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Microbial Diversity in Sulfate-Reducing Marine Sediment Enrichment Cultures Associated with Anaerobic Biotransformation of Coastal Stockpiled Phosphogypsum (Sfax, Tunisia)

Microbial Diversity in Sulfate-Reducing Marine Sediment Enrichment Cultures Associated with Anaerobic Biotransformation of Coastal Stockpiled Phosphogypsum (Sfax, Tunisia)

FIGURE 6 | Maximum-likehood (ML) tree based on 16S rRNA gene sequences showing the phylogenetic position of Firmicutes from marine sediment (as inoculum) using different electron donors and sulfate sources (sodium sulfate or phosphogypsum). Representative sequences in the tree were obtained from GenBank (accession number in the brackets). Bootstrap values >75% are indicated at nodes. The bars represent the relative abundance (in %) of each OTU affiliated with Firmicutes in the enrichment cultures. The blue bars indicate the relative abundance of OTUs in sodium sulfate cultures, whereas the red bars represent the relative abundance of OTUs in PG cultures.
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Effect of 2,4-dinitrotoluene on the anaerobic bacterial community in marine sediment

Effect of 2,4-dinitrotoluene on the anaerobic bacterial community in marine sediment

as Clostridium acetobutylicum, were also reported to reduce 2,4-DNT and 2,6-DNT to their amino derivatives (Hughes et al. 1999). Recently, we found that the mixed indigenous micro- organisms can degrade 2,4-DNT and 2,6-DNT in marine sediment (Yang et al. 2008), but little is known about the impact of these chemicals on the microbial community in the sediment. We hypothesized that exposing the sedi- ment to 2,4-DNT followed by incubation under anoxic conditions might induce a change in the composition of the indigenous microbial community. Bacteria that are enriched by the presence of 2,4-DNT would tolerate the presence of the pollutant and degrade the chemical at a contaminated site. Therefore, identifying the types of micro-organism enriched by the presence of 2,4-DNT would help find indicators for the potential occurrence of natural attenuation at the contaminated site.
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Biodegradation of the nitramine explosives hexahydro-1,3-5-trinitro-1,3,5-triazine and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine in cold marine sediment under anaerobic and oligotrophic conditions

Biodegradation of the nitramine explosives hexahydro-1,3-5-trinitro-1,3,5-triazine and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine in cold marine sediment under anaerobic and oligotrophic conditions

The objective of the present study was to evaluate the biodegradation of RDX and HMX in marine sediment from a dumping site, located at the Emerald Basin (215 m deep, 50 nautical miles from Halifax Harbor, Nova Scotia, Can- ada), where warships unloaded live ordnance during war- time. Traces of explosives were recently found in the sediment and water column from this harbor (Darrach et al. 1998). Marine sediment is mostly anaerobic with low amounts of nutrients (oligotrophic) and high salt content (Karl and Dore 2001; Bowman 2001). Also marine sedi- ments are subjected to high pressure under cold tempera- tures. Psychrotrophic bacteria that can grow at low temperatures (7–18 °C) have been found in marine sedi- ments (Knoblauch et al. 1999). Such bacteria are either psychrophilic with low temperature growth optima (<15 °C) or psychrotrophic (grow at low temperature but have a nor- mal temperature optima). The biodegradability of the two explosives in the sediment was therefore evaluated under oligotrophic and anaerobic experimental conditions at 10 °C. A Remotely Operated Vehicle carried by the Canadian Navy Deep Seabed Intervention System used an aluminum container to collect the sediment. The sediment was sealed with seawater and kept at 4 °C during shipment and storage. The sediment (pH 6.5) was composed of silt (90%, particle size 2–50 µm), clay (8.3%, particle size <2 µm), and sand (1.3%, particle size >50 µm). The water content of wet sedi-
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Impact of cigarette butts on microbial diversity and dissolved trace metals in coastal marine sediment

Impact of cigarette butts on microbial diversity and dissolved trace metals in coastal marine sediment

2 19 Abstract 20 21 Cigarette butts are the most common plastic form of litter found in the marine coast, threatening 22 the quality of the seawater and marine life. However, the impact of cigarette butts known to 23 contain toxic chemicals has been investigated to date in very few marine species. This study 24 aimed to evaluate the effects of cigarette filters (smoked or unsmoked) on the microbial 25 diversity inhabiting coastal sediments by high-throughput sequencing of the 16S rRNA genes. 26 Both bacterial structure and metals distribution were impacted by cigarette filter addition in 27 laboratory sediment experiments, compared to control sediment incubations without filter. Both 28 smoked and unsmoked cigarette filters decreased pH and dissolved Cd, Mo and V 29 concentrations in marine sediment incubations, while they increased dissolved Fe, Mn, Zn 30 levels in the surrounding environment. Smoked filters dramatically decreased the relative 31 abundance of the phyla Bacteroidetes and Cyanobacteria, while the members of the phyla
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On-line determination of silver in sea-water and marine sediment by inductively coupled plasma mass spectrometry

On-line determination of silver in sea-water and marine sediment by inductively coupled plasma mass spectrometry

Received 16th October 2001, Accepted 10th December 2001 First published as an Advance Article on the web 3rd January 2002 An on-line flow injection method for the direct determination of silver in sea-water using isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) is described. A mini-column packed with 50 ml Dowex 1-X8 anion exchange resin was used to separate and concentrate Ag from sea-water following on-line merging with 0.5 M HCl. Recoveries of 100¡1% and 96¡1% were obtained for NRC CRMs SLEW-3 and CASS-4, respectively. One run can be completed in less than 6 min using a 12 ml volume of sea-water. The detection limit (3s), estimated at 0.06 pg ml 21 , is superior to previously published methods. Dissolved Ag concentrations of 1.93¡0.10, 5.15¡0.10 and 5.42¡0.10 pg ml 21 were obtained in SLEW-3, CASS-2 and CASS-4 CRMs, respectively. The method was also assessed for determination of Ag in a marine sediment CRM MESS-3, and a concentration of 0.169¡0.002 mg g 21 was obtained using ID ICP-MS after an off-line column separation, in agreement with the certified value of 0.18¡0.02 mg g 21 . The on-line method was also applied to analyses of sea-water and sufficiently diluted digests of marine sediments using an external calibration technique. Concentrations of 1.96¡0.10 pg ml 21 (mean and one standard deviation, n ~ 3) and 5.55¡0.15 (n ~ 3) pg ml 21 were obtained for dissolved Ag in SLEW-3 and CASS-4, respectively, in agreement with results generated by ID ICP-MS. A concentration of 0.181¡0.004 (n ~ 3) mg g 21 in MESS-3 was obtained, based on 200-fold diluted digests, in agreement with the certified value.
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The earthquake sedimentary record in marine sediment from cores in the western part of the Marmara Sea, Turkey

The earthquake sedimentary record in marine sediment from cores in the western part of the Marmara Sea, Turkey

The earthquake sedimentary record in marine sediment from cores in the western part of the Marmara Sea, Turkey \author{L.Drab, A.Hubert-Ferrari, S.Schmidt, P.Martinez} The North Anatolian Fault (NAF) is a 1500km long dextral strike-slip fault that accommodates the extrusion of the Anatolian Plate away from the Arabia/Eurasia collision zone at a rate of 20-25mm/yr.

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Discovery of a large 2.4 Ma Plinian eruption of Basse-Terre, Guadeloupe, from the marine sediment record

Discovery of a large 2.4 Ma Plinian eruption of Basse-Terre, Guadeloupe, from the marine sediment record

ERUPTION RECONSTRUCTION It is difficult to unequivocally determine whether more than one eruption was responsible for deposition of T 2.36 . Hemipelagic sedimenta- tion rates of ~2.8 cm k.y. -1 make sub-centennial gaps between eruptions difficult to identify. Het- erogeneous grain-size distribution, morphology, and geochemistry are also observed in single large deposits (Wiesner et al., 2004), so cannot easily be used to address this problem, but visual inspection of T 2.36 indicates that it is composed of an upper layer of ~6 cm and a lower layer of ~12 cm thickness (Fig. 1). Grain-size analyses of the upper and lower layers in the core from Hole U1396A (see the Data Repository) show that the lower layer is coarser grained while the upper layer contains a higher percentage of fine- grained particles (Fig. 3). This pattern is similar to that observed in andesitic fallout deposits (coarser grained) overlain by finer-grained co- pyroclastic/co-ignimbrite flow cloud deposits from the A.D. 2004–2006 eruptions of Colima, Mexico (Evans et al., 2009) and in both subaerial and marine tephra deposits of the Campanian ig- nimbrite (Engwell et al., 2014), and suggest that T 2.36 comprises the products of a Plinian eruption (lower layer) and associated lofted co-pyroclas- tic/co-ignimbrite flow deposits (upper layer).
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Limited influence of marine sediment lyophilization on prokaryotic community structure assessed via amplicon sequencing: an example from environmentally contrasted sediment layers in Toulon harbor (France)

Limited influence of marine sediment lyophilization on prokaryotic community structure assessed via amplicon sequencing: an example from environmentally contrasted sediment layers in Toulon harbor (France)

As demonstrated by Fig. 6 , the large majority of community structure variation was recorded between the surface layer and the other two samples, their separation being evident on the first axis of the PCoA representing more than 90% of the variability whatever treatment before DNA extraction was applied ( Figs. 6A and 6B ). Some variability among replicates (at 0–1 cm for frozen sediments and 19–20 cm for lyophilized ones) could be observed along the second axis, representing 3.0–4.3% of the variability. When considering both treatments together ( Fig. 6C ), the second axis allowed to discriminate intermediate (10 –11 cm) and deep samples (19–20 cm) as well as support the influence of sediment treatment (fro vs. lyo). Although this observation could suggest some phylogeny-related susceptibility to lyophilization, the small representation of
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Biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine by novel fungi isolated from unexploded ordnance (UXO) contaminated marine sediment

Biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine by novel fungi isolated from unexploded ordnance (UXO) contaminated marine sediment

Isolation and identification of fungi Fungi were enriched by incubating sediment (10 g) in marine fungal medium (100 ml) in 500 ml Erlenmeyer flask on a rotary shaker (80 rpm) at room temperature for 7 days. Chloramphenicol (0.2 g l 1 ) was added to the medium as ethanol stock solution after passing through a 0.2 lm filter to inhibit bacterial growth. The undiluted fungal enrichment culture (10 ll) was then spread on marine fungal agar plates followed by incu- bation at room temperature for 1 week. Several mor- phologically different fungal colonies were picked and further purified by streaking on fresh solid marine fungal medium. Four strains named HAW-OCF1, HAW- OCF2, HAW-OCF3, and HAW-OCF5 that were tested positive for their potential to degrade RDX under aer- obic conditions were selected for further identification (see below).
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Stabilization of contaminated marine sediment by addition of bauxite residues : evaluation of potential mobility of trace elements

Stabilization of contaminated marine sediment by addition of bauxite residues : evaluation of potential mobility of trace elements

54 regarded as one of the major contributor in the generation of solid by-products. By- products produced during extraction of metals are of no or little economic value depending upon their composition. Solid by-products valorization is necessary and new scientific advances are vital for utilization of by-products in remediation techniques (Zheng and Kozinsk, 1996; Panias et al., 2001; Kumar et al., 2006) . Alumina industry is regarded to be one of the major contributors towards the generation of solid by-products and its appropriate management is of increasing environmental concern. Industrial by-products can be classified as hazardous or non-hazardous depending on the possible release of pollutants from the matrix into environmental media (Panias et al., 2001; Kumar et al., 2006). Prior to the decision about industrial by-products management the characterization of solid by-products according to globally accepted protocols and regulations is mandatory (Panias et al., 2001; Siddique, 2014).Over the last few decades, efforts have been made to find cost effective and sustainable solutions for by-products minimization and utilization (Bandopadhyay et al., 2002). Re-use or recycling of industrial by-products has become an attractive alternative since it could reduce the risk of environmental pollution as well as space for their disposal (Siddique, 2014). In this review paper, we attempt to present a critical overview of the uses of an alumina industry by-product called red mud (RM), the different treatments applied to that kind of by-product to make it suitable for specific re- use, its use for treatment of contaminated water, soil and sediment depending on the contaminant types, and finally the ecotoxicity investigations.
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Negligible microbial heterotrophic quantitative contribution onto trace metals remobilization during marine sediment resuspension - insights from a Mediterranean urbanized bay

Negligible microbial heterotrophic quantitative contribution onto trace metals remobilization during marine sediment resuspension - insights from a Mediterranean urbanized bay

constant depends on temperature and pressure as well as sediment / seawater ratio, an increase in solubilization of 202 the metals at high temperatures may have introduce some equilibrium changes. Thus, to study the microbial 203

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Trophic Ecology of Coastal Soft Botoms: A Dive into the Stew of Marine Sediment

Trophic Ecology of Coastal Soft Botoms: A Dive into the Stew of Marine Sediment

bottom SPOM available for benthic primary consumers mainly consisted of marine phytoplankton detritus. Isotope fractionation Stable isotope analysis has proved to be a very effec- tive method for tracking energy and nutrient flows in ecosystems (Fry & Sherr 1984, Post 2002). The common assumption of this approach is the stepwise enrichment in heavy isotopes along food chains. According to seminal empirical datasets, carbon isotopic composition of ani- mals should reflect their diet within about 1 ‰ (De Niro & Epstein 1978, Peterson & Fry 1987) and trophic nitro- gen enrichment should be near 3.4 ‰ (Minagawa & Wada 1984). Even if δ 13 C and δ 15 N fractionation can deviate
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Reconstructing last glacial changes in Atlantic meridional overturning rate using marine sediment (231Pa/230Th)

Reconstructing last glacial changes in Atlantic meridional overturning rate using marine sediment (231Pa/230Th)

Both  these  variations  are  interpreted  as  a  decrease  in  northern  tropics  precipitation,  related  to  a  southward  shift  of  the  Inter  Tropical  Convergence  Zone  (ITCZ).  Indeed,  at  the same time, the southern tropics experienced increased precipitation, which are seen  in marine sediment cores from the Brazilian margin (Jaeschke et al., 2007) as well as in  South American speleothems (Cheng et al., 2013). Climate models are able to reproduce  these ITCZ shifts by simulating a cold SST anomaly in the northern tropics. Indeed, the  ITCZ  lies  above  warm  waters,  where  air  convection  and  intense  precipitation  occurs  (Hastenrath, 2011) so that a cold anomaly in the northern tropics induces a shift of the  tropical  rain‐belt  towards  the  warmer  southern  tropics.  Modelling  experiments  can  produce a cold SST anomaly in the northern tropics by two different mechanisms. In the  first  mechanism  (Chiang  and  Bitz,  2005),  extended  sea  ice  or  ice  sheet  cover  in  the  northern  high  latitudes  cools  and  dries  the  atmosphere.  This  cooling  and  drying  propagates  to  the  entire  northern  high  and  mid  latitude  by  atmospheric  transport  and  mixing. In the tropics, northeastern trade winds are intensified because of the cool mid‐ latitude  ocean,  which  leads  to  further  evaporation  and  cooling  and  pushes  the  SST  anomaly southwards leading to a southward shift of the ITCZ. In the second mechanism  (Kageyama et al., 2010), an AMOC slowdown causes the northern tropical ocean to cool  and southern tropical ocean  to  warm,  as  predicted  by  the  bipolar  seesaw  concept.  The  ITCZ therefore shifts towards the warmer southern tropics. 
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Approaches to evaluate spatial and temporal variability of deep marine sediment characteristics under the impact of dense water formation events

Approaches to evaluate spatial and temporal variability of deep marine sediment characteristics under the impact of dense water formation events

Statistical analyses Permanova Both univariate and multivariate nonparametric permutational ANOVAs (PERMANOVA) based on Bray-Curtis dissimilarity (Anderson, 2001; Anderson & Braak, 2003; Anderson & Robinson, 2003) are robust al- ternatives to the parametric multivariate analysis of vari- ance. They were used here to test for differences in the geochemical composition of sediment between sites and between deployments relating to the same site. Multivar- iate data were analysed based on any distance measure, according to any linear ANOVA model, using permuta- tions. Random factor 1 (the site) has three levels; ran- dom factor 2 is nested within factor 1 and also has three levels, the sample size is 3 (n = 3 core replicates within a deployment). Calculation of the F-ratio and p-value re- quired unrestricted permutations of raw data (univariate), or 4999 permutations of the residuals under a reduced model (multivariate). The set of data used in the multi- variate PERMANOVA test was POC content (%), δ 13 C
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Radiocarbon Dating of Small-sized Foraminifer Samples: Insights into Marine sediment Mixing

Radiocarbon Dating of Small-sized Foraminifer Samples: Insights into Marine sediment Mixing

acid, or possibly to coccoliths remaining at the surface of the foraminifera shells (as they can be present on the analyzed specimens; see Figure S3A [c, d, e, f]). Overall, this material has been exposed to the modern atmosphere since core retrieval and therefore, the leach fraction has usually slightly younger 14 C ages than the main fraction, which corresponds to the inner shells (see Figure S4 ). However, an altered sample (i.e. a shell that has undergone significant dissolution/recrystallization), would display an outer shell (leach fraction) generally older than the inner shell (main fraction), which can be related to the incorporation of older or even 14 C dead carbon content from the underlying sediment layers during dissolution/recrystallization processes, as suggested by (Broecker et al. 1984 ; Barker et al. 2007 ). Importantly, altered shells will also be characterized by a high difference between the outer part (leach fraction) and the inner part (main fraction). To distinguish potentially contaminated (e.g. by coccoliths), altered or dissolved samples we discard the samples for which the 14 C age difference between the main and the leach fraction largely exceeds the expectations. Assuming distinct exponential relationships between the sample 14 C age (i.e. content) and the analytical uncertainty for both the main fraction and the leach fraction, we estimate from 10,000 Monte Carlo draws the expected apparent 14 C age offset between a main and a leach fraction having supposedly the same 14 C age (Figure S4 ). Note that the analytical uncertainty of the leach fraction is larger than the one of the main fraction, for a given age because the leach fraction is of a smaller size. Besides, for our samples, the main and leach fraction are not expected to strictly have the same age due to potential contaminations of the sample. In this study we tolerate an age offset between the main and leach fraction which is up to 3 times equal to the mean expected age offset accrued by 1 σ. We also rejected the samples displaying a very negative main-leach fraction offset (i.e. below the expected mean, 2 σ) as older leach fraction is a potential indicator for recrystallization as discussed above. By following this procedure, we excluded 9-paired leach and main fraction 14 C gas measurements from our dataset (see Figure S4 ), representing less than 10% of our available gas measurements. Interestingly the benthic sample which appeared off-trend (Figure 2 ) did not pass the leaching test.
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Modelling Marine Sediment Biogeochemistry: Current Knowledge Gaps, Challenges, and Some Methodological Advice for Advancement

Modelling Marine Sediment Biogeochemistry: Current Knowledge Gaps, Challenges, and Some Methodological Advice for Advancement

The benthic environment is a crucial component of marine systems in the provision of ecosystem services, sustaining biodiversity and in climate regulation, and therefore important to human society. With the contemporary increase in computational power, model resolution and technological improvements in quality and quantity of benthic data, it is necessary to ensure that benthic systems are appropriately represented in coupled benthic-pelagic biogeochemical and ecological modelling studies. In this paper we focus on five topical challenges related to various aspects of modelling benthic environments: organic matter reactivity, dynamics of benthic-pelagic boundary layer, microphytobenthos, biological transport and small-scale heterogeneity, and impacts of episodic events. We discuss current gaps in their understanding and indicate plausible ways ahead. Further, we propose a three-pronged approach for the advancement of benthic and benthic-pelagic modelling, essential for improved understanding, management and prediction of the marine environment. This includes: (A) development of a traceable and hierarchical framework for benthic-pelagic models, which will facilitate integration among models, reduce risk of bias, and clarify model limitations; (B) extended cross-disciplinary approach to promote effective collaboration between modelling and empirical scientists of various backgrounds and better involvement of stakeholders and end-users; (C) a common vocabulary for terminology used in benthic modelling, to promote model development and integration, and also to enhance mutual understanding.
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La télédétection spatiale et SIG marine pour la conception et la mise à jour de la carte marine électronique de navigation

La télédétection spatiale et SIG marine pour la conception et la mise à jour de la carte marine électronique de navigation

L’approche adoptée dans cette étude concerne les techniques actuelles d’extraction automatique des objets géographiques du littoral les mieux définis par les géographes : Les détails topographiques naturels et artificiels, les Amers , les estrans et les l’installations portuaires, en appliquant une nouvelle approche de classification « Orientée-Objet » d’une image à THRS, associée aux techniques de la digitalisation manuelle de la partie marine , et l’intégration des résultats obtenues sous forme des couches vectorielles dans une base d’information géographique pilotée par un SIG normalisé, dont le but est de réaliser un système d’informations géographiques formalisé pour la cartographie marine de navigation.
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Prediction of sediment load by sediment rating curve and neural network (ANN) in El Kebir catchment, Algeria

Prediction of sediment load by sediment rating curve and neural network (ANN) in El Kebir catchment, Algeria

Based on the 90% (978 sets) and 85% (924 sets) training data, the training phase used to find the model parameters was deduced through the regres- sion analysis. The multiple regression of dependent variables C or Qs at day t versus those variables of Q, C, and Qs, at days t, t −1, t−2, have revealed a positive, yet somewhat a less strong relation- ship between water discharge and sediment con- centration data but a strong relationship between water discharge and sediment discharge (r = 0.93). A comparative analysis, in terms of statistical mea- sures, of RMSE, EF and r is summarized in table 1 . The results have shown less error and slightly better efficiency for the Q −Qs relationship; how- ever, the testing set revealed that performance of the models did not capture the complex behaviour of suspended sediments well. The results were not significant in relation to the error (RMSE > 400) and efficiency factor (EF = 0.79 and less) values, whereas, values of r in this testing phase equal to 0.91 were considered fairly good. Apparently, it seemed that the estimated suspended sediment discharges did not approximate the corresponding observed sediment discharges at medium and high values.
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Investigating the source of radiocesium contaminated sediment in two Fukushima coastal catchments with sediment tracing techniques

Investigating the source of radiocesium contaminated sediment in two Fukushima coastal catchments with sediment tracing techniques

Decreases in the sediment contributions modelled from the upstream area in the Niida catchment from April 2012 to May 2013 may be indicative of ongoing decontamination works that commenced in 2012. To reduce contamination, there has been a massive remediation effort in the Niida catchment since the 2012 summer with vegetation and the uppermost soil layer (~5cm) removed from cultivated soils (Yasutaka & Naito, 2015). It has been demonstrated that decontamination may potentially increase the dose rates measured in river sediment (Evrard et al., 2014b; Lepage et al., 2014a). Therefore, the increased contribution of the upstream soils to the coastal plain sediments could be related to the occurrence of these decontamination works. Indeed, the application of this modified 137 Cs-tracing technique could monitor the impact of decontamination works in the Fukushima region.
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Assessing sediment connectivity to understand dynamics of contaminated sediment within coastal catchments of Fukushima Prefecture (Japan)

Assessing sediment connectivity to understand dynamics of contaminated sediment within coastal catchments of Fukushima Prefecture (Japan)

Assessing sediment connectivity to understand dynamics of contaminated sediment within coastal catchments of Fukushima Prefecture (Japan) Caroline Chartin, O. Evrard, Yuichi Onda, Catherine Ottle, Camille Brossoni, Irène Lefevre, Hugo Lepage, Philippe Bonté, Jérémy Patin, Sophie Ayrault

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