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Pesticide pressure and fish farming in barrage pond in northeastern France. Part III: how management can affect pesticide profiles in edible fish? Texte intégral
2013
Lazartigues, Angélique | Banas, Damien | Feidt, Cyril | Brun-Bellut, Jean | Gardeur, Jean-Noel | Le Roux, Yves | Thomas, Marielle | Unité de Recherches Animal et Fonctionnalités des Produits Animaux (URAFPA) ; Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL) | Agence de l'Eau Rhin-Meuse; Zone Atelier Moselle
International audience | The quality of fish produced in ponds needs to be ensured. Indeed, pond is often strongly connected to an agricultural watershed, and pesticides are a main health and environmental issue of concern. In this context, the purpose of this study is to highlight the management practices which could impact the pesticide contamination profiles in edible fish and to give recommendations for better practices. A principal component analysis, coupled to a hierarchical cluster analysis, was performed to evaluate temporal evolution of contamination profiles and to assess variability among fish species and among sites according to watershed characteristics. The explicative variables correspond to muscular concentrations of pesticides (azoxystrobin, clomazone, diflufenican, carbendazim, isoproturon, metazachlor, napropamid) in three species of fish (Perca fluviatilis, Cyprinus carpio and Rutilus rutilus), caught in five ponds during two sampling campaigns. Management data are added variables in order to discuss about parameters suspected to be implicated in the contamination profiles recorded. This work shows that high amounts of pesticides applied, short crop rotation durations and bare soil practices led to contamination of sediments and fish and were associated to a ``bad'' management of watershed. Breeding fish that had low masses and establishing the fishing period at the end of winter seemed to be ``bad'' management of pond. Aggravating topological parameters were big watershed coupled to small pond and high proportions of sand soils in the watershed. Reducing amounts of pesticide used (e.g. policy agency plans, farmer acceptance), favouring long-term rotations and inter-cultures, adapting pond creation and fish farming practices to watershed management and topography all could reduce pesticide levels in edible fish and contribute to a better sustainability of the extensive fish farming in pond.
Afficher plus [+] Moins [-]Habitat degradation correlates with tolerance to climate-change related stressors in the green mussel Perna viridis from West Java, Indonesia Texte intégral
2013
Wendling, Carolin | Huhn, Mareike | Nurina, Ayu | Bactiar, Ramadian | von Juterzenka, Karen | Lenz, Mark
Habitat degradation correlates with tolerance to climate-change related stressors in the green mussel Perna viridis from West Java, Indonesia
2013
Wendling, Carolin | Huhn, Mareike | Nurina, Ayu | Bactiar, Ramadian | von Juterzenka, Karen | Lenz, Mark
It is unclear whether habitat degradation correlates with tolerance of marine invertebrates to abiotic stress. We therefore tested whether resistance to climate change-related stressors differs between populations of the green mussel Perna viridis from a heavily impacted and a mostly pristine site in West Java, Indonesia. In laboratory experiments, we compared their oxygen consumption and mortality under lowered salinity (�13 and �18 units, both responses), hypoxia (0.5 mg/l, mortality only) and thermal stress (+7 �C, mortality only). Mussels from the eutrophied and polluted Jakarta Bay showed a significantly smaller deviation from their normal oxygen consumption and higher survival rates when stressed than their conspecifics from the unaffected Lada Bay. This shows that human induced habitat degradation correlates with mussel tolerance to environmental stress. We discuss possible mechanisms – e.g. the selection of tolerant genotypes or habitat-specific differences in the nutritional status of the mussels – that could explain our observation.
Afficher plus [+] Moins [-]Habitat degradation correlates with tolerance to climate-change related stressors in the green mussel Perna viridis from West Java, Indonesia Texte intégral
2013
Wendling, Carolin Charlotte | Huhn, Mareike | Ayu, Nurina | Bachtiar, Ramadian | Juterzenka, Karen von | Lenz, Mark
It is unclear whether habitat degradation correlates with tolerance of marine invertebrates to abiotic stress. We therefore tested whether resistance to climate change-related stressors differs between populations of the green mussel Perna viridis from a heavily impacted and a mostly pristine site in West Java, Indonesia. In laboratory experiments, we compared their oxygen consumption and mortality under lowered salinity (−13 and −18 units, both responses), hypoxia (0.5mg/l, mortality only) and thermal stress (+7°C, mortality only). Mussels from the eutrophied and polluted Jakarta Bay showed a significantly smaller deviation from their normal oxygen consumption and higher survival rates when stressed than their conspecifics from the unaffected Lada Bay. This shows that human induced habitat degradation correlates with mussel tolerance to environmental stress. We discuss possible mechanisms – e.g. the selection of tolerant genotypes or habitat-specific differences in the nutritional status of the mussels – that could explain our observation.
Afficher plus [+] Moins [-]Whole cell hybridisation for monitoring harmful marine microalgae Texte intégral
2013
Toebe, Kerstin
Whole cell hybridisation for monitoring harmful marine microalgae Texte intégral
2013
Toebe, Kerstin
Fluorescence in situ hybridisation (FISH) is a powerful molecular biological tool to detect and enumerate harmful microorganism in the marine environment. Different FISH methods are available, and especially in combination with automated counting techniques, the po- tential for a routine monitoring of harmful marine micro- algae is attainable. Various oligonucleotide probes are developed for detecting harmful microalgae. However, FISH-based methods are not yet regularly included in mon- itoring programmes tracking the presence of harmful marine microalgae. A limitation factor of the FISH technique is the currently available number of suited fluorochromes attached to the FISH probes to detect various harmful species in one environmental sample at a time. However, coupled automated techniques, like flow cytometry or solid-phase cytometry, can facilitate the analysis of nu- merous field samples and help to overcome this draw- back. A great benefit of FISH in contrast to other molecular biological detection methods for harmful ma- rine microalgae is the direct visualisation of the hybridised target cells, which are not permitted in cell free formats, like DNA depending analysis methods. Therefore, an additional validation of the FISH-generated results is simultaneously given.
Afficher plus [+] Moins [-]Whole cell hybridisation for monitoring harmful marine microalgae Texte intégral
2013
Toebe, Kerstin
Fluorescence in situ hybridisation (FISH) is a powerful molecular biological tool to detect and enumerate harmful microorganism in the marine environment. Different FISH methods are available, and especially in combination with automated counting techniques, the potential for a routine monitoring of harmful marine microalgae is attainable. Various oligonucleotide probes are developed for detecting harmful microalgae. However, FISH-based methods are not yet regularly included in monitoring programmes tracking the presence of harmful marine microalgae. A limitation factor of the FISH technique is the currently available number of suited fluorochromes attached to the FISH probes to detect various harmful species in one environmental sample at a time. However, coupled automated techniques, like flow cytometry or solid-phase cytometry, can facilitate the analysis of numerous field samples and help to overcome this drawback. A great benefit of FISH in contrast to other molecular biological detection methods for harmful marine microalgae is the direct visualisation of the hybridised target cells, which are not permitted in cell free formats, like DNA depending analysis methods. Therefore, an additional validation of the FISH-generated results is simultaneously given.
Afficher plus [+] Moins [-]ECOFUN-MICROBIODIV: an FP7 European project for developing and evaluating innovative tools for assessing the impact of pesticides on soil functionalmicrobial diversity—towards new pesticide registration regulation? Texte intégral
2013
Martin-Laurent, Fabrice | Kandeler, Ellen | Petric, Ines | Djuric, Simonida | Karpouzas, Dimitrios | Agroécologie [Dijon] ; Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement | Institute of Soil Science and Land Evaluation, Soil Biology Section ; Universität Hohenheim = University of Hohenheim | Division for Marine and Environmental Research ; Rudjer Boskovic Institute [Zagreb] | University of Novi Sad | Department of Biochemistry and Biotechnology ; University of Thessaly
EA EcolDur | International audience
Afficher plus [+] Moins [-]Geo-Chip analysis reveals reduced functional diversity of the bacterial community at a dumping site for dredged Elbe sediment Texte intégral
2013
Störmer, Rebecca | Wichels, Antje | Gerdts, Gunnar
Geo-Chip analysis reveals reduced functional diversity of the bacterial community at a dumping site for dredged Elbe sediment Texte intégral
2013
Störmer, Rebecca | Wichels, Antje | Gerdts, Gunnar
The dumping of dredged sediments represents a major stressor for coastal ecosystems. The impact on the ecosystem function is determined by its complexity not easy to assess. In the present study, we evaluated the potential of bacterial community analyses to act as ecological indicators in environmental monitoring programmes. We investigated the functional structure of bacterial communities, applying functional gene arrays (GeoChip 4.2). The relationship between functional genes and environmental factors was analysed using distance-based multivariate multiple regression. Apparently, both the function and structure of the bacterial communities are impacted by dumping activities. The bacterial community at the dumping centre displayed a significant reduction of its entire functional diversity compared with that found at a reference site. DDX compounds separated bacterial communities of the dumping site from those of un-impacted sites. Thus, bacterial community analyses show great potential as ecological indicators in environmental monitoring.
Afficher plus [+] Moins [-]Geo-Chip analysis reveals reduced functional diversity of the bacterial community at a dumping site for dredged Elbe sediment Texte intégral
2013
Störmer, Rebecca | Wichels, Antje | Gerdts, Gunnar
The dumping of dredged sediments represents a major stressor for coastal ecosystems. The impact on the ecosystem function is determined by its complexity not easy to assess. In the present study, we evaluated the potential of bacterial community analyses to act as ecological indicators in environmental monitoring programmes. We investigated the functional structure of bacterial communities, applying functional gene arrays (GeoChip4.2). The relationship between functional genes and environmental factors was analysed using distance-based multivariate multiple regression. Apparently, both the function and structure of the bacterial communities are impacted by dumping activities. The bacterial community at the dumping centre displayed a significant reduction of its entire functional diversity compared with that found at a reference site. DDX compounds separated bacterial communities of the dumping site from those of un-impacted sites. Thus, bacterial community analyses show great potential as ecological indicators in environmental monitoring.
Afficher plus [+] Moins [-]Effects of mono-(2-ethylhexyl) phthalate (MEHP) on chicken germ cells cultured in vitro Texte intégral
2013
Guibert, Edith | Prieur, Bérénice | Cariou, Ronan | Courant, Frédérique | Antignac, Jean-Philippe | Pain, Bertrand | Brillard, Jean Pierre | Froment, Pascal | Physiologie de la reproduction et des comportements [Nouzilly] (PRC) ; Institut National de la Recherche Agronomique (INRA)-Institut Français du Cheval et de l'Equitation [Saumur] (IFCE)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS) | Laboratoire d'étude des Résidus et Contaminants dans les Aliments (LABERCA) ; École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Institut cellule souche et cerveau (SBRI) ; Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL) ; Université de Lyon-Université de Lyon-Institut National de la Santé et de la Recherche Médicale (INSERM) | Fertilité et Reproduction Avicole (FERTIL'AVI) | Institut National de la Recherche Agronomique, French Ministry of Environment LOLF 189
Effects of mono-(2-ethylhexyl) phthalate (MEHP) on chicken germ cells cultured in vitro Texte intégral
2013
Guibert, Edith | Prieur, Bérénice | Cariou, Ronan | Courant, Frédérique | Antignac, Jean-Philippe | Pain, Bertrand | Brillard, Jean Pierre | Froment, Pascal | Physiologie de la reproduction et des comportements [Nouzilly] (PRC) ; Institut National de la Recherche Agronomique (INRA)-Institut Français du Cheval et de l'Equitation [Saumur] (IFCE)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS) | Laboratoire d'étude des Résidus et Contaminants dans les Aliments (LABERCA) ; École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Institut cellule souche et cerveau (SBRI) ; Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL) ; Université de Lyon-Université de Lyon-Institut National de la Santé et de la Recherche Médicale (INSERM) | Fertilité et Reproduction Avicole (FERTIL'AVI) | Institut National de la Recherche Agronomique, French Ministry of Environment LOLF 189
In recent decades, many toxicological tests based on in vivo or in vitro models, mainly from mammalian (rat-mouse) and fish species, were used to assess the risks raised by contact or ingestion of molecules of pharmaceutical, agricultural, or natural origin. But no, or few, in vitro tests using other non-mammalian models such as bird have been explored despite their advantages: the embryonic gonads of birds have a high plasticity of development sensitive to estrogen, and sperm production is nearly two times faster than in rodents. Hence, we have established an in vitro culture of germ cells and somatic cells from chicken post-natal testis, and we have evaluated the sensitivity against the endocrine disruptor compound mono-(2-ethylhexyl) phthalate (MEHP) in comparison to previous studies using rodent and human models. After 96 h of exposure in presence of 10 μM MEHP, chicken seminiferous tubules cultures present a structural alteration, a reduction in cell proliferation and in germ cells population. Apoptosis of germ and somatic cells increases in presence of 1 μM MEHP. Furthermore, MEHP does not affect inhibin B and lactate production by Sertoli cells. These results are in accordance with previous studies using rat, mice, or human culture of testicular cells and in similar range of exposures or even better sensitivity for some "end-points" (biological parameters). In conclusion, the establishment of this postnatal testicular cells culture could be considered as an alternative method to in vivo experiments frequently used for evaluating the impact on the terrestrial wildlife species. This method could be also complementary to mammal model due to the limiting number of animals used and its elevated sensitivity.
Afficher plus [+] Moins [-]Effects of mono-(2-ethylhexyl) phthalate (MEHP) on chicken germ cells cultured in vitro Texte intégral
2013
Guibert, Edith | Prieur, Bérénice | Cariou, Ronan | Courant, Frédérique | Antignac, Jean Philippe | Pain, Bertrand | Brillard, Jean Pierre | Froment, Pascal
In recent decades, many toxicological tests based on in vivo or in vitro models, mainly from mammalian (rat–mouse) and fish species, were used to assess the risks raised by contact or ingestion of molecules of pharmaceutical, agricultural, or natural origin. But no, or few, in vitro tests using other non-mammalian models such as bird have been explored despite their advantages: the embryonic gonads of birds have a high plasticity of development sensitive to estrogen, and sperm production is nearly two times faster than in rodents. Hence, we have established an in vitro culture of germ cells and somatic cells from chicken post-natal testis, and we have evaluated the sensitivity against the endocrine disruptor compound mono-(2-ethylhexyl) phthalate (MEHP) in comparison to previous studies using rodent and human models. After 96 h of exposure in presence of 10 μM MEHP, chicken seminiferous tubules cultures present a structural alteration, a reduction in cell proliferation and in germ cells population. Apoptosis of germ and somatic cells increases in presence of 1 μM MEHP. Furthermore, MEHP does not affect inhibin B and lactate production by Sertoli cells. These results are in accordance with previous studies using rat, mice, or human culture of testicular cells and in similar range of exposures or even better sensitivity for some “end-points” (biological parameters). In conclusion, the establishment of this postnatal testicular cells culture could be considered as an alternative method to in vivo experiments frequently used for evaluating the impact on the terrestrial wildlife species. This method could be also complementary to mammal model due to the limiting number of animals used and its elevated sensitivity.
Afficher plus [+] Moins [-]Organochlorinated pesticides, PCBs, dioxins, and PBDEs in grey mullets (Liza ramada) and allis shads (Alosa alosa) from the Vilaine estuary (France) Texte intégral
2013
Bocquene, Gilles | Abarnou, Alain
Organochlorinated pesticides, PCBs, dioxins, and PBDEs in grey mullets (Liza ramada) and allis shads (Alosa alosa) from the Vilaine estuary (France) Texte intégral
2013
Bocquene, Gilles | Abarnou, Alain
This study aimed to compare the contamination levels of various organohalogenated compounds in two migratory fish species in the Vilaine River in western France. Organochlorinated pesticides, polychlorinated biphenyls (PCBs), dioxins (polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDDs/Fs)), and polybrominated diphenyl ethers (PBDEs) were analyzed in two diadromous species from the Vilaine estuary, the grey mullet (Liza ramada)-an amphihaline species, and the allis shad (Alosa alosa)-an anadromous species. Fish were collected in spring 2004 and spring 2005, upstream and downstream of the Arzal Dam. PCB contamination varied from 27 to 200 ng g(-1) dry weight (d.w.). PCDDs/Fs, expressed in toxicity equivalent quantity (TEQ) varied from 0.4 to 2.8 pg g(-1) d.w. Dioxins and dioxin-like PCBs expressed in total TEQ varied from 1.4 to 18.8 pg g(-1) d.w. PBDE47 was present at around 2-10 ng g(-1) d.w. and concentrations of the insecticide dichlorodiphenyltrichloroethane breakdown product p,p'-dichlorodiphenylchloroethylene varied from 1 to 14 ng g(-1) d.w. For both species, specimens collected upstream were more contaminated. The grey mullet specimens were less contaminated than the allis shad when taken downstream of the dam but were more contaminated upstream. The allis shads presented intermediate contaminant concentrations with a less pronounced difference between upstream and downstream specimens. However, it is thought that shads do not feed when they spawn in the upstream parts of rivers, which should modify the contaminant concentrations. However, measurements in upstream shad samples show an unexpected increase of the contamination, which remains unexplained.
Afficher plus [+] Moins [-]Organochlorinated pesticides, PCBs, dioxins, and PBDEs in grey mullets (Liza ramada) and allis shads (Alosa alosa) from the Vilaine estuary (France) Texte intégral
2013
Bocquené, Gilles | Abarnou, Alain
This study aimed to compare the contamination levels of various organohalogenated compounds in two migratory fish species in the Vilaine River in western France. Organochlorinated pesticides, polychlorinated biphenyls (PCBs), dioxins (polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDDs/Fs)), and polybrominated diphenyl ethers (PBDEs) were analyzed in two diadromous species from the Vilaine estuary, the grey mullet (Liza ramada)—an amphihaline species, and the allis shad (Alosa alosa)—an anadromous species. Fish were collected in spring 2004 and spring 2005, upstream and downstream of the Arzal Dam. PCB contamination varied from 27 to 200 ng g⁻¹ dry weight (d.w.). PCDDs/Fs, expressed in toxicity equivalent quantity (TEQ) varied from 0.4 to 2.8 pg g⁻¹ d.w. Dioxins and dioxin-like PCBs expressed in total TEQ varied from 1.4 to 18.8 pg g⁻¹ d.w. PBDE47 was present at around 2–10 ng g⁻¹ d.w. and concentrations of the insecticide dichlorodiphenyltrichloroethane breakdown product p,p′-dichlorodiphenylchloroethylene varied from 1 to 14 ng g⁻¹ d.w. For both species, specimens collected upstream were more contaminated. The grey mullet specimens were less contaminated than the allis shad when taken downstream of the dam but were more contaminated upstream. The allis shads presented intermediate contaminant concentrations with a less pronounced difference between upstream and downstream specimens. However, it is thought that shads do not feed when they spawn in the upstream parts of rivers, which should modify the contaminant concentrations. However, measurements in upstream shad samples show an unexpected increase of the contamination, which remains unexplained.
Afficher plus [+] Moins [-]Toxicity of Epoxiconazole to the Marine Diatom Chaetoceros calcitrans: Influence of Growth Conditions and Algal Development Stage Texte intégral
2013
Amara, Anis | Quiniou, Francoise | Durand, Gael | El Bour, Monia | Boudabous, Abdellatif | Hourmant, Annick
Toxicity of Epoxiconazole to the Marine Diatom Chaetoceros calcitrans: Influence of Growth Conditions and Algal Development Stage Texte intégral
2013
Amara, Anis | Quiniou, Francoise | Durand, Gael | El Bour, Monia | Boudabous, Abdellatif | Hourmant, Annick
The triazole fungicide epoxiconazole is extensively used to control fungi on crops and may present some potential risk from runoff on coastal ecosystems located close to agricultural areas. Phytotoxicity assessments were conducted on the marine diatom Chaetoceros calcitrans using both the active ingredient and its formulated product (Opus). The 3-day EC50 using cell count was 2.31 mg/L for epoxiconazole active ingredient and 2.9 mu g/L for epoxiconazole-formulated. The fungicide produced an increase of cellular volume, pigment (chlorophylls a, c, and carotenoids) content, ATP synthesis, and rates of photosynthesis and respiration. Progressive algal cell recovery from epoxiconazole effects occurred after 3 days, with the increasing cell density. Differences in cell age, light, and nutrient composition induced changes in epoxiconazole sensitivity. Since these parameters affect cellular division rates, the cellular density is an important parameter in toxicity tests.
Afficher plus [+] Moins [-]Toxicity of Epoxiconazole to the Marine Diatom Chaetoceros calcitrans: Influence of Growth Conditions and Algal Development Stage Texte intégral
2013
Amara, Anis | Quiniou, Franc̦oise | Durand, Gaël | El Bour, Monia | Boudabous, Abdellatif | Hourmant, Annick
The triazole fungicide epoxiconazole is extensively used to control fungi on crops and may present some potential risk from runoff on coastal ecosystems located close to agricultural areas. Phytotoxicity assessments were conducted on the marine diatom Chaetoceros calcitrans using both the active ingredient and its formulated product (Opus). The 3-day EC₅₀ using cell count was 2.31 mg/L for epoxiconazole active ingredient and 2.9 μg/L for epoxiconazole-formulated. The fungicide produced an increase of cellular volume, pigment (chlorophylls a, c, and carotenoids) content, ATP synthesis, and rates of photosynthesis and respiration. Progressive algal cell recovery from epoxiconazole effects occurred after 3 days, with the increasing cell density. Differences in cell age, light, and nutrient composition induced changes in epoxiconazole sensitivity. Since these parameters affect cellular division rates, the cellular density is an important parameter in toxicity tests.
Afficher plus [+] Moins [-]Accumulated sediments in a detention basin: chemical and microbial hazard assessment linked to hydrological processes Texte intégral
2013
Sébastian, C. | Barraud, S. | Ribun, Sébastien | Zoropogui, A. | Blaha, Didier | Becouze-Lareure, C. | Kouyi, G. Lipeme | Cournoyer, B. | Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM) ; Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL) ; Université de Lyon-Université de Lyon-Ecole Nationale Vétérinaire de Lyon (ENVL)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)
International audience | Accumulated sediments in a 32,000-m3 detention basin linked to a separate stormwater system were characterized in order to infer their health hazards. A sampling scheme of 15 points was defined according to the hydrological behaviour of the basin. Physical parameters (particle size and volatile organic matter content) were in the range of those previously reported for stormwater sediments. Chemical analyses on hydrocarbons, PAHs, PCBs and heavy metals showed high pollutant concentrations. Microbiological analyses of these points highlighted the presence of faecal indicator bacteria (Escherichia coli and intestinal enterococci) and actinomycetes of the genus Nocardia. These are indicative of the presence of human pathogens. E. coli and enterococcal numbers in the sediments were higher at the proximity of the low-flow gutter receiving waters from the catchment. These bacteria appeared to persist over time among urban sediments. Samples highly contaminated by hydrocarbons were also shown to be heavily contaminated by these bacteria. These results demonstrated for the first time the presence of Nocardial actinomycetes in such an urban context with concentrations as high as 11,400 cfu g-1.
Afficher plus [+] Moins [-]Analysis of the bacterial community in the two typical intertidal sediments of Bohai Bay, China by pyrosequencing Texte intégral
2013
Wang, Liping | Liu, Lusan | Zheng, Binghui | Zhu, Yanzhong | Wang, Xing
For full understanding of the bacterial community in the intertidal zones of Bohai Bay, China, we used pyrosequencing-based approach to analyze the 16S rRNA gene of bacteria in the sediments from the two typically intertidal zones – Qikou (Qi) and Gaoshaling (Ga). Results showed that, at a 0.03 distance, the sequences from the Qi sediment were assigned to 3252 operational taxonomic units (OTUs) which belong to 34 phyla, 69 classes and 119 genera, while the 3740 OTUs from the Ga sediment were affiliated with 33 phyla, 66 classes and 146 genera. Comparing the bacterial communities inhabiting in the two intertidal sediments, we observed significant difference in the dominant composition and distribution at phylum, class and genus levels. Canonical correspondence analysis (CCA) showed that the median grain size and DO were the most important factors regulating the bacterial abundance and diversity, while the other environmental factors have effects with different degree.
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