We have identified important chemical reactions that control the fate of metal-contaminated estuarine sediments if they are left undisturbed (in situ) or if they are dredged. We combined information on the molecular bonding of metals in solids from X-ray absorption spectroscopy (XAS) with thermodynamic and kinetic driving forces obtained from dissolved metal concentrations to deduce the dominant reactions under reduced and oxidized conditions. We evaluated the in situ geochemistry of metals (cadmium, chromium, iron, lead, manganese and zinc) as a function of sediment depth (to 100 cm) from a 60 year record of contamination at the Alameda Naval Air Station, California. Results from XAS and thermodynamic modeling of porewaters show that cadmium and most of the zinc form stable sulfide phases, and that lead and chromium are associated with stable carbonate, phosphate, phyllosilicate, or oxide minerals. Therefore, there is minimal risk associated with the release of these trace metals from the deeper sediments contaminated prior to the Clean Water Act (1975) as long as reducing conditions are maintained. Increased concentrations of dissolved metals with depth were indicative of the formation of metal HS 2 complexes. The sediments also contain zinc, chromium, and manganese associated with detrital iron-rich phyllosilicates and/or oxides. These phases are recalcitrant at near-neutral pH and do not undergo reductive dissolution within the 60 year depositional history of sediments at this site.
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Abstract: We isolated 100 morphologically-distinct halotolerant/halophilic yeasts from five estuarine sediments in Qua Iboe estuary, South-South Nigeria. A three-way analysis of variance (ANOVA) of the distribution was significant at p < 0.01; adjusted r 2 = 0.851 suggesting that 85.1% of the variations in the number of halotolerant/halophilic yeast could be explained by the model. Sample, media and salt level main effects were all significant at p < 0.01, r 2 = 0.732; 0.403 and 0.463 respectively. Only 17% of the yeasts demonstrated biosurfactant production potential by the oil displacement assay. Positive isolates were identified by macro/micro-morphological and physiological characterizations as species of Torulaspora, Pichia, Saccharomyces, Candida, Debaryomyces, Kluyveromyces, Schizosaccharomyces, Rhodotorula and Hortaea but the dominant halotolerant genus was Candida. Douglas creek sample harbored the highest number of halotolerant biosurfactant-producing yeasts probably by reason of its better proximity to Qua Iboe terminal where petroleum activity is high. Biosurfactants produced by all 17 yeasts could reduce surface tension to < 40 mN/m suggesting that halotolerant/halophilic yeasts in stressed environments secrete only effective surface-active compounds or not at all. Significant but moderate correlations existed between all correlate pairs involving oil displacement activity, surface tension, critical micelle concentration and emulsification activity of biosurfactants. The Pillai’s Trace test of a one-way multivariate analysis of variance (MANOVA) involving surface tension reduction, oil displacement activity and emulsification activity was significant at F (48,102) = 3119.004, p < 0.005, partial ƞ 2 = 0.999.
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Abstract: Estuarine sediments are a reservoir for faecal bacteria, such as E. coli, where they reside at greater concentrations and for longer periods than in the overlying water. Faecal bacteria in sediments do not usually pose significant risk to human health until resuspended into the water column, where transmission routes to humans are facilitated. The erosion resistance and corresponding E. coli loading of intertidal estuarine sediments was monitored in two Scottish estuaries to identify sediments that posed a risk of resuspending large amounts of E. coli. In addition, models were constructed in an attempt to identify sediment characteristics leading to higher erosion resistance. Sediments that exhibited low erosion resistance and a high E. coli loading occurred in the upper- and mid-reaches of the estuaries where sediments had higher organic content and smaller particle sizes, and arose predominantly during winter and autumn, with some incidences during summer. Models using sediment characteristics explained 57.2% and 35.7% of sediment shear strength and surface stability variance respectively, with organic matter content and season being important factors for both. However large proportions of the variance remained unexplained. Sediments that posed a risk of resuspending high amounts of faecal bacteria could be characterised by season and sediment type, and this should be considered in the future modelling of bathing water quality.
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Pazhayar is one of the main river systems in Kanyakumari District. It receives water from both Pechiparai and Perunchani reservoirs. The Pazhayar takes its origin at Surulacode. The total length of the river is about 37km and it passes through Boothapandi, Thazhakudi, Putheri, Nagercoil, Suchindrum and finally joins with Arabian Sea through a Manakudy estuary. The present investigation was done to evaluate the sediment characteristics of riverine and estuarine zones. For the study three stations were taken in the riverine zone (S1, S2 and S3) and three stations were selected on the estuarine zone (S4, S5 and S6).The sediment texture revealed the fact that grain size ranged from 0.063mm to 0.5mm. Sand was predominant in the riverine side. The mud (silt + clay) was abundant in the estuarine region than the riverine zone. The estuarine zone was highly silty. The sulphur content decreased from the riverine side to estuarine zone. The organic carbon also showed the same trend of decreasing from the riverine zone to estuarine region. However a negative trend was observed in calcium carbonate which increased from the riverine zone to estuarine region. Probably due to the abundance of molluscan shells in the estuarine zone. The various parameters of surface sediments in the six stations were subjected to two way ANOVA and it was found that they are significantly correlated.
Twenty gram sub-samples of sediment were refluxed in 6% w/v KOH in methanol for 4 h. The cooled supernatant was decanted and centrifuged to remove remaining solids (5 min at 500 rpm). Non-polar sterols were partitioned into hex- ane after the addition of pure water (after Mudge and Nor- ris, 1997). All appropriate measures were taken to minimise potential contamination. An attempt was made to establish the use of a novel internal standard, 1-docosanol. However, it was found that docosanol also occurred in the sediments and therefore was unsuitable for the purpose. It was not pos- sible to distinguish between 1-docosanol and an epimer in the sediments and so absolute identification was not possi- ble. It is suggested that the soft fruit industry on the Carse of Gowrie (north shore of Tay Estuary) may be the source of the alcohol. Docosanol has been isolated from raspberry strains grown there (Scottish Crop Research Institute, pers. comm.) An external standard (4 µg 5α-cholestane in 100 µl heptane) was therefore added. Based on preliminary exper- imentation, extraction efficiency (reported to be essentially 100% by Mudge and Norris, 1997) was found to average >90%; a result which compares favourably with reported ex- traction efficiencies using this protocol (62%–96%: LeBlanc et al., 1992). Sterols were derivatised using 100 ml of 1:10 TMCS/BSFTA at 60 ◦ C for 1 h.
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Being able to identify key correlations between physicochemical and PTE parameters is crucial in order to identify ‘stressors’ within the local environ- ment. With past discharges to the River Clyde being reworked by estuarine processes and exposure condi- tions having a dynamic temporal context, there is a unique ecosystem to test the prevalence of pollution- related impacts. For example, the link between AMR and metal content which has previously been identi- fied as a promoter of genetic dissemination by cross and/or co-resistance (Ashbolt et al. 2013; Baker- Austin et al. 2006; Berg et al. 2010; Seiler and Berendonk 2012; Perry and Wright 2013; Martinez et al. 2009; Knapp et al. 2017).
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Abstract: The problems associated with environmental biofouling and the limitation of currently available antifouling compounds has intensified the search for novel eco-friendly antifouling compounds from new sources. The present study reports bioprospecting of culturable actinobacteria from less explored marine ecosystems against biofouling bacteria. Fifty five bacterial isolates were recovered from fouling samples collected from Muttom, Parangipettai, Nagapattinam and Ennore coastal areas. Morphologically distinct isolates were phenotypically characterized. The isolates were belongs to species of the genus Bacillus, Aeromonas, Micrococcus, Alcaligenes, Lactobacillus, Staphylococcus, Pseudomonas and Kurthia. Biofilm forming capacity of all the isolates evaluated by adopting plate as well as tube method. Out of 55 bacterial isolates, 25 isolates produced positive results for biofilm formation in which the species belongs to the genus Staphylococcus, Micrococcus, Vibrio and Alcaligenes were identified as strong biofilm producers. For the isolation of potential antifouling compounds, totally 50 actinobacterial isolates were recovered from mangrove and estuarine sediment samples collected from Parangipettai and Pitchavaram coastal areas, Tamil Nadu and were phenotypically characterized. In agar plug method, 42 out of 50 actinobacterial isolates inhibited one/more number of biofouling bacteria tested. Two actinobacterial isolates viz., strain PM33 and the strain PE7 showed promising activity against maximum number of biofouling bacteria tested. Isolation of bioactive metabolites from both the actinobacterial strains will leads to the development of promising antifouling candidates.
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diverse environments (Nealson 1997). Numerous conditions affect the presence and quantity of microbial communities (including those species with antimicrobial resistant genes (ARGs) present), and the knowledge of expected key com- munity characteristics can be linked to their responses to physicochemical properties (e.g., conductivity (EC), pH and redox), nutritional quality (e.g., total nitrogen, phosphorus, carbon and minerals), source of carbon—including organic matter (Wang et al. 2016)—and pollutant conditions (includ- ing PTE and PAH content) of sediments (Fig. 1). This can create extreme spatial differences of species composition and community structures (Abd-El-Aziz et al. 2017). Fortu- nately, the advent of community DNA extractions and high- throughput sequencing has provided wealth of information related to this through metagenomics, whether targeted (e.g., via small sub-unit rRNA or specific genes) or “shot gun” (i.e., random).
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Abstract The aim of this study was to assess Cu, Pb and Zn contamination in estuarine and urban sediments along Grand River North West (GRNW) during 2009-2013. Pb and Zn were significantly higher in the GRNW estuary though unleaded petrol was introduced since 2002. In fact, the potential sources of Cu, Pb and Zn in the urban estuarine sediments at GRNW were considered to arise from brakedust, road runoff and galvanized road furniture causing significant quantities to be trapped in coastal sediments with increasing vehicles. The mean concentration of Pb and Zn in the urban sediments along GRNW were however still below the limits of 700 and 2500 mg kg -1
Physicochemical sediment data, water column parameters, and nutrient flux rates are reported as mean ± standard deviation. Estimates of sediment-water column nutrient fluxes ( µ mol m −2 h −1 ) and sediment depth profiles of bioavailable nutrients are utilised to investigate the potential release of nutrients following sediment disturbance within the estuarine sediments of Saltwater Creek. Comparisons of physicochemical parameters of the various depth horizons were performed by ANOVA and the means were compared using Tukey’s HSD analysis. Pearson correlations were used to identify relationships between physicochemical sediment parameters of the various depth horizons. The significance of observed differences between TSS and dissolved inorganic nutrient concentrations, and nutrient flux rates before and following the sediment disturbance and resuspension event (n = 6), was calculated with a paired t-test. Normality was tested using the Kolmogorov-Smirnov test, and adjusted as necessary to satisfy the ANOVA assumptions. The total suspended sediments, dissolved inorganic nutrient concentrations, and flux rates following the resuspension event, were compared by ANOVA using SPSS for Windows (version 19, SPSS Inc., Chicago, IL, USA).
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Mike Elliott is the Director of the Institute of Estuarine and Coastal Studies and Professor of estuarine and coastal sciences at the University of Hull and a marine biologist with a wide experience of marine and estuarine biology and its environ ment, management, and policy. His teaching, research, and advisory and consultancy work have included studies of most ecological components as well as policy, govern ance, and management. In many instances, he has concentrated on the interactions between these aspects, usually in relation to human activities and on the way in which environmental change influences organisms and vice versa. He has taken a particular interest in the way in which water bodies are defined and analyzed for policy and management. Mike has produced more than 140 peer-reviewed scientific publications and has co-authored or edited 11 books and conference proceedings on estuarine and marine issues. This includes co-authoring The Estuarine Ecosystem: Ecology, Threats and Management (with DS McLusky, OUP, 2004) and Ecology of Marine Sediments: Science to Management (with JS Gray, OUP, 2009). He has been/is a chair and/or member of many advisory panels for teaching and research both in the UK and elsewhere and is a member of the editorial boards of several international scientific journals as well as the Editor-in-Chief of Estuarine, Coastal and Shelf Science. He was previously employed by the Forth River Purification Board (now the Scottish Environmental Protection Agency), Tidal Waters Section as the Senior Marine Biologist. Professor Elliott has recently been appointed to the UK governmental Marine Conservation Zone Science Advisory Panel.
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The Great Barrier Reef Lagoon (GBRL) is an area of great biodiversity containing 350 species of corals, 10 of which are endemic to the region. In recent years many threats to this ecosystem have been revealed, such as crown-of-thorns starfish and coral bleaching as well as excess concentrations of nutrients and sediments. Information on the effects of water quality and also the amounts of nutrients and sediments that reefs are subjected to is limited. This is especially true for inshore reefs where issues of water quality are most important.
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When we talk about the problems and productivity of the sea, for most people this means the estuaries, coasts, and shores that they can see and explore. When students study marine science in all its aspects, they usually study their local estuaries and coasts and rarely set sail for the deep open ocean. When socio-economists study estuaries and coastal waters, they focus on valuing in economic terms the direct (i.e., with direct monetary values) and indirect values of the ecosystem services that these waters provide to humanity; such valuation is essential for planning the future of estuaries and coastal waters in a crowded, full world anthroposphere. Thus, while estuaries and coasts make up only a small fraction of the total area of the world ’ s seas, they are not only responsible for much of the fish production that we consume but, just as important, are also essential for the quality of life of the 50% of the human population on Earth that lives near the coast. The link between the watersheds and the estuaries and coastal seas, the direct human impact on estuaries and coasts, and the resilience of these waters to human impact determines the severity of environmental problems that mankind faces in connection with the sea. In turn, science can offer solutions for improving estuarine and coastal management practices at the local scale and at the watershed scale in order to improve the resilience of the system and mitigate or even reverse, partially at least, environmental degradation. In the context of climate change, some estuaries and coastal seas may be measurably impacted by small changes to sea level, temperature, and pH, but other estuaries and coasts have the potential to adapt to climate change and to provide our culture and economy a level of future protection. For all these reasons, it is vital that scientists use all the information available to them for the management of our estuaries and coasts. All this information was gathered together for this Treatise. All the editors involved in the production of this Treatise believe that complete information about the science of our estuaries and coasts is vital for the future of this planet.
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The construction of fully closed check dam (CD) is a conventional flood prevention mechanism implemented on rivers. Fully closed CDs trap large amounts of sediments in rivers to stabilize the river slopes and control erosion. However, fully closed CDs cannot selectively trap sediment and may easily overflow, causing them to losing their ability to mediate and hold sediments. Previous studies proposed the concept of “breathable CDs”. The researcher introduced metal slit dam (SD) that could be assembled and disassembled quickly and conveniently. Once a CD reaches maximum capacity, operators must ensure that the water channels of the dam are free from blockage. More- over, they must inspect the internal accumulation conditions of the dam periodically or imme- diately following heavy typhoon rains. When necessary, either the sediment buildup in the upriver blockage must be cleared, or the transverse structure of the dam must be removed to allow fine particles to be discharged along with a moderate amount of water. These actions can free up the sediment-storing capacity of the dam for the next heavy typhoon rains. In addition, operators should also inspect the damages inflicted on the dam, such as erosion, wear and tear, and defor- mation conditions. Damaged components should be disassembled and repaired if possible, or re- cycled and reused. The present study performed channel tests to simulate closed CDs, SDs, steel pipe dam (SPDs), and steel pipe plus slit dam (SPSDs) for 50-year and 100-year frequency floods. Results were then analyzed to determine the sediment trapping (ST) effects of various CDs, the ef- fects of “adjustable CDs”, and the changes of moderated riverbeds.
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downstream sites LD 2 and LD 1 generally had higher concentration of dissolved reactive phosphorus during the May to December 2001 study period. 137 Cs dating of sediment cores from the floodplains at the three LD locations reveal that the sedimentation rates vary from 0.5 cm/yr at LD 3 to 1.5 cm/yr and 1.3 cm/yr at LD 2 and LD 1, respectively. The sedimentation rates correspond well to the total sediment phosphorus concentrations, indicating that sediment deposition during the recent decades (≈ 40 years) has caused an increase in nutrient loading to the CFR. The floodplain sediments at LD 2 had the greatest phosphorus binding capacity, while the most downstream site, LD 1, had the lowest. However, the intra-site variability in phosphorus sorption capacity and mineral element composition increases downstream, most likely in response to differential sorting of the riverine sediment. 31 P Nuclear Magnetic Resonance (NMR) analyses of
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River plumes have a short-term and local influence on turbidity (Wolanski 1994, Taylor 1996). If winds are favourable the plumes can reach the mid and outer reef shelves (Brodie 1996, Brodie and Furnas 1996). The scale of the influence of river plumes is greatly debated. Plumes may only occur for a few days each year but they supply a significant amount of all the sediments added by terrestrial runoff, so some believe that they are of great importance to the annual SSC budget (Wolanski 2003, Devlin et al. 2001, Furnas 2003). Conversely the river plumes tend to be only a few metres thick and carry a small load of sediment compared to sediment loads observed during resuspension events (Taylor 1996). For example a major plume from the Barron River which stretched over an area of 45km by 10km only contained about 9000 tonnes of suspended sediment (Larcombe and Woolfe 1999). In contrast, swell waves in Cleveland Bay acting over an area of 200 km 2 and a depth of 5 m are able to disturb
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think about doing a scientific research on the nature and distribution of the deposited sediments on the bottom of the Dukan Dam Reservoir that is to elongate its operating age, avoiding the Region from an environmental catastrophe, i.e. , dam failure, water scarcity and water pollution, too. To achieve this goal, it has been mainly dependent on grain size analysis and its statistical parameters because they are useful tools for more understanding the sedimentary environments, transport history and depositional con- ditions -.
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(ETM) zone has much more amounts of suspended par- ticles than its upstream and downstream . They can trap land-based debris (e.g., fine sediments, organic mat- ters and pollutants) and transferred them into bottom sediments [11, 12]. Sediments are widely known as long- term reservoir and continuous sources for OTC residues based on their more than 10 years of half-life [13, 14]. The Yangtze Estuary, as a typical tidal estuary, also includes the ETM zone where many OTC-sensitive species inhibit (e.g., snails, clams) [15, 16]. In recent years, this estu- ary has been experiencing significant industrialization and urbanization and became one of the most impor- tant shipbuilding bases in China. Local human activi- ties greatly disturb the normal marine ecosystem. Chen et al.  found a widespread distribution of OTCs in the Yangtze Estuary in 2014, but no data is available about their temporal variation, potential sources and environ- mental behaviors based on the specific geographic condi- tions (e.g., hydrophobic pollutants “accumulation” effects in the ETM zone) locally.
Saccharomonospora are not observed in the present study and their absence may be attributed to habitat variation. They suggested that Actinobacteria are an indigenous part of the microbial community in the marine ecosystem and the „„Micromonospora- Rhodococcus- Streptomyces‟‟ grouping should definitively be revisited. They further stated that “there is indeed an urgent need to improve traditional selective isolation methods to recover the untapped majority of microbes not only from the sea but also from terrestrial samples but, at the same time, „„old‟‟ culture/selective isolation media can still help us to recover putative novel species from one of the most important biotechnologically microbial groups studied worldwide”. Suthindhran & Kannabiran (2009) recorded the genera Streptomyces, Micromonospora, Actinopolyspora and Saccharopolyspora from shallow water sediments of Marakkanam,
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Swansea Docks are owned by Associated British Ports (ABP) and all three docks are currently operational (although Prince of Wales Dock is only used to transport fish to the quayside market). In Queen’s Dock, there is a BP terminal and large cargo ships enter the terminals to distribute oil and petroleum through large pipelines. Other activities within the dock complex include: general cargo handling; maintenance of vessels along the quayside; dry docking for tankers, ferries and cargo vessels and lay-by facilities for the numerous tugs operating from the port (ABP, pers. comm., 1996). King’s Dock was selected as the case study location because it is known to be contaminated with PCBs (Reed & Waldock, 1998), has recently been refused licences to dredge sediments and appears to have a spatial distribution of sediment PCBs which is difficult to characterise under the current CEFAS sampling scheme. The main difficulties have been few sample numbers, patchy distributions, no clear trends, no identification of point sources nor an idea of potential diffuse sources. To date, no firm conclusions have been reached as to the source of PCB contamination in the dock. The EA suspect that mishandling of PCB waste material, destined for the RECHEM site, has accidentally entered the dock in 1992 from a visiting Swedish vessel (Hutchings, D.,
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