Search

Infectious disease can shape community structure, particularly when pathogens affect foundation species. Seagrasses are foundation species that form meadows along coasts worldwide, controlling sediment deposition and biogeochemical cycling while supporting a diverse community of fish and invertebrates. These plants are hosts to wasting diseases that cause necrotic tissue lesions, which could alter seagrass value as food, habitat and mediators of ecosystem processes. However, such biotic interactions and influences on disease dynamics are still not well understood. We investigated whether a common herbivore affected the development of wasting disease on eelgrass. We measured the severity and prevalence of eelgrass wasting disease in a meadow across two summers through repeated field surveys. We assessed the role of the eelgrass herbivore on disease spread and growth using microcosm and mesocosm experiments. We further explored herbivore feeding preferences in a choice trial, which was paired with chemical analysis of plant tissue and analysed using a structural equation model. While the herbivore facilitates the growth of new disease lesions among isolated leaves, on balance they reduce lesion severity by more than 50% in comparison with no-herbivore controls in field-realistic settings. This was likely because the herbivore strongly prefers to eat diseased rather than healthy tissue, consuming nearly twice as much lesion area in choice trials. This preference arises from pathogen-driven changes in the host plant; lesioned tissue requires less force to penetrate than non-lesioned tissue. Additionally, as lesions increase in size, their polyphenolic concentrations drop, which further increases the magnitude of preference for lesioned tissue. Synthesis: These results suggest that these herbivores could help maintain disease in this system at a high prevalence (by facilitating disease development) but low severity (through preferential consumption), which is consistent with our field observations of nearly 100% prevalence and low severity in a natural bed where herbivore density is high. Describing such multi-species interactions in marine systems will advance our predictions of future disease states, as current understandings focus primarily on how environmental change contributes to pathogen outbreaks.

Since 2011, holopelagic Sargassum have been massively stranding in the coastal environments of the Caribbean Islands inducing damages to coastal ecosystems, public health and the economy. To limit the risks associated with Sargassum stranding, floating barriers with nets can be placed in front of sensitive areas, to divert Sargassum away from the coast. To evaluate the potential transfer of metallic trace element (MTE) from Sargassum to adjacent marine life, seagrasses (Halophila stipulacea, Thalassia testidinum) and urchin (Lytechinus variegatus) were sampled, both close (0 m) and far (200 m) from barriers installed during 4 years in two bays: Baie Cayol (BC) and Cap Est (CE) in Martinique (FWI). A bay without barriers Baie-Tresor (BT) was also sampled in order to compare the effects of Sargassum accumulated in a natural environment versus an environment with floating barriers. The short-term effects of barriers were evaluated by measuring the evolution of MTE after four days, in the algae (Dictyota spp.), located close to Sargassum accumulations. All sampling was realized during two periods of active (July 2021) and reduced (January 2022) Sargassum stranding. The measured concentrations of 19 metal(loid)s trace elements revealed that the proximity of Sargassum to the barriers did not increase MTE concentration. The absence of increase in MTE was observed all sites (BT, BC and CE) and during periods of limited and important Sargassum stranding. Similarly, translocations of Dictyota close to Sargassum accumulations did not reveal any increase in MTE concentrations in the algae after 4 days. The present study suggests that the use of barriers to manage Sargassum stranding would not constitute an important threat of MTE contamination of marine environments. [ABSTRACT FROM AUTHOR]

Coastal wetlands, including saltmarshes, mangrove forests, and seagrass meadows, can support fisheries by providing habitat and exporting food and nutrients to adjacent or distant ecosystems. However, there is insufficient understanding about the extent to which wetland restoration can benefit fishery species. Here, we report qualitative and quantitative reviews of literature to evaluate the approaches used to measure or estimate fisheries outcomes of coastal wetland restoration and test for the effects of restoration on fisheries outcomes. Most studies focused on saltmarshes and mangroves, with fewer studies focussing on seagrasses. We found that effects of wetland restoration on fish populations have mainly been assessed for species that reside in coastal wetlands for at least part of their life cycle, while few studies have tested effects on fish populations via trophic subsidies. Moreover, few studies have directly assessed the effects of restoration on fisheries production. Instead, most studies have measured abundances of individual species at restored sites and compared those to undisturbed and/or disturbed areas. Restored areas contained similar fish densities to undisturbed or disturbed areas; but few studies compared restored areas to both undisturbed and disturbed areas at the same time. Overall, we did not find consistent and robust evidence for fisheries outcomes from wetland restoration projects because (1) there were not many studies, (2) the studies reported substantial variability in outcomes, and (3) the density of fish measured at a restoration site is not an accurate measure of the total fisheries benefit as adult fishes do not always reside in the restored habitat. [ABSTRACT FROM AUTHOR]

Seagrass meadows are well-known for their capacity to capture and store blue carbon in sediments. However carbon stocks vary significantly between meadows, spanning more than three orders of magnitude on both local and global scales. Understanding the drivers of seagrass carbon stocks could help improve strategies for incorporating blue carbon into management plans. Here, we measured sediment carbon stocks in eelgrass (Zostera marina) meadows and unvegetated areas along the Norwegian coast, spanning wide gradients in temperature, wave exposure, water depth, salinity, and eelgrass biomass. Carbon stocks were generally higher in eelgrass meadows than in adjacent unvegetated areas, yet they displayed considerable variation (400 − 30 000 g C m−2 at 50 cm sediment depth) even among nearby sites. Overall, the highest carbon stocks were found in deeper, muddier, sheltered meadows near river mouths. These sites likely have the highest input and retention of carbon from different sources. Consequently, they should be prioritized as conservation targets for preserving coastal blue carbon stocks. Despite ever-increasing efforts to quantify seagrass blue carbon globally, high uncertainties still persist, partly due to differing methodologies, processes, and environmental context. Blue carbon stock estimates could be improved through the coordination of standardised mapping and sampling methods. [ABSTRACT FROM AUTHOR]

Nearshore seagrass, kelp, and other macroalgae beds (submerged aquatic vegetation [SAV]) are productive and important ecosystems. Mitigating anthropogenic impacts on these habitats requires tools to quantify their ecological value and the debits and credits of impact and mitigation. To summarize and clarify the state of SAV habitat quantification and available tools, we searched peer‐reviewed literature and other agency documents for methods that either assigned ecological value to or calculated equivalencies between impact and mitigation in SAV. Out of 47 tools, there were 11 equivalency methods, 7 of which included a valuation component. The remaining valuation methods were most commonly designed for seagrasses and rocky intertidal macroalgae rather than canopy‐forming kelps. Tools were often designed to address specific resource policies and associated habitat evaluation. Frequent categories of tools and methods included those associated with habitat equivalency analyses and those that scored habitats relative to reference or ideal conditions, including models designed for habitat suitability indices and the European Union's Water and Marine Framework Directives. Over 29 tool input metrics spanned 3 spatial scales of SAV: individual shoots or stipes, bed or site, and landscape or region. The most common metric used for both seagrasses and macroalgae was cover. Seagrass tools also often employed density measures, and some categories used measures of tissue content (e.g., carbon, nitrogen). Macroalgal tools for rocky intertidal habitats frequently included species richness or incorporated indicator species to assess habitat. We provide a flowchart for decision‐makers to identify representative tools that may apply to their specific management needs. [ABSTRACT FROM AUTHOR]

Seagrasses provide critical ecosystem services such as carbon sequestration, sediment stabilisation and nursery habitat for juvenile fish. Zostera muelleri is ubiquitous within Australian and New Zealand estuaries, however, as a species is relatively understudied. We sourced seeds from a thermally affected east Australian estuary and investigated whether germination rates differed between ambient and thermally affected seeds over a variety of temperatures (16°C–28°C) to determine how seagrass systems might react in a warming climate. Germination for the experiment was low and totalled 5% of all seeds; however, similar numbers are typical in seed germination studies. Germination was highest at 16°C and was enhanced through the simulation of a 48‐h freshwater pulse. Thermally affected sites germinated faster and had greater mean maximum germination when compared to control sites regardless of experimental temperature. These findings indicate that Z. muelleri in this system may be exhibiting transgenerational plasticity due to the thermal stress the parent experiences. This result provides an alternate viewpoint to the current literature by suggesting that unknown transgenerational effects may provide Z. muelleri with greater germination plasticity against temperatures expected under predicted climate change scenarios than previously expected. [ABSTRACT FROM AUTHOR]

Submerged aquatic vegetation (SAV) growth can be limited by light and nutrient availability. Infauna are common inhabitants of SAV meadows. Their activity increases nutrient mobility, and they can positively affect plant growth, but we do not know their role in plant trait‐biomass production relationships. We approached this problem using a 15‐week in situ transplant experiment in the Baltic Sea with experimental additions of Macoma balthica, a sedentary bivalve, to experimental SAV communities. Experimental plant communities were tricultures with varying species composition, compiled from a pool of six different species, to create an experimental gradient of trait community weighted means that allowed us to detect changes more clearly in plant trait‐biomass production relationships in response to the M. balthica treatment. We evaluated the relationships between plant height, leaf area, maximum root length (MMRL), specific root length (SRL), and SAV biomass production, then compared M. balthica condition index (soft tissue biomass [WW, mg]/valve length [mm]) to plant community leaf tissue nutrient concentrations (N (%DW), δ15N). Community biomass production was significantly related to plant height in the control treatment, but this relationship was decoupled in the M. balthica treatment, where community biomass production was instead significantly related to MMRL and SRL. This suggested a shift in the predominant SAV growth strategy, from height‐related to root‐related community biomass production. Leaf tissue δ15N was significantly related to M. balthica condition index. The growth of one species, Potamogeton perfoliatus, was significantly inhibited by the M. balthica treatment. Our results show that infauna have an important role in the plant traits related to community biomass production, and they have the potential to shape plant community structure via selective influences on different plant species. [ABSTRACT FROM AUTHOR]

This study examined the adsorption ability of Ni(II) metal ions from aqueous solutions on a physically activated adsorbent of Posidonia oceanica seagrass (AC-PO), which is both economically and naturally available. The effects of pH, amount of adsorbent, concentration of nickel ions, temperature, and contact time, which are among the parameters affecting the adsorption of Ni(II) ions on AC-PO, were examined. The kinetic data fit well with the pseudo-second-order model. The adsorption of Ni(II) ions showed compliance with Langmuir, Freundlich, and D-R isotherms. The Langmuir model showed better representation of data (0.9993). The maximum adsorption capacity of AC-PO for nickel ions was 138.89 mg·g−1.at 25 °C The thermodynamic parameters such as ∆G°, ∆H°, and ∆S° were calculated for the Ni(II) ion, and it was determined that the adsorption was spontaneous and endothermic. In qualitative chemical analysis by energy dispersive spectroscopy (EDS), it was found that there was ion exchange with adsorption of nickel ions on the AC-PO adsorbent. According to the results obtained from this study, it can be said that the adsorption ability of the AC-PO adsorbent is quite high in the removal of Ni(II) ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

Marine Heat Waves (MHWs) occurrence has been increasing in the Mediterranean Sea. The effects of field simulated MHWs of different intensity (medium and high temperature) on the transcriptome expression of the endemic seagrass Posidonia oceanica were evaluated considering different origins of the plant. The aim of the study was reached through a common garden transplant experiment in the North-west of Sardinia (Italy), where two P. oceanica meadows characterized by different thermal regimes (cold and warm) were chosen. MHWs were simulated in front of a power plant, that creates a natural laboratory by releasing warm water in the sea. Differential gene expression and GO enrichment analyses highlighted differences in the transcriptomic profiles of plants from cold and warm environments suggesting that the MHWs induced different levels of stress due to different tolerance to the heat event. Plants from both origins activated processes to achieve protein homeostasis, but only cold plants activated an antioxidant defense and altered sugar metabolism, both indicators of heat stress. Within plants of the same origin, a different response to MHW intensity was also detected: while warm plants showed the most complex response at high temperature rather than at medium temperature, cold plants seemed to better cope with the medium temperature intensity rather than with high temperature. [ABSTRACT FROM AUTHOR]

Seagrasses are considered to be globally important for carbon sequestration and they provide a range of ecosystem services. However, they are also known to be vulnerable to various anthropogenic activities, not least bottom contacting fishing gears such as dredging and potting. We set out to test the effects of dredge fishing, in early spring and potting in late summer, in a historically fished but considered "pristine" seagrass meadow on the west coast of Ireland. We found that despite dredging and potting pressures, growth of seagrasses was driven by seasonal changes in light and temperature and that neither fishing activity had any effect on rhizome weight or shoot or blade densities during the growing season. We hypothesize that it is possible for fishing to co‐occur with seagrass if fishing activities are restricted to winter or early spring, before the main seagrass growing season, and/or if particular types of gear, such as the traditional gears described here are used. High levels of dredging and potting had positive increases in the count of both sessile and mobile epifauna suggesting that for mobile species at least, they may take advantage of post‐fishing scavenging opportunities. [ABSTRACT FROM AUTHOR]

Seagrass is an important marine habitat that provides benefits to society in the form of ecosystem services. Services include the provision of food via fisheries, the regulation of water quality and the ability to sequester and store carbon. In the UK, seagrass beds are in decline, increasing the risk of ecosystem service loss. Current efforts to protect, restore and create seagrass habitat, beyond spatial management measures, rely on grant funding and donations. Emerging carbon, biodiversity and wider ecosystem service markets offering potential revenue sources could facilitate the enhancement of seagrass habitat at scale. Participation in ecosystem service markets, requires that projects deliver on the ecosystem service benefits defined. As the benefits will have been paid for, there are risks associated with not delivering on ecosystem service benefits. It is important that the risk is clearly defined. In this study we further the marine natural capital and risk register approach and apply the method to a case study area to support the development of sustainable funding options for seagrass habitat enhancement in Plymouth Sound, UK. Habitat Suitability modelling is also used to map potential areas for seagrass habitat enhancement. We find that, in the Plymouth Sound area, the risk of loss of ecosystem services for subtidal seagrass habitats is, at present, high. This is primarily linked to the declining extent and condition of subtidal seagrass assets. Under current governance, all of Plymouth Sound's subtidal seagrass are within a Marine Protected Area, though this conservation designation does not guarantee that the seagrass bed is protected from damaging activity. Under current environmental conditions there is opportunity for widespread seagrass restoration and creation. Risk to seagrass beds and any future private funding could be reduced by governance actions that enable effective direct protection of the seagrass assets and mitigate harmful pressures (e.g., reduction of water pollution). Emerging financial 'products' from seagrass ecosystem services that can support restoration and creation, require a high degree of integrity. The natural capital asset and risk register framework can provide information to underpin product development. With the development of revenue streams from ecosystem services there is a need for more intentional governance and site-based monitoring of these habitats as natural capital assets. Further research is needed to define any social or economic outcomes. Synthesis and Application: By assessing the risk to the status of seagrass assets through this approach, it is possible to determine the complementary governance actions needed to underpin investment in seagrass habitat enhancement. The methods are transferable to other locations where data exists to define the asset status. These specific findings are relevant nationally where similar vectors of risk (pressures) are identified. [ABSTRACT FROM AUTHOR]

Removal of Lindane pesticide from the environment is of utmost requirement. Besides, production of adsorbents to remove Lindane releases other pollutants and greenhouse gases into the environment. Therefore, in this study, the application of environmentally friendly low-cost, and readily available Halodule uninervis seagrass powder (SG) as an adsorbent is reported for the removal of Lindane from contaminated water. The environmental footprint of SG production was investigated using life cycle inventory (LCI). To investigate the adsorption parameters and reduce the wastage associated with the one variable at a time (OVAT) conventional investigation approach, response surface method (RSM) and artificial intelligence (AI) approaches were engaged. However, to investigate the isotherm and adsorption kinetics, OVAT parameter optimization was conducted. It is found that 16 h and 24 °C were the optimum time and temperature, respectively, and pH does not affect Lindane removal. Pseudo-second-order kinetics and Freundlich isotherm models were found the best to describe Lindane adsorption onto SG which was seen to be exothermic (− 29.17 kJ mol−1). The spent SG was found to be reusable in the synthetic wastewater with a value of 74% removal efficiency. XPS characterization results indicated that Lindane is physically adsorbed onto SG. LCI data showed that SG adsorbent has promising performance with very low negative environmental impacts. [ABSTRACT FROM AUTHOR]

Plant traits which vary both within and between species often drive biogeochemical cycling. Understanding the relative role of within‐ and between‐species trait variability in driving carbon cycling is essential to scaling site measurements to global carbon budgets. In seagrass meadows, carbon and nitrogen mineralization rates and associated greenhouse gas emissions are highly variable, impeding our ability to reliably predict whether meadows are net carbon sinks. Evaluating the influence of within‐ and between‐species trait variability on greenhouse gas fluxes will improve our understanding of local‐scale drivers of greenhouse gas production and consumption in seagrass meadows. To test the effects of plant traits on dissolved greenhouse gas fluxes, we performed mesocosm incubations with live, intact seagrass plants. We compared methane (CH4) and nitrous oxide (N2O) fluxes under dark and light conditions from sediments dominated by Halodule wrightii and Thalassia testudinum across dormant, early and peak growing seasons in a subtropical meadow along the west coast of peninsular Florida. We also measured oxygen (O2) fluxes to interpret greenhouse gas fluxes within the context of community metabolism. We measured several seagrass traits, such as above‐ and below‐ground biomass and leaf and root area and assessed their impact as well as the impact of species identity on dissolved gas fluxes. We found that abiotic factors linked to metabolism (i.e. light and temperature) influenced greenhouse gas fluxes across seasons. In addition to light conditions and sampling month, plant size (a composite trait variable) was a significant predictor of O2 consumption and CH4 production under dark conditions, and better predicted fluxes than individual plant traits. CH4 production was slightly higher in H. wrightii‐dominated sediments, but species identity was less important than plant size in driving CH4 production. N2O fluxes were low and not influenced by plant traits or species identity. Synthesis: Our results indicate that within‐species more so than between‐species trait variability drives the direction and magnitude of CH4 fluxes in seagrass meadows. We identified a trade‐off where seagrass biomass is often associated with enhanced sediment carbon storage, but in our study, plant size promoted CH4 production, potentially offsetting the benefits of long‐term storage. [ABSTRACT FROM AUTHOR]

This editorial titled "Restoration of coastal marine ecosystems" discusses the importance of ecosystem restoration in coastal marine habitats and the goals set by the United Nations to protect and restore degraded ecosystems. It highlights the challenges and uncertainties associated with large-scale restoration efforts in marine ecosystems and presents new insights and achievements in marine ecosystem restoration. The document covers various topics and ecosystems, including seagrass beds, macroalgal forests, estuarine wetlands, oyster reefs, and coral reefs, and provides successful restoration case studies. The article emphasizes the importance of stakeholder involvement, long-term monitoring, and measures to improve the resilience of restored ecosystems in the face of climate change. It concludes by calling for intensified and scaled-up restoration efforts, supported by government actions and partnerships with commercial and industrial sectors. [Extracted from the article]

Coastal marine habitats (i.e. mangroves, saltmarshes, and seagrasses) have a high capacity for carbon sequestration (termed "blue carbon") and the potential to reduce the effects of greenhouse gas emissions. However, blue carbon habitats have historically decreased as a consequence of land conversion, coastal development, and pollution and are under threat in many locations. Restoration of these habitats can reverse historic losses and generate carbon credits through increased carbon sequestration. With a long coastline, we hypothesized that there would be significant opportunities for coastal blue carbon in Aotearoa New Zealand. Results revealed Aotearoa estuaries and coastal areas contain approximately 20,932 ha of saltmarsh, 30,533 ha of mangrove, and 61,340 ha of seagrass, estimated to sequester a total of approximately 57,800 tC/year. A further 87,861 ha of land was estimated to be potentially suitable for blue carbon projects via tidal restoration, of which 56,482 ha was suitable for saltmarsh restoration (equivalent to 60,435 tC yr if restored), 17,291 ha was suitable for mangroves (26,455 tC/year), and 14,087 ha was suitable for seagrass (4790 tC/year). Both existing extent and restoration opportunity varied throughout the country, with greater opportunity in some regions than others. Nationwide, the total sequestration potential for blue carbon restoration was estimated at 91,680 tC yr−1 if all potential areas were restored. Carbon credits generated by blue carbon projects could be traded on a carbon market in Aotearoa, generate revenue for landowners, provide an additional pathway to meet domestic and international climate change targets, and result in a diversity of other ecological, social, and cultural co‐benefits from coastal restoration. [ABSTRACT FROM AUTHOR]

The scale at which New Zealand is currently storing and sequestering blue carbon, and could create additional blue carbon via restoration, has been unclear. Here, we calculate a preliminary estimate for the current extent of three key blue carbon ecosystems (saltmarshes, mangrove forests and seagrass meadows), their carbon stocks and their carbon sequestration rates using the best available data to provide a preliminary estimate of blue carbon in New Zealand. We also use local examples to explore opportunities to create additional blue carbon. Based on the available literature, we estimate the current extent of New Zealand's blue carbon ecosystems to be 76,152 ha, which is 1.0% of the area of terrestrial native forests. Our preliminary estimate of New Zealand's blue carbon stock is 2.66–3.76 Mt of carbon, with a current carbon sequestration rate of 0.12 (0.05–0.26) Mt/CO2/yr, which is equivalent to 0.16% of New Zealand's 2021 gross emissions. Restoration of saltmarshes could enhance their carbon sink capacity, mangrove forests are naturally expanding and seagrass meadow restoration techniques at scale are still in development. Developing a national framework for blue carbon protection, monitoring and restoration is important as part of New Zealand's climate change mitigation and adaptation efforts. [ABSTRACT FROM AUTHOR]

Dwarf eelgrass, Zostera noltii, is an important ecosystem engineer that creates dense meadows along the coasts of Europe and Northwest Africa. During the last century, this seagrass species suffered severe population declines, and to counteract these losses, restoration has emerged as an important management tool. Thus far, restoration efforts with Z. noltii have only been performed with shoot‐ and core‐based methods, which are challenging to upscale sustainably.Here, we explored if Z. noltii can be restored with seeds, thus potentially offering an upscalable solution for future restoration efforts. With the newly developed dispenser injection seeding (DIS) method, we tried seed‐based Z. noltii restoration in the intertidal Wadden Sea. With a field experiment, we investigated how seeding depth (1.5 and 3 cm) and seed amount (5, 10 and 20 seeds/injection) affected Z. noltii recruitment success and efficiency.Most importantly, our results show that Z. noltii can be restored with seeds, as 3 months after seeding, 184 individual patches had emerged from our 7000 seeds (2.6% recruitment). Recruitment success (number of restored patches/plot) was enhanced by higher seed amounts (20 > 5 seeds/injection), while the opposite was true for recruitment efficiency (number of restored patches/seed), which was reduced by higher seed amounts (20 < 5 seeds/injection). Restored Z. noltii survived the first winter in all experimental plots, but seagrass cover (square metre/plot) reduced in two‐thirds of the plots compared to the first growing season.In conclusion, our findings show the potential of seed‐based Z. noltii restoration and provide insights on how upscaling of restoration efforts for this species can be performed more efficiently and sustainably in the future. [ABSTRACT FROM AUTHOR]

As a consequence of anthropogenic activities and climate change, accelerated terrestrial sediment runoff is causing the gradual mudification of soft sediment estuarine habitats worldwide. Increased sediment mud content (< 63 µm) has been recognised to alter seagrass morphology and cause declines in primary production in unvegetated habitats. However, the effect of increased mud content on primary production in seagrass meadows remains largely unknown. To address this, primary production in intertidal seagrass meadows (Zostera muelleri) and adjacent unvegetated habitats was measured in situ using benthic incubation chambers across an existing sedimentary gradient (nine sites spanning 5–33% mud content). An additional two unvegetated mudflat sites (39–49% mud content) were also sampled to expand the gradient. Seagrass net (NPP) and gross primary production (GPP) was greater than in the adjacent unvegetated habitat and did not vary with mud content, even after standardising GPP by photosynthesising biomass (i.e. photosynthetic efficiency). In contrast, in the adjacent unvegetated habitat, photosynthetic efficiency declined with increasing mud content. Inclusion of the additional mudflat sites negatively impacted NPP, GPP, and photosynthetic efficiency in the unvegetated habitat. Thus, while primary production in seagrass meadows may have some resilience to future increases in mud content (up to ~33%), further degradation and loss of seagrass habitats could result in the expansion of unvegetated habitats and ultimately lead to production losses, likely to be most acute in areas with high mud content (≥ 39%). [ABSTRACT FROM AUTHOR]

While a record-high in situ water temperature of 38.4 °C on July 24, 2023, has been measured from a local site in Florida's Manatee Bay, satellite images revealed more extensive record-high water temperature in South Florida estuaries and the Florida Keys Reef Tract in July 2023 as a response to the 2023 heatwave, with an average sea surface temperature (SST) anomaly of 1.59 °C above the 2003–2022 mean. Long-term annual SST anomalies and long-term SST trend components of the time series both show significant warming trends in these regions between 2003 and 2023 (0.70 °C/decade), which is 67% higher than in the Gulf of Mexico (0.42 °C/decade). Furthermore, the warming trend appears to have accelerated over the past decade. In the context of global warming in the twenty-first century, such a warming trend and response to heatwaves may lead to more heat stress on the precious coral reefs and seagrasses both in and downstream from these already fragile estuaries. [ABSTRACT FROM AUTHOR]

Seagrasses have long been a focal point for management efforts aimed at restoring ecosystem health in estuaries worldwide. In Tampa Bay, Florida (USA), seagrass coverage has declined since 2016 by nearly a third (11,518 acres), despite sustained reductions of nitrogen loads supportive of light environments for growth. Changing physical water quality conditions related to climate change may be stressing seagrasses beyond their optimal growth ranges, requiring an assessment to determine if this decline can be linked to climate stress. Three ambient water quality datasets of varying sampling designs and coverage were evaluated to characterize physicochemical environments in Tampa Bay and the potential relationships with seagrass change. Tampa Bay has become hotter and fresher with water temperature increasing by 0.03–0.04 °C per year and salinity decreasing by 0.04–0.06 ppt per year, translating to an increase of 1.3 to 1.7 °C and a decrease of 1.6 to 2.6 ppt over the last 50 years. Additionally, the number of days when temperature was above 30 °C or salinity was below 25 ppt has increased on average across all bay segments by 48 and 37 days, respectively, since 1975. These changes varied spatially and seasonally, with the most dramatic changes observed in the upper bay. Generalized Additive Models provided a weight-of-evidence that recent seagrass declines are somewhat associated with hotter and fresher conditions. Trends in warming and increased precipitation in the region are likely to continue, further creating suboptimal conditions for seagrasses in Tampa Bay. These results should compel resource managers to consider the likelihood that reduced resilience of estuarine resources due to shifting ecological baselines driven by additional climate change drivers will complicate long-standing management paradigms. While conventional management approaches that focus on limiting nutrient loads should be continued, their future effectiveness may be confounded by climate change drivers and warrant additional, complementary interventions and continuous monitoring data to support ecosystem health into the future. [ABSTRACT FROM AUTHOR]

Microplastics are fast-emerging as another potential threat to already globally declining seagrass ecosystems, but there is a paucity of in situ surveys showing their accumulations. Here, we surveyed multiple Zostera marina L. meadows in 2020 and 2021 across Massachusetts, USA, for microplastic contamination, as well as identified factors related to patterns of accumulation. We found that microplastics were ubiquitous throughout all sites regardless of proximity to human development, with fibers being the most common microplastic type. In addition, we showed that accumulation of microplastics within seagrass meadows was related to epiphytic cover on leaves, plant morphology, and bulk-density in sediments. The results of this study provide the first in situ baseline microplastic concentrations on Z. marina plants and sediments for the temperate western North Atlantic. Additionally, we identify specific biotic and abiotic factors related to patterns of microplastic accumulation in these ecosystems. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Marine & Coastal Science is the property of Universitas Airlangga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Since 2011, holopelagic Sargassum have been massively stranding in the coastal environments of the Caribbean Islands inducing damages to coastal ecosystems, public health and the economy. To limit the risks associated with Sargassum stranding, floating barriers with nets can be placed in front of sensitive areas, to divert Sargassum away from the coast. To evaluate the potential transfer of metallic trace element (MTE) from Sargassum to adjacent marine life, seagrasses (Halophila stipulacea, Thalassia testidinum) and urchin (Lytechinus variegatus) were sampled, both close (0 m) and far (200 m) from barriers installed during 4 years in two bays: Baie Cayol (BC) and Cap Est (CE) in Martinique (FWI). A bay without barriers Baie-Tresor (BT) was also sampled in order to compare the effects of Sargassum accumulated in a natural environment versus an environment with floating barriers. The short-term effects of barriers were evaluated by measuring the evolution of MTE after four days, in the algae (Dictyota spp.), located close to Sargassum accumulations. All sampling was realized during two periods of active (July 2021) and reduced (January 2022) Sargassum stranding. The measured concentrations of 19 metal(loid)s trace elements revealed that the proximity of Sargassum to the barriers did not increase MTE concentration. The absence of increase in MTE was observed all sites (BT, BC and CE) and during periods of limited and important Sargassum stranding. Similarly, translocations of Dictyota close to Sargassum accumulations did not reveal any increase in MTE concentrations in the algae after 4 days. The present study suggests that the use of barriers to manage Sargassum stranding would not constitute an important threat of MTE contamination of marine environments.

Abstract Seagrass meadows are well-known for their capacity to capture and store blue carbon in sediments. However carbon stocks vary significantly between meadows, spanning more than three orders of magnitude on both local and global scales. Understanding the drivers of seagrass carbon stocks could help improve strategies for incorporating blue carbon into management plans. Here, we measured sediment carbon stocks in eelgrass (Zostera marina) meadows and unvegetated areas along the Norwegian coast, spanning wide gradients in temperature, wave exposure, water depth, salinity, and eelgrass biomass. Carbon stocks were generally higher in eelgrass meadows than in adjacent unvegetated areas, yet they displayed considerable variation (400 − 30 000 g C m−2 at 50 cm sediment depth) even among nearby sites. Overall, the highest carbon stocks were found in deeper, muddier, sheltered meadows near river mouths. These sites likely have the highest input and retention of carbon from different sources. Consequently, they should be prioritized as conservation targets for preserving coastal blue carbon stocks. Despite ever-increasing efforts to quantify seagrass blue carbon globally, high uncertainties still persist, partly due to differing methodologies, processes, and environmental context. Blue carbon stock estimates could be improved through the coordination of standardised mapping and sampling methods.

Seagrass bed has an important role for biota in waters. The existence of fish in seagrass is influenced by other ecosystems close to seagrass, such as mangroves and coral reefs. This study focuses on fish associated with seagrass in Bama Beach. The data include seagrass coverage and the number of fish for the Diversity, Uniformity, and Dominance. The study was carried out on March 15 to 20, 2018 using the Underwater Visual Census. Results show that seagrass cover was highest in seagrass stations near mangroves (62,66%), while at stations near coral reefs was 37,66. The composition of fish associated with seagrass near mangroves was 361 individuals, while near reefs was 1.454 individuals. The values of diversity, uniformity, and dominance of fish associated with seagrass near mangroves are 2,62; 0,88; and 0,09 respectively while those associated with coral reefs have values of 2,93; 0,85; and 0,06. Family Aulostomidae was dominant in the morning at the station near mangroves, and in the afternoon was dominated by Apogonidae. At the station near coral reefs, the Family Pomacentridae was dominant both in the morning and afternoon. The seagrass conditions in this study are in the healthy category with quite diverse fishes. The level of fish diversity in seagrass was influenced by habitats associated with seagrasses than seagrass cover levels. The condition of Bama Beach as a conservation area is quite good, but the activity of tourists around the coastline must be monitored to maintain the environment.

Seagrass meadows are highly productive ecosystems which provide many ecological services to organisms. Seagrass canopies create a hydrodynamically low-energy environment which can increase sediment deposition and reduce resuspension, thus enhancing habitat stability. Direct measurements of sediment deposition usually employ cylindrical traps, but results from this method have been debated. Flat sediment plates are an alternative method that minimise the problems of cylindrical traps but do not measure the exact same processes. Plate traps were used in conjunction with cylindrical traps to measure sediment deposition in a seagrass bed and nearby barren site in Estero Bay, Florida, U.S.A. Sediment plates and cylindrical plates were deployed every 2–3 months in a Thalassia testudinum dominant seagrass bed and nearby barren site to examine seasonal differences in sediment deposition and differences between the vegetated site and the barren site. The data from the plate traps corroborate the reduction of resuspension in the seagrass bed compared to the barren site found in other studies. This result was supported by measurements of reduced near-bed velocity and shear stress in the seagrass meadow. Plate traps had more consistent results than cylindrical traps. Differences between the barren and vegetated sites from the cylindrical traps were variable.

Zostera marina is a temperate seagrass exhibiting a mixed-annual life history strategy at its southern range limit in North Carolina (NC), relying on a transient seed bank to return from annual die-offs caused by summer heat stress. Tropical cyclones in the Atlantic are expected to increase in frequency and intensity, posing a potential threat to Z. marina populations. In this study, we observed seed bank and meadow response over 2 years in which hurricanes made landfall in NC, 2018 (Florence) and 2019 (Dorian). Given the importance of sexual reproduction to Z. marina meadow persistence and resilience, this study quantified (1) seed bank density and viability before and after each tropical cyclone and (2) annual reestablishment of the meadow (biomass, shoot density, and % flowering shoots) in the year following each storm. Seagrass and soil core samples were obtained from three sites in Middle Marsh, NC from April 2018 to August 2020. Zostera marina seed density and viability, seagrass biomass, and seagrass shoot density were quantified. Seed bank density and viability were similar to the decade prior, indicating long-term stability of meadow reproduction despite regular disturbance by hurricanes. Meadow biomass and shoot density did not change much from before to after Florence and Dorian. The results suggest that NC Z. marina meadows and their seed banks were resistant to these two sequential storm events. Given the expected increase in Atlantic tropical cyclone frequency and intensity, continued monitoring of seed bank and meadow responses to tropical cyclones in the future is imperative for the management of this important foundation species. [ABSTRACT FROM AUTHOR]

North Carolina (NC) is in a biogeographic transition zone where climate change is altering the relative abundances (e.g., areal extent, percent cover, biomass) of Zostera marina and Halodule wrightii. Warmer water temperatures are driving losses in Z. marina, leading to increased meadow patchiness. Although water temperatures are rising in NC, heat-tolerant H. wrightii is not filling in bare patches, which may result from abiotic stressors. This study investigated H. wrightii cold tolerance across different populations by quantifying the effects of cold stress on biomass and photosynthetic efficiency during a 3-week laboratory experiment and a 3-month observational study. H. wrightii shoots for the experiment were collected from NC, Mississippi (MS), and Florida (FL) and exposed to 23 °C, 10 °C, and 5 °C. Seagrass was also collected from FL, MS, and at 3 sites in NC during November–January of 2022–2023. Post experiment, there was a significant increase in the belowground biomass in the NC 10 °C treatment but no difference between populations in photosynthetic efficiency. Field metrics displayed population-specific differences, with the northernmost sites having the highest shoot density and belowground biomass per unit area. These findings suggest that H. wrightii at its biogeographic limit may allocate more carbon into belowground material than populations at the central part of the species range in response to thermal stress as a means of winter torpor, which may explain the lack of patch expansion in NC. Cold tolerance in tropical species like H. wrightii may therefore be essential to examine as a limiting factor for the tropicalization of temperate seagrass meadows. [ABSTRACT FROM AUTHOR]

Seagrass beds are composed of foundation species, providing essential nursery grounds, feeding areas, and refuge for various marine life. Several species of fish and invertebrates utilize seagrasses as essential habitat. The Dwarf Seahorse (Hippocampus zosterae) is an understudied species in Texas, and little is known about its density, distribution, and habitat associations in this area of their range. Physicochemical water parameters, nekton community data, habitat data, and Dwarf Seahorse catch data were collected at 80 sites in Texas. The highest catch per unit effort (CPUE) of the target species was in Aransas Bay (0.038/m2). There was a positive relationship between the presence and percent cover of turtle grass (Thalassia testudinum) and the presence and CPUE of Dwarf Seahorses. Dwarf Seahorses were detected more often and at a higher CPUE in locations with a higher seagrass community diversity and richness. The nekton community at sites where Dwarf Seahorses were detected was also more abundant, diverse, and species rich. This is the first comprehensive study of the distribution of the Dwarf Seahorse along the Texas coast. Dwarf Seahorses were generally found in higher abundances in association with mature, stable, and diverse seagrass beds. Recommended conservation strategy to protect Dwarf Seahorses should prioritize the protection of established and mature seagrass beds. Continued directed monitoring of this species is recommended to better understand their distribution and population status. [ABSTRACT FROM AUTHOR]

The Gulf toadfish (Opsanus beta) is a soniferous and abundant species native to Gulf of Mexico estuarine environments—now considered a likely invasive species in coastal Brazil. Males produce distinctive boatwhistle calls during their reproduction behaviors, offering an acoustic cue for ecological functions such as mate selection, prey detection, and predator avoidance. Their calls can also be readily detected with passive acoustics to monitor Gulf toadfish distributions and serve as acoustic indicators for their preferred nesting habitats. In this study, we describe the spatial, annual, seasonal, monthly, daily, daytime, and diel variation of Gulf toadfish call occurrence in Cedar Key, Florida (USA), with multiple sampling efforts at seagrass and dock sampling locations in the years 2019–2022. From April through June during our dock sampling, calls were detected across almost all our sampled dates and often every hour of the day, with daily and diel fluctuations in call occurrence. In our seagrass meadow sampling, call occurrence showed some positive correlation with manatee grass (Syringodium filiforme) and salinity. Moreover, snapshot recordings as short as 5 min were sufficient to detect calls in 37 of our 45 sampling events compared to only five where trawls captured Gulf toadfish. Our findings demonstrate the efficacy of listening to Gulf toadfish calls for monitoring applications and can support future efforts seeking to understand the availability of a prevalent acoustic cue in estuarine soundscapes. [ABSTRACT FROM AUTHOR]

Conservation efforts have raised awareness about the impact of small-scale fisheries on the distribution of seagrass plants. The patterns of recovery of the seagrass Zostera noltei and of the commercial bivalves Cerastoderma edule, Ruditapes decussatus and Ruditapes philippinarum after shellfish harvesting were studied in a field experiment in a shellfish bed in NW Spain. Sample plots were subjected to a single disturbance in two types of shellfish harvesting treatments in three zones characterized by different harvesting frequency and seagrass density. The photosynthetic efficiency (Fv/Fm), shoot density, leaf length and carbohydrate content of Z. noltei were monitored every three months during one year, and the C and N content of leaves and biomass of plants were measured one year after the disturbance. The abundance of adults, juveniles and recruits and the condition index of adult bivalves were quantified after the experimental harvesting. Shoot density and biomass of Z. noltei remained low during the ten months after the disturbance but recovered to control values after one year. Carbohydrate contents of apical rhizomes were lower in disturbed (treated) plots, whereas no effect was observed on Fv/Fm. Denser and more complex seagrass patches recovered faster. The abundance of adult bivalves below commercial size was lower in the disturbed plots, while the abundance of adults of commercial size, juveniles and recruits did not vary, indicating that abundance and condition were not hampered by harvesting pressure. The findings also suggest that Z. noltei meadows can recover within one year of the impact of shellfish harvesting if the harvesting areas are rotated and dense patches are preserved. [ABSTRACT FROM AUTHOR]

Abstract Background Several studies have been reported previously on the bioactivities of different extracts of marine molluscs. Therefore, we decided to evaluate the cytotoxic and antimicrobial activities of S. pharaonis ink as a highly populated species in the Red Sea. We extracted the flavonoids from the ink and analyzed their composition. Then we evaluated systematically the cytotoxic and antimicrobial properties of this extract. A pharmacokinetic study was also conducted using SwissADME to assess the potential of the identified flavonoids and phenolic compounds from the ink extract to be orally active drug candidates. Results Cytotoxic activity was evaluated against 5 cell lines (MCF7, Hep G2, A549, and Caco2) at different concentrations (0.4 µg/mL, 1.6 µg/mL, 6.3 µg/mL, 25 µg/mL, 100 µg/mL). The viability of examined cells was reduced by the extract in a concentration-dependent manner. The highest cytotoxic effect of the extract was recorded against A549 and Hep G2 cancer cell lines cells with IC50 = 2.873 and 7.1 µg/mL respectively. The mechanistic analysis by flow cytometry of this extract on cell cycle progression and apoptosis induction indicated that the extract arrests the cell cycle at the S phase in Hep G2 and MCF7, while in A549 cell arrest was recorded at G1 phase. However, it causes G1 and S phase arrest in Caco2 cancer cell line. Our data showed that the extract has significant antimicrobial activity against all tested human microbial pathogens. However, the best inhibitory effect was observed against Candida albicans ATCC 10,221 with a minimum inhibitory concentration (MIC) of 1.95 µg/mL. Pharmacokinetic analysis using SwissADME showed that most flavonoids and phenolics compounds have high drug similarity as they satisfy Lipinski’s criteria and have WLOGP values below 5.88 and TPSA below 131.6 Å2. Conclusion S. pharaonis ink ethanolic extract showed a promising cytotoxic potency against various cell lines and a remarkable antimicrobial action against different pathogenic microbial strains. S. pharaonis ink is a novel source of important flavonoids that could be used in the future in different applications as a naturally safe and feasible alternative of synthetic drugs.

The aim of this study was to measure consequences of the arsenic pollution released from a sewage treatment plant into the seawater in Jazan province in the southwest of Saudi Arabia. The impact of the release of arsenic on the ecosystem is the adsorption of arsenic by sea plants. To do so, samples were collected alongside a distance of seven kilometers from the treatment plant. The algae samples: Sargassum sp., Cladophora sp., and seagrasses: Halodule uninervis and Cymodocea rotunda were digested in nitric acid, and the assays of arsenic levels were taken by ICP-AES according to EPA methods. The results showed that algae are more efficient than seagrass with absorbing arsenic. Also, the treatment plant was not the only source of arsenic contamination, as ships and boats were adding more arsenic to the ecosystem.

This study presents a comprehensive checklist of sea cucumber species found in Biluhu Timur waters, Tomini Bay, Gorontalo, Indonesia, across the new moon and full moon lunar phases. The survey identified eight species across five genera, including Actinopyga miliaris, A. mauritiana, Holothuria scabra, and H. leucospilota, noting significant distribution patterns influenced by lunar cycles and different biomes at three stations. Actinopyga miliaris and A. mauritiana, both classified as Vulnerable, were more active in the seagrass biome of Station I during the full moon. H. leucospilota, classified as Least Concern, was highly prevalent in the sandy substrate biome of Station II during the new moon, indicating a strong ecological association with that habitat. Stichopus horrens, classified as Data Deficient, showed notable activity in the coral reef biome of Station III. Environmental parameters such as water temperature, salinity, and pH were measured at each station to understand the conditions influencing these species. This study highlights the importance of lunar phases, biomes, and environmental variables on sea cucumber distribution. The findings underscore the need for conservation efforts that consider these factors to protect species vulnerable to overfishing and habitat degradation. Further research should include genetic analysis and expanded temporal and spatial scales to develop effective conservation strategies and sustainable management practices

Abstract Background Breast cancer is the most common type of cancer diagnosed in women. Finding novel therapeutic agents with significant cytotoxic action and minimal adverse impact on normal cells becomes crucial. Today, natural anticancer agents present an unconventional method of treating cancer, either as a curative or preventative agent, with considerable concern for marine organisms. Methods The anticancer effect of the alcoholic extract of different Red Sea Seagrasses on MCF-7 human breast cancer cell line has been investigated. Seagrasses were collected from Wadi El Gamal, Red Sea and extracted. Qualitative HPLC analysis was performed on the extracts for the identification of their active biomarkers. This study was aimed to explore the cytotoxic impact of Thalassia hemprichii (Ehren.) and Enhalus acoroides (L.f.) Royle on MCF-7 and their mode of action. Their anti-proliferative effects on cancer cells were performed using Neutral red assay. On the other hand, their apoptotic effect and their capacity to induce cell cycle arrest were investigated by flow cytometry assay. The effect of Seagrasses on the mitochondrial membrane potential (ΔψM) was studied by using JC-1 mitochondrial membrane potential assay kit in Seagrasses treated cancer cells to Δψ Caspases 3/7activity was examined using the colorimetric method. Gene expression analysis and quantitative real time RT-PCR for the sea grasses on MCF-7 was performed. Immune-blotting technique for Bcl-2 and p53 was investigated. Results HPLC analysis demonstrated that the extracts contained mainly flavonoids and polyphenols such as Caffeic acid, Chlorogenic acids, catechin and kaempferol that might be responsible for these anticancer effects. Seagrasses alcoholic crude extract markedly suppressed the growth and expansion of MCF-7 cells concentration-dependently with no toxicity against normal human skin fibroblast HSF. Thalassia hemprichii and Enhalus acoroides trigger mode of cell death primarily via apoptosis as confirmed by the flow cytometry. Additionally, they have ability to induce G0/S cell cycle arrest in MCF-7. The data showed the depletion in mitochondrial membrane potential (ΔψM) in the treated cells dose-dependently Caspases 3/7activities markedly increased following 24 h treatment. Finally, Gene expression analysis showed a marked reduction in Bcl-2, Survivin and CDC2 gene expression levels and a significant increase in the expression of p53 and CC2D1A as compared to control cells. Conclusion In summary, the Methanolic extract of seagrass, Thalassia hemperchii and Enhalus ocoroides are able to induce concentration-dependent cytotoxic effects in human MCF-7 cells through intrinsic pathway of apoptosis in MCF-7 cells. This study reveals the beneficial importance of sea grasses as a source of anticancer agents. Further in vivo study is recommended for the active isolated biomolecules.

Posidonia Oceanica (PO) is an endemic marine plant in the Mediterranean Sea. In an experimental study conducted in the Eastern Mediterranean, the effects of natural PO leaves on reducing the height of incident waves impacting a beach were measured. The transmission coefficient (Kt) was found to vary between 0.73 and 0.94, which is equivalent to a wave height decay of 6–27%. The results show that in their natural environment, free-floating dead PO leaves dissipate incoming wave energy and have the capacity to protect beaches against erosion. Further analysis in separate frequency bands showed that waves with periods between 4.5–6.2 s were more sensitive to PO leaves in terms of energy dissipation. The transmission coefficient for medium-period waves, calculated using the medium-frequency part of the wave spectrum, delivered a maximum transmission coefficient of 0.5, corresponding to a 50% decay in wave height due to PO leaves. [ABSTRACT FROM AUTHOR]

Background: Several studies have been reported previously on the bioactivities of different extracts of marine molluscs. Therefore, we decided to evaluate the cytotoxic and antimicrobial activities of S. pharaonis ink as a highly populated species in the Red Sea. We extracted the flavonoids from the ink and analyzed their composition. Then we evaluated systematically the cytotoxic and antimicrobial properties of this extract. A pharmacokinetic study was also conducted using SwissADME to assess the potential of the identified flavonoids and phenolic compounds from the ink extract to be orally active drug candidates. Results: Cytotoxic activity was evaluated against 5 cell lines (MCF7, Hep G2, A549, and Caco2) at different concentrations (0.4 µg/mL, 1.6 µg/mL, 6.3 µg/mL, 25 µg/mL, 100 µg/mL). The viability of examined cells was reduced by the extract in a concentration-dependent manner. The highest cytotoxic effect of the extract was recorded against A549 and Hep G2 cancer cell lines cells with IC50 = 2.873 and 7.1 µg/mL respectively. The mechanistic analysis by flow cytometry of this extract on cell cycle progression and apoptosis induction indicated that the extract arrests the cell cycle at the S phase in Hep G2 and MCF7, while in A549 cell arrest was recorded at G1 phase. However, it causes G1 and S phase arrest in Caco2 cancer cell line. Our data showed that the extract has significant antimicrobial activity against all tested human microbial pathogens. However, the best inhibitory effect was observed against Candida albicans ATCC 10,221 with a minimum inhibitory concentration (MIC) of 1.95 µg/mL. Pharmacokinetic analysis using SwissADME showed that most flavonoids and phenolics compounds have high drug similarity as they satisfy Lipinski's criteria and have WLOGP values below 5.88 and TPSA below 131.6 Å2. Conclusion: S. pharaonis ink ethanolic extract showed a promising cytotoxic potency against various cell lines and a remarkable antimicrobial action against different pathogenic microbial strains. S. pharaonis ink is a novel source of important flavonoids that could be used in the future in different applications as a naturally safe and feasible alternative of synthetic drugs. [ABSTRACT FROM AUTHOR]

The article discusses the need for breakthrough innovation in order to achieve ambitious targets for marine macrophyte restoration. The UN Decade on Ecosystem Restoration has called for the restoration of critical habitats such as kelp forests and seagrass meadows. While new restoration projects and methods have been developed, achieving these targets remains challenging due to the difficulties of working in marine environments and the limitations of current restoration methods. The authors argue that a transformative approach, involving interdisciplinary collaboration and diverse perspectives, is necessary to overcome these challenges and scale up restoration efforts. They suggest that breakthrough innovation, similar to NASA's open innovation challenges, could harness diverse skills and perspectives to solve the problem of scaling up marine macrophyte restoration. However, it is also emphasized that efforts to reduce ongoing stressors and prevent further macrophyte decline should remain a priority. [Extracted from the article]

Halophila stipulacea (Forsskål and Niebuhr) Ascherson is a small marine seagrass that belongs to the Hydrocharitaceae family. It is native to the Red Sea, Persian Gulf, and Indian Ocean and has successfully invaded the Mediterranean and Caribbean Seas. This article summarizes the pharmacological activities and phytochemical content of H. stipulacea, along with its botanical and ecological characteristics. Studies have shown that H. stipulacea is rich in polyphenols and terpenoids. Additionally, it is rich in proteins, lipids, and carbohydrates, contributing to its nutritional value. Several biological activities are reported by this plant, including antimicrobial, antioxidant, anticancer, anti-inflammatory, anti-metabolic disorders, and anti-osteoclastogenic activities. Further research is needed to validate the efficacy and safety of this plant and to investigate the mechanisms of action underlying the observed effects. [ABSTRACT FROM AUTHOR]

Seagrasses are marine angiosperms that inhabit tropical and subtropical regions around the world. They play a vital role in marine biodiversity and the ecosystem by providing habitats and food for several marine organisms, stabilizing sediments, and improving water quality. Halodule uninervis from the family Cymodoceaceae has been used in traditional folk medicine for the treatment of many ailments. Additionally, several identified bioactive metabolites have been shown to contribute to its pharmacological activities, including anticancer, anti-inflammatory, and antioxidant. As such, H. uninervis could contribute to the development of novel drugs for various diseases. This review aims to compile the phytochemical composition and pharmacological activities of H. uninervis. Furthermore, details about its botanical characteristics and ecological significance are also discussed. By providing valuable insights into the role of H. uninervis in both the marine ecosystem and biomedicine, this review helps to highlight its potential as a therapeutic agent for future drug discovery and development. [ABSTRACT FROM AUTHOR]

Enhalus acoroides, a tropical seagrass, is known for its significant contribution to marine ecosystems and its potential health benefits due to bioactive compounds. This study aims to compare the carotenoid levels in E. acoroides using green extraction via ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) and to evaluate the biological properties of these extracts against oxidative stress, diabetes, and obesity through in silico and in vitro analyses. E. acoroides samples were collected from Manado City, Indonesia, and subjected to UAE and MAE. The extracts were analyzed using UHPLC-ESI-MS/MS to identify carotenoids, including β-carotene, lutein, lycopene, β-cryptoxanthin, and zeaxanthin. In silico analysis was conducted to predict the compounds' bioactivity, toxicity, and drug-likeness using WAY2DRUG PASS and molecular docking with CB-Dock2. The compounds C3, C4, and C7 demonstrated notable interactions, with key metabolic proteins and microRNAs, further validating their potential therapeutic benefits. In vitro assays evaluated antioxidant activities using DPPH and FRAP assays, antidiabetic properties through α-glucosidase and α-amylase inhibition, and antiobesity effects via lipase inhibition and MTT assay with 3T3-L1 cells. Results indicated that both UAE and MAE extracts exhibited significant antioxidant, antidiabetic, and antiobesity activities. MAE extracts showed higher carotenoid content and greater biological activity compared to UAE extracts. These findings suggest that E. acoroides, mainly when extracted using MAE, has promising potential as a source of natural bioactive compounds for developing marine-based antioxidant, antidiabetic, and antiobesity agents. This study supplements existing literature by providing insights into the efficient extraction methods and the therapeutic potential of E. acoroides carotenoids. [ABSTRACT FROM AUTHOR]

Worldwide seagrass habitats are under severe anthropogenic threat. In the United Kingdom (UK), the health of habitats of the widely distributed Zostera species is particularly threatened by eutrophication that can lead to detrimental macroalgae overgrowth. To manage and conserve seagrass habitats, effective monitoring tools are required.We use an off‐the‐shelf consumer‐grade multispectral (RGB, red edge, and near‐infrared) camera mounted on an unoccupied aerial vehicle (UAV) to map an intertidal multispecies seagrass environment in Lindisfarne National Nature Reserve, Northumberland, UK.Field surveys were undertaken of three seagrass areas, including those dominated by Zostera noltii, Zostera marina and macroalgae. Using the Maximum Likelihood Classifier (MLC), results indicated an overall accuracy (OA) between 84% and 91% across classified habitat maps. As expected, the red edge and near‐infrared bands offered an advantage beyond RGB imagery to discriminate between the vegetation types for accurate habitat mapping.Our research provides a foundation for accurately mapping a complex intertidal seagrass environment through the utilisation of an off‐the‐shelf multispectral UAV. The study may aid the implementation and development of effective monitoring programmes for the management of Zostera spp. decline and macroalgae proliferation to prevent seagrass degradation and conserve these valuable yet fragile ecosystems. [ABSTRACT FROM AUTHOR]

Background: Cancer is a disorder when abnormal body cells proliferate out of control and invade other organ sites. Objective: Our goal is to study how the marine sea grass Cymodocea rotundata (CR) suppresses breast and liver cancer growth by inducing cell cycle arrest in vitro. Materials and methods: Using high performance liquid chromatography (HPLC), the phenolic chemicals in CR were identified. The anti-proliferative effects on MCF-7, HepG-2 and normal cell of HSF were evaluated using the MTT test. Using flow cytometry, the cell cycle arrest processes were examined in both cancerous cell lines. Lastly, utilizing quantitative RT-PCR, the expression level of BCL-2, survivin, CDC-2, and CC2D1A and P53 genes was examined. Results: HepG-2 and MCF-7 cell growth was concentration-dependently inhibited by the seagrass extract, while normal cells HSF was not adversely affected. The S phase cell cycle arrest was indicated by a marked drop in the G0/G1 phase and an increase in S phase cells. A quantitative real-time RT-PCR study for CR seagrass on HepG-2 concluded that CR extract showed a significant decrease in the expression levels of the genes BCL-2, Survivin. Additionally, compared to control cells, it also showed a significant increase in the expression of the CC2D1A, CDC-2 and p53 gene. Moreover, BCL-2, survivin, and CDC-2 expression levels were markedly increased, however CC2D1A and p53 expression levels were markedly decreased in MCF-7. Conclusion: CR may prove to be a unique adjuvant in the treatment of liver and breast cancer. [ABSTRACT FROM AUTHOR]

The aim of this study was to measure consequences of the arsenic pollution released from a sewage treatment plant into the seawater in Jazan province in the southwest of Saudi Arabia. The impact of the release of arsenic on the ecosystem is the adsorption of arsenic by sea plants. To do so, samples were collected alongside a distance of seven kilometers from the treatment plant. The algae samples: Sargassum sp., Cladophora sp., and seagrasses: Halodule uninervis and Cymodocea rotunda were digested in nitric acid, and the assays of arsenic levels were taken by ICPAES according to EPA methods. The results showed that algae are more efficient than seagrass with absorbing arsenic. Also, the treatment plant was not the only source of arsenic contamination, as ships and boats were adding more arsenic to the ecosystem. [ABSTRACT FROM AUTHOR]

Estuaries are crucial feeding, nursery and resting sites for fish but can also be subject to the impacts of severe flooding. The environmental features of estuaries can mediate how they respond to these impacts. For example, the size, configuration, and context of estuarine habitats across seascapes affects the value of patches for fish, and so fish assemblages at sites with a greater habitat extent or closer to the mouth of an estuary may rebound more quickly from flooding. We investigated how a once in 100-year flood event affected fish assemblages at approximately 600 sites across 13 estuaries and six estuarine habitats (bare sediments, log snags, mangrove forests, rocky structures, saltmarsh and seagrass meadows) in southeast Queensland, Australia, and determined whether flood impacts were mediated by the position of sites within the broader estuarine seascape. Sites were surveyed annually in 2020/2021 (pre-flood) and 2022 (6 months post-flood) using underwater videography. Flooding modified the structure of the fish community and reduced the abundance of fish targeted by local fisheries in all six habitats. Crucially, flood effects on fish were greater at sites near more expansive urbanisation in some ecosystems, but lower at sites nearer to the estuary mouth. Maximising the extent of natural habitats across estuaries can mediate the effects of floods and should be priorities for restoration and management plans seeking to maintain biodiversity and fisheries productivity in the face of increasing climate-related disturbances. [ABSTRACT FROM AUTHOR]

Seagrass serves as a quintessential reservoir for obligate marine Lulworthiaceae fungi. Our current knowledge of the mycological diversity associated with seagrass in Hong Kong remains poor. We analyzed the diversity of fungi associated with the most widely distributed seagrass species in Hong Kong Halophila ovalis (Hydrocharitaceae), using a combination of culture-based methods and high-throughput amplicon sequencing. Halophilomyces hongkongensis, a novel fungal species in a newly proposed genus within the Lulworthiaceae family, was isolated from H. ovalis roots and rhizomes. The novel fungus showed distinct morphological characteristics, while both combined 18S-28S and internal transcribed spacer (ITS) phylogenetic trees based on maximum likelihood and Bayesian methods supported its discrimination from other existing Lulworthiaceae members. The ITS2 region in the Illumina sequencing results of multiple H. ovalis compartments, water, and adjacent non-seagrass sediments revealed continuous recruitment of H. hongkongensis by H. ovalis throughout the year despite dramatically fluctuating environmental conditions, with remarkably high proportions of this taxon found in root and rhizome internal tissues, possibly indicating a strong and specialized relationship established between the Lulworthiaceae fungal partner and its seagrass host. The inhibitory abilities exhibited by H. hongkongensis against Staphylococcus aureus SA29213 and ATCC 43300 (methicillin-resistant) may imply its capacity in producing (novel) antibacterial compounds. The discovery of H. hongkongensis as the first novel Lulworthiaceae taxon in Hong Kong, along with its distributional pattern in the seagrass meadow, provides valuable insights into the systematics and ecology of this strictly marine fungal family. [ABSTRACT FROM AUTHOR]

Seagrass meadows provide an important nursery and feeding habitat for fish, globally. However, limited data exist on how these vegetated coastal ecosystems affect local fish stocks over longer time periods. By means of beach seine hauling with a bio‐monitoring seine net, we collected fish data in Kronborg Bay (Denmark) over 4 years. The bay contains both vegetated and bare sediment areas in close proximity to Kronborg Castle in Elsinore and is part of the Øresund strait; a dynamic marine environment linking the Baltic Sea with the inner Danish waters (Kattegat). We investigated the biodiversity and fish abundance in a healthy seagrass meadow and compared it with a bare adjacent sediment area. We show that seagrass is important for fish species like the Atlantic cod, the two‐spotted goby, and the broadnosed pipefish. The seagrass meadow harboured more fish species and higher biodiversity, while the number of individuals was higher in the adjacent bare sediment area as a result of high abundances of lesser sand eel. Pilou's evenness and the Shannon‐Wiener index showed 2–4‐fold higher biodiversity in the seagrass meadow. The seagrass meadow harboured about 35% more fish species than the bare adjacent sediment. The Atlantic cod was almost entirely found in the seagrass meadow, while lesser sand eel that showed an overall increase in abundance in both habitats, represented the largest proportion of the total number of fish individuals (up to about 60%) and was mostly found on the bare adjacent sediment. Species abundance was analysed for changes over time, where, for example the European plaice showed an increase in abundance over the 4‐year period of investigation. Seagrass meadows can thus be very important for the Atlantic cod population in the Øresund strait and generally for local fish productivity, abundance and diversity. [ABSTRACT FROM AUTHOR]

Marine nutrients underpin productivity and functioning of oceanic island ecosystems. On islands where they nest, seabirds represent a primary source of marine nutrients. In tropical regions, some of the largest seabird populations nest on atolls, yet there is limited information available on seabird contributions to atoll ecosystem nutrient dynamics. To investigate the spatial and seasonal dynamics of seabird contributions, we assessed seabird colonies of different taxa, including red‐footed boobies and terns, nesting on separate islands of Farquhar Atoll, Seychelles. We assessed nutrient concentrations of guano, soil, coastal plants, and nearby seagrass in seabird colonies and at a control island with no seabirds, during the wet and dry seasons. Sooty terns contributed the highest quantities of nutrients, estimated at 71.2 N tonne/year and 52.2 P tonne/year. Seabird‐derived nutrient transfer occurred year‐round from seabird colonies to soil, coastal plants and seagrass. Soil macro‐ and inorganic nutrients were higher in the high‐density tern colony and during the dry season, coinciding with the breeding period of sooty terns. Both red‐footed booby and tern colonies maintained high nitrogen levels in coastal plants year‐round, while phosphorus levels did not differ between islands or seasons. Seabird‐derived nitrogen reversed nitrogen limitation of seagrass during the dry season. We provide the first insights into seabird nutrient contributions to atoll ecosystems in Seychelles, with recommendations for seabird conservation to boost and support atoll and island ecosystem resilience. Our results from a relatively undisturbed atoll serve as a baseline with which more impacted atolls and future changes can be assessed. [ABSTRACT FROM AUTHOR]

UK recreational boating infrastructure in UK ports and harbors consistently coincides with Marine Protected Area designation. Under UK Marine Protected Area designations, vulnerable seabed habitats such as seagrass beds require protection and/or restoration. Mooring and anchoring activity has coincided with increasing concerns over the conservation status of the climate-buffering properties of seagrass beds in the literature and from empirical studies. Up until this study, there has yet to be a significant UK based trial of a number of modified moorings to see their impact on the reduction in pressure on vulnerable benthic habitats. In May 2019, we installed and tested five Advanced Mooring Systems (AMS) in Cawsand Bay, Plymouth Sound, UK. A further 10 such devices were installed in 2021 after the COVID 19 pandemic. The original five devices tested were 'Stirling' systems, whereby the rode is raised above the seabed by use of several submerged floats set at 1.5–2 m intervals along the chain, leading to a top mark that secures the vessel. Each AMS were attached to the seabed using helical screwpiles by commercial divers using a waterproof hydraulic wrench. The devices have held securely since May 2019, and monitoring of seagrass around these five moorings has occurred regularly (at approximately 6 monthly intervals) between May 2019 and May 2023. No seeding or transplantation to prime seagrass recovery has taken place around the base of the moorings during this period. Nevertheless, during the sixth dive survey in May 2023, 4 years after installation, a 212% increase in seagrass density was recorded within the zone previously abraded by the moorings and riser chains. Blade length of the longest seagrass shoots has also increased over the test period. Semi-structured interviews were held with participants in the trial from boat users, NGOs and government agencies to ascertain attitudes and responses to seagrass conservation and the use of AMS. Interaction with stakeholders are important to securing positive community buy-in to such interventions. We recommend that for small sailing craft and powerboats these systems provide a fit-for-purpose engineering and ecological solution to support the restoration of seagrass beds, but that such initiatives must be accompanied by significant understanding and interaction with local stakeholders. [ABSTRACT FROM AUTHOR]

Background: Breast cancer is the most common type of cancer diagnosed in women. Finding novel therapeutic agents with significant cytotoxic action and minimal adverse impact on normal cells becomes crucial. Today, natural anticancer agents present an unconventional method of treating cancer, either as a curative or preventative agent, with considerable concern for marine organisms. Methods: The anticancer effect of the alcoholic extract of different Red Sea Seagrasses on MCF-7 human breast cancer cell line has been investigated. Seagrasses were collected from Wadi El Gamal, Red Sea and extracted. Qualitative HPLC analysis was performed on the extracts for the identification of their active biomarkers. This study was aimed to explore the cytotoxic impact of Thalassia hemprichii (Ehren.) and Enhalus acoroides (L.f.) Royle on MCF-7 and their mode of action. Their anti-proliferative effects on cancer cells were performed using Neutral red assay. On the other hand, their apoptotic effect and their capacity to induce cell cycle arrest were investigated by flow cytometry assay. The effect of Seagrasses on the mitochondrial membrane potential (ΔψM) was studied by using JC-1 mitochondrial membrane potential assay kit in Seagrasses treated cancer cells to Δψ Caspases 3/7activity was examined using the colorimetric method. Gene expression analysis and quantitative real time RT-PCR for the sea grasses on MCF-7 was performed. Immune-blotting technique for Bcl-2 and p53 was investigated. Results: HPLC analysis demonstrated that the extracts contained mainly flavonoids and polyphenols such as Caffeic acid, Chlorogenic acids, catechin and kaempferol that might be responsible for these anticancer effects. Seagrasses alcoholic crude extract markedly suppressed the growth and expansion of MCF-7 cells concentration-dependently with no toxicity against normal human skin fibroblast HSF. Thalassia hemprichii and Enhalus acoroides trigger mode of cell death primarily via apoptosis as confirmed by the flow cytometry. Additionally, they have ability to induce G0/S cell cycle arrest in MCF-7. The data showed the depletion in mitochondrial membrane potential (ΔψM) in the treated cells dose-dependently Caspases 3/7activities markedly increased following 24 h treatment. Finally, Gene expression analysis showed a marked reduction in Bcl-2, Survivin and CDC2 gene expression levels and a significant increase in the expression of p53 and CC2D1A as compared to control cells. Conclusion: In summary, the Methanolic extract of seagrass, Thalassia hemperchii and Enhalus ocoroides are able to induce concentration-dependent cytotoxic effects in human MCF-7 cells through intrinsic pathway of apoptosis in MCF-7 cells. This study reveals the beneficial importance of sea grasses as a source of anticancer agents. Further in vivo study is recommended for the active isolated biomolecules. [ABSTRACT FROM AUTHOR]