2+, respectively. Two buffer factors (βDIC and βH) were also calculated to study the variability of the buffer capacity of the Guadalquivir Estuary. These indicate that the estuary is well buffered for salinities above 10, while the inner part is more vulnerable to acidification effects. Using a non-linear 1D hydrodynamic model, net inorganic carbon system transports were calculated, showing that the Guadalquivir Estuary is exporting TA, DIC and Ca2+ to the Gulf of Cadiz.
Continue reading ‘Buffer properties in the Guadalquivir Estuary (SW Iberian Peninsula)’Projections of coral reef carbonate production from a global climate coral reef coupled model
Published 17 December 2024 Science ClosedTags: biological response, BRcommunity, calcification, communitymodeling, corals, modeling, multiple factors, temperature
Coral reefs are under threat due to climate change and ocean acidification. However, large uncertainties remain concerning future carbon dioxide emissions, climate change and the associated impacts on coral reefs. While most previous studies have used climate model outputs to compute future coral reef carbonate production, we use a coral reef carbonate production module embedded in a global carbon-climate model. This enables the simulation of the response of coral reefs to projected changes in physical and chemical conditions at finer temporal resolution. The use of a fast-intermediate complexity model also permits the simulation of a large range of possible futures by considering different greenhouse gas concentration scenarios (Shared Socioeconomic Pathways (SSPs)), different climate sensitivities (hence different levels of warming for a given level of acidification), as well as the possibility of corals adapting their thermal bleaching thresholds. We show that without thermal adaptation, global coral reef carbonate production decreases to less than 25% of historical values in most scenarios over the twenty-first century, with limited further declines between 2100 and 2300 irrespective of the climate sensitivity. With thermal adaptation, there is far greater scenario variability in projections of reef carbonate production. Under high-emission scenarios the rate of twenty-first century declines is attenuated, with some global carbonate production declines delayed until the twenty-second century. Under high-mitigation scenarios, however, global coral reef carbonate production can recover in the twenty-first and twenty-second century, and thereafter persists at 50-90% of historical values, provided that the climate sensitivity is moderate.
Continue reading ‘Projections of coral reef carbonate production from a global climate coral reef coupled model’Science update: ocean and coastal acidification: building community resilience to our changing ocean
Published 17 December 2024 Events ClosedJoin us on Thursday, March 13, 2025, from 7:00 PM to 8:00 PM ET, to learn about ocean acidification.
The ocean acts like a sponge, absorbing carbon dioxide from the atmosphere. Increased absorption by the ocean causes changes to our ocean’s chemistry from pole to pole. This is known as ocean acidification. Ocean acidification has regional and local impacts on marine life, ecosystems, and the people who depend on them. Additional processes and stressors near our coasts like nutrient pollution and algae blooms cause coastal acidification, introducing additional impacts. We’ve advanced our science enough to be able to assess regional vulnerability and identify and build adaptive strategies to help people prepare for and mitigate these challenges.
In this web seminar, the presenters will talk about NOAA’s efforts to assess resilience and vulnerability to ocean and coastal acidification and provide resources and solutions supporting coastal and inland communities. The presenters will also share the latest research in the emerging field of marine carbon dioxide removal to mitigate ocean acidification.
All individuals receive a certificate of participation and 100 NSTA activity points for attending the live seminar and completing the end-of-program survey. A certificate of participation is not awarded for watching the recorded version of the program.
We invite you to register for upcoming web seminars at NSTA.
Register today to participate in this web seminar. Upon registering you will receive an e-mail confirmation including information about the program and suggested links to visit in preparation of the event. Additional information about the web seminar will be e-mailed to you days before the program.
New Users: Log in 15 minutes prior to the start time for an introduction to NSTA web seminars.
Each web seminar is a unique, stand-alone, program. Archives of the web seminars and the presenters’ PowerPoint presentations will be available through the links on this web page. Read answers to frequently asked questions from participants.
For more information contact: webseminars@nsta.org
Continue reading ‘Science update: ocean and coastal acidification: building community resilience to our changing ocean’Long-term warming and acidification interaction drives plastic acclimation in the diatom Pseudo-nitzschia multiseries
Published 17 December 2024 Science ClosedTags: adaptation, biological response, growth, laboratory, molecular biology, multiple factors, otherprocess, physiology, phytoplankton, temperature
Highlights
- Temperature shows stronger effects than CO2 on P. multiseries growth and stress reponses.
- Multi-omics analysis reveals phenotypic plasticity and molecular adaptations under long-term warming and acidification.
- Short-term experiments effectively predict long-term P. multiseries responses to combined temperature and CO2 changes.
Abstract
Ocean warming (OW) and acidification (OA) are expected to interactively impact key phytoplankton groups such as diatoms, but the underlying mechanisms, particularly under long-term acclimation, remain poorly understood. In this study, we investigated the responses of the toxic diatom Pseudo-nitzschia multiseries to combined changes in temperature (20 °C and 30 °C) and CO2 concentration (pCO2 400 μatm and 1000 μatm) using a multi-omics approach over an acclimation period of at least 251 generations. Physiological data suggest that elevated temperature, either alone or in combination with CO2, reduced the net photosynthesis and nitrate uptake rate, thus inhibiting P. multiseries growth. Conversely, elevated CO2 alone stimulated P. multiseries growth. Comparative genome analysis revealed the phenotypic plasticity in response to temperature and pCO2 variations, even after more than 251 generations acclimation period. Temperature was identified as the dominant environmental factor, showing stronger effects than CO2. Transcriptomic profiles indicated that genes involved in stress- and intracellular homeostasis such as Hsps, ubiquitination process and antioxidant defense were mostly down-regulated under long-term warming acclimation. This study demonstrates that P.multiseries responds similarly to both short-term and long-term experimental selection, suggesting that short-term experiments can be used to predict long-term responses.
Continue reading ‘Long-term warming and acidification interaction drives plastic acclimation in the diatom Pseudo-nitzschia multiseries’
