Résumé : Map including the coasts of the southern United States, Central America, northern South America, and the West Indies. The map is very detailed, depicting rivers and mountain elevations in all of these areas.
Mexico, Gulf of

Droits : Use of this item is provided for non-commercial, personal, educational, and research use only. For information about the copyright and reproduction rights for this item, please contact Special Collections, Florida State University Libraries, Tallahassee, Florida.
fsu:6691
FSDT2975597
oai:fsu.digital.flvc.org:fsu_6691
http://ufdc.ufl.edu/FSUM000009/00001

Éditeur(s) : HAL CCSD American Geophysical Union (AGU)
Résumé : The role of the Karakorum fault zone (KFZ) is debated. South of 33°N, ongoing dextral-oblique slip along the SW edge of the Gar basin exhumes metamorphic and magmatic rocks of the Ayilari range. Minerals have recorded a continuum of deformation from temperatures >600–400°C down to <250_C. The 40Ar/39Ar ages, the oldest being 21.2 ± 1.0 Ma, yield minimum estimates for the initiation of the KFZ. These are in agreement with the U-Th/Pb ages constraining the onset of deformation at ca 25–22 Ma. Thermochronologic results show slow cooling for the period ca 21– 14 Ma, followed by rapid cooling between 14 and 4 Ma. These data demonstrate that right-lateral motion was in progress in the early Miocene and that shear continued at least until 4 Ma, pointing to >20 Ma of deformation along the fault. Greenschist facies deformation superimposed upon the medium- to high-grade deformation marks a kinematic change from pure dextral to dextral-normal motion associated with the onset of rapid cooling. At the regional scale, the coexistence of transtension in the Gar basin with transpression documented along the Pangong range farther north suggests another example of the ‘‘zipper tectonics'' model developed along the Red River fault. The kinematic shift induced the rise of the Ayilari range starting at 16–12 Ma and the incision of major river courses. The Indus River might have become captive of the relief at this time. The river's 120 km of apparent offset implies dextral motion at a long-term rate of ca 8.5 ± 1.5 mm/yr.
ISSN: 0278-7407

hal-00197561
https://hal.archives-ouvertes.fr/hal-00197561
https://hal.archives-ouvertes.fr/hal-00197561/document
https://hal.archives-ouvertes.fr/hal-00197561/file/Valli_Karakorum_thermochron_Tectonics_07_pre_print.pdf
DOI : 10.1029/2005TC001913

Éditeur(s) : Université de Brest
Résumé : The channel-lobe transition zone has been studied in two turbiditic systems: the Amazon channel-mouth lobe complex at the termination of the last eight channel-levee systems and the Neochannel termination, the last active channel of the Petit-Rhone turbidite system. - In the two cases, the internal geometry and stacking pattern of the deposits show a significant control of the configuration (size and shape) of the receiving basins, their morphology (gradients and subtle gradient changes), and their degree of confinement. - The Amazon and Petit-Rhone systems, with lobes built after the Last Glacial Maximum and the ensuing sea-level rise, evidence the major impact of external forcings (climatic events and eustatic variations) that induce variations in sediment fluxes delivered to the deep basin and therefore exert a control on channel-mouth lobes construction. The channel-mouth lobes of the Amazon and Petit-Rhone systems, even if they are located at great distances from the river mouths, at the termination of the turbidite systems and in areas characterised by subtle morphological variations, are both constrained by combined internal (accommodation and compensation) and external factors (post-glacial deconnection between the fluvial system and the deep basin).
La zone de transition chenal-levées/lobes a été étudiée dans 2 systèmes turbiditiques : le complexe de lobes à la terminaison des 8 derniers chenaux de l'éventail de l'Amazone et la terminaison du Néochenal, dernier chenal de l'éventail du Petit-Rhône. - Dans les deux cas, l'agencement des dépôts et leur évolution dans l'espace et le temps révèlent un fort contrôle de la configuration des réceptacles (taille et forme), de la morphologie des fonds (pentes et taux de changement des pentes) et du degré de confinement. - Les systèmes de l'Amazone et du Petit-Rhône, dont les lobes se sont construits à partir du Dernier Maximum Glaciaire et lors de la remontée du niveau marin qui a suivi, ont en outre permis de souligner l'impact majeur, sur la mise en place des lobes terminaux, de certains forçages externes (événements climatiques et variations eustatiques), qui déterminent les variations des flux sédimentaires arrivant au bassin. Ainsi, bien que situés à des distances considérables des sources fluviatiles et dans des zones distales où les variations de relief sont très ténues, les lobes terminaux de ces deux grands systèmes turbiditiques se sont révélés contraints à la fois par des processus internes (processus de compensation) et par des processus externes (déconnexion post-glaciaire du fleuve et du bassin).

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2008/these-6796.pdf
http://archimer.ifremer.fr/doc/00000/6796/

Résumé : The slides were taken on collecting trips sponsored by the William L. Bryant Foundation, where books, music and art indigenous to the regions were gathered. The are organized by geographical location.
A man standing on a large river boulder in Jamaica. In the distance is a small wooden hut near the top of the hill. Slide labeled Blue Mts.
Jamaica -- Caribbean region

Droits : All rights to images are held by the respective holding institution. This image is posted publicly for non-profit educational uses, excluding printed publication. For permission to reproduce images and/or for copyright information contact Special Collections & University Archives, University of Central Florida Libraries, Orlando, FL 32816 phone (407) 823-2576, email: speccoll@mail.ucf.edu
CFM1972_01a
http://ufdc.ufl.edu/AA00031015/00001

Éditeur(s) : Amer Geophysical Union
Résumé : Large rivers are key hydrologic components in oceanography, particularly regarding air-sea and land-sea exchanges and biogeochemistry. We enter now in a new era of Sea Surface Salinity (SSS) observing system from Space with the recent launches of the ESA Soil Moisture and Ocean Salinity (SMOS) and the NASA Aquarius/Sac-D missions. With these new sensors, we are now in an excellent position to revisit SSS and ocean color investigations in the tropical northwest Atlantic using multi-year remote sensing time series and concurrent in situ observations. The Amazon is the world's largest river in terms of discharge. In its plume, SSS and upper water column optical properties such as the absorption coefficient of colored detrital matter (acdm) are strongly negatively correlated (<-0.7). Local quasi-linear relationships between SSS and acdm are derived for these plume waters over the period of 2010-2013 using new spaceborne SSS and ocean color measurements. Results allow unprecedented spatial and temporal resolution of this coupling. These relationships are then used to estimate SSS in the Amazon plume based on ocean color satellite data. This new product is validated against SMOS and in situ data and compared with previously developed SSS retrieval models. We demonstrate the potential to estimate tropical Atlantic SSS for the extended period from 1998 to 2010, prior to spaceborne SSS data collection.
Journal Of Geophysical Research-oceans (0148-0227) (Amer Geophysical Union), 2015-05 , Vol. 120 , N. 5 , P. 3177-3192

Droits : 2015. American Geophysical Union. All Rights Reserved.
http://archimer.ifremer.fr/doc/00255/36610/35742.pdf
DOI:10.1002/2014JC010109
http://archimer.ifremer.fr/doc/00255/36610/

Éditeur(s) : "El Siglo XX" "El Siglo XX" ( Habana )
Résumé : (Bibliography) Includes bibliographies.
(Statement of Responsibility) recopilación dirigida, prologada y anotada por José Manuel Carbonell & Rivero.
Publisher varies: v. 7-17 published by Montalvo y Cardenas.

001491661
23298160
AHA3873

Résumé : The slides were taken on collecting trips sponsored by the William L. Bryant Foundation, where books, music and art indigenous to the regions were gathered. The are organized by geographical location.
Moore Town Primary and Junior High School girl dressed in a pink and blue school uniform. In the distance is a river and houses in Portland, Jamaica. Inhabitants of Moore Town are descendants of Maroons, escaped slaves who were able to maintain some aspects of their African cultures. Slide labeled Jam. Moore Town.
Jamaica -- Caribbean region -- Moore Town, Portland

Droits : All rights to images are held by the respective holding institution. This image is posted publicly for non-profit educational uses, excluding printed publication. For permission to reproduce images and/or for copyright information contact Special Collections & University Archives, University of Central Florida Libraries, Orlando, FL 32816 phone (407) 823-2576, email: speccoll@mail.ucf.edu
CFM1972_01a
http://ufdc.ufl.edu/AA00031042/00001

Éditeur(s) : Elsevier Science Bv
Résumé : Mechanisms controlling the transfer and retention of silicon (Si) along continental margins are poorly understood, but play a major role in the functioning of coastal ecosystems and the oceanic biological pump of carbon. Deep-sea fans are well recognized as carbon sink spots, but we lack knowledge about the importance of the fans in the global Si cycle. Here, we provide a first estimate of the role played by the Congo deep-sea fan, one of the biggest in the world, in the Si cycle. Sediment cores sampled in the deep-sea fan were analyzed to build a Si mass balance. An exceptionally high accumulation rate of amorphous silica aSiO(2) (2.29 +/- 0.58 mol Si m(-2) y(-1)) was found, due to a high sedimentation rate and the presence of aluminum in the sediments. Although favored by bioirrigation, recycling fluxes remained low (0.3 mol Si m(-2) y(-1)) and reconstructed input fluxes could only be explained by lateral inputs coming from the canyon. Preliminary calculations show that the rapid transport of aSiO(2) through the canyon and the excellent preservation efficiency in the sediments imply that 50% of aSiO(2) river inputs from the Congo River accumulate annually in the deep-sea fan. Si:C ratios in deep-sea fan sediments were very low (0.2) and only three times as high as those measured in the river itself, which suggests that material from the river and the continental shelf was delivered directly through the canyon, with very little time for Si and C cycle decoupling to take place.
Journal Of Marine Systems (0924-7963) (Elsevier Science Bv), 2015-01 , Vol. 141 , P. 71-79

Droits : 2014 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00251/36242/35797.pdf
DOI:10.1016/j.jmarsys.2014.07.010
http://archimer.ifremer.fr/doc/00251/36242/

Éditeur(s) : HAL CCSD Linnean Society of London
Résumé : Disentangling the impact of landscape features such as rivers and historical events on dispersal is a challenging but necessary task to gain a comprehensive picture of the evolution of diverse biota such as that found in Amazonia. Adenomera andreae, a small, territorial, terrestrial frog species of the Amazonian forest represents a good model for such studies. We combined cytochrome b sequences with 12 microsatellites to investigate the genetic structure at two contrasted spatial scales in French Guiana: along a similar to 6-km transect, to evaluate dispersal ability, and between paired bank populations along a similar to 65-km stretch of the Approuague river, to test the effect of rivers as barriers to dispersal. We observed significant spatial genetic structure between individuals at a remarkably small geographical scale, and conclude that the species has a restricted dispersal ability that is probably tied to its life-history traits. Mitochondrial and microsatellite data also indicate a high level of differentiation among populations on opposite banks of the river, and, in some cases, among populations on the same riverbank. These results suggest that the observed population structure in A. andreae is the result of restricted dispersal abilities combined with the action of rivers and Quaternary population isolation. Given that Amazonia hosts a great portion of anurans, as well as other small vertebrates, that display life-history traits comparable with A. andreae, we argue that our analyses provide new insights into the complex interactions among evolutionary processes shaping Amazonian biodiversity. (c) 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106, 356373.
ISSN: 0024-4066

hal-01032422
https://hal.archives-ouvertes.fr/hal-01032422
DOI : 10.1111/j.1095-8312.2012.01871.x

Résumé : The slides were taken on collecting trips sponsored by the William L. Bryant Foundation, where books, music and art indigenous to the regions were gathered. The are organized by geographical location.
The town of Bath is located in the John Crow Mountains in Saint Thomas, Jamaica. Mineral springs flow from the rocks and are piped into the bath house, pictured, where the cold and hot waters of the springs are mixed together. The water’s high mineral (sulfur and lime) content is believed to have medicinal properties. The bath has been officially known as the Bath of the Saint Thomas the Apostle. Bath Fountain Hotel and Spa is run by the Jamaican Ministry of Tourism. In front of the building are many automobiles including a taxi. Along the stream, pictured, are dasheens (taros), ferns, palms, and other trees. Slide labeled Jam. St. Thomas min bath at Bath (SE).
Jamaica -- Caribbean region -- Bath, Saint Thomas

Droits : All rights to images are held by the respective holding institution. This image is posted publicly for non-profit educational uses, excluding printed publication. For permission to reproduce images and/or for copyright information contact Special Collections & University Archives, University of Central Florida Libraries, Orlando, FL 32816 phone (407) 823-2576, email: speccoll@mail.ucf.edu
CFM1972_01a
http://ufdc.ufl.edu/AA00030895/00001

Éditeur(s) : Elsevier
Résumé : The Okinawa Trough is a natural laboratory for the study of later Quaternary land-ocean interaction and paleoenvironmental changes. In this study we reconstruct the evolution of clay mineral assemblages in Core DGKS9604 retrieved from the central Okinawa Trough. Illite dominates the clay mineral compositions, with average contents above 60%. Clay mineral evolution since 28 ka is closely related to changes in sediment provenance and paleoenvironment. Sea level rise and the strength of the Kuroshio Current control the dispersal and deposition of clays on the East China Sea shelf and in the Okinawa Trough, and thus, determine the clay mineral compositions in the core sediments. During the late last glacial period (28.0-14.0 ka), the paleo-Changjiang River mouth was situated at the shelf edge close to the central Okinawa Trough and thus, together with the outer shelf, supplied large volumes of terrigenous sediments directly into the trough. From 14.0 to 8.4 ka influence from the Changjiang decreased while the mid-outer shelf of the East China Sea became the dominant sediment source to the central Okinawa Trough as sea level rose and the Changjiang river mouth migrated west. Strong sediment reworking and erosion at the shelf edge at 15-13 ka significantly increased the lateral transport of fine-grained shelf sediments to the central Okinawa Trough. Since ca. 8.4 ka clays from Taiwan have dominated the sediment flux to the site, coinciding with the re-entry of the Kuroshio Current into the trough. The increasing influence of the Changjiang-sourced sediments since 1.5 ka was probably related to the weakening of the Kuroshio Current and/or a higher river flux. (C) 2010 Elsevier B.V. All rights reserved.
Palaeogeography, Palaeoclimatology, Palaeoecology (0031-0182) (Elsevier), 2010-03 , Vol. 288 , N. 1-4 , P. 108-117

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00002/11367/7977.pdf
DOI:10.1016/j.palaeo.2010.01.040
http://archimer.ifremer.fr/doc/00002/11367/

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : We tested the applicability of the BIT (branched and isoprenoid tetraether) index as a proxy for palaeoflood events in the river-dominated continental margin of the Gulf of Lions (NW Mediterranean). We compared the concentrations of branched glycerol dialkyl glycerol tetraethers (br GDGTs) and crenarchaeol in suspended particulate matter (SPM) collected downstream in the Rhône River, as well as in surface sediments and a ca. 8m piston core from the Rhône prodelta. The core covered the last 400 yr, with four distinct intervals recording the river influence under natural and man-induced shifts in four main channels of the river mouth (Bras de Fer, Grand Rhône, Pégoulier,and Roustan). The results indicate that there are mixed sources of br GDGTs and crenarchaeol in the prodelta, complicating applicationof the BIT index as an indicator of continental organic carbon input and thus as a palaeoflood proxy. However, the sedimentary BIT record for the period when continental material was delivered by the river more directly to the core site (Roustan phase;1892 to present) mimics the historical palaeoflood record. This shows the potential of the BIT index as a palaeoflood proxy, provided that the delivery route of the continental material by rivers to the core sites remains constant over time. The study also highlights the idea that shifts in river channels should be taken into account for the use of the BIT index as a palaeoflood proxy.
Organic Geochemistry (0146-6380) (Pergamon-elsevier Science Ltd), 2014-10 , Vol. 75 , P. 99-108

Droits : 2014 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00198/30969/29345.pdf
DOI:10.1016/j.orggeochem.2014.06.011
http://archimer.ifremer.fr/doc/00198/30969/

Résumé : 2009, Scott Zona -- CC: at-ncsa (Creative Commons license requiring attribution, prohibiting commercial uses, and requiring rights-share for use of this image)
voucher specimen deposited at Rancho Sana Ana Botanic Garden (RSA), Claremont, CA; the Florida Museum of Natural History (FLAS), Gainesville, FL & Bailey Hortorium (BH), Ithaca, NY, USA.
specimen cited in: Zona, S. 1996. Roystonea (Arecaceae: Arecoideae). Flora Neotropica 71: 1–36.
Jamaica -- Elizabeth -- Black River

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In oblique collision settings, parallel and perpendicular components of the relative plate motion can be partitioned into different structures of deformation and may be localized close to the plate boundary, or distributed on a wider region. In the Southern Alps of New Zealand, it has been proposed that one-third of the regional convergence is distributed in a broad area along the Southern Alps orogenic wedge. To better document and understand the regional dynamics of such systems, reliable markers of the horizontal tectonic motion over geological time scales are needed. River networks are able to record a large amount of distributed strain and they can thus be used to reconstruct the mode and rate of distribution away from major active structures. To explore the controls on river resilience to deformation, we develop an experimental model to investigate river pattern evolution over a doubly-vergent orogenic wedge growing in a context of oblique convergence. We use a rainfall system to activate erosion, sediment transport and river development on the model surface. At the end of the experiment, the drainage network is statistically rotated clockwise, confirming that rivers can record the distribution of motion along the wedge. Image analysis of channel time-space evolution shows how the fault-parallel and fault-perpendicular components of motion decrease toward the fault and impose rotation to the main trunk valleys. However, rivers do not record the whole imposed rotation rate, which suggest that the natural lateral channel dynamics can alter the capacity of rivers to act as passive markers of deformation.
ISSN: 0040-1951

hal-01467564
https://hal.archives-ouvertes.fr/hal-01467564
DOI : 10.1016/j.tecto.2016.04.016

Éditeur(s) : HAL CCSD Taylor & Francis (Routledge)
Résumé : International audience
The Maroni basin, an isolated region delineating the border between Suriname and French Guiana has been affected by the human immunodeficiency virus (HIV) epidemic 10 years after coastal French Guiana. However, the rise in HIV prevalence was sharp, exceeding 1% within 10 years. The aim of the present study is to compare, using the first quantitative data from the general population in remote villages, the knowledge, attitudes, and behaviors regarding HIV between Maroon and Amerindian populations, the two most frequent populations living along the Maroni. Data were collected in 2012 using a structured questionnaire among a random sample of 896 individuals residing in the remote villages on the Maroni river. Proportions were compared between the Maroni and the coastal general population, and between Maroon and Amerindian populations. The present study shows significant differences between territories and between communities living on the Maroni river: the multiple sexual partnerships, more common among population living on the Maroni river, were more frequently reported in Maroons than in Amerindians. Condom use was more frequently reported among men on the Maroni river than on the coast, but these findings were reversed for women. Moreover, among people living on the Maroni river, condom use was more frequently reported among Maroons than among Amerindians. Regarding genital factors that may affect transmission, penile implant seemed to have no ethnic boundaries, steam baths seemed specific to Maroon women. The present results should help to improve community-based specific interventions.
ISSN: 0954-0121

hal-01260915
https://hal.archives-ouvertes.fr/hal-01260915
https://hal.archives-ouvertes.fr/hal-01260915/document
https://hal.archives-ouvertes.fr/hal-01260915/file/2015%2C%20Van%20Melle%20-%20Knowledge%2C%20attitudes%2C%20behaviors%2C%20and%20practices%20differences%20regarding%20HIV.pdf
DOI : 10.1080/09540121.2015.1032203

Éditeur(s) : HAL CCSD
Résumé : International audience
Energy is a critical enabler. In tropical countries, access to modern electricity is vital to reducing poverty and improving health, increasing productivity and promoting economic growth. However, the International Energy Agency reported in 2015 more than 1.2 billion people still did not have access to electricity in 2013, around 80% of them live in developing and tropical countries. Then, the same agency report also in 2016 around 6.5 million premature deaths each year can be attributed to air pollution. Therefore, it is time to support appropriate renewable energy developments, particularly the river hydrokinetic developments seems to be a better solution in tropics because of large and powerful rivers in these areas.In French Guiana, 35% of the inland populations are still not connected to the electrical grid (Région Guyane, 2012). This could be ascribed to the fact that extending grid wires hundreds of kilometers through difficult terrain and thick jungles just to serve a small remote village is economically unviable initiative (Ajan et al., 2003; Anyi et al., 2010). As an alternative, French Guiana and most of the tropical countries resort to diesel-powered generators which requires significant imports of expensive fuel, difficult to bring into remote areas (Région Guyane, 2012).This works proposes guidelines to estimate river hydrokinetic fluxes in the vicinity of remote communities in tropics. The method is applied to identify and characterise potential sites along an important reach of the Maroni river in French Guiana. First, a novel method to carry out river terrain elevation model is presented and some results about the Maroni river are reported. It begins from how to conduct ADCP survey, which corrections on them should be made and ends up by interpolating bathymetry over curvilinear profiles which handle the flow lines. That approach involves how mutli-source data (sparse ADCP-cross profiles, incomplete LiDAR tiles and hydroligic data) are merged and combined to estimate local cross section shape, maximum water depth and carry out cross profile in ungauged sites.This is followed by a deep characterisation about time-evolution of hydrokinetic fluxes field in the areas of interest by implementation of a full 2D hydrodynamic model (TELEMAC2D) over an important reach of the Maroni river. To optimise computational cost, river sections outside the areas of interest are modelled as a porous media where only the flows variables up and down stream must fulfil the field data.
CAS
Deshaies, Guadeloupe

hal-01514240
https://hal.archives-ouvertes.fr/hal-01514240

Éditeur(s) : U.S. Coast and Geodetic Survey ( Washington D.C )
Résumé : Shows navigable lakes, rivers, bays and canals within the Everglades National Park as well as a portion of the Gulf of Mexico and Florida Bay; also distinguishes areas of mangrove, marsh and marl prairie.
Orientation compass shown at 7 points.
Includes tidal information.
C.&G.S. 598-599.
"Continued on chart 1250".
"Soundings in feet at mean low water".
Depths shown by isolines and soundings.
(Funding) Funded in part by the University of Florida, the Florida Heritage Project of the State University Libraries of Florida, the Institute for Museum and Library Services, and the U.S. Department of Education's TICFIA granting program.
(Statement of Responsibility) U.S. Coast and Geodetic Survey.
Florida
Everglades National Park.
Mexico, Gulf of
Mexico, Gulf of
Whitewater Bay (Fla.)
Mexico, Gulf of
Gulf Coast (Fla.)
Everglades National Park (Fla.)
Whitewater Bay (Fla.)
Florida
Everglades National Park
Mexico, Gulf of
Everglades National Park (Fla.)
Whitewater Bay (Fla.)

Droits : All rights reserved, Board of Trustees of the University of Florida.
AAA6304
52198639
http://ufdc.ufl.edu/UF00005038/00001

Éditeur(s) : HAL CCSD Société géologique de France
Résumé : U-Pb ages obtained from detrital zircon from terrigenous sediments are used to determine the sources. Present fluvial sand-bars of the Ogooue river yield age spectra of detrital zircons in agreement with Archean and Early Proterozoic Sources found in the drainage. The large proportion of Late Proterozoic zircons cannot be derived from primary erosion of the watershed basement rocks, since there is no formation of that age in the area. This later group of zircons is in good agreement with reworking of the aeolian Paleogene Bateke Sands, by regressive erosion in the upper reaches of the Ogooue river, as they contain a majority of Late Proterozoic age zircons. The sources of Late Proterozoic zircons in the Bateke Sand are very distant, and transported and reworked - at least in part - by aeolian processes. Our results, together with the widely distributed Paleogene sediments over continental Africa, suggests that Paleogene was it time of subdued erosion of the cratonic areas and extensive reworking, transport and deposition within continental Africa. In contrast, our results from the Ogooue river indicate active present incision of the cratonic area, erosion of the previous continental sediments, and export of the river bed-load to the continental margin. This temporal evolution of erosion-transport-deposition is correlated with the drastic climate change that occurred during the Cenozoic, leading to a more efficient mechanical erosion, and it correlates with the increase of terrigenous flux to the margin, observed during the Neogene.
EISSN: 1777-5817

hal-00411165
https://hal.archives-ouvertes.fr/hal-00411165
DOI : 10.2113/gssgfbull.179.1.29

Éditeur(s) : Springer
Résumé : Batch culture experiments using viral enrichment were conducted to test the response of a coastal bacterial community to autochthonous (i.e., co-existing) or allochthonous riverine viruses. The effects of viral infections on bacterial dynamics and activity were assessed by epifluorescence microscopy and thymidine incorporation, respectively, whereas the effect of viral infection on bacterial community composition was examined by polymerase chain reaction-single strand conformation polymorphism 16S ribosomal RNA fingerprinting. The percentages of high nucleic acid-containing cells, evaluated by flow cytometry, were significantly correlated (r (2) = 0.91, n = 12, p < 0.0001) to bacterial production, making this value a good predictor of active cell dynamics along the study. While confinement and temperature were the two principal experimental factors affecting bacterial community composition and dynamics, respectively, additions of freshwater viruses had significant effects on coastal bacterial communities. Thus, foreign viruses significantly reduced net bacterial population increase as compared to the enrichment treated with inactivated virus. Moreover, freshwater viruses recurrently and specifically affected bacterial community composition, as compared to addition of autochthonous viruses. In most cases, the combined treatment viruses and freshwater dissolved organic matter helped to maintain or even enhance species richness in coastal bacterial communities in agreement to the 'killing the winner' hypothesis. Thus, riverine virus input could potentially influence bacterial community composition of the coastal bay albeit with modest modification of bulk bacterial growth.
Microbial Ecology (0095-3628) (Springer), 2009-02 , Vol. 57 , N. 2 , P. 295-306

Droits : 2009 Springer
http://archimer.ifremer.fr/doc/2009/publication-6636.pdf
DOI:10.1007/s00248-008-9428-1
http://archimer.ifremer.fr/doc/00000/6636/

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Objective: The first aim of this study was to evaluate the antimicrobial resistance of Enterobacteriaceae in different water environments of Guadeloupe and especially those impacted by waste water treatment plants (WWTP) effluents. The second objective was to characterize the genetic basis for antibiotic resistance of extended-spectrum beta-lactamase (ESBL) and AmpC beta-lactamase producing Enterobacteriaceae isolates (ESBLE and AmpCE).Methods: We have collected 70 surface waters (river and sea samples) impacted or not by WWTP and 18 waste waters from 2 WWTPs in 2012 and 2013. We i) determined the total and resistant bacterial counts and ii) tested isolated Enterobacteriaceae for their antimicrobial susceptibility. We also studied the genetic basis for antibiotic resistance of ESBLE and AmpCE, and the genetic background of Escherichia coli.Results: In rivers, contamination with Escherichia coli and antibiotic resistant coliforms (ARC) increased from the source to the mouth. Highest levels of river contamination with E. coli (9.26 x 105 MPN/100mL) and ARC (2.26 x 108 CFU/mL) were observed in surface water sampled near the discharge. A total of 246 Enterobacteriaceae strains resistant to antibiotics were isolated, mostly from waste waters and from river water collected near the discharge. Among these strains, 33 were Extended Spectrum Beta Lactamase (ESBLE) and 8 E. coli were AmpC beta-lactamase producers. All the ESBLE were isolated from waste waters or from river water collected near the discharge. The blaCTX-M gene was present in 29 of the 33 ESBLE strains, with 24 belonging to group 1. Numerous strains (68.7%) showed more than one acquired antibiotic resistance mechanism. E. coli strains belonged to different phylogenetic groups; among the B2 group, most strains belonged to the ST131 clone.Conclusion: Our results demonstrated that many human activities can supply antibiotic-resistant bacteria in surface water. Nevertheless, WWTPs were the most important supplier of ESBLE in water environment of Guadeloupe.
ISSN: 1932-6203

Droits : http://creativecommons.org/licenses/by/
hal-01485327
http://hal.upmc.fr/hal-01485327
http://hal.upmc.fr/hal-01485327/document
http://hal.upmc.fr/hal-01485327/file/journal.pone.0173155.pdf
DOI : 10.1371/journal.pone.0173155.t002