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Coastal vegetated ecosystems such as saltmarshes and seagrasses are important sinks of organic carbon (OC) and total nitrogen (TN), with large global and local variability, driven by the confluence of many physical and ecological factors. Here we show that sedimentary OC and TN stocks of intertidal saltmarsh (Sporobolus maritimus) and seagrass (Zostera noltei) habitats increased between two- and fourfold along a decreasing flow velocity gradient in Ria Formosa lagoon (south Portugal). A similar twofold increase was also observed for OC and TN burial rates of S. maritimus and of almost one order of magnitude for Z. noltei. Stable isotope mixing models identify allochthonous particulate organic matter as the main source to the sedimentary pools in both habitats (39–68%). This is the second estimate of OC stocks and the first of OC burial rates in Z. noltei, a small, fast-growing species that is widely distributed in Europe (41,000 ha) and which area is presently expanding (8600 ha in 2000s). Its wide range of OC stocks (29–99 Mg ha−1) and burial rates (15–122 g m2 y−1) observed in Ria Formosa highlight the importance of investigating the drivers of such variability to develop global blue carbon models. The TN stocks (7–11 Mg ha−1) and burial rates (2–4 g m−2 y−1) of Z. noltei were generally higher than seagrasses elsewhere. The OC and TN stocks (29–101 and 3–11 Mg ha−1, respectively) and burial rates (19–39 and 3–5 g m−2 y−1) in S. maritimus saltmarshes are generally lower than those located in estuaries subjected to larger accumulation of terrestrial organic matter. [ABSTRACT FROM AUTHOR]

In the present study, the correlation between bacterial abundance and soil physicochemical properties along the heavy metal contamination gradient in the area of non-ferrous metal processing plant was assessed. Our results showed that bacterial abundance (number of heterotrophic bacteria and number of 16S rRNA gene copies) decreased with 45-56% (CFU) and 54-87% (16S rRNA gene) along the Zn, Pb and Cd contamination gradient. The total bacterial abundance (16S rRNA gene) increased exponentially in contrast to the abundance of heterotrophic bacteria. The reduction of bacterial abundance in heavily contaminated soil indicated that the soil properties (soil pH, total organic carbon, inorganic ions, soil texture) could modify the effects of heavy metals and the response of microorganisms to that stress in long-term contaminated soils. [ABSTRACT FROM AUTHOR]

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The area of the Coastal Landscape Park (CLP) due to its location is extremely attractive touristic area. In the summer season, a significant increase in population density is observed, which influences surface water quality. Large numbers of tourists generate an increased amount of municipal wastewater, being treated in local treatment plants and discharged into rivers and streams. The paper presents preliminary research from summer 2016 on three watercourses ending in the Baltic Sea: Piaśnica, Karwianka and Czarna Wda rivers. It is a part of a long-term project conducted in CLP to assess surface waters quality. The scope of research included measurements of in situ parameters (temperature, conductivity, pH, dissolved oxygen). Chemical Oxygen Demand was determined using a spectrophotometer. Ion chromatography was used to determine ions concentrations (including biogenic compounds). Sanitary state of watercourses was assessed based on fecal coliforms abundance, which number was determined by the cultivation method. The determination of microbiological parameters such as: prokaryotic cell abundance expressed as total cells number (TCN), prokaryotic cell biovolume expressed as average cell volume (ACV), the prokaryotic biomass (PB) and prokaryotic cell morphotype diversity was determined using epifluorescence microscopy method. Results showed that water quality of Piaśnica and Czarna Wda rivers were affected by discharged treated wastewater. In the case of Karwianka River, the main pollution source could be surface runoff from fields and unregulated sewage management in this area. The conducted research confirmed the urgent need for better protection of this area to conserve both its ecosystem and value for tourism. [ABSTRACT FROM AUTHOR]

Varicosaviruses (the genus Varicosavirus) are bipartite, negative-sense, single-stranded RNA viruses that infect plants. We analyzed a transcriptome dataset isolated from the common eelgrass (Zostera marina) and identified a novel varicosavirus named Zostera associated varicosavirus 1 (ZaVV1). The ZaVV1 genome consists of two genomic segments: RNA1 (6,632-nt) has an open reading frame (ORF) encoding a large multi-functional polymerase protein (L), while RNA2 (4,304-nt) has four ORFs: one for a nucleocapsid protein and three for proteins with unknown functions (P2, P3, and P4). Sequence comparison and phylogenetic analysis using L proteins showed that ZaVV1 is a novel member of the genus Varicosavirus of the family Rhabdoviridae. The conserved regulatory elements involved in transcription termination/polyadenylation and transcription initiation were identified in the ZaVV1 gene-junction regions with the consensus sequence 3'-UAUUAUUCUUUUUGCUCU-5' (in the negative-sense genome). The ZaVV1 genome sequence may be useful for studying the phylogenetic relationships of varicosaviruses and genome evolution of rhabdoviruses. [ABSTRACT FROM AUTHOR]

Salt marshes and seagrass meadows can sequester and store high quantities of organic carbon (OC) in their sediments relative to other marine and terrestrial habitats. Assessing carbon stocks, carbon sources, and the transfer of carbon between habitats within coastal seascapes are each integral in identifying the role of blue carbon habitats in coastal carbon cycling. Here, we quantified carbon stocks, sources, and exchanges in seagrass meadows, salt marshes, and unvegetated sediments in six bays along the California coast. In the top 20 cm of sediment, the salt marshes contained approximately twice as much OC as seagrass meadows did, 4.92 ± 0.36 kg OC m -2 compared to 2.20 ± 0.24 kg OC m -2 , respectively. Both salt marsh and seagrass sediment carbon stocks were higher than previous estimates from this region but lower than global and US-wide averages, respectively. Seagrass-derived carbon was deposited annually into adjacent marshes during fall seagrass senescence. However, isotope mixing models estimate that negligible amounts of this seagrass material were ultimately buried in underlying sediment. Rather, the vast majority of OC in sediment across sites was likely derived from planktonic/benthic diatoms and/or C 3 salt marsh plants. [ABSTRACT FROM AUTHOR]

Eutrophication is one of the main threats to seagrass meadows, but there is limited knowledge on the interactive effects of nutrients under a changing climate, particularly for tropical seagrass species. This study aimed to detect the onset of stress in the tropical seagrass, Halophila stipulacea , by investigating the effect of in situ nutrient addition during an unusually warm summer over a 6-month period. We measured a suite of different morphological and biochemical community metrics and individual plant traits from two different sites with contrasting levels of eutrophication history before and after in situ fertilization in the Gulf of Aqaba. Nutrient stress combined with summer temperatures that surpassed the threshold for optimal growth negatively affected seagrass plants from South Beach (SB), an oligotrophic marine protected area, while H. stipulacea populations from North Beach (NB), a eutrophic and anthropogenically impacted area, benefited from the additional nutrient input. Lower aboveground (AG) and belowground (BG) biomass, reduced Leaf Area Index (LAI), smaller internodal distances, high sexual reproductive effort and the increasing occurrence of apical shoots in seagrasses from SB sites indicated that the plants were under stress and not growing under optimal conditions. Moreover, AG and BG biomass and internodal distances decreased further with the addition of fertilizer in SB sites. Results presented here highlight the fact that H. stipulacea is one of the most tolerant and plastic seagrass species. Our study further demonstrates that the effects of fertilization differ significantly between meadows that are growing exposed to different levels of anthropogenic pressures. Thus, the meadow's "history" affects it resilience and response to further stress. Our results suggest that monitoring efforts on H. stipulacea populations in its native range should focus especially on carbohydrate reserves in leaves and rhizomes, LAI, internodal length and percentage of apical shoots as suitable warning indicators for nutrient stress in this seagrass species to minimize future impacts on these valuable ecosystems. [ABSTRACT FROM AUTHOR]

Posidonia oceanica is a key foundation species in the Mediterranean providing valuable ecosystem services. However, this species is particularly vulnerable towards high coastal nutrient inputs and the rising frequency of intense summer heat waves, but their combined effect in situ has received little attention so far. Here, we investigated the effects of in situ nutrient addition during an unusually warm summer over a 4-month period, comparing different morphological, physiological and biochemical population metrics of seagrass meadows growing in protected areas (Ischia) with meadows already exposed to significant anthropogenic pressure (Baia – Gulf of Pozzuoli). Our study highlights that the effects of warmer than usual summer temperatures on the population level of seagrass meadows can be exacerbated if the plants are already exposed to higher anthropogenic pressures. Morphological and population level indicators mainly changed over time, possibly impacted by season and the warmer temperatures, and displayed more pronounced reductions in seagrasses from impacted sites. The additional nutrient supply had even more deleterious effects, as shown by a decrease in approximately 67% in cover in fertilized plots at high impacted sites and 33% at low impacted sites. Moreover, while rhizome starch concentration showed a seasonal increase in plants from low impacted sites it displayed a trend of a 27% decrease in fertilized plots of the high impacted sites. Epiphyte biomass was approximately four-fold higher on leaves of plants growing in impacted sites and even doubled with the additional nutrient input. Predicting and anticipating stress in P. oceanica is of crucial importance for conservation and management efforts, given the limited colonizing and reproductive ability and extremely slow growth of this ecosystem engineer. Our results suggest that monitoring efforts should focus especially on leaf area index (LAI), carbohydrate concentrations in the rhizomes, and epiphyte cover on leaves as indicators of the onset of stress in Posidonia oceanica , which can be used by decision makers to take appropriate measures before damage to the ecosystem becomes irreversible, minimize future human interference and strengthen the resilience of these important ecosystems. [ABSTRACT FROM AUTHOR]

The main purpose of the paper is to explore the relationship between the CORINE Land Cover (CLC) classification and the MAES typology in order to develop a basis for mapping of ecosystems at national level in Bulgaria, which could ensure a spatial framework for mapping and assessment of the ecosystem services provided by the natural heritage. Identifying the necessary data for our purposes, we found that, in spatial terms, CLC data is the only appropriate data source. The subtypes of ecosystems at Level 3 of the classification of ecosystems in Bulgaria (based on the European MAES classification) are identified as mapping units. Firstly, we decided to analyze the links between the CLC and the MAES BG classes through five categories of correspondence: 1) full correspondence - one CLC class corresponds to one MAES BG subtype; 2) multi-directional links - one or more CLC classes correspond to one MAES BG subtype; 3) discrepancies that necessitate further analyses; 4) CLC classes that are not found in Bulgaria; 5) MAES BG subtypes that have no correspondence to a CLC class. Secondly, we prepared a comparison table to determine the correspondence between the CLC classes and ecosystem subtypes, which we integrated into the GIS environment. Thirdly, we developed an algorithm for modifications of the spatial distribution of ecosystem subtypes. The algorithm was applied particularly to grasslands, where at Level 3 of CLC there are two classes of "grassland", whereas at Level 3 of the classification of ecosystems in Bulgaria, the subtypes are five. This algorithm was applied to the 2018 CLC spatial data so as to develop a GIS database providing the basis for subsequent analyzes related to ecosystems. The database was used to delineate and map the ecosystems at national level in Bulgaria. Furthermore, a map of the potential of the natural heritage to provide ecosystem services was produced. [ABSTRACT FROM AUTHOR]

Seagrass meadows play a key role in the provisioning of ecosystem goods and services. These systems are extremely vulnerable to multiple anthropogenic impacts. Therefore, there is an urgent need to develop new techniques to efficiently restore degraded seagrass meadows. Here we tested the efficacy and efficiency of a new technique of seagrass transplant (Cymodocea nodosa) using biodegradable containers. We investigated the effects of this transplant technique in the Adriatic Sea comparing the transplanted seagrass meadows with adjacent donor seagrass meadows and bare sediments used as control. We assessed the recovery rates and the ecological implications of this transplant on key ecosystems functions, including the biomass and detritus provision to local biological communities, and the effects on the biodiversity of the associated benthic fauna. Our results show that this restoration technique was successful, enabling the seagrass survival (approximately 30%) even in high‐energy conditions occurring in winter. The sediments hosting the transplanted seagrasses showed an increase of trophic availability and of rates of organic matter cycling. Despite this, 1 year after the transplant, the abundance and biodiversity of meiofaunal assemblages in the restored seagrasses were still lower than in donor seagrass meadows. These results indicate that the restoration process of seagrass meadows can take a long time, and that a multilevel approach (including the analysis of biodiversity and of the sedimentary processes and biogeochemical cycles) is needed to assess the success of restoration actions in these habitats. [ABSTRACT FROM AUTHOR]

Seagrass meadows rank among the most significant organic carbon (Corg) sinks on earth. We examined the variability in seagrass soil Corg stocks and composition across Australia and identified the main drivers of variability, applying a spatially hierarchical approach that incorporates bioregions and geomorphic settings. Top 30 cm soil Corg stocks were similar across bioregions and geomorphic settings (min‐max: 20–26 Mg Corg ha−1), but meadows formed by large species (i.e., Amphibolis spp. and Posidonia spp.) showed higher stocks (24–29 Mg Corg ha−1) than those formed by smaller species (e.g., Halodule, Halophila, Ruppia, Zostera, Cymodocea, and Syringodium; 12–21 Mg Corg ha−1). In temperate coastal meadows dominated by large species, soil Corg stocks mainly derived from seagrass Corg (72 ± 2%), while allochthonous Corg dominated soil Corg stocks in meadows formed by small species in temperate and tropical estuarine meadows (64 ± 5%). In temperate coastal meadows, soil Corg stocks were enhanced by low hydrodynamic exposure associated with high mud and seagrass Corg contents. In temperate estuarine meadows, soil Corg stocks were enhanced by high contributions of seagrass Corg, low to moderate solar radiation, and low human pressure. In tropical estuarine meadows formed by small species, large soil Corg stocks were mainly associated with low hydrodynamic energy, low rainfall, and high solar radiation. These results showcase that bioregion and geomorphic setting are not necessarily good predictors of soil Corg stocks and that site‐specific estimates based on local environmental factors are needed for Blue Carbon projects and greenhouse gases accounting purposes. Key Points: Australian seagrasses contain higher soil organic carbon stocks than adjacent unvegetated areas due to higher seagrass inputsSeagrass soil carbon stocks are similar over bioregions and geomorphic settings but higher in larger species compared to smaller speciesFactors determining seagrass soil carbon stocks differ across bioregions and coastal geomorphic settings within bioregions [ABSTRACT FROM AUTHOR]

Context: Seagrass meadows act as efficient natural carbon sinks by sequestering atmospheric CO2 and through trapping of allochthonous organic material, thereby preserving organic carbon (Corg) in their sediments. Less understood is the influence of landscape configuration and transformation (land-use change) on carbon sequestration dynamics in coastal seascapes across the land–sea interface. Objectives: We explored the influence of landscape configuration and degradation of adjacent mangroves on the dynamics and fate of Corg in seagrass habitats. Methods: Through predictive modelling, we assessed sedimentary Corg content, stocks and source composition in multiple seascapes (km-wide buffer zones) dominated by different seagrass communities in northwest Madagascar. The study area encompassed seagrass meadows adjacent to intact and deforested mangroves. Results: The sedimentary Corg content was influenced by a combination of landscape metrics and inherent habitat plant- and sediment-properties. We found a strong land-to-sea gradient, likely driven by hydrodynamic forces, generating distinct patterns in sedimentary Corg levels in seagrass seascapes. There was higher Corg content and a mangrove signal in seagrass surface sediments closer to the deforested mangrove area, possibly due to an escalated export of Corg from deforested mangrove soils. Seascapes comprising large continuous seagrass meadows had higher sedimentary Corg levels in comparison to more diverse and patchy seascapes. Conclusion: Our results emphasize the benefit to consider the influence of seascape configuration and connectivity to accurately assess Corg content in coastal habitats. Understanding spatial patterns of variability and what is driving the observed patterns is useful for identifying carbon sink hotspots and develop management prioritizations. [ABSTRACT FROM AUTHOR]

Microbial communities are major players in the biogeochemical processes and ecosystem functioning of river networks. Despite their importance in the ecosystem, biomonitoring tools relying on prokaryotes are still lacking. Only a few studies have employed both metabarcoding and quantitative techniques such as catalysed reported deposition fluorescence in situ hybridization (CARD‐FISH) to analyse prokaryotic communities of epilithic biofilms in river ecosystems. We intended to investigate the efficacy of both techniques in detecting changes in microbial community structure associated with environmental drivers. We report a significant correlation between the prokaryotic community composition and pH in rivers from two different geographical areas in Norway. Both CARD‐FISH and metabarcoding data were following the pattern of the environmental variables, but the main feature distinguishing the community composition was the regional difference itself. Beta‐dispersion analyses on both CARD‐FISH abundance and metabarcoding data revealed higher accuracy of metabarcoding to differentiate regions and river systems. The CARD‐FISH results showed high variability, even for samples within the same river, probably due to some unmeasured microscale ecological variability which we could not resolve. We also present a statistical method, which uses variation coefficient and overall prevalence of taxonomic groups, to detect possible biological indicators among prokaryotes using metabarcoding data. The development of new prokaryotic bioindicators would benefit from both techniques used in this study, but metabarcoding seems to be faster and more reliable than CARD‐FISH for large scale bio‐assessment. [ABSTRACT FROM AUTHOR]

This study is aimed to reveal the heavy metal contamination in brown seaweed species distribute in the Northeastern Black Sea coast. This study provides important preliminary information about heavy metal accumulation in brown seaweed. Indirectly, this also provides information on the environmental pollution in the study area. Heavy metal accumulations observed were Cr: 6.8-34.9 Mn: 32.8-116, Fe: 1721-5685, Co: 0.90-3.12, Ni: 31.8-173, Cu: 6.01-20.3, Zn: 24.3-88.2, Cd: 0.16-0.69 and Pb: 0.84-3.15 mg kg-1. Such studies should be conducted occasionally to update the knowledge on accumulation of heavy metals in marine organisms and to verify the results of this study. [ABSTRACT FROM AUTHOR]

Saline wastewater contaminated with aromatic compounds can be frequently found in various industrial sectors. Those compounds need to be degraded before reuse of wastewater in other process steps or release to the environment. Halophiles have been reported to efficiently degrade aromatics, but their application to treat industrial wastewater is rare. Halophilic processes for industrial wastewater treatment need to satisfy certain requirements: a continuous process mode, low operational expenditures, suitable reactor systems and a monitoring and control strategy. The aim of this review is to provide an overview of halophilic microorganisms, principles of aromatic biodegradation, and sources of saline wastewater containing aromatics and other contaminants. Finally, process examples for halophilic wastewater treatment and potential process monitoring strategies are discussed. To further illustrate the significant potential of halophiles for saline wastewater treatment and to facilitate development of ready-to-implement processes, future research should focus on scale-up and innovative process monitoring and control strategies. [ABSTRACT FROM AUTHOR]

Seagrass meadows are carbon (C) sinks and nitrogen (N)-limited ecosystems that experience degradation from climate change and anthropogenic stressors, including prop-scarring disturbances by boating vessels. To better understand the variability in C and N pools of undisturbed seagrass soils and the recovery of these pools following boat propeller scarring, we quantified organic carbon (Corg) and N pools within the top 1 m of soils in undisturbed Thalassia testudinum seagrass beds of the Lower Laguna Madre (LLM), Texas, USA—a sub-tropical, uniquely hypersaline, and heavily used recreational boating lagoon—and used a chronosequence approach to compare these undisturbed soil pools to those in different aged prop scars (1–3, 4–6, 7–9, and 10+ years). We found that undisturbed soils stored 108.41 ± 2.93 and 6.65 ± 0.26 Mg (megagram) ha−1 of Corg and N, respectively, in the top 1 m, with ~ 30% of these pools stored within the top 20 cm. Scarring impacted these shallow, organic-rich pools, exposing higher bulk density (BD) mineral soils with lower %Corg and %N. Consequently, young scars (1–3 years) had significantly lower %Corg and %N values in the top 20 cm of soil compared with undisturbed soils, but the greater BD offset these changes, leading to no differences in total Corg and N pools in the top 1 m between scarred and undisturbed soils. Scars 10+ years had similar %Corg, %N, and BD soil characteristics to undisturbed soils, producing similar Corg and N pools in both upper and lower soil horizons. These findings indicate that recovery of Corg and N pools of prop-scarred seagrass soils within T. testudinum beds of the LLM will likely recover a decade or more post-disturbance. Our findings contribute to the growing global database on seagrass C and N storage and demonstrate the rate at which seagrass meadows recover post-disturbance. [ABSTRACT FROM AUTHOR]

The current study investigates published data, concerning carbon sequestration on a global scale. The investigation is based on the use of the search engine of Nature Research Journal in order to acquire information about the studies, concerning carbon sequestration - the latter words were used as key words. Two main periods are examined, covering the years 1845-1999 and 2000-2019. During the first period - 1845-1999 29 manuscripts, regarding carbon sequestration were published. The second period saw an unprecedented boom when a total count of 513 results came into being. Some of the most important among them are a part of several scientific journals, including Scientific Reports, Nature Communications, Nature Journal, Nature Sustainability and Nature Climate Change with Nature Journal having an impact factor of 43.070 in 2018. This can serve as a proof of the quality of the scientific research. The results also show a division by country for several of these scientific works. The author stress on the need of such an overview study in order to reveal the present day importance of this subject. [ABSTRACT FROM AUTHOR]

Increasing the protection of coastal vegetated ecosystems has been suggested as one strategy to compensate for increasing carbon dioxide (CO2) in the atmosphere as the capacity of these habitats to sequester and store carbon exceeds that of terrestrial habitats. Seagrasses are a group of foundation species that grow in shallow coastal and estuarine systems and have an exceptional ability to sequester and store large quantities of carbon in biomass and, particularly, in sediments. However, carbon stocks (Corg stocks) and carbon accumulation rates (Corg accumulation) in seagrass meadows are highly variable both spatially and temporally, making it difficult to extrapolate this strategy to areas where information is lacking. In this study, Corg stocks and Corg accumulation were determined at 11 eelgrass meadows across New England, representing a range of eutrophication and exposure conditions. In addition, the environmental factors and structural characteristics of meadows related to variation in Corg stocks were identified. The objectives were accomplished by assessing stable isotopes of δ13C and δ15N as well as %C and %N in plant tissues and sediments, measuring grain size and 210Pb of sediment cores, and through assessing site exposure. Variability in Corg stocks in seagrass meadows is well predicted using commonly measured environmental variables such as grain size distribution. This study allows incorporation of data and insights for the northwest Atlantic, where few studies on carbon sequestration by seagrasses have been conducted. [ABSTRACT FROM AUTHOR]

The paper presents a study on the relative importance of wind regime and wave fetch for limitation of seagrass spatial distribution in Burgas Bay, the Black Sea. In Burgas Bay the relative importance of both factors is obviously changing from northern to southern coasts. The seagrass meadows facing north-northeast direction have two times smaller integral fetch and are three times more often wave impacted than those facing south-southeast. Along the southern coast the fetch (maximum and number of azimuths) is more important to allow seagrass presence, while in front of the northern coast - it is the wind speed recurrence. In the first scenario the habitat is expected to be less frequently but more strongly affected by the wave action, contrary to the second scenario, where the reversed effect is supposed. [ABSTRACT FROM AUTHOR]

Analysis of shotgun metagenomic data generated from next generation sequencing platforms can be done through a variety of bioinformatic pipelines. These pipelines employ different sets of sophisticated bioinformatics algorithms which may affect the results of this analysis. In this study, we compared two commonly used pipelines for shotgun metagenomic analysis: MG-RAST and Kraken 2, in terms of taxonomic classification, diversity analysis, and usability using their primarily default parameters. Overall, the two pipelines detected similar abundance distributions in the three most abundant taxa Proteobacteria, Firmicutes, and Bacteroidetes. Within bacterial domain, 497 genera were identified by both pipelines, while an additional 694 and 98 genera were solely identified by Kraken 2 and MG-RAST, respectively. 933 species were detected by the two algorithms. Kraken 2 solely detected 3550 species, while MG-RAST identified 557 species uniquely. For archaea, Kraken 2 generated 105 and 236 genera and species, respectively, while MG-RAST detected 60 genera and 88 species. 54 genera and 72 species were commonly detected by the two methods. Kraken 2 had a quicker analysis time (~4 hours) while MG-RAST took approximately 2 days per sample. This study revealed that Kraken 2 and MG-RAST generate comparable results and that a reliable high-level overview of sample is generated irrespective of the pipeline selected. However, Kraken 2 generated a more accurate taxonomic identification given the higher number of "Unclassified" reads in MG-RAST. The observed variations at the genus level show that a main restriction is using different databases for classification of the metagenomic data. The results of this research indicate that a more inclusive and representative classification of microbiomes may be achieved through creation of the combined pipelines. [ABSTRACT FROM AUTHOR]

Seagrass meadows are productive ecosystems that contribute to climate change mitigation by accumulating 'Blue Carbon' in their plant biomass and sediments. However, there is wide variation in reported sediment carbon stocks (Cstocks) across different global regions and between meadows composed of different seagrass species. Therefore, understanding the drivers for sediment Cstocks variation is crucial to developing effective conservation and restoration projects for seagrass ecosystems. This study analyses the influence of environmental factors on the variation in sediment Cstocks for six intertidal seagrass meadows within the Solent region, in southern England. There were significant differences between sites for all variables, except leaf density, and concentrations of the sediment pore water nutrients. Sediment dry bulk density, mean grain size, sorting coefficient, % mud, elevation above sea level, and pore water salinity showed high levels of association with Cstocks when assessed individually. Multivariate analyses showed that sediment dry bulk density, sorting coefficient, % mud, and pore water pH and concentration of nutrients greatly influenced Cstock. Moreover, sediment characteristics acted in conjunction to explain most of the variation in Cstock among sites. Therefore, sediment characteristics should be considered as important indicators for carbon storage potential in intertidal temperate seagrass meadows. [ABSTRACT FROM AUTHOR]

Underwater imagery is increasingly used as an effective and repeatable method to monitor benthic ecosystems. Nevertheless, extracting ecologically relevant information from a large amount of raw images remains a time-consuming and somewhat laborious challenge. Thus, underwater imagery processing needs to strike a compromise between time-efficient image annotation and accuracy in quantifying benthic community composition. Designing and implementing robust image sampling and image annotation protocols are therefore critical to rationally address these trade-offs between ecological accuracy and processing time. The aim of this study was to develop and to optimize a reliable image scoring strategy based on the point count method using imagery data acquired on tide-swept macroepibenthic communities. Using a stepwise approach, we define an underwater imagery processing protocol that is effective in terms of (i) time allocated to overall image, (ii) reaching a satisfactory accuracy to estimate the occurrence of dominant benthic taxa, and (iii) adopting a sufficient taxonomic resolution to describe changes in community composition. We believe that our method is well adapted to investigate the composition of epibenthic communities on artificial reefs and can be useful in surveying colonization of other human structures (wind turbine foundations, pipelines, etc.) in coastal areas. Our strategy meets the increasing demand for inexpensive and time-effective tools for monitoring changes in benthic communities in a context of increasing coastal artificialization pressures. [ABSTRACT FROM AUTHOR]

There is increasing urgency to implement climate change mitigation strategies that enhance greenhouse gas removal from the atmosphere and reduce carbon dioxide (CO2) emissions. Recently, coastal "blue carbon" habitats⁠—mangroves, salt marshes, and seagrass meadows—have received attention for their ability to capture CO2 and store organic carbon (OC), primarily in their sediments. Across habitat types and regions, however, information about the sequestration rates and sources of carbon to local sediments remains sparse. Here we compiled recently obtained estimates of sediment OC stocks and sequestration rates from 139 cores collected from temperate seagrass (Zostera marina) meadows in Alaska, British Columbia, Washington, and Oregon. Across all cores sediment OC content averaged 0.75%. Organic carbon stocks in the top 25 cm and 1 m of the sediment averaged 1,846 and 7,168 g OC m−2, respectively. Carbon sequestration rates ranged from 4.6 to 93.0 g OC m−2 yr−1 and averaged 24.8 g OC m−2 yr−1. Isotopic data from this region suggest that OC in the sediments is largely from noneelgrass sources. In general, these values are comparable to those from other temperate Z. marina meadows, but significantly lower than previously reported values for seagrasses globally. These results further highlight the need for local and species‐level quantification of blue carbon parameters. While temperate eelgrass meadows may not sequester and store as much carbon as seagrass meadows elsewhere, climate policy incentives should still be implemented to protect existing sediment carbon stocks and the other critical ecosystem services associated with eelgrass habitats. Plain Language Summary: As we search for innovative solutions to capture and store atmospheric carbon, coastal wetlands are doing so for free and at rates greater than mature forests. The carbon market, by brokering carbon offset monies, can fund coastal wetland restoration projects where a net greenhouse gas reduction can be shown. Yet seagrass carbon sequestration capacity varies among species and even within meadows of the same species. Thus, obtaining site‐specific carbon storage values is essential for restoration planning. Here we report carbon stocks and sequestration rates compiled from 30 eelgrass meadows (Zostera marina) in Oregon, Washington, British Columbia, and Alaska, areas underrepresented in current literature. We then compare these findings to previously reported values for Z. marina and for seagrasses globally. While carbon stocks and sequestration rates varied at small spatial scales, we observed no latitudinal patterns. Our values were similar to those found in other Z. marina meadows, but significantly lower than global seagrass averages. Through isotopic analysis we found that the majority of the carbon originated from noneelgrass sources and very little from eelgrass itself. These results, the first to reveal eelgrass carbon sequestration capacities in the Northeastern Pacific, expose the importance of obtaining local values for carbon sequestration. Key Points: Sediment carbon content varied both within and among Northeast Pacific eelgrass meadows, yet there was no clear latitudinal trendCarbon in eelgrass meadow sediments appears to be derived largely from noneelgrass sourcesNortheast Pacific carbon stocks and accumulation rates are comparable to other Z. marina meadows but lower than global seagrass values [ABSTRACT FROM AUTHOR]

One of the most prominent manifestations of climate change is the changing Arctic sea-ice regime with a reduction in the summer sea-ice extent and a shift from thicker, perennial multiyear ice towards thinner, first-year ice. These changes in the physical environment are likely to impact microbial communities, a key component of Arctic marine food webs and biogeochemical cycles. During the Norwegian young sea ICE expedition (N-ICE2015) north of Svalbard, seawater samples were collected at the surface (5 m), subsurface (20 or 50 m), and mesopelagic (250 m) depths on 9 March, 27 April, and 16 June 2015. In addition, several physical and biogeochemical data were recorded to contextualize the collected microbial communities. Through the massively parallel sequencing of the small subunit ribosomal RNA amplicon and metagenomic data, this work allows studying the Arctic's microbial community structure during the late winter to early summer transition. Results showed that, at compositional level, Alpha- (30.7%) and Gammaproteobacteria (28.6%) are the most frequent taxa across the prokaryotic N-ICE2015 collection, and also the most phylogenetically diverse. Winter to early summer trends were quite evident since there was a high relative abundance of thaumarchaeotes in the under-ice water column in late winter while this group was nearly absent during early summer. Moreover, the emergence of Flavobacteria and the SAR92 clade in early summer might be associated with the degradation of a spring bloom of Phaeocystis. High relative abundance of hydrocarbonoclastic bacteria, particularly Alcanivorax (54.3%) and Marinobacter (6.3%), was also found. Richness showed different patterns along the depth gradient for prokaryotic (highest at mesopelagic depth) and protistan communities (higher at subsurface depths). The microbial N-ICE2015 collection analyzed in the present study provides comprehensive new knowledge about the pelagic microbiota below drifting Arctic sea-ice. The higher microbial diversity found in late winter/early spring communities reinforces the need to continue with further studies to properly characterize the winter microbial communities under the pack-ice. [ABSTRACT FROM AUTHOR]

Ten percent of all organic carbon (Corg) absorbed by the ocean each year is stored in seagrass‐bearing sediments. The preservation of these carbon stores is considered a vital method to mitigate climate change. Seagrass‐bearing sediments have been correlated with sediment geophysical properties yet have not been related to sediment acoustic properties. For this purpose, sediment cores were collected from a Thalassia testudinum seagrass meadow in South Texas, USA, where geophysical, acoustical, and Corg properties were measured. It is hypothesized that when deposits of Corg adsorb onto mineral surfaces and are stored in pore spaces, compliant layers between grain contacts and the formation of an organic‐rich suspension reduce sediment stiffness. Results from this seagrass meadow demonstrated a strong correlation between sediment P wave modulus and Corg and show promise toward the development of an in situ ultrasonic sediment probe to more rapidly quantify and monitor seagrass carbon stores. Key Points: Seagrass‐bearing sediment P wave modulus correlated better with organic carbon content than with mud contentPresence of organic carbon between grains can affect bulk wave propagationEx situ results show promise for rapid in situ organic carbon estimation within the studied seagrass meadow [ABSTRACT FROM AUTHOR]

Increasing attention in global blue carbon investigation in these contemporary times, salt marsh has the distinctive importance in coastal ecosystems. We examined sediment organic carbon stock in the four dominant salt marsh species areas viz. Suaeda maritima, Sesuvium portulacastrum, Arthrocnemum indicum, and Salicornia brachiata from Tuticorin, southeast coast of India in two seasons i.e. dry (July 2015) and wet season (January 2016). We examined above ground (AGB) and below ground biomass (BGB), sediment physico-chemical properties like pH, BD, composition, OM%, Corg%, C and N%, sediment organic carbon stocks (SOCS) and multivariate analysis on studied variables. Maximum AGB was recorded in A. indicum in both dry and wet season (10.91 ± 0.15 g/cm2 and 14.87 ± 0.68 g/cm2). The highest BGB was observed in S. maritima in both seasons, as 2.01 ± 0.35 g/cm2 and 4.49 ± 0.35 g/cm2, respectively. The OM percentage ranged between 4.13 ±.083 and 7.23 ±.088% and the highest was observed in the wet season from S. maritima. Sediment organic stocks (Mg ha −1) ranged from 8.42 ±.640 to 54.46 ± 1.46 Mg ha −1 reflects nearly 7 times higher than the dry season. The present study can be useful for the estimation of blue carbon budgets in tropical coastal ecosystem since this type was the first hand information from this area. [ABSTRACT FROM AUTHOR]

Comparisons between terrestrial and marine ecosystems are generally not in the main stream of scientific literature even though Webb (2012) listed several points for which the transfer of knowledge and concepts related to one or to the other system would benefit our understanding of both. Even sharing this view, the leading hypothesis behind this contribution is that the pelagic system, where the dominant biotic component by number and biomass is microscopic, has specific features which strongly differentiate it from the abovethe- surface terrestrial systems. Due to this, climate change, i.e. changes in temperature, precipitation and most importantly in the dynamics of the two fluid media, atmosphere and ocean, act with different mechanisms which prevents proceeding with analogies in many cases. In addition, the non-linearity of most of the processes and responses to perturbations requires, in order to obtain reliable forecasts or hindcasts, a detailed analysis of the path followed by the system which is normally overlooked in the step-change simulations or projections. [ABSTRACT FROM AUTHOR]

An extensive area of seagrass covering the shore of part of the South African estuary ranked highest in overall national conservation and biodiversity importance (the Knysna estuarine bay) was killed by a series of seasonal green‐tidal blankets of Ulva starting in the late austral summer of 2015, leaving bare muddy sediment. An earlier (2011) survey of then seagrass macrobenthic assemblages at 27 stations along over 1 km of that shore was exactly repeated in 2018 after this event.After loss of seagrass, intertidal macrofauna became significantly less speciose (1:0.61), spatially and systematically more uniform (1:1.30 and 1:1.63), but more (not the usual less) abundant (0.62:1). Assemblage composition also changed, with polychaete numbers (small nereidids, spionids, fabriciids and an endemic paraonid) increasing from <50% of total macrofaunal individuals to >90% (although cirratulids decreased), whereas small malacostracan crustaceans (except the amphipod Grandidierella sp.) and microgastropods diminished to insignificant levels—microgastropods for reasons possibly unconnected with the green tide.Comparison with areas not vegetated in 2014, however, indicated that although macrofaunal abundance was greater in the 2018 Ulva‐induced bare areas, levels of per unit area biodiversity (number of species, species and taxonomic diversity per station) were comparable. This suggests that the effect of local loss of seagrass cover is context dependent, particularly with regard to pre‐existing local seagrass versus adjacent bare‐sediment differentials, and does not necessarily lead to any "degraded" state.Decreased local importance of small malacostracans may severely impact the region's usage by the adult and juvenile fish for which it is an important nursery and feeding ground. [ABSTRACT FROM AUTHOR]

Vegetated coastal ecosystems, including tidal marshes, mangroves and seagrass meadows, are being increasingly assessed in terms of their potential for carbon dioxide sequestration worldwide. However, there is a paucity of studies that have effectively estimated the accumulation rates of sediment organic carbon (Corg), also termed blue carbon, beyond the mere quantification of Corg stocks. Here, we discuss the use of the 210Pb dating technique to determine the rate of Corg accumulation in these habitats. We review the most widely used 210Pb dating models to assess their limitations in these ecosystems, often composed of heterogeneous sediments with varying inputs of organic material, that are disturbed by natural and anthropogenic processes resulting in sediment mixing and changes in sedimentation rates or erosion. Through a range of simulations, we consider the most relevant processes that impact the 210Pb records in vegetated coastal ecosystems and evaluate how anomalies in 210Pb specific activity profiles affect sediment and Corg accumulation rates. Our results show that the discrepancy in sediment and derived Corg accumulation rates between anomalous and ideal 210Pb profiles is within 20% if the process causing such anomalies is well understood. While these discrepancies might be acceptable for the determination of mean sediment and Corg accumulation rates over the last century, they may not always provide a reliable geochronology or historical reconstruction. Reliable estimates of Corg accumulation rates might be difficult at sites with slow sedimentation, intense mixing and/or that are affected by multiple sedimentary processes. Additional tracers or geochemical, ecological or historical data need to be used to validate the 210Pbderived results. The framework provided in this study can be instrumental in reducing the uncertainties associated with estimates of Corg accumulation rates in vegetated coastal sediments. [ABSTRACT FROM AUTHOR]

Microbial planktonic communities are critical components of marine biogeochemical pathways. Despite this, there is still limited knowledge on the dynamics of this group in warm and oligotrophic waters. We used high-throughput sequencing to characterise the bacterial (16S rRNA) and eukaryotic (18S rRNA) microbial plankton communities in two regions under the influence of anthropogenic impacts (a port and sewage outflow) and a coastal region with no direct anthropogenic disturbances in the central Red Sea. Overall, bacterial and eukaryotic components responded in a similar way to the environmental conditions. Community composition and structure were more sensitive than alpha diversity measures to environmental impacts. With the exception of eukaryotes, for which the number of OTU differed significantly between sampling periods in all the regions, environmental changes associated with anthropogenic pressures seem to be better reflected by variations in the relative dominance of microbial groups. For example, elevated proportional abundances of nitrifying and sewage-/faecal-related bacteria at the impacted sites were observed compared with the coastal region. The recently developed microgAMBI also appeared to correlate well with the level of anthropogenic impact the regions experienced, showing the potential to be applied in oligotrophic waters. [ABSTRACT FROM AUTHOR]

Despite the importance of coastal ecosystems for the global carbon budgets, knowledge of their carbon storage capacity and the factors driving variability in storage capacity is still limited. Here we provide an estimate on the magnitude and variability of carbon stocks within a widely distributed marine foundation species throughout its distribution area in temperate Northern Hemisphere. We sampled 54 eelgrass (Zostera marina) meadows, spread across eight ocean margins and 36° of latitude, to determine abiotic and biotic factors influencing organic carbon (Corg) stocks in Zostera marina sediments. The Corg stocks (integrated over 25‐cm depth) showed a large variability and ranged from 318 to 26,523 g C/m2 with an average of 2,721 g C/m2. The projected Corg stocks obtained by extrapolating over the top 1 m of sediment ranged between 23.1 and 351.7 Mg C/ha, which is in line with estimates for other seagrasses and other blue carbon ecosystems. Most of the variation in Corg stocks was explained by five environmental variables (sediment mud content, dry density and degree of sorting, and salinity and water depth), while plant attributes such as biomass and shoot density were less important to Corg stocks. Carbon isotopic signatures indicated that at most sites <50% of the sediment carbon is derived from seagrass, which is lower than reported previously for seagrass meadows. The high spatial carbon storage variability urges caution in extrapolating carbon storage capacity between geographical areas as well as within and between seagrass species. Key Points: The Z. marina Corg stocks varied widely within and across studied regions; majority of this variation was explained by five sediment and environmental variablesThe Z. marina Corg stocks were comparable to other seagrass species and other blue carbon habitats such as salt marshes and mangrove forestsCarbon isotopic signatures indicated that at most sites, only less than half of the sediment carbon is derived from seagrass, though variation was significant [ABSTRACT FROM AUTHOR]

Seagrass meadows provide a multitude of ecosystem services, including a capacity to sequester carbon dioxide (CO2) within their sediments. Seagrass research in the UK is lacking and there is no published data on sediment carbon (C) within UK seagrass meadows. We sampled 13 Zostera marina meadows along the southwest coast of the UK to assess the variability in their sedimentary organic carbon (OC) stocks. The study sites were considered representative of sub-tidal Z. marina meadows in the UK, spanning a gradient of sheltered to exposed sites, varying in formation, size and density, but found along the same latitudinal gradient. OC stocks (Cstocks) integrated across 100cm depth profiles were similar among all sites (98.01 ± 2.15 to 140.24 ± 10.27 Mg C ha-1), apart from at Drakes Island, which recorded an unusually high Cstock (380.07 ± 17.51 Mg C ha-1) compared to the rest of the region. The total standing stock of C in the top 100cm of the surveyed seagrass meadows was 66,337 t C, or the equivalent of 10,512 individual UK people’s CO2 emissions per year. This figure is particularly significant relative to the seagrass area, which totalled 549.79 ha. Using estimates of seagrass cover throughout the UK and recent UK C trading values we approximate that the monetary value of the UK’s seagrass standing C stock is between £2.6 million and £5.3 million. The C stock of the UK’s seagrass meadows represent one of the largest documented C stocks within Europe and are, therefore, of important ecosystem service value. The research raises questions concerning the reliability of using global or regional data as a proxy for local seagrass C stock estimates and adds to a growing body of literature that is looking to understand the mechanisms of seagrass C storage. When taken with the fact that seagrass meadows are an important habitat for commercially important and endangered species in the UK, along with their declining health and cover, this research supports the need for more robust conservation strategies for UK seagrass habitats. [ABSTRACT FROM AUTHOR]

Ecosystem-based management (EBM) addresses the fundamental need to account for cumulative impacts of human activities with the aim of sustainably delivering ecosystem services. The Saronikos Gulf, a large embayment of the Aegean Sea, provides a wide range of ecosystem services that are impacted by multiple human activities, deriving from the metropolitan area of Athens (situated at the northeast part of the Gulf). The anthropogenic impacts affect the status of several marine ecosystem components, e.g., seagrass meadows. Cymodocea nodosa meadows are only present at the most confined western part of the Gulf, whereas Posidonia oceanica meadows are mainly distributed in the inner and outer part of the Gulf. The aim of this study is to assess the cumulative impacts from multiple human activities on the seagrass meadows in the Gulf. The main results indicated that most impacted meadows are P. oceanica in the inner part of the Gulf, adjacent to the most urbanized coastal areas, and near port infrastructures. Land-based pollution, as well as physical damage and loss seem to be the main pressures exerted on the meadows. Understanding cumulative impacts is crucial for informing policy decisions under an EBM approach. [ABSTRACT FROM AUTHOR]

The aim of this work was to explore the feasibility of using plant functional traits to identify differences in sediment organic carbon (OC) storage within seagrass meadows. At 19 sites within three seagrass meadows in the coastal waters of Zanzibar, Tanzania, species cover was estimated along with three community traits hypothesized to influence sediment OC storage (above and belowground biomass, seagrass tissue nitrogen content, and shoot density). Sediments within four biogeographic zones (fore reef, reef flat, tidal channel, and seagrass meadow) of the landscape were characterized, and sediment cores were collected within seagrass meadows to quantify OC storage in the top 25 cm and top meter of the sediment. We identified five distinct seagrass communities that had notable differences in the plant traits, which were all residing within a thin veneer (ranging from 19 to 78 cm thick) of poorly sorted, medium to coarsely grained carbonate sands on top of carbonate rock. One community (B), dominated by Thalassodendron ciliatum, contained high amounts of above (972±74 gDWm-2) and belowground (682±392 gDWm-2) biomass composed of low-elemental-quality tissues (leaf C:ND24.5; rhizome C :ND97). While another community (C), dominated by small-bodied ephemeral seagrass species, had significantly higher shoot density (4178 shootsm-2). However, these traits did not translate into differences in sediment OC storage and across all communities the percentage of OC within sediments was similar and low (ranging from 0.15% to 0.75 %), as was the estimated OC storage in the top 25 cm (14.1±2.2Mg Cha-1) and top meter (33.9±7.7Mg Cha-1) of sediment. These stock estimates are considerably lower than the global average (194.2±20.2Mg C ha-1) reported for other seagrass ecosystems and are on the lower end of the range of estimates reported for the tropical Indo-Pacific bioregion (1.9 to 293Mg Cha-1). The uniformly low OC storage across communities, despite large inputs of lowquality belowground tissues in community B, indicates that the geophysical conditions of the coarse, shallow sediments at our sites were not conducive to OC stabilization and outweighed any variation in the quantity or quality of seagrass litter inputs. These results add to a growing body of evidence showing that geophysical conditions of the sediment modulate the importance of plant traits in regards to retention of OC within blue carbon ecosystems and cautions against the use of plant traits as a proxy for sediment OC storage across all seagrass ecosystems. [ABSTRACT FROM AUTHOR]

Globally, seagrass ecosystems are considered major blue carbon sinks and thus indirect contributors to climate change mitigation. Quantitative estimates and multi-scale appraisals of sources that underlie long-term storage of sedimentary carbon are vital for understanding coastal carbon dynamics. Across a tropical-subtropical coastal continuum in the Western Indian Ocean, we estimated organic (Corg) and inorganic (Ccarb) carbon stocks in seagrass sediment. Quantified levels and variability of the two carbon stocks were evaluated with regard to the relative importance of environmental attributes in terms of plant-sediment properties and landscape configuration. The explored seagrass habitats encompassed low to moderate levels of sedimentary Corg (ranging from 0.20 to 1.44% on average depending on species- and site-specific variability) but higher than unvegetated areas (ranging from 0.09 to 0.33% depending on site-specific variability), suggesting that some of the seagrass areas (at tropical Zanzibar in particular) are potentially important as carbon sinks. The amount of sedimentary inorganic carbon as carbonate (Ccarb) clearly corresponded to Corg levels, and as carbonates may represent a carbon source, this could diminish the strength of seagrass sediments as carbon sinks in the region. Partial least squares modelling indicated that variations in sedimentary Corg and Ccarb stocks in seagrass habitats were primarily predicted by sediment density (indicating a negative relationship with the content of carbon stocks) and landscape configuration (indicating a positive effect of seagrass meadow area, relative to the area of other major coastal habitats, on carbon stocks), while seagrass structural complexity also contributed, though to a lesser extent, to model performance. The findings suggest that accurate carbon sink assessments require an understanding of plant-sediment processes as well as better knowledge of how sedimentary carbon dynamics are driven by cross-habitat links and sink-source relationships in a scale-dependent landscape context, which should be a priority for carbon sink conservation. [ABSTRACT FROM AUTHOR]

All over the world marine waters are under increasing pressure from human activities affecting marine ecosystems. Several EU Directives require assessment of the condition of marine environments; in particular the Marine Strategy Framework Directive (MSFD) applies an ecosystem approach to the management of human activities. In this context, the mapping of pressures in a standardized and comparable way is a critical step to assess the spatial pattern, the temporal change and the ecological impacts of human pressures. Within the MSFD, one of the stressors directly affecting the seafloor is the Physical Loss (PL) pressure, representing the permanent or long-term alteration of marine habitats. The main purpose of this study was to propose a method to estimate the spatial extent of PL pressure in the framework of the Initial Assessment phase of the MSFD. Furthermore, considering that human activities PL-related cause the loss of benthic habitats, and that the Mediterranean sea is characterized by sensitive and protected habitats such as the biogenic substrates sensu MSFD, the distribution of PL pressure was overlaid with the distribution of the seabed habitats to estimate the loss of biogenic substrates. This study represents a useful tool for establishing the baseline condition for PL pressure, to compare future conditions and to evaluate different management scenarios. Moreover, it allows identification of the areas where pressure tends to accumulate as ‘hot spots’ on which to focus in future impact analyses and the areas where few stressors are present. [ABSTRACT FROM PUBLISHER]

Spatial data visualization techniques may have a great influence in several disciplines related to spatial management and hence decision-making process. Among them, marine spatial planning (MSP) constitutes an integrated procedure aiming at the optimal allocation of human activities in marine space. In MSP, mapping process referred either in human activities, marine ecosystems or indicative indices is based on the implementation of a grid approach. The present paper discusses some critical issues related to visualization procedure while a new data-driven approach is introduced towards the identification of grid cell size threshold. The proposed method gives a critical suggestion that may be easily extended in each field that considers this type of visualization for spatial data handling. [ABSTRACT FROM AUTHOR]

The seagrass Zostera muelleri Irmisch ex Asch. is abundant in estuaries in Australia and is under pressure from coastal developments. We studied sulfide intrusion in Z. muelleri along a gradient of anthropogenic impact at five stations in theWallis Lake estuary,Australia.Results showed differences in sediment biogeochemical conditions, seagrass metrics as well as nutrient content and sulfide intrusion along the gradient from the lower estuary (affected) to the lagoon (unaffected). Sulfide intrusion was driven by complex interactions and related to changes in seagrass morphology and sediment biogeochemistry and wasmodified by the exposure to wind and wave action. The sediments in the lower estuary had high contributions fromphytoplanktonic detritus,whereas the organic pools in the lagoonwere dominated by seagrass detritus. Despite high concentrations of organic matter, sulfide intrusion was lower at stations dominated by seagrass detritus, probably because of lower sulfide pressure from the less labile nature of organic matter. Porewater diffusive gradients in thin-film (DGT) sulfide samplers showed efficient sulfide reoxidation in the rhizosphere, with high sulfur incorporation in the plants from sedimentary sulfides being likely due to sulfate uptake from reoxidised sulfide. This is a unique adaptation of Z. muelleri, which allows high productivity in estuarine sediments. [ABSTRACT FROM AUTHOR]

Coastal wetlands are known for high carbon storage within their sediments, but our understanding of the variation in carbon storage among intertidal habitats, particularly over geomorphological settings and along elevation gradients, is limited. Here, we collected 352 cores from 18 sites across Moreton Bay, Australia. We assessed variation in sediment organic carbon ( OC) stocks among different geomorphological settings (wetlands within riverine settings along with those with reduced riverine influence located on tide-dominated sand islands), across elevation gradients, with distance from shore and among habitat and vegetation types. We used mid-infrared ( MIR) spectroscopy combined with analytical data and partial least squares regression to quantify the carbon content of ~2500 sediment samples and provide fine-scale spatial coverage of sediment OC stocks to 150 cm depth. We found sites in river deltas had larger OC stocks (175-504 Mg/ha) than those in nonriverine settings (44-271 Mg/ha). Variation in OC stocks among nonriverine sites was high in comparison with riverine and mixed geomorphic settings, with sites closer to riverine outflow from the east and south of Moreton Bay having higher stocks than those located on the sand islands in the northwest of the bay. Sediment OC stocks increased with elevation within nonriverine settings, but not in riverine geomorphic settings. Sediment OC stocks did not differ between mangrove and saltmarsh habitats. OC stocks did, however, differ between dominant species across the research area and within geomorphic settings. At the landscape scale, the coastal wetlands of the South East Queensland catchments (17,792 ha) are comprised of approximately 4,100,000-5,200,000 Mg of sediment OC. Comparatively high variation in OC storage between riverine and nonriverine geomorphic settings indicates that the availability of mineral sediments and terrestrial derived OC may exert a strong influence over OC storage potential across intertidal wetland systems. [ABSTRACT FROM AUTHOR]

Oceans and coasts provide a wide array of services to humans, including climate regulation, food security, and livelihoods. Managing them well is vital to human well-being as well as the maintenance of marine biodiversity and ocean-dependent economies., Carbon sequestration and storage is increasingly recognized as a valuable service provided by coastal vegetation. Carbon sequestered and stored by mangrove forests, tidal marshes, and seagrass meadows is known as 'blue' carbon. These habitats capture and store carbon within the plants themselves and in the sediment below them. When the habitats are destroyed, much of their carbon is released back to the atmosphere and ocean contributing to global climate change., Therefore, blue carbon ecosystem protection is becoming a greater priority in marine management and is an area of interest to scientists, policy makers, coastal communities, and the private sector including those that contribute to ecosystem degradation but also those that are looking to reduce their carbon footprint. A range of policy and management responses aim to reduce coastal ecosystem loss, including the establishment of marine protected areas (MPAs)., This paper explores how MPA design, location, and management could be used to protect and increase carbon sequestration and ensure integrity of carbon storage through conservation and restoration activities. While additional research is necessary to validate the proposed recommendations, this paper describes much needed first steps and highlights the potential for blue carbon finance mechanisms to provide sustainable funding for MPAs. [ABSTRACT FROM AUTHOR]

We Investigated The Biodesulfurization Potential Of A Mixed Culture Ak6 Enriched From Petroleum Hydrocarbons-Polluted Soil With Dibenzothiophene (Dbt) As A Sulfur Source. In Addition To Dbt, Ak6 Utilized The Following Compounds As Sulfur Sources: 4-Methyldibenzothiophene (4-Mdbt), Benzothiophene (Bt), And 4,6- Dimethyldibenzothiophene (4,6-Dm-Dbt). None Of These Compounds Supported The Growth Of Ak6 As The Sole Carbon And Sulfur Source. Ak6 Could Not Grow On Dibenzylsulfide (Dbs) As A Sulfur Source. The Ak6 Community Structure Changed According To The Provided Sulfur Source. The Major Dgge Bands Represented Members Of The Genera Sphingobacterium, Klebsiella, Pseudomonas, Stenotrophomonas, Arthrobacter, Mycobacterium, And Rhodococcus. Sphingobacterium Sp. And Pseudomonas Sp. Were Abundant Across All Cultures Utilizing Any Of The Tested Thiophenic S-Compounds. Mycobacterium/Rhodococcus Spp. Were Restricted To The 4-Mdbt Culture. The 4-Mdbt Culture Had The Highest Species Richness And Diversity. Biodesulfurization Of Dbt By Resting Cells Of Ak6 Produced 2-Hydroxybiphenyl (2-Hbp) In Addition To Trace Amounts Of Phenylacetate. Ak6 Transformed Dbt To 2-Hydroxybiphenyl With A Specific Activity Of 9 ± 0.6 µM 2-Hbp G Dry Cell Weight-1 H-1. Pcr Confirmed The Presence In The Ak6 Community Of The Sulfur-Specific (4S) Pathway Genes Dszb And Dszc. Mixed Cultures Hold A Better Potential Than Axenic Ones For The Development Of A Biodesulfurization Technology. [ABSTRACT FROM AUTHOR]

The study represents an attempt to correlate three popular broad-scale marine benthic habitat classification systems with such developed by the author. The focus is on the diversity of shallow submarine landscapes found within the central sector of the Bulgarian Black Sea coastal zone. The core of the investigation is a landscape-based identification and subsequent classification of the seabed complexes occupying the shallow marine area between cape Kaliakra and cape Emine, Bulgarian Black Sea coastal zone. A GIS-aided synthesis of the submarine landscape units was applied based on available graphic and narrative data about the main components and factors of the seabed environment, e.g. seafloor lithology and geomorphology, bathymetry, intensity of the wave-induced sediment transport, trends in the prevailing geomorphodynamic processes, dominant benthic biota etc. The proposed landscape classification scheme comprises 82 kinds aggregated hierarchically in 7 genera, 4 types and 2 classes. Subsequent step of the research was to correlate the developed classification system with these of the seabed habitats enlisted in Council Directive 92/43/EEC (Habitats Directive), Directive 2008/56/EC (Marine Strategy Framework Directive), and Volume 3 (Natural Habitats) of the Bulgarian Red Data Book. The cited correlation was performed at the lowest taxonomic level (landscape kind) and visualized as GIS-compiled maps of the submarine landscape units and the associated benthic habitat types. Results obtained during the correlation process revealed a good relationship between the principal abiotic landscape properties and the physical characteristics of the seabed habitats. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are potent environmental pollutants, and some of them have been identified as carcinogenic and mutagenic. To advance the knowledge of the environmental fate of PAHs, we systematically investigated the influence of different UV wavelengths irradiation on photolysis of PAHs on sandy soil under tow wavelengths (254 and 306 nm) UV irradiation for six PAHs. In addition, kinetic model and influence of several parameters on PAHs photolysis have been studied. The results obtained indicated that UV radiation with a wavelength of 306 nm was more efficient in the photolysis of the polycyclic aromatic hydrocarbons. Our results showed that fluoranthene (Flt) was the fastest in decomposition, has the greatest value for the coefficient of photolysis (7.4 × 10 h), and has less half-life, reaching 94 h when using a wavelength of 254 nm. The results indicated that the pyrene (Pyr) was more resistant to photolysis in comparison with indeno(1,2,3-cd) pyrene (IP) and fluoranthene (Flt). The results indicate that photolysis is a successful way to remediate the six studied PAHs compounds. [ABSTRACT FROM AUTHOR]

In view of the general paucity of integrated information on offshore benthic communities in the Adriatic Sea and given the vulnerability of this particular coastal system, microphytobenthos, meiofauna and macrofauna were synoptically investigated in front of the Emilia-Romagna coast (northern Adriatic Sea) in September 2010 and March 2011. As required by the Marine Strategy Framework Directive, which extends its action beyond the territorial waters (within 12 nmi) of the Member States, our findings could help to fill the gap of knowledge on the environmental status in offshore areas since the study was carried out also at >12 nmi from the coastline. In fact, sediment samples for the analysis of the benthic communities were collected from a 10-point-station grid that covered an area of about 400 km2 with water depths ranging from 13 to 50 m. The variability of the sediment grain size and other chemical variables in the sediment suggests the presence of two distinct environmental contexts that enhance the proliferation of different benthic communities. At the inshore stations (depth <20 m) the higher sand percentages and the maxima of dissolved inorganic nitrogen concentrations indicated the presence of hydrodynamic perturbations and the influence of nutrient loads of terrestrial origin. Inshore, both meio- and macrofaunal communities were poorly structured and dominated by relatively more opportunistic taxa, such as nematodes and the bivalve Corbula gibba. Offshore stations (depth >20 m) had muddier sediments, which likely exerted a greater retention of sediment-bound organic matter. These conditions seemed to favour benthic deposit feeders like meio- and macrofaunal annelids. Surprisingly, a conspicuous microphytobenthic community, mainly represented by the diatom Paralia sulcata, has been observed even at remarkable depths (~50 m) opening new questions regarding the role of these organisms in dim-light conditions. Although the investigated benthic communities were, to some extent, moderately influenced by multiple stressors, the co-existence of sensitive taxa (such as meiofaunal copepods and the amphipod Ampelisca spp.) with opportunistic ones (i.e., C. gibba) suggests that the benthic domain in the investigated area is not severely impacted. [ABSTRACT FROM AUTHOR]

A membrane extraction-gas chromatography method was developed for determination of organophosphorus pesticides and related compounds including methamidophos, DDVP, dimethoate, methyl parathion, parathion, thiophosphoric acid trimethyl ester, and thiophosphoramidic acid dimethyl ester in water samples. In this method, surface-modified acetic cellulose membranes were used to extract the target analytes in water samples, the extracted analytes were back-extracted into a small amount of methanol, and gas chromatography with pulsed flame photometric detector (GC-PFPD) was used to determine the concentrations of target analytes in the extracts. The recoveries obtained for the target analytes spiked into the water samples ranged from 66 to 94%. The method detection limit for each target analyte was 0.05 μg L-1. The method developed in this study had shown the advantages of being cheap, simple, fast, and reliable. It had been used successfully to determine the concentrations of target analytes in river water samples. [ABSTRACT FROM AUTHOR]