The global proliferation of plastics and their degradation into microplastics (<5 mm) have created a pervasive environmental crisis with severe ecological and human health consequences. Despite the exponential growth in microplastic research over the past decade, standardized protocols are still lacking. The absence of consistent sampling, analysis, and reporting methods limits data comparability, interoperability, and harmonization across studies. This study conducted a systematic bibliographic review of 355 peer-reviewed articles published between 2010 and 2022 that investigated microplastics in freshwater as well as marine water and sediment environments. The goal was to evaluate methodological consistency, sampling instruments, measurement units, reported characteristics, and data-sharing practices to identify pathways toward harmonized and FAIR (Findable, Accessible, Interoperable, and Reusable) microplastic data. Results show that 80.6% of studies focused on marine environments, 18% on freshwater, and 1.4% on both. This highlights persistent data gaps in freshwater systems, which function as key transport pathways for plastics to the ocean. Most studies targeted water (59%) rather than sediment (41%) and were mostly based on single-time sampling, limiting long-term analyses. Surface layers (<1 m) were predominantly sampled, while deeper layers remain understudied. Nets, particularly Manta, neuston, and plankton nets were the dominant tools for water sampling, whereas grabs, corers, and metallic receptacles were used for sediments. However, variations in mesh size and sampling depth introduce substantial biases in particle size recovery and reduce comparability across studies. The most common units were counts/volume for water and counts/g dry weight for sediments, but more than ten unit expressions were identified, complicating conversions. Only 35% of studies reported all four key microplastic characteristics (color, polymer type, shape, and size), and less than 20% made datasets publicly available. To advance harmonization, we recommend the adoption of consistent measurement units, mandatory reporting of key metadata, and wider implementation of open data practices aligned with the FAIR principles. These insights provide a foundation for developing robust monitoring strategies and evidence-based management frameworks. This is especially important for freshwater systems, where data remain scarce, and policy intervention is urgently needed.

Seagrasses are foundational species threatened by chronic and acute abiotic stressors. Seagrasses reallocate carbon and alter their physiology to cope with these changes; however, it is unclear whether those responses are coordinated with molecular changes. Molecular and physiological responses related to abiotic change could elucidate their ability to acclimate to current conditions. We hypothesized that seagrass gene expression and physiology are linked to temporal and storm-induced environmental variation. Between February and October 2020, we assessed variation in water quality concurrently with in situ measures of metabolism, photosynthetic efficiency, and gene expression of the seagrass Halodule wrightii in a dynamic northern Gulf of Mexico estuary. The study started 227 d before and finished 38 d after landfall of Hurricane Sally. Irradiance, pH, and dissolved oxygen showed diel patterns of variation, while temperature exhibited diel and seasonal oscillations. Hurricane passage disrupted environmental variability and caused rapid reductions in water quality. Despite this perturbation, most physiological measures did not exhibit consistent patterns of variation across the study. Primary productivity was not affected by hurricane passage. However, effective quantum yield was negatively related to the relative expression of photosynthesis- and stress-related genes, whereas maximum quantum yield was positively related to the abundance of those transcripts. Variation in maximum quantum yield and relative expression of photosynthesis-related genes PsaJ , psbA , and psbD appeared to be driven by poor water quality following the hurricane. Results indicate that major disturbances can trigger seagrass physiological responses via gene expression, improving our understanding of seagrass biology and response to short-term disturbance.

The Coral Research and Development Accelerator Platform (CORDAP) seeks to fund innovative, transformative ideas and technologies that could allow us to conserve and/or restore coral reefs and other coral-based habitats affordably and at-scale. Although science is at the heart of this novel initiative, it will also be critical to simultaneously work towards growing the capacity to undertake effect coral research, conservation, and, when necessary, restoration in those areas where coral reefs in particular are located; the majority of the planet’s coral reefs are located in the territorial waters of low- to middle-income countries, many of which lack the personnel and infrastructure needed to successfully stage coral reef interventions. In an effort to develop capacity for successful coral research in developing nations, CORDAP has been 1) requiring that all proposals submitted to our “Coral Accelerator Program” (1.5-million USD awards for projects up to three years) include at least one developing country partner (and preferably being led by a developing country researcher and based at their major area of work), 2) staging workshops whereby developing country coral visionaries discuss their needs with capacity development experts to draft actionable plans to overcome barriers, 3) raising the visibility of both senior coral “champions” and more junior “rising stars” and providing them with both funding opportunities for their research and conservation/restoration projects and a research support network (including mentorships by more established members in the field) that they can depend upon to realize their coral projects, and 4) initiating a coral conservation and restoration academy (“Coral School”) that will provide training in not only basic coral biology, reef ecology, and the latest methods needed to conserve and restore reefs, but also the skills needed to serve as local and regional trainers of the aforementioned material (i.e., “train the trainers”). Through these, and other, capacity development initiatives, we seek to grow a large network of coral scientists, conservationists, and restoration practitioners through which we will implement the in-water activities flowing from the groundbreaking science and technologies developed through our CAP program. In this way, we will have cemented both the scientific and human capacity needed to climate-proof intact reefs, or restore degraded ones, on a truly global scale in a manner in which cutting-edge approaches rapidly make their way to those on-the-ground practitioners who serve as the stewards of their imperiled reefs.

The attraction‐production continuum in fishery management centers on the extent to which artificial reefs increase fish production or whether they simply redistribute fish. Reef systems could produce carbon to support growth of higher trophic levels. Therefore, we aimed to understand carbon flows at lower trophic levels on shallow‐water (11 m) artificial reefs within a region which hosts an extensive artificial reef network. We described benthic communities and quantified changes in oxygen content within in situ enclosures to assess reef, sediment, and water‐column community metabolism. We tested spatial and temporal differences in metrics by repeatedly sampling at three sites across two seasons for 2 yrs. Suspension feeders were abundant on reef surfaces and these communities were often heterotrophic. In sediments, lancelets, amphipods, and bivalves were scarcer adjacent to the reef (2 m) and more numerous 20 m away. Infauna communities at adjacent reefs were significantly dissimilar, suggesting biotic (e.g., predation) and, or abiotic (e.g., sand scour) conditions cause large differences in infauna communities near reefs. Sediment and water‐column communities were mostly autotrophic and net productivity did not consistently increase or decrease with distance from the reef. Metabolic metrics were often best explained by temporal intervals and site. The integrated system was autotrophic in 9 out of 11 instances where reef, sediment, and water‐column contributed −0.46 to 0.27, −14.8 to 66.8, and 33.5% to 91.4% respectively to net system productivity. When planning artificial reef deployment projects with heterotrophic reefs, managers should ensure ample water‐column space is provisioned to support them trophically.

ABSTRACT Aim Abundant species distribution models (SDMs) of deep‐sea corals and sponges (DSCS) allow one to make community‐level predictions about DSCS. Pairing that with the conservation information of Vulnerable Marine Ecosystems (VMEs) due to their sensitivity to seafloor trawling, one can assess the efficacy of established seafloor protections, known as Essential Fish Habitat and Conservation Areas (trawl closure areas), in the United States West Coast on a multi‐taxon basis. From this, we seek to answer the following questions: (1) can accurate multi‐taxon, trawl‐sensitive DSCS distribution predictions be made for the US West Coast and (2) to what extent do current trawl protections overlap with multi‐taxon distribution predictions and what are the conservation and management implications? Location United States West Coast marine waters. Methods A cluster analysis was run on 40 SDMs of DSCS, identifiable as VME indicators and assigned a VME indicator score based on criteria used by regional fisheries management organisations. SDMs of taxa in clusters were stacked and averaged to produce stacked SDM (S‐SDM) prediction maps. All prediction maps were classified into five habitat suitability classes to facilitate interpretation. The total area within benthic ecoregion‐bathymetric boundaries and the percentage overlap with the bottom trawl closure zone were computed for spatial contextualization and to determine protection coverage for S‐SDMs, respectively. Results Cluster analysis identified 10 groups that represent unique S‐SDMs for the region. Taxa clustered together have previously been documented together in surveys but some novel associations are reported. Geographically, the predicted occurrences can range along the entire western continental margin, be highly restricted, or constrained by recognised biogeographic boundaries. VME indicator metrics ranged from low to moderate. When trawl coverage was computed relative to the suitability's prevalence in the modelling domain, trawl protection was shown to be large for the highest suitability classes for most of the S‐SDMs. Main Conclusions Results indicate the clustering approach has some strengths in identifying known and documented associations between DSCS taxa but some are problematic and produce low to moderate VME indicator scores for S‐SDMs, undercutting the conservation information the metric should convey. Coupled with the small predicted areas of the highest suitability classes, the wholesale recommendation for this approach for management purposes is difficult. We discuss avenues for methodological improvements.

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Seagrasses, corals, marsh plants, kelps, and mangroves support valuable coastal ecosystems but are threatened by environmental stressors. The need to manage these foundation taxa has spurred more than a decade of study on the relationship between genetic diversity and function or stability. We synthesized this literature base (129 relevant publications) and found more reported instances of neutral to positive relationships between genetic diversity and function than negative. However, much of the scientific understanding is based on the response of three genera and from unreplicated observational studies that correlate genetic diversity to measured response variables. When a disturbance was present, the studies often lacked controls or baseline data. Only 5.5% of the studies robustly tested for stability. These shortcomings preclude a rigorous evaluation of whether more genetically diverse foundation populations increase stability and hinder the use of genetics-based conservation strategies. Future studies should be focused on diverse species and ecosystem-level impacts using manipulative designs.

The global ocean's oxygen content has declined significantly over the past several decades and is expected to continue decreasing under global warming, with far-reaching impacts on marine ecosystems and biogeochemical cycling. Determining the oxygen trend, its spatial pattern, and uncertainties from observations is fundamental to our understanding of the changing ocean environment. This study uses a suite of CMIP6 Earth system models to evaluate the biases and uncertainties in oxygen distribution and trends due to sampling sparseness. Model outputs are sub-sampled according to the spatial and temporal distribution of the historical shipboard measurements, and the data gaps are filled by a simple optimal interpolation method using Gaussian covariance with a constant e-folding length scale. Sub-sampled results are compared to full model output, revealing the biases in global and basin-wise oxygen content trends. The simple optimal interpolation underestimates the modeled global deoxygenation trends, capturing approximately two-thirds of the full model trends. The North Atlantic and subpolar North Pacific are relatively well sampled, and the simple optimal interpolation is capable of reconstructing more than 80 % of the oxygen trend in the non-eddying CMIP models. In contrast, pronounced biases are found in the equatorial oceans and the Southern Ocean, where the sampling density is relatively low. The application of the simple optimal interpolation method to the historical dataset estimated the global oxygen loss to be 1.5 % over the past 50 years. However, the ratio of the global oxygen trend between the sub-sampled and full model output has increased the estimated loss rate in the range of 1.7 % to 3.1 % over the past 50 years, which partially overlaps with previous studies. The approach taken in this study can provide a framework for the intercomparison of different statistical gap-filling methods to estimate oxygen content trends and their uncertainties due to sampling sparseness.

Shallow coastal systems act as nursery habitat for many species of fish and macroinvertebrates. Juveniles of these species may show selective use of certain habitat types over others, but the degree of such selectivity is not well studied for many species. Analysis of habitat selectivity is often hindered by inherently different gear types used in the habitats examined, which may not allow for direct comparison between the habitats. Here, we carry out nekton catches in the fringing marsh, using fyke nets, and in the adjacent seagrass habitat, using trawls, in the northern Gulf of Mexico to assess the relative use of the two habitats by the juveniles of six widespread important species. To resolve issues of gear comparability between fyke nets and trawls, we develop a habitat use index (HUI_S) . The results reveal a consistent trend where, in relation to pinfish, speckled sea trout shows slightly higher (from 8.4 to 66.9 times); American silver perch and brown shrimp show moderately higher (from 2.3 to 369.4 times); and blue crab and white shrimp show greatly higher (from 90.6 to 2366.4 times) use of marsh over seagrass habitat. Thus, while similar in direction, differences in the use of marsh over seagrass habitat in relation to pinfish were more pronounced in some sites. We propose an index that can resolve issues of gear comparability and improve our understanding of coastal habitat selectivity by fish and macroinvertebrates.

Extreme winter temperatures govern the northern range limit of black mangroves ( Avicennia germinans ) in southeastern North America. There is a pressing need for studies that advance our understanding of how extreme cold temperature events affect mangroves near their range limits. However, such events are infrequent and challenging to study at regional scales. Here, we compared the damage to mangroves from extreme freeze events in 2018 and 2021, using local data from sites in USA (Florida, Louisiana, and Texas) and northeastern Mexico (Tamaulipas). In 2018, mangrove damage was concentrated in Louisiana and the upper Texas coast, where minimum temperatures ranged from -4 °C to -7 °C. In 2021, damage from a more severe freeze event was concentrated along the central to northern coasts of Texas, where minimum temperatures ranged from -4 °C to -10 °C. We used regional temperature and vegetation data from these events to quantify temperature thresholds for A. germinans leaf damage. Our results indicate that A. germinans leaf damage is likely to occur when temperatures are between -4 °C and -6 °C. These findings help refine temperature thresholds for A. germinans leaf damage and advance understanding of the effects of extreme freeze events on mangrove range expansion. This information is valuable for anticipating future range dynamics in a warming world.

Substantial losses of the seagrass Posidonia oceanica have initiated investigations into localized resilience declines related to anthropogenic disturbances. In this study, we determined reconstructed shoot age and interannual growth metrics can detect anthropogenic impact effects on P. oceanica production. Interannual rhizome vertical growth, leaf production, and demographics of shoots collected from sewage and trawling impacted areas were examined using mixed effects modeling. Detected impact effects were specific to the type of impact, manifesting as an older-skewed age distribution of sewage outfall shoots and reduced vertical growth and reduced leaf production of trawling site shoots. A stress event period was also detected for all shoots >5 years old, with trawling impacted shoots indicating little recovery. Reconstructed age and growth metrics are simple to measure, incorporate multiple years of in situ shoot development, and are advantageous for identification of declining P. oceanica resilience prior to catastrophic losses.

Climate change is altering the frequency and intensity of extreme weather events. Quantifying ecosystem responses to extreme events at the landscape scale is critical for understanding and responding to climate-driven change but is constrained by limited data availability. Here, we integrated remote sensing with ground-based observations to quantify landscape-scale vegetation damage from an extreme climatic event. We used ground- and satellite-based black mangrove ( Avicennia germinans ) leaf damage data from the northern Gulf of Mexico (USA and Mexico) to examine the effects of an extreme freeze in a region where black mangroves are expanding their range. The February 2021 event produced coastal temperatures as low as − 10 °C in some areas, exceeding thresholds for A. germinans damage and mortality. We used Sentinel-2 surface reflectance data to assess vegetation greenness before and after the freeze, along with ground-based observations of A. germinans leaf damage. Our results show a negative, nonlinear threshold relationship between A. germinans leaf damage and minimum temperature, with a temperature threshold for leaf damage near − 6 °C. Satellite-based analyses indicate that, at the landscape scale, damage was particularly severe along the central Texas coast, where the freeze event affected > 2000 ha of A. germinans -dominated coastal wetlands. Our analyses highlight the value of pairing remotely sensed data with regional, ground-based observations for quantifying and extrapolating the effects of extreme freeze events on mangroves and other tropical, cold-sensitive plants. The results also demonstrate how extreme freeze events govern the expansion and contraction of mangroves near northern range limits in North America.

Abstract. The global ocean’s oxygen content has declined significantly over the past several decades and is expected to continue decreasing under global warming with far reaching impacts on marine ecosystems and biogeochemical cycling. Determining the oxygen trend, its spatial pattern and uncertainties from observations is fundamental to our understanding of the changing ocean environment. This study uses a suite of CMIP6 Earth System Models to evaluate the biases and uncertainties in oxygen distribution and trends due to sampling sparseness. Model outputs are sub-sampled according to the spatial and temporal distribution of the historical shipboard measurements, and an optimal interpolation method is applied to fill data gaps. Sub-sampled results are compared to full model output, revealing the biases in global and basin-wise oxygen content trends. The optimal interpolation underestimates the modeled global deoxygenation trends, capturing approximately two-thirds of the full model trends. North Atlantic and Subpolar North Pacific are relatively well sampled, and the optimal interpolation is capable of reconstructing more than 80 % of the oxygen trend. In contrast, pronounced biases are found in the equatorial oceans and the Southern Ocean, where the sampling density is relatively low. Optimal interpolation of the historical dataset estimated the global oxygen loss of 1.5 % over the past 50 years. However, the ratio of global oxygen trend between the subsampled and full model output, increases the estimated loss rate to 1.7 to 3.1 % over the past 50 years, which partially overlaps with previous studies. The approach taken in this study can provide a framework for the intercomparison of different statistical gap-fill methods to estimate oxygen content trends and its uncertainties due to sampling sparseness.

Microplastics (<5 mm) pollution is a growing problem affecting coastal communities, marine ecosystems, aquatic life, and human health. The widespread occurrence of marine microplastics, and the need to curb its threats, require expansive, and continuous monitoring. While microplastic research has increased in recent years and generated significant volumes of data, there is a lack of a robust, open access, and long-term aggregation of this data. The National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI) now provides a global open access to marine microplastics data on an easily discoverable and accessible GIS web map and data portal ( https://www.ncei.noaa.gov/products/microplastics ). The objective of this data portal is to develop a repository where microplastics data are aggregated, archived, and served in a user friendly, consistent, and reliable manner. This work contributes to NCEI’s efforts towards data standardization, integration, harmonization, and interoperability among national and international collaborators for monitoring global marine microplastics. This paper describes the NOAA NCEI global marine microplastics database, its creation, quality control procedures, and future directions.

Abstract Coastal vegetated ecosystems are acknowledged for their capacity to sequester organic carbon (OC), known as blue C. Yet, blue C global accounting is incomplete, with major gaps in southern hemisphere data. It also shows a large variability suggesting that the interaction between environmental and biological drivers is important at the local scale. In southwest Atlantic salt marshes, to account for the space occupied by crab burrows, it is key to avoid overestimates. Here we found that southern southwest Atlantic salt marshes store on average 42.43 (SE = 27.56) Mg OC·ha−1 (40.74 (SE = 2.7) in belowground) and bury in average 47.62 g OC·m−2·yr−1 (ranging from 7.38 to 204.21). Accretion rates, granulometry, plant species and burrowing crabs were identified as the main factors in determining belowground OC stocks. These data lead to an updated global estimation for stocks in salt marshes of 185.89 Mg OC·ha−1 (n = 743; SE = 4.92) and a C burial rate of 199.61 g OC·m−2·yr−1 (n = 193; SE = 16.04), which are lower than previous estimates.

The years since 2000 have been a golden age in in situ ocean observing with the proliferation and organization of autonomous platforms such as surface drogued buoys and subsurface Argo profiling floats augmenting ship-based observations. Global time series of mean sea surface temperature and ocean heat content are routinely calculated based on data from these platforms, enhancing our understanding of the ocean’s role in Earth’s climate system. Individual measurements of meteorological, sea surface, and subsurface variables directly improve our understanding of the Earth system, weather forecasting, and climate projections. They also provide the data necessary for validating and calibrating satellite observations. Maintaining this ocean observing system has been a technological, logistical, and funding challenge. The global COVID-19 pandemic, which took hold in 2020, added strain to the maintenance of the observing system. A survey of the contributing components of the observing system illustrates the impacts of the pandemic from January 2020 through December 2021. The pandemic did not reduce the short-term geographic coverage (days to months) capabilities mainly due to the continuation of autonomous platform observations. In contrast, the pandemic caused critical loss to longer-term (years to decades) observations, greatly impairing the monitoring of such crucial variables as ocean carbon and the state of the deep ocean. So, while the observing system has held under the stress of the pandemic, work must be done to restore the interrupted replenishment of the autonomous components and plan for more resilient methods to support components of the system that rely on cruise-based measurements.

EDITORIAL article Front. Mar. Sci., 17 July 2023Sec. Marine Pollution Volume 10 - 2023 | https://doi.org/10.3389/fmars.2023.1253605

Climate change is altering species’ range limits and transforming ecosystems. For example, warming temperatures are leading to the range expansion of tropical, cold-sensitive species at the expense of their cold-tolerant counterparts. In some temperate and subtropical coastal wetlands, warming winters are enabling mangrove forest encroachment into salt marsh, which is a major regime shift that has significant ecological and societal ramifications. Here, we synthesized existing data and expert knowledge to assess the distribution of mangroves near rapidly changing range limits in the southeastern USA. We used expert elicitation to identify data limitations and highlight knowledge gaps for advancing understanding of past, current, and future range dynamics. Mangroves near poleward range limits are often shorter, wider, and more shrublike compared to their tropical counterparts that grow as tall forests in freeze-free, resource-rich environments. The northern range limits of mangroves in the southeastern USA are particularly dynamic and climate sensitive due to abundance of suitable coastal wetland habitat and the exposure of mangroves to winter temperature extremes that are much colder than comparable range limits on other continents. Thus, there is need for methodological refinements and improved spatiotemporal data regarding changes in mangrove structure and abundance near northern range limits in the southeastern USA. Advancing understanding of rapidly changing range limits is critical for foundation plant species such as mangroves, as it provides a basis for anticipating and preparing for the cascading effects of climate-induced species redistribution on ecosystems and the human communities that depend on their ecosystem services.

The annual cycle of global dissolved oxygen content (O2C) and mean oxygen concentration in the surface mixed layer are estimated using monthly climatological oxygen fields from the World Ocean Atlas 2018 (WOA18). The largest seasonal variability in the mixed layer O2C occurs in the extra-tropics between 30° and 70° latitude of each hemisphere. A global view of the role of entrainment, air-sea flux, and biological activity in controlling the oxygen content/concentration annual cycle in the mixed layer is determined using an oxygen mass balance model. Based on the relative percentage from the mass balance model, entrainment is only a significant driver (contributing to 20-40% of the total changes) from mid-fall to early spring when the mixed layer deepens and transfers oxygen to deeper waters. Both the air-sea oxygen flux and biological activity show strong annual cycles and play critical roles in the annual cycle of O2C in the mixed layer. Air-sea oxygen flux is ingassing from late fall to early spring and outgassing between late spring and early fall. It is a substantial factor throughout the year and controls 40-60% of the oxygen changes in most months. Biological activity is a net source (production) in the spring and summer and a net sink (consumption) in the late fall and winter for the mixed layer oxygen content. Biological activity plays a more important role during spring/summer (40-60%) than that during fall/winter (10-30%) in controlling the overall oxygen change in each month. The model estimates a mean value (±SD) of 3.06±1.61 mol C m-2 yr-1 and a total of 863.7±73.8 Tmol C yr-1 for the global annual net ocean community production (ANCP) between 60°S and 60°N latitude, which are in fairly good agreement with previous studies.