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Population surges of crown‐of‐thorns starfish (COTS) (Acanthaster spp.) are a leading cause of coral cover loss on Australia's Great Barrier Reef (GBR). While COTS culling has been undertaken since 2012 little is known about how the public perceive COTS culling or how perceptions vary among social groups. Drawing on survey data collected in 2018 and 2022 we test the relative influence of demographic variables, social and institutional variables, and beliefs concerning the risks and benefits of culling, on public acceptance for the culling of COTS on the GBR. In contrast with previous research suggesting a polarization of views, we found limited opposition to culling (12% in 2018 and 8% in 2022). Remaining respondents, however, were almost equally divided between those who agreed or strongly agreed with culling and those who were neutral or only slightly in agreement. The strongest predictors of support, in terms of standardized mean odds ratios, were the perceived social, environmental, and ethical responsibility of culling (1.57), the manageability of culling risks (1.46), the personal importance of the GBR to the respondent (1.33), trust in science to deliver solutions (1.30), confidence in management of the GBR (1.26), and how much of a threat respondents believed COTS posed to the Reef (1.25). These findings suggest public communications about COTS culling might usefully focus on how scientific understanding, ongoing research, ecosystem monitoring, and partnerships with Reef Traditional Owners and stakeholders guide operations. [ABSTRACT FROM AUTHOR]

Quantifying the biomass, or number of individuals, diversity, and distribution of marine species is a critical aspect of understanding and managing marine ecosystems. In recent years, there has been growing interest in using environmental DNA (eDNA) for marine ecosystem management and biodiversity assessment. However, the main challenge hindering eDNA applicability has been the inability to infer absolute species abundances from multispecies analysis (eDNA metabarcoding). In this study, we demonstrate a way forward by estimating the abundance of commercially important fish species in a Norwegian fjord using a joint Bayesian statistical model of traditional trawl-catch data and molecular data derived from eDNA. Using this model, we accurately predict out-of-sample trawl catches using eDNA alone. Moreover, our model provides empirical estimates for key processes linking marine eDNA concentration to the fish population abundance estimated from trawl observations, including trawl catchability, DNA shedding, degradation, dilution, transport, recovery rate, and isolation efficiency. These processes, including amplification efficiencies correcting for Polymerase Chain Reaction (PCR) bias, are species-specific and enable the translation of eDNA metabarcoding data into abundances. These findings have broad implications for the use of eDNA in marine ecosystem management and conservation efforts. [ABSTRACT FROM AUTHOR]

Daya Bay, a semi-enclosed bay in the northern South China Sea and to the east of the Pearl River Estuary, is rich in biological resources and diverse habitats. Current research on mesozooplankton in Daya Bay has mainly focused on aspects such as species composition, biomass, and biodiversity in the zooplankton community. However, there is limited research on the top-down effects of mesozooplankton on prey communities. This study conducted seasonal in-situ cultivation experiments from 2015 to 2017. By combining mesozooplankton grazing experiments and microzooplankton dilution experiments, the mesozooplankton clearance rate and trophic cascading effect on low trophic levels were calculated. Results showed evident mesozooplankton selective feeding behavior and corresponding trophic cascades with seasonal variations, these being significantly higher in the spring and summer and lower in the autumn and winter. Different sizes of phytoplankton showed significant differences; large-sized phytoplankton received high feeding rates but low trophic cascades by mesozooplankton, while the opposite was true for small-sized phytoplankton. Trophic cascades contribute in three ways: offsetting direct grazing mortality, changing prey community structure via its effects on different phytoplankton sizes, and reducing ciliate grazing impacts at an average of 14.4 ± 7.8%, maintaining around 70% ciliate grazing impacts in nature. The composition of mesozooplankton was the primary reason for explaining feeding preferences, including size selectivity and omnivory. For instance, high cladoceran abundance caused high feeding rates while, on the other hand, high omnivorous copepods abundance caused high trophic cascades on small-sized phytoplankton. General additive model (GAM) analysis revealed that the changes in trophic cascades were highly dependent on temperature, ciliate abundance, mesozooplankton feeding rates on ciliates, and ciliate feeding rates on phytoplankton. The significance of this study lies in its contribution to providing valuable insights into the role of mesozooplankton in the marine food web and their impact on lower trophic levels. In addition, the findings can help inform the management and conservation of marine ecosystems, as well as guide future research in this field. [ABSTRACT FROM AUTHOR]

Breeding seabirds challenge the concept of niche segregation among competing species because similar competitors with comparable life histories can coexist in large multi‐species colonies. This makes them an ideal model organism for studying the Hutchisonian niche model, which proposes interspecific niche segregation, across n‐dimensions. Recent advances in assessment of ecological niches have improved our understanding of the mechanisms leading to at‐sea segregation. We examine 152 published studies investigating one or more of three niche spaces in breeding seabirds: dietary items, stable isotopes (isotopic niche) and spatial distribution (horizontal and vertical). Most studies focused on one rather then multiple niche spaces in combination. When multiple niche spaces were combined, higher segregation than overlap was reported, compared with when niche spaces were assessed individually, as is predicted by the n‐dimensional hypervolume concept. Studies investigating vertical (diving) foraging dimensions in addition to the more traditional horizontal (spatial) assessment reported more spatial segregation than overlap, compared with studies focusing only on horizontal or vertical dimensions. Segregation increased with colony size, suggesting an effect of competition. Segregation also increased during chick‐rearing, when taxa were more phylogenetically distant, and when foraging ecology was more similar. To gain a comprehensive understanding of sympatric competitors' interactions and their ecological niche space, it is important to combine approaches and standardize methodologies. Embracing multidimensional approaches to assess niche segregation in seabird species can inform effective conservation and management practices in marine ecosystems. [ABSTRACT FROM AUTHOR]

Turbidity serves as a crucial indicator of coastal water health and productivity. Twenty years of remote sensing data (2003–2022) from the Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) satellite were used to analyze the spatial and temporal variations in turbidity, as measured by total suspended matter (TSM), in the Berau Coastal Shelf (BCS), East Kalimantan, Indonesia. The BCS encompasses the estuary of the Berau River and is an integral part of the Coral Triangle, renowned for its rich marine and coastal habitats, including coral reefs, mangroves, and seagrasses. The aim of this research is to comprehend the seasonal and interannual patterns of turbidity and their associations with met-ocean parameters, such as wind, rainfall, and climate variations like the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). The research findings indicate that the seasonal spatial pattern of turbidity is strongly influenced by monsoon winds, while its temporal patterns are closely related to river discharge and rainfall. The ENSO and IOD climate cycles exert an influence on the interannual turbidity variations, with turbidity values decreasing during La Niña and negative IOD events and conversely increasing during El Niño and positive IOD events. Furthermore, the elevated turbidity during negative IOD and La Niña coincides with rising temperatures, potentially acting as a compound stressor on marine habitats. These findings significantly enhance our understanding of turbidity dynamics in the BCS, thereby supporting the management of marine and coastal ecosystems in the face of changing climatic and environmental conditions. [ABSTRACT FROM AUTHOR]

Aim: Genetic diversity of marine forests results from complex interactions of eco‐evolutionary processes. Among them, oceanographic connectivity driven by dispersal through water transport is hypothesized to play a pivotal role, yet its relative contribution has not been addressed at the global scale. Here, we test how present‐day oceanographic connectivity is correlated with the distribution of genetic diversity of marine forests across the ocean. Location: Global. Time period: Contemporary. Major taxa studied: Marine forests of brown macroalgae (order: Fucales, Ishigeales, Laminariales and Tilopteridales). Methods: Through literature review, we compiled a comprehensive dataset of genetic differentiation, encompassing 699 populations of 30 species. A biophysical model coupled with network analyses estimated multigenerational oceanographic connectivity and centrality across the marine forest global distribution. This approach integrated propagule dispersive capacity and long‐distance dispersal events. Linear mixed models tested the relative contribution of site‐specific processes, connectivity and centrality in explaining genetic differentiation. Results: We show that spatiality‐dependent eco‐evolutionary processes, as described by our models, are prominent drivers of genetic differentiation in marine forests (significant models in 91.43% of the cases with an average R2 of 0.50 ± 0.07). Specifically, we reveal that 18.7% of genetic differentiation variance is explicitly induced by predicted contemporary connectivity and centrality. Moreover, we demonstrate that long‐distance dispersal is key in connecting populations of species distributed across large water masses and continents. Main conclusions: Our findings highlight the role of present‐day oceanographic connectivity in shaping the extant distribution of genetic diversity of marine forests on a global scale, with significant implications for biogeography and evolution. This understanding can pave the way for future research aimed at guiding conservation efforts, including the designation of well‐connected marine protected areas, which is particularly relevant for sessile ecosystems structuring species such as brown macroalgae. [ABSTRACT FROM AUTHOR]

The Bay of Fundy is a highly productive ecosystem within the Northwest Atlantic where extreme tides and strong currents result in a large gradient of sediment concentrations across and along the bay. We processed daily satellite data from the MODerate resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite from 2003 to 2021 at 300-m resolution to understand and quantify spatial and temporal trends in chlorophyll-a concentration (chl-a, a measure of phytoplankton biomass), and suspended particulate matter concentration (SPM) in the Bay of Fundy surface waters. To account for high sediment loading (up to 100's g m−3) and moderate chl-a (median in situ chl-a of 1.5 mg m−3 from 2003 to 2021), coefficients of the OC3M chl-a algorithm were regionally tuned using in situ chl-a data, and satellite-derived SPM was incorporated within the chl-a retrieval algorithm to account for possible bias. The updated new algorithm was denoted as OCX-SPMCor. Chl-a computed using OCX-SPMCor showed better performance against in situ chl-a than the generic OC3M with a coefficient of determination that increased from 0.01 to 0.28 and a root mean square logarithmic error that decreased by 35%. Unlike previous remote sensing studies, OCX-SPMCor correctly predicted the particular chl-a seasonality in the Bay of Fundy, which does not follow the typical occurrence of spring/fall blooms as observed in the adjacent Gulf of Maine and Scotian Shelf. For the first time, satellite-predicted chl-a aligned with the phenology of in situ chl-a, where chl-a continually increased from April to June and remained high all summer, with a small secondary summer peak before decreasing in the fall. SPM seasonality followed an opposite trend where SPM reached a maximum in winter and a minimum in summer. A small number of matchups and high temporal variability on the hourly time scale precluded a robust assessment of the satellite-derived SPM. However, comparisons between time series of remotely sensed and in situ SPM demonstrated the ability of the satellite-derived SPM to capture temporal variations, though the absolute values may be slightly underestimated. Accurate maps of phytoplankton biomass and sediment concentrations are essential variables required for effective management and conservation of marine ecosystems in the Bay of Fundy. [ABSTRACT FROM AUTHOR]

Decadal-scale oceanographic, environmental, and ecological changes have been reported in the Salish Sea, an ecologically productive and biodiverse inland sea in the northeast Pacific that supports the economies and cultures of millions of people; however, there are substantial observational gaps pertaining to physical water properties that make linkages between physical drivers and ecosystem effects difficult to ascertain. With the aim of addressing these gaps, we present the Hindcast of the Salish Sea (HOTSSea) v1 with temporal coverage from 1980–2018, developed using the NEMO ocean engine. An inter-model comparison and preliminary evaluation was performed to assess sensitivity to different atmospheric and ocean reanalysis products used for boundary forcings. Biases inherited from forcings were quantified and the effectiveness of a simple temperature bias correction factor applied at one ocean boundary was evaluated. Evaluation of salinity and temperature indicates performance is best in the Strait of Georgia where the model simulates temperature anomalies and a secular warming trend over the entire water column in general agreement with observations. Analyses of modelled ocean temperature trends throughout the northern and central part of the domain where model skill was high and where observations are relatively sparse yielded fresh insights, including that ocean temperature trends are spatially and temporally variable. HOTSSea v1 will support development of an end-to-end spatial-temporal ecosystem model for the Strait of Georgia and has potential for other research and management applications related to decadal-scale climate effects on marine ecosystems, fish, and fisheries. [ABSTRACT FROM AUTHOR]

Phytoplankton form the base of the marine food web by transforming CO 2 into organic carbon via photosynthesis. Despite the importance of phytoplankton for marine ecosystems and global carbon cycling, projections of phytoplankton biomass in response to climate change differ strongly across Earth system models, illustrating uncertainty in our understanding of the underlying processes. Differences are especially large in the Southern Ocean, a region that is notoriously difficult to represent in models. Here, we argue that total (depth-integrated) phytoplankton biomass in the Southern Ocean is projected to largely remain unchanged under climate change by the Coupled Model Intercomparison Project Phase 6 (CMIP6) multi-model ensemble because of a shifting balance of bottom-up and top-down processes driven by a shoaling mixed-layer depth. A shallower mixed layer is projected on average to improve growth conditions, consequently weaken bottom-up control, and confine phytoplankton closer to the surface. An increase in the phytoplankton concentration promotes zooplankton grazing efficiency, thus intensifying top-down control. However, large differences across the model ensemble exist, with some models simulating a decrease in surface phytoplankton concentrations. To reduce uncertainties in projections of surface phytoplankton concentrations, we employ an emergent constraint approach using the observed sensitivity of surface chlorophyll concentration, taken as an observable proxy for phytoplankton, to seasonal changes in the mixed-layer depth as an indicator for future changes in surface phytoplankton concentrations. The emergent constraint reduces uncertainties in surface phytoplankton concentration projections by around one-third and increases confidence that surface phytoplankton concentrations will indeed rise due to shoaling mixed layers under global warming, thus favouring intensified top-down control. Overall, our results suggest that while changes in bottom-up conditions stimulate enhanced growth, intensified top-down control opposes an increase in phytoplankton and becomes increasingly important for the phytoplankton response to climate change in the Southern Ocean. [ABSTRACT FROM AUTHOR]

At present, the marine ecological environment is facing enormous pressure from human activities, and there is an urgent need for coordinated governance by multiple entities to ensure that the marine ecological environment can continuously meet the needs of sustainable development. Marine ecological environmental governance plays multiple roles in the sustainable development of the ocean characteristics. Most existing studies have explored this field from the perspective of the government and public, while failing to adequately account for the factors influencing enterprises' participation in marine ecological environmental governance. This paper is an effort to provide some empirical research on the influencing factors of enterprises' participation in marine ecological environmental governance. Based on existing literature, empirical research (213 middle managers were surveyed from 68 coastal enterprises in Zhejiang, China), this study extracts eight core factors that influence corporate participation in marine ecosystems and uses the Fuzzy Decision-making Trial and Evaluation Laboratory approach (Fuzzy DEMATEL). Furthermore, experts from Chinese backgrounds elucidated the complex interdependencies among the factors, based on which key influencing factors were identified. The empirical results indicate that government attention and support, legal and regulatory requirements, and cost-benefit accounting have a positive net effect on corporate participation in marine ecosystem management; when these factors are improved, they drive improvements in other factors(Corporate Capital Capability, Corporate Social Responsibility, Government Enforcement and Appraisal, The Attention of Corporate Leaders, Corporate Internal Management System). Additionally, interviews with Chinese business people support the robustness of the findings and suggest that policymakers cannot ignore government enforcement and assessment efforts. Overall, the study findings can help advance corporate participation in marine environmental governance. [ABSTRACT FROM AUTHOR]

The southern waters of the Sumatra‐Java Islands, within the Indo‐Pacific Warm Pool, are highly susceptible to global climate change impacts. Understanding particulate inorganic carbon (PIC) dynamics and environmental responses in this region is critical for assessing climate change effects on marine ecosystems. Utilizing two decades of remote sensing PIC data (2003–2022), we identified five sub‐regions via K‐means clustering: the Sunda Strait, southern coastal/offshore waters of Sumatra Island, and southern coastal/offshore waters of Java Island. Self‐Organizing Map explored interannual PIC variations, while Generalized Additive Models delineated driving factors. In the Sunda Strait, PIC dynamics are influenced by water exchanges between the Indonesian Seas (ISs) and eastern Indian Ocean (EIO). Seasonally, PIC concentrations peak during the east monsoon (boreal summer); decreasing during positive Indian Ocean Dipole (+IOD) and El Niño events. Along the southern Sumatra, PIC variations positively correlate with rainfall and photosynthetically active radiation (PAR). Along the southern Sumatra, upwelling drives PIC variations, with higher concentrations during mature summer monsoon induced upwelling periods. PIC increases during +IOD and decreases during El Niño. Our study highlights the nexus between nutrients, physical factors (e.g., rainfall), and climatic events (e.g., El Niño) on PIC concentrations. Climate‐induced changes in oceanic physical processes modulate nutrient concentrations, thereby governing PIC variations. We propose a mechanistic model to elucidate PIC variations in upwelling areas. Findings suggest that prospective climate variability, encompassing alterations in climate events, rainfall, and temperature, may escalate PIC concentrations within the study area, advocating PIC as a forward‐looking climate change indicator. Plain Language Summary: Understanding the response of particulate inorganic carbon (PIC)—a primary form of oceanic carbon ‐ to environmental changes in the vulnerable southern waters of the Sumatra‐Java Islands is crucial for assessing the marine ecosystem. We used satellite image data to examine the variability of PIC, from 2003 to 2022. Our research showed that PIC concentrations varied across the area. In the Sunda Strait, a narrow body of water between land masses, water movement between the Indonesian Seas and eastern Indian Ocean influences PIC concentrations. In the southern waters of Sumatra Island, we discovered that increased rainfall and sunlight contribute to higher PIC concentrations. In the southern waters of Java Island, upwelling, an ocean physical process that brings nutrient‐rich water to the surface, plays a significant role. Our study delineates the interplay between nutrients, physical factors (e.g., rainfall), and climatic events (e.g., El Niño) on coccolithophore biomass. Climate changes drive alterations in oceanic physical processes, which in turn affect nutrient availability, thereby governing the growth of coccolithophores. Findings suggest prospective climate variability, inclusive of alterations in climate events, rainfall, and temperature, may escalate PIC concentrations within the study area, advocating PIC concentrations alterations as a forward‐looking climate change indicator. Key Points: Climate alters oceanic physical processes, thereby modulating nutrient availability, which in turn directly governs Particulate Inorganic Carbon (PIC) variationsA 20‐year analysis identified three core mechanisms driving PIC spatiotemporal variations in the study areaRising PIC under future climates predicts higher carbon sedimentation rates, marking PIC as a key climate indicator [ABSTRACT FROM AUTHOR]

Understanding and managing the response of marine ecosystems to human pressures including climate change requires reliable large-scale and multidecadal information on the state of key populations. These populations include the pelagic animals that support ecosystem services including carbon export and fisheries. The use of research vessels to collect information using scientific nets and acoustics is being replaced with technologies such as autonomous moorings, gliders, and meta-genetics. Paradoxically, these newer methods sample pelagic populations at ever-smaller spatial scales, and ecological change might go undetected in the time needed to build up large-scale, long time series. These global-scale issues are epitomised by Antarctic krill (Euphausia superba), which is concentrated in rapidly warming areas, exports substantial quantities of carbon and supports an expanding fishery, but opinion is divided on how resilient their stocks are to climatic change. Based on a workshop of 137 krill experts we identify the challenges of observing climate change impacts with shifting sampling methods and suggest three tractable solutions. These are to: improve overlap and calibration of new with traditional methods; improve communication to harmonise, link and scale up the capacity of new but localised sampling programs; and expand opportunities from other research platforms and data sources, including the fishing industry. Contrasting evidence for both change and stability in krill stocks illustrates how the risks of false negative and false positive diagnoses of change are related to the temporal and spatial scale of sampling. Given the uncertainty about how krill are responding to rapid warming we recommend a shift towards a fishery management approach that prioritises monitoring of stock status and can adapt to variability and change. [ABSTRACT FROM AUTHOR]

As the world's largest carbon sink, the oceans are essential to achieving the 1.5 °C target. Marine ecosystems play a crucial role in the "sink enhancement" process. A deeper comprehension of research trends, hotspots, and the boundaries of ocean carbon sinks is necessary for a more effective response to climate change. To this end, academic literature in the field of ocean carbon sinks was investigated and analyzed using the core database of the Web of Science. The results show that (1) The ocean carbon sink is a global study. The number of literatures in the field of ocean carbon sinks is growing, and the USA and China are the main leaders, with the USA accounting for 31.19% of the global publications and China accounting for 26.57% of the global publications, and the environmental science discipline is the most popular in this field. (2) Keyword burst detection shows that the keywords "sink, sensitivity, land, dynamics, and seagrass" appear earliest and have high burst intensity, which are the hot spots of research in this field; the keyword clustering shows that the global ocean carbon sinks research mainly focuses on three themes: (i) carbon cycle and climate change; (ii) carbon sinks estimation models and techniques; and (iii) carbon sinks capacity and ocean biological carbon sequestration in different seas. Finally, targeted research recommendations are proposed to further match the ocean carbon sink research. [ABSTRACT FROM AUTHOR]

Ecosystems experiencing pressures are at risk of rapidly transitioning ("tipping") from one state to another. Identifying and managing these so-called tipping points continue to be a challenge in marine, freshwater, and terrestrial ecosystems, particularly when multiple potentially interacting drivers are present. Knowledge of tipping points, the mechanisms that cause them, and their implications for management practices are evolving, but often in isolation within specific ecological realms. Here, we summarize current knowledge of tipping points in marine, freshwater, and terrestrial realms and provide a multi-realm perspective of the challenges and opportunities for applying this knowledge to ecosystem management. We brought together conservation practitioners and global experts in marine, freshwater, and terrestrial tipping points and identified seven challenges that environmental policymakers and managers contend with including (1) predictability, (2) spatiotemporal scales, (3) interactions, (4) reversibility, (5) socio-ecological context, (6) complexity and heterogeneity, and (7) selecting appropriate action. We highlight opportunities for cross-scalar and cross-realm knowledge production and provide recommendations for enabling the management of tipping points. Although knowledge of tipping points is imperfect, we stress the need to continue working toward incorporating tipping points perspectives in environmental management across all realms. [ABSTRACT FROM AUTHOR]

Understanding the interplay of ocean physics and biology at the submesoscale and below (<30 km) is an ongoing challenge in oceanography. While poorly constrained, these scales may be of critical importance for understanding how changing ocean dynamics will impact marine ecosystems. Fronts in the ocean, regions where two disparate water masses meet and isopycnals become tilted toward vertical, are considered hotspots for biophysical interaction, but there is limited observational evidence at the appropriate scales to assess their importance. Fronts around western boundary currents like the Gulf Stream are of particular interest as these dynamic physical regions are thought to influence both productivity and composition of primary producers; however, how exactly this plays out is not well known. Using satellite data and 2 years of in situ observations across the Gulf Stream front near Cape Hatteras, North Carolina, we investigate how submesoscale frontal dynamics could affect biological communities and generate hotspots of productivity and export. We assess the seasonality and phenology of the region, generalize the kilometer‐scale structure of the front, and analyze 69 transects to assess two physical processes of potential biogeochemical importance: cold shelf filament subduction and high salinity Sargasso Sea obduction. We link these processes observationally to meanders in the Gulf Stream and discuss how cold filament subduction could be exporting carbon and how obduction of high salinity water from depth is connected with high chlorophyll‐a. Finally, we report on phytoplankton community composition in each of these features and integrate these observations into our understanding of frontal submesoscale dynamics. Plain Language Summary: The interplay of physics and biology in determining the biomass and composition of phytoplankton communities is poorly understood and is key to understanding marine ecosystem resilience and structure in a changing ocean. In this work we investigated the impact of physics and biology on phytoplankton across scales focusing on the Gulf Stream front. Fronts in the ocean are where lines of equal density go from being horizontal to having a vertical tile, and because of this can enable nutrients and plankton to move from depth to the surface and vice versa. The objective of this work is to understand how physics might drive important changes in phytoplankton biomass and composition in the Gulf Stream front, which is amongst the sharpest gradients in temperature, density, and current speed in the global ocean. We find two frequent processes at the front, the apparent downward movement of cold filaments along the edge of the Gulf Stream, associated with meander troughs, and upward movement of high salinity Sargasso Sea water into the front linked to meander crests. While ephemeral, these processes are frequent and could have a large impact on local phytoplankton biomass, phytoplankton composition, and the export of organic matter to depth. Key Points: The frontal zone of the Gulf Stream has an interface water mass with different origins and a range of biogeochemical impactsMeanders appear to control the front interface: troughs lead to shelf filament subduction and crests lead to high salinity water obductionSubduction and obduction appear to be common at the front and could lead to ephemeral kilometer‐scale export and productivity [ABSTRACT FROM AUTHOR]

Marine Ecosystem Models (MEMs) are increasingly driven by Earth System Models (ESMs) to better understand marine ecosystem dynamics, and to analyze the effects of alternative management efforts for marine ecosystems under potential scenarios of climate change. However, policy and commercial activities typically occur on seasonal‐to‐decadal time scales, a time span widely used in the global climate modeling community but where the skill level assessments of MEMs are in their infancy. This is mostly due to technical hurdles that prevent the global MEM community from performing large ensemble simulations with which to undergo systematic skill assessments. Here, we developed a novel distributed execution framework constructed of low‐tech and freely available technologies to enable the systematic execution and analysis of linked ESM/MEM prediction ensembles. We apply this framework on the seasonal‐to‐decadal time scale, and assess how retrospective forecast uncertainty in an ensemble of initialized decadal ESM predictions affects a mechanistic and spatiotemporal explicit global trophodynamic MEM. Our results indicate that ESM internal variability has a relatively low impact on the MEM variability in comparison to the broad assumptions related to reconstructed fisheries. We also observe that the results are also sensitive to the ESM specificities. Our case study warrants further systematic explorations to disentangle the impacts of climate change, fisheries scenarios, MEM internal ecological hypotheses, and ESM variability. Most importantly, our case study demonstrates that a simple and free distributed execution framework has the potential to empower any modeling group with the fundamental capabilities to operationalize marine ecosystem modeling. Plain Language Summary: Climate change and human activities like fishing are affecting the balance of marine ecosystems and the services they provide. To understand impacts better, scientists use computer models that consider climate, ocean conditions, and ocean life. To make robust decisions, decision makers need robust science delivered by robust models. This requires running many computer simulations, but the complexity of marine ecosystems models makes this difficult. Typically, only institutions with sufficient financial and technical means can overcome these difficulties, which leaves the majority of marine ecosystem modelers wanting. Here we introduce a possible solution to overcome the difficulties, using only simple and free technologies to facilitate the systematic execution of complex ecosystem models across networks of computers, to allow any modeling group to perform these exercises. We demonstrate our solution by running a global marine ecosystem model, EcoOcean, hundreds of times to see how it is affected by variability in ocean conditions. Using available laptops and desktops, we can now complete this task in 30 hr; where prior this modeling task would have taken weeks to complete. It is conceptually simple solutions such as these that may make the process of marine ecosystem modeling easier and more operational around the globe, thus opening the door for scientific management breakthroughs. Key Points: Most marine ecosystem modellers lack the skills and resources to systematically calibrate, validate and assess the models for uncertaintyHere we present a low‐tech and open source run framework to use any computer network as a distributed model execution and assessment systemWe use the framework to mass‐execute an Earth System/Ecosystem Model ensemble to assess the ecosystem impact of ESM uncertainty [ABSTRACT FROM AUTHOR]

Mesoscale and submesoscale processes have crucial impacts on ocean biogeochemistry, importantly enhancing the primary production in nutrient‐deficient ocean regions. Yet, the intricate biophysical interplay still holds mysteries. Using targeted high‐resolution in situ observations in the South China Sea, we reveal that isopycnal submesoscale stirring serves as the primary driver of vertical nutrient transport to sustain the dome‐shaped subsurface chlorophyll maximum (SCM) within a long‐lived cyclonic mesoscale eddy. Density surface doming at the eddy core increased light exposure for phytoplankton production, while along‐isopycnal submesoscale stirring disrupted the mesoscale coherence and drove significant vertical exchange of tracers. These physical processes play a crucial role in maintaining the elevated phytoplankton biomass in the eddy core. Our findings shed light on the universal mechanism of how mesoscale and submesoscale coupling enhances primary production in ocean cyclonic eddies, highlighting the pivotal role of submesoscale stirring in structuring marine ecosystems. Plain Language Summary: Both physical and biogeochemical processes affect marine ecosystems. Mesoscale cyclonic eddies are known to boost biological productivity by lifting the water in the center of the eddy up to where light is plentiful, which results in a subsurface chlorophyll maximum (SCM) layer. However, the SCM persists long after this eddy lifting process has completed. This study utilizes high‐resolution observations across some eddies to see if smaller, submesoscale processes replenish nutrients by stirring water along density surfaces into the SCM. The results indicate that isopycnal submesoscale stirring plays a significant role, helping the SCM persist within the eddy. We propose that this process might be universal and enhance primary production in all eddy‐rich oceans. Key Points: Isopycnal stirring serves as the primary driver of nutrient supply to sustain subsurface chlorophyll maximum in ocean cyclonic eddiesFrontogenesis and submesoscale centrifugal–symmetric instabilities are the most likely dynamical mechanisms for isopycnal stirring [ABSTRACT FROM AUTHOR]

Elasmobranch population declines due to human impacts have been documented at a global scale, having impacts on the functioning and structure of marine ecosystems. This situation leads to an international focus on the conservation of their populations and a key step in the management and conservation of elasmobranch populations is to understand their trophic ecology. Here, by using stable isotopes analysis, we investigated the trophic relationships, trophic niche breadth, and trophic redundancy among 21 batoids and 12 sharks inhabiting the Persian Gulf and Gulf of Oman, two productive areas of the Arabian Sea considered global elasmobranch hotspots. Isotopic results revealed differences in the trophic niche and trophic position among the elasmobranch sampled at species and at family level. For example, the batoids of the family Torpedinidae and the sharks of the family Triakidae occupied higher trophic positions and the family Glaucostegidae showed a lower trophic niche width, whereas the batoids of the family Myliobatidae or Gymnuridae, in overall, showed lower higher trophic niche width, reflecting the trophic habits described for most of the sampled species. We also provided some insights into the ecology of poorly known species, especially relevant for those that are endangered at a global or regional scale. In conclusion, we provide new information about the trophic ecology among batoids and sharks inhabiting the Persian Gulf and Gulf of Oman. This information is highly useful to study the consequences of future changes on their feeding preferences due to natural or human-related factors. [ABSTRACT FROM AUTHOR]

Systematic literature syntheses are a key element in the scientific realm, considering the steadily growing amount of available knowledge. Involving stakeholders in the research process brings a wide range of advantages, like broadening the perspectives on the problem in question, increasing the relevance of results for policy- and decision-making, the public and other end-users and thus enhancing the impact and acceptance of research. While participatory approaches are on the rise, reflections on stakeholder involvement in systematic syntheses on environmental management are scarce. We reflect on the process of involving stakeholders with expertise also from outside academia during three literature syntheses with different foci of marine and coastal ecosystem services in the Baltic Sea. Our analysis is based on notes, e-mails, minutes and recordings of internal project meetings, interviews and workshops involving both researchers and stakeholders. We discuss the challenges the participatory approach introduced and develop lessons learned to support the planning of stakeholder engagement for future literature syntheses. We conclude that stakeholder identification, communication, collaboration and knowledge translation are highly time- and resource-intensive processes. Furthermore, appropriate training and experience are necessary for the design, execution and evaluation of participatory methods tailored to each project stage. Therefore, we underline the importance of adequate consideration of the required resources during project planning and implementation. To encourage and support valuable stakeholder engagement and knowledge exchange between the research community and actors of policy and practice, more appreciation of such efforts by funding institutions and within the wider scientific community is needed. [ABSTRACT FROM AUTHOR]

Understanding and monitoring the ecological quality of coastal waters is crucial for preserving marine ecosystems. Eutrophication is one of the major problems affecting the ecological state of coastal marine waters. For this reason, the control of the trophic conditions of aquatic ecosystems is needed for the evaluation of their ecological quality. This study leverages space-based Sentinel-3 Ocean and Land Color Instrument imagery (OLCI) to assess the ecological quality of Mediterranean coastal waters using the Trophic Index (TRIX) key indicator. In particular, we explore the feasibility of coupling remote sensing and machine learning techniques to estimate the TRIX levels in the Ligurian, Tyrrhenian, and Ionian coastal regions of Italy. Our research reveals distinct geographical patterns in TRIX values across the study area, with some regions exhibiting eutrophic conditions near estuaries and others showing oligotrophic characteristics. We employ the Random Forest Regression algorithm, optimizing calibration parameters to predict TRIX levels. Feature importance analysis highlights the significance of latitude, longitude, and specific spectral bands in TRIX prediction. A final statistical assessment validates our model's performance, demonstrating a moderate level of error (MAE of 0.51) and explanatory power (R2 of 0.37). These results highlight the potential of Sentinel-3 OLCI imagery in assessing ecological quality, contributing to our understanding of coastal water ecology. They also underscore the importance of merging remote sensing and machine learning in environmental monitoring and management. Future research should refine methodologies and expand datasets to enhance TRIX monitoring capabilities from space. [ABSTRACT FROM AUTHOR]

In recent years, the frequent outbreaks of Ulva prolifera in the South Yellow Sea have become the largest-scale green tide disasters in the world. The causes of its outbreaks have garnered widespread attention, particularly the coupled effects of multiple factors. Leveraging the Google Earth Engine (GEE) platform, this study conducted a long-term investigation of the Yellow Sea green tide disaster and the factors using multi-source satellite imagery. Finally, the combined effects of natural environmental changes and human activities on Ulva prolifera were analyzed by redundancy analysis (RDA) and variation partitioning analysis (VPA). The results indicate: (1) Since 2018, the scale of Ulva prolifera in the South Yellow Sea has shown a distinct "biennial" trend. (2) Regarding environmental factors, SST, PAR, precipitation, and windspeed have certain effects on the growth of Ulva prolifera. However, they cannot be considered as determining factors for the outbreak of Ulva prolifera (0.002 < R2 < 0.14). Regarding anthropogenic factors, the recycle time of Pyropia yezoensis culture rafts has a relatively minor influence on the extent of Ulva prolifera. There exists a certain positive correlation (R2 = 0.45) between the human footprint index (HFI) of Jiangsu Province and the annual variation in Ulva prolifera area in the South Yellow Sea. (3) The combined effects of multiple factors influence green tide outbreaks. The Ulvatotal explanatory power of SST, PAR, precipitation, windspeed, HFI, and the recycle time of Pyropia yezoensis culture rafts for the annual variation in the Ulva prolifera area is 31.8%, with these factors interweaving and mutually influencing each other. This study offers important insights into quantifying the driving forces behind Ulva prolifera in the South Yellow Sea, providing valuable information for a deeper comprehension of the complexity of marine ecosystems and sustainable management. [ABSTRACT FROM AUTHOR]

As entering the twenty-first century, the degradation of Africa’s marine environment has become increasingly severe due to rapid population growth, urbanisation, natural disasters, the pressures of overfishing and economic development. Therefore, protecting and restoring Africa’s marine ecosystems is essential to realize the benefits of these resources at the global and regional levels. This paper drew on ecological indicators such as catch data, mean trophic level (TLm), relative primary production required (%PPR), and loss in secondary production index (L index) to measure and assess the impact of marine fisheries on ecosystems. Meanwhile, it constructed a pathway model based on the Environmental Kuznets Curve (EKC) hypothesis to assess ecosystem-level impacts by analysing how economic growth and urbanisation affect the structural diversity of marine ecosystems in West Africa, to study the more complete processes associated with marine resource depletion. Economic growth and urbanisation were found to have both direct and indirect effects on marine trophic structure, and the combined effects suggest that the economic EKC hypothesis does not apply to the marine ecosystem of West Africa, while the urban EKC hypothesis is supported, and that increased levels of urbanisation will benefit diversity of marine fishery catch in West Africa. [ABSTRACT FROM AUTHOR]

Species distribution models (SDMs) have been widely used to project terrestrial species' responses to climate change and are increasingly being used for similar objectives in the marine realm. These projections are critically needed to develop strategies for resource management and the conservation of marine ecosystems. SDMs are a powerful and necessary tool; however, they are subject to many sources of uncertainty, both quantifiable and unquantifiable. To ensure that SDM projections are informative for management and conservation decisions, sources of uncertainty must be considered and properly addressed. Here we provide ten overarching guidelines that will aid researchers to identify, minimize, and account for uncertainty through the entire model development process, from the formation of a study question to the presentation of results. These guidelines focus on correlative models and were developed at an international workshop attended by over 50 researchers and practitioners. Although our guidelines are broadly applicable across biological realms, we provide particular focus to the challenges and uncertainties associated with projecting the impacts of climate change on marine species and ecosystems. [ABSTRACT FROM AUTHOR]

Invasive species are the second most important reason for species extinction since 1500 ad. In addition, these invasive species can cause vast economic loss. In marine ecoregions, alien species introductions are increasing, and those that become invasive have caused profound changes in many marine ecoregions. We compiled a database consisting of information about where species are alien, where they are not, and which species are listed as threatened by invasive species. In addition, we developed an interactive Webapp for visualizing and analyzing the results. We used the Ocean Biogeographic Information System (OBIS) for identifying the presence of a species in a marine ecoregion. Information from the World Register of Marine Species (WoRMS), the Global Invasive Species Database (GISD), and the Nature Conservancy database on marine invasive species (NatCon) was used to identify the names and locations of marine alien species. Information from the International Union for Conservation of Nature (IUCN) Red List revealed which species are considered to be threatened by invasive species. Our database lists 112,399 marine species, of which 966 are alien species and 1655 are listed as threatened by invasive species by the IUCN. These are distributed throughout 225 marine ecoregions (97% of marine ecoregions). Our results confirm previous studies about the prevalence of alien and invasive species and provide an up‐to‐date status about known and recorded species and their distribution. This information can be used as a fundament for developing impact assessment models and identifying management strategies to combat marine invasive species. [ABSTRACT FROM AUTHOR]

Anthropogenic carbon emissions and associated climate change are driving rapid warming, acidification, and deoxygenation in the ocean, which increasingly stress marine ecosystems. On top of long‐term trends, short term variability of marine stressors can have major implications for marine ecosystems and their management. As such, there is a growing need for predictions of marine ecosystem stressors on monthly, seasonal, and multi‐month timescales. Previous studies have demonstrated the ability to make reliable predictions of the surface ocean physical and biogeochemical state months to years in advance, but few studies have investigated forecast skill of multiple stressors simultaneously or assessed the forecast skill below the surface. Here, we use the Community Earth System Model (CESM) Seasonal to Multiyear Large Ensemble (SMYLE) along with novel observation‐based biogeochemical and physical products to quantify the predictive skill of dissolved inorganic carbon (DIC), dissolved oxygen, and temperature in the surface and subsurface ocean. CESM SMYLE demonstrates high physical and biogeochemical predictive skill multiple months in advance in key oceanic regions and frequently outperforms persistence forecasts. We find up to 10 months of skillful forecasts, with particularly high skill in the Northeast Pacific (Gulf of Alaska and California Current Large Marine Ecosystems) for temperature, surface DIC, and subsurface oxygen. Our findings suggest that dynamical marine ecosystem prediction could support actionable advice for decision making. Plain Language Summary: Human‐driven climate change is rapidly altering the global ocean, with strong warming, increasing acidity, and declining oxygen trends. On top of long‐term trends, short term variations can lead to rapid changes that can have major effects on marine ecosystems. There is a growing need to predict these short‐term changes in order to better inform marine fisheries managers. In this study, we use a climate model designed to predict changes in the real world months‐to‐years in advance to better determine our ability to forecast changes. Previous studies with similar goals have been limited by sparse observations of acidity and oxygen. We utilize brand new observational products that estimate acidity and oxygen levels in the subsurface ocean for the first time to analyze subsurface forecasts. Our results demonstrate a high potential to predict warming, acidity, and oxygen levels in key marine ecosystems with this climate model. These results suggest that there is potential for eventual operational forecasts of marine ecosystems to better inform marine managers. Key Points: Community Earth System Model Seasonal to Multiyear Large Ensemble (SMYLE) forecasts variations in multiple marine stressors up to a year in advance and outperforms statistical persistenceNovel observation‐based products allow for the first skill analysis of subsurface carbon and oxygenAnalysis of predictability from the SMYLE reconstruction reveals high potential to gain additional temperature and oxygen forecast skill [ABSTRACT FROM AUTHOR]

Kuwait Bay, increasingly susceptible to contamination due to urbanization and effluent discharge, serves as a focal point for environmental research. This study aims to provide a scientifically grounded assessment of sediment contamination within the bay, emphasizing the role of effluents as primary pollutants. Sediments, as repositories for both organic and inorganic pollutants, bear significant implications for marine ecosystems. A systematic sampling approach was employed at forty-six georeferenced sites across the bay, utilizing a grab sampler aboard a research vessel. The sediment samples were rigorously analyzed for inorganic geochemistry, encompassing trace elements, nutrients, and heavy metals. A comparative analysis was conducted between the trace element concentrations obtained in this study and established background levels, as well as the guidelines set forth by the United States Environmental Protection Agency (USEPA). The findings indicate a discernible level of contamination in Kuwait Bay. While the current contamination levels are classified as low, there is a pronounced risk of escalating contamination if the practice of discharging untreated effluents persists. In light of these results, the study underscores the urgent need for effluent decontamination prior to discharge into the bay. This research not only maps the spatial distribution of contaminants in Kuwait Bay but also provides a critical evaluation of potential risks to the marine environment, thereby informing future mitigation strategies. The comprehensive nature of this assessment, integrating geochemical analysis with environmental impact evaluation, marks a significant contribution to the field of marine contamination research. [ABSTRACT FROM AUTHOR]

The "blue economy" idea promotes the responsible and sustainable use of coastal and marine resources. The need to balance the exploitation and economic use of these resources has moved to the top of the research agenda and management priorities for small island developing states (SIDS). SIDS face unique challenges due to their geographic, economic, and environmental characteristics. While the specific challenges can vary based on the individual SIDS, some common future challenges include (i) climate change and sea-level rise resulting from the increased frequency and intensity of storms and coastal erosion; (ii) natural disasters such as hurricanes, cyclones, tsunamis, and earthquakes, resulting in extensive damage, disruption of essential services, and lead to loss of lives and livelihoods; (iii) lack of sustainable development and economic diversification leading to reliance on few key sectors, such as tourism and agriculture, which are vulnerable to market fluctuations; (iv) energy security and renewable energy transition; as there is dependency on imported fossil fuels for their energy needs, price fluctuations and supply disruptions occurs; (v) biodiversity conservation and marine resource management; they host unique ecosystems and rich biodiversity, including coral reefs, mangroves, and marine species; and (vi) access to finance and technology; there are direct opportunities, for accessing funds to support technology development under sustainable finance projects. This themed article set attracted 14 submissions, 7 of which were accepted for publication. The topics covered fisheries, climate change effects, marine litter, and development of new technologies and finance mechanisms to support the SIDS. Overall, these contributions have emphasized the remarkable role that SIDS play in the protection and management of coastal and marine ecosystems, but also highlighted several needs and key priorities. [ABSTRACT FROM AUTHOR]

One of the existential threats facing all species on planet earth is global warming. Its impact has already been felt in many parts of the world, but more severely in coastal areas containing marine ecosystems. The effects of climate change are adversely affecting the marine ecosystems of South Asia, posing considerable threats to biodiversity, fisheries, and the economic systems of the region. There is a significant shift in biodiversity, productivity, and functionality of these marine ecosystems due to increased sea temperatures, ocean acidification, and sea level rise. As a result of climate change, the region has been experiencing ecological changes, which have prompted an analysis of the resulting ecological alterations, including coral reef bleaching, changes to marine species migration patterns, and a decrease in fish populations. As a result of global warming, Pakistan has significant concerns regarding the persistence of marine life, which is crucial to its exports, and is also a significant part of its labour force. To mitigate this threat, several strategies are recommended, which address the government's weak policies and emphasize the support of international organizations. Taking precautions, it is now imperative to combat global warming's negative effects on marine life. This study highlights climate change as an imminent non-traditional threat with significant consequences for South Asia's marine biodiversity and marine life. [ABSTRACT FROM AUTHOR]

Marine heatwaves are known to have a detrimental impact on marine ecosystems, yet predicting when and where they will occur remains a challenge. Here, using a large ensemble of initialized predictions from an Earth System Model, we demonstrate skill in predictions of summer marine heatwaves over large marine ecosystems in the Arabian Sea seven months ahead. Retrospective forecasts of summer (June to August) marine heatwaves initialized in the preceding winter (November) outperform predictions based on observed frequencies. These predictions benefit from initialization during winters of medium to strong El Niño conditions, which have an impact on marine heatwave characteristics in the Arabian Sea. Our probabilistic predictions target spatial characteristics of marine heatwaves that are specifically useful for fisheries management, as we demonstrate using an example of Indian oil sardine (Sardinella longiceps). Plain Language Summary: Marine heatwaves (MHWs) are prolonged extreme events associated with exceptionally high ocean water temperatures. Such events impose heat stress on marine life, and thus predicting such events is beneficial for management applications. In this work we show that the occurrence of MHWs in summer in the Arabian Sea can be skilfully predicted seven month in advance. Our prediction system benefits from the information of sea surface temperature anomalies in the eastern Pacific Ocean in the preceding winter, among other aspects. Our predictions suggest potential for using climate information in fisheries management in this region. Key Points: Summer marine heatwaves in the Arabian Sea are predictable seven months in advanceThe prediction skill in summer is mainly associated with a preceding El Niño event in winterProbabilistic predictions of Arabian Sea area under heatwave can be tailored to benefit fisheries [ABSTRACT FROM AUTHOR]

Marine heatwaves (MHWs) off Western Australia (110°–116°E, 22°–32°S; herein, WA MHWs) can cause devastating ecological impacts, as was evidenced by the 2011 extreme event. Previous studies suggest that La Niña is the major large-scale driver of WA MHWs, while the Indian Ocean dipole (IOD) may also play a role. Here, we investigate historical WA MHWs and their connections to these large-scale climate modes in an ocean model (ACCESS-OM2) simulation driven by a prescribed atmosphere from JRA-55-do over 1959–2018. Rather than analyzing sea surface temperature, the WA MHWs and climate mode indices were characterized and investigated in vertically averaged temperature (VAT) to ∼300-m depth to afford the longer ocean dynamic time scales, including remote oceanic connections. We develop a cyclostationary linear inverse model (CS-LIM; from 35°S to 10°N, across the Indo-Pacific Ocean), to investigate the relative contributions of La Niña VAT and positive IOD VAT to the predictability of WA VAT MHWs. Using a large ensemble of CS-LIM simulations, we found that ∼50% of WA MHWs were preceded about 5 months by La Niña, and 30% of the MHWs by positive IOD about 20 months prior. While precursor La Niña or positive IOD, on their own, were found to correspond with increased WA MHW likelihood in the months following (∼2.7 times or ∼1.5 times more likely than by chance, respectively), in combination these climate mode phases were found to produce the largest enhancement in MHW likelihood (∼3.2 times more likely than by chance). Additionally, we found that stronger and longer La Niña and/or positive IOD tend to lead stronger and longer WA MHWs. Significance Statement: This study examines seasonal-to-interannual time-scale predictability of marine heatwaves off Western Australia. We developed and applied a linear inverse model, informed by numerical model results, to generate a large number of 60-yr temperature simulations across the broader Indian–Pacific Ocean region to quantify this marine heatwave predictability. We found that La Niña typically increases the likelihood of marine heatwaves off Western Australia about 5 months (3–7 months) later, while positive Indian Ocean dipole events increase their likelihood about 20 months (18–22 months) later. Marine heatwaves can severely impact local marine ecosystems and the economy. Our findings are expected to be valuable for marine heatwave prediction system development on time scales that can be beneficial to marine ecosystem conservation and fishery management. [ABSTRACT FROM AUTHOR]

The Caribbean is one of the world's most vulnerable regions to the projected impacts of climate change, and changes in coral reef ecosystems have been studied over the last two decades. Lately, new technology-based methods using satellites and unmanned vehicles, among others have emerged as tools to aid the governance of these ecosystems by providing managers with high-quality data for decision-making processes. This paper addresses the development of a Google Earth Engine (GEE)-based application for use in the management processes of shallow coral reef ecosystems, using images acquired with Remotely Piloted Aircraft Systems (RPAS) known as drones, at the Old Providence McBean Lagoon National Natural Park; a Marine Protected Area (MPA) located northwest of Old Providence Island, Colombia. Image acquisition and processing, known as drone imagery, is first described for flights performed using an RTK multispectral drone at five different monitoring stations within the MPA. Then, the use of the GEE app is described and illustrated. The user executes four simple steps starting with the selection of the orthomosaics uploaded to GEE and obtaining the reef habitat classification for four categories: coral, macroalgae, sand, and rubble, at any of the five monitoring stations. Results show that these classes can be effectively mapped using different machine-learning (ML) algorithms available inside GEE, helping the manager obtain high-quality information about the reef. This remote-sensing application represents an easy-to-use tool for managers that can be integrated into modern ecosystem monitoring protocols, supporting effective reef governance within a digitized society with more demanding stakeholders. [ABSTRACT FROM AUTHOR]

Temperate fisheries grounds are exposed to compound effects of jellyfish proliferations and fishing pressure, which affect local fisheries, cause economic losses, and threaten seafood supply. Here, we quantify the interlink between climate variability and jellyfish blooms and their impact on the Japanese anchovy (Engraulis japonicus), in the Korean coastal waters. We used a bioclimate dataset (2010–2019) that includes quantitative information of two major bloom-former species, Aurelia coerulea and Nemopilema nomurai, in the Korean Peninsula. We show that climate phenomena governing East Asia regions explain circa half of jellyfish variability. In turn, jellyfish blooms have a significant negative effect on anchovy interannual changes (r = -0.47, P < 0.01), which varies along with the bloom magnitude. Our results indicate that the intensity of jellyfish blooms, more than their duration, has a predominant effect on anchovy and coastal fisheries production. We also suggest the possibility of using climate signals for assessing and eventually predicting, interannual abundance changes of jellyfish in the Korean Peninsula. These results stress the challenge posed by jellyfish blooms to the provisioning of ecosystem services via their influence on marine harvested fish and further highlight the need for their integration into ecosystem-based management. [ABSTRACT FROM AUTHOR]

Ocean chlorophyll time series exhibit temporal variability on a range of timescales due to environmental change, ecological interactions, dispersal, and other factors. The differences in chlorophyll temporal variability observed at stationary locations (Eulerian perspective) or following water parcels (Lagrangian perspective) are poorly understood. Here we contrasted the temporal variability of ocean chlorophyll in these two observational perspectives, using global drifter trajectories and satellite chlorophyll to generate matched pairs of Eulerian‐Lagrangian time series. We found that for most ocean locations, chlorophyll variances measured in Eulerian and Lagrangian perspectives are not statistically different. In high latitude areas, the two perspectives may capture similar variability due to the large spatial scale of chlorophyll patches. In localized regions of the ocean, however, chlorophyll variability measured in these two perspectives may significantly differ. For example, in some western boundary currents, temporal chlorophyll variability in the Lagrangian perspective was greater than in the Eulerian perspective. In these cases, the observing platform travels rapidly across strong environmental gradients and constrained by the shelf topography, potentially leading to greater Lagrangian variability in chlorophyll. In contrast, we found that Eulerian chlorophyll variability exceeded Lagrangian variability in some key upwelling zones and boundary current extensions. In these cases, variability in the nutrient supply may generate intermittent chlorophyll anomalies in the Eulerian perspective, while the Lagrangian perspective sees the transport of such anomalies off‐shore. These findings aid with the interpretation of chlorophyll time series from different sampling methodologies, inform observational network design, and guide validation of marine ecosystem models. Plain Language Summary: The differences in phytoplankton variability through time observed at fixed locations (Eulerian perspective) or following water parcels (Lagrangian perspective) are poorly understood. We created a large set of satellite chlorophyll matched time series pairs in the Eulerian and Lagrangian perspective, using global drifter trajectories as an approximation of how surface ocean currents move. We found that for most ocean locations, chlorophyll variability measured in Eulerian and Lagrangian perspectives is not different. In high latitude zones, chlorophyll appears to vary similarly over large areas. However, in localized regions of the ocean, such as western boundary currents and upwelling regions, chlorophyll variability in these two perspectives may significantly differ. The causes are linked to the specific ocean dynamics of each area. Key Points: For most ocean locations, chlorophyll variances measured in Eulerian and Lagrangian perspectives are not statistically differentIn some western boundary currents, chlorophyll variance was greater in the Lagrangian perspectiveIn some key upwelling zones and boundary current extensions, chlorophyll variance was greater in the Eulerian perspective [ABSTRACT FROM AUTHOR]

Simple Summary: The selection of fish community survey methods based on their efficiency and reliability is critical for ecosystem conservation, protection and management. In this study, we used environmental DNA (eDNA) metabarcoding and traditional (gillnet) fishing to assess the diversity of fishes along a mangrove–seagrass–coral reef continuum of marine habitats in Hainan, China. Higher fish taxonomic diversity was identified using eDNA; however, gillnet fishing was better at identifying fish communities from different habitats along the sampled continuum. Results from both survey methods indicate that some fish species use multiple habitats along mangrove–seagrass–coral reef continuums. Therefore, the concurrent use of eDNA and gillnet survey methods provides a more comprehensive approach to understanding the heterogeneity of fish taxonomic and functional diversity along mangrove–seagrass–coral reef continuums. The effective and reliable monitoring of fish communities is important for the management and protection of marine ecosystems. Environmental DNA (eDNA) metabarcoding is a relatively new method that has been widely used in recent years, while traditional sampling via fish catching (i.e., gillnets) is one of the most common and reliable fish monitoring methods used to date. We compared the taxonomic and functional diversity of fish detected within a mangrove–seagrass–coral reef continuum using both survey methods. One liter seawater and gillnet samples were collected in August 2021 from mangrove forests, seagrass meadows and coral reef habitats (n = 3 each) in Hainan, China. Surveys using eDNA and gillnets identified 139 genera belonging to 66 families and 58 genera belonging to 42 families, respectively. Regardless of the survey method, fish detected in mangrove, seagrass and coral reef habitats were heterogeneous in their communities; however, the shared species between habitats suggest some degree of connectivity. There were no significant differences between habitats in terms of taxonomic and functional diversity, but a higher taxonomic diversity was detected using eDNA. Both methods were able to distinguish fish assemblages between different habitats; however, gillnet surveys performed better than eDNA surveys for distinguishing mangrove from seagrass assemblages. Therefore, the concurrent use of eDNA and gillnet survey methods provides a more comprehensive approach to understanding the heterogeneity of fish taxonomic and functional diversity along mangrove–seagrass–coral reef continuums. [ABSTRACT FROM AUTHOR]

Eutrophication in marine waters is traditionally assessed by checking if nutrients, algal biomass and oxygen are below/above a given threshold. However, increased biomass, nutrient concentrations and oxygen demand do not lead to undesirable environmental effects if the flow of carbon/energy from primary producers toward high trophic levels is consistently preserved. Consequently, traditional indicators might provide a misleading assessment of the eutrophication risk. To avoid this, we propose to evaluate eutrophication by using a new index based on plankton trophic fluxes instead of biogeochemical concentrations. A preliminary, model-based, assessment suggests that this approach might give a substantially different picture of the eutrophication status of our seas, with potential consequences on marine ecosystem management. Given the difficulties to measure trophic fluxes in the field, the use of numerical simulations is recommended although the uncertainty associated with biogeochemical models inevitably affects the reliability of the index. However, given the effort currently in place to develop refined numerical tools describing the marine environment (Ocean Digital Twins), a reliable, model-based, eutrophication index could be operational in the near future. [ABSTRACT FROM AUTHOR]

Ecosystem-based fisheries management (EBFM) aims to go beyond single-species management by incorporating ecosystem considerations to guarantee the sustainable use of marine resources. Although many countries have formally committed to the implementation of EBFM, at a practical level progress has been very slow. At the analytical level, many advances have been made, developing sophisticated ecosystem models and, on the other side, rigorous stock assessment models. Yet it is still unclear how these two parallel approaches can be brought together to provide an efficient EBFM. Here we first present the two groups of models, we then discuss ways to integrate both approaches and their resulting possible implications for fisheries advice towards sustainable management, with a special focus on spatially explicit information. [ABSTRACT FROM AUTHOR]

Understanding how future ocean conditions will affect populations of marine species is integral to predicting how climate change will impact both ecosystem function and fisheries management. Fish population dynamics are driven by variable survival of the early life stages, which are highly sensitive to environmental conditions. As global warming generates extreme ocean conditions (i.e., marine heatwaves) we can gain insight into how larval fish growth and mortality will change in warmer conditions. The California Current Large Marine Ecosystem experienced anomalous ocean warming from 2014 to 2016, creating novel conditions. We examined the otolith microstructure of juveniles of the economically and ecologically important black rockfish (Sebastes melanops) collected from 2013 to 2019 to quantify the implications of changing ocean conditions on early growth and survival. Our results demonstrated that fish growth and development were positively related to temperature, but survival to settlement was not directly related to ocean conditions. Instead, settlement had a dome-shaped relationship with growth, suggesting an optimal growth window. Our results demonstrated that the dramatic change in water temperature caused by such extreme warm water anomalies increased black rockfish growth in the larval stage; however, without sufficient prey or with high predator abundance these extreme conditions contributed to reduced survival. [ABSTRACT FROM AUTHOR]

The South China Sea (SCS), situated in southern China, at the junction of the Pacific Plate, the Eurasian Plate, and the Indian Ocean Plate, is a northeast-southwest trending semi-enclosed sea. It spans an area of approximately 3.5 million square kilometers and has an average water depth of about 1 200 m, its deepest point reaching 5 559 m. In 2021, a scientific expedition (called as U1 voyage) in the South China Sea was organized by the Innovation Research Team of Guangdong Special Key Program from March to April, this marks the first comprehensive scientific research voyage to the southern U-boundary corridor. Consisting of a total of 30 papers, this special issue is to share a portion of the research findings from this scientific expedition U1 voyage, covering six aspects: 1) characteristics of the marine ecosystem in the SCS and its response to marine dynamic processes; 2) multi-scale marine dynamic processes, sea-air interactions, and forecasting techniques in the SCS; 3) geomorphology and geological structure; 4) sedimentary processes and resource potential in the SCS; 5) geostrategy, rights and interests maintenance and strategic countermeasures in the SCS; 6) marine scientific instruments. By integrating the scientific research with the study of history, jurisprudence and international strategies, this issue presents new insights into the formation history and scope evolution of the SCS, and it also seeks to establish a new scientific framework based on the marine governance and development of the SCS. [ABSTRACT FROM AUTHOR]

In the 1950s, the Soviet Union expanded the range of its fisheries operations into international water traditionally fished by American vessels. In the USA, government officials and fisheries experts alike expressed concerns that the Soviets were overfishing Atlantic stocks, or even potentially engaging in off-shore espionage. Despite these fears, members of the US fisheries management community reached out and engaged with their Soviet counterparts directly. This initial communication led to a series of collaborations between US and Soviet scientific agencies aimed at developing a deeper understanding of marine ecosystems and improving the sustainability of international fisheries. The joint US–USSR research efforts beginning in the 1960s laid the foundation for continued cooperative studies through the 1980s and into the post-Soviet era. This paper uses historical records from the US National Archives and data products currently available on the web to examine the legacy of this Cold War cooperative research program. These materials demonstrate how American and Soviet scientists collaborated to generate and describe data on fisheries. It also considers how they negotiated recordkeeping and data management activities across radically different governmental structures, while also navigating the transition to digital recordkeeping and data exchange. This case offers perspective on the preservation of at-risk ecological records and the continued value of these data in our contemporary world. [ABSTRACT FROM AUTHOR]

Benthic habitats mapping is essential to the management and conservation of marine ecosystems. The traditional methods of mapping benthic habitats, which involve multibeam data acquisition and manually collecting and annotating imagery data, are time-consuming. However, with technological advances, using machine learning (ML) algorithms with structure-from-motion (SfM) photogrammetry has become a promising approach for mapping benthic habitats accurately and at very high resolutions. This paper explores using SfM photogrammetry and extreme gradient boosting (XGBoost) classifier for benthic habitat 3D mapping of a vertical wall at the Charlie-Gibbs Fracture Zone in the North Atlantic Ocean. The classification workflow started with extracting frames from video footage. The SfM was then applied to reconstruct the 3D point cloud of the wall. Thereafter, nine geometric features were derived from the 3D point cloud geometry. The XGBoost classifier was then used to classify the vertical wall into rock, sponges, and corals (Case 1 - three classes). In addition, we separated the sponges class into three types of sponges: Demospongiae, Hexactinellida, and other Porifera (Case 2 - five classes). Moreover, we compared the results from XGBoost with the widely used ML classifier, random forest (RF). For Case 2, XGBoost achieved an overall accuracy (OA) of 74.45%, while RF achieved 73.10%. The OA improved by about 10% from both classifiers when the three types of sponges were combined into one class (Case 1). Results showed that the presented 3D mapping of benthic habitat has the potential to provide more detailed and accurate information about marine ecosystems. [ABSTRACT FROM AUTHOR]

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Biological reference points for fishery management depend on estimates of current stock status relative to unfished biomass (depletion). The ratio of fish density outside to inside a marine reserve, the density ratio, could serve as a proxy for depletion for data-poor management. However, transient dynamics associated with time lags in returning to the unfished state following reserve implementation make that proxy inaccurate on short time scales. We assessed density ratio management rules using an age-structured, spatially explicit model of four US west coast nearshore fishes following reserve implementation, with scenarios encompassing sampling error, recruitment variability, and uncertainty in natural mortality. In deterministic simulations, management incorporating time lags generally resulted in a higher mean and lower variability in biomass over 20 years, but lower mean yield compared to management that did not. However, when stochastic recruitment was included, differences among simulations due to stochasticity were much greater than any difference in performance between management strategies. Nonetheless, in certain cases, accounting for time lags could help avoid unwarranted increases in harvest effort after reserve implementation. [ABSTRACT FROM AUTHOR]

Human activities and climate change have profound effects on marine ecosystems, leading to changes in ecosystem functionality and even reduced resilience. Hence, a systematic assessment of the marine ecosystem resilience and the drivers of resilience is needed. This study provides an approach to help measure the resilience of reduction marine ecosystems by calculating early warning signs of marine net primary productivity, while introducing fishing activities and environmental data in the study area to evaluate the factors affecting marine ecosystem resilience. The results showed that in 36.29% of the Chinese exclusive economic zone, resilience was likely to be significantly decreased. There was a non-linear relationship between fishing activities and indicators of resilience reduction, with pixels with high-intensity fishing activities being more susceptible to resilience reduction. Fishing regulations are urgently needed in areas where marine ecosystem resilience may be reducing. Effective management and protection of marine ecosystems require assessment of the spatial overlap between marine ecosystems states and human activities. This study provides a scientific basis for sustainable management of social-ecological systems by comparing high-precision fishing data to marine environmental data, thereby analysing marine ecosystem resilience through the use of early warning indicators. [ABSTRACT FROM AUTHOR]