Éditeur(s) : Université des Antilles AREBio Groupe de recherche BIOSPHERES : BIOlogie, Sciences Physiques & Humaines pour les énergies Renouvelables, l
Extrait de : 1er colloque international BIOSPHERES, du 18 au 20 juin 2019. Université des Antilles
Description : Chlordecone is a persistent organochlorine pesticide widely used between 1972 and 1993 in the French West Indies to control the root borer in banana fields. Chlordecone use resulted in long-term pollution of soils, contamination of waters, of aquatic organisms, and of fields. Chlordecone is known to be neurotoxic, to increase prostate cancer, and to have negative effects on cognitive and motor development during infancy. In Guadeloupe, most of the freshwater species living in contaminated rivers exceed the French legal limit of 20 ?g·kg?1 wet weight. In the present study (ANR MACHLOMA), we chose a transcriptomic approach to study the cellular effects of chlordecone in the giant freshwater prawn Macrobrachium rosenbergii, an important economical species in Guadeloupe.

Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V19065
V19065

Résumé : 2009, Scott Zona -- CC: at-ncsa (Creative Commons license requiring attribution, prohibiting commercial uses, and requiring rights-share for use of this image)
Dominica -- Freshwater Lake, 800m elev.

Résumé : 2009, Scott Zona -- CC: at-ncsa (Creative Commons license requiring attribution, prohibiting commercial uses, and requiring rights-share for use of this image)
Dominica -- Freshwater Lake

Résumé : 2009, Scott Zona -- CC: at-ncsa (Creative Commons license requiring attribution, prohibiting commercial uses, and requiring rights-share for use of this image)
Dominica -- Freshwater Lake

Résumé : 2009, Scott Zona -- CC: at-ncsa (Creative Commons license requiring attribution, prohibiting commercial uses, and requiring rights-share for use of this image)
Dominica -- Freshwater Lake

Résumé : 2009, Scott Zona -- CC: at-ncsa (Creative Commons license requiring attribution, prohibiting commercial uses, and requiring rights-share for use of this image)
Dominica -- Freshwater Lake

Résumé : 2009, Scott Zona -- CC: at-ncsa (Creative Commons license requiring attribution, prohibiting commercial uses, and requiring rights-share for use of this image)
Dominica -- Freshwater Lake

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/

Résumé : 2009, Scott Zona -- CC: at-ncsa (Creative Commons license requiring attribution, prohibiting commercial uses, and requiring rights-share for use of this image)
Dominica -- Freshwater Lake

Résumé : 2009, Scott Zona -- CC: at-ncsa (Creative Commons license requiring attribution, prohibiting commercial uses, and requiring rights-share for use of this image)
Dominica -- Freshwater Lake, 800 m elev.

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The Nile delta sedimentation constitutes a continuous high resolution (1.6 mm/year) record of Ethiopian African monsoon regime intensity. Multiproxy analyses performed on core MS27PT recovered in hemipelagic Nile sediment margin (<90 km outward of the Rosetta mouth of the Nile) allow the quantification of the Saharan aeolian dust and the Blue/White Nile River suspended matter frequency fluctuations during the last 21 cal. ka BP. The radiogenic Sr and Nd isotopes, clay mineralogy, bulk elemental composition and palynological analyses reveal large changes in source components, oscillating between a dominant aeolian Saharan contribution during the LGM and the Late Holocene (~4 to 2 cal. ka BP), a dominant Blue/Atbara Nile River contribution during the early Holocene (15 to 8.4 cal. ka BP) and a probable White Nile River contribution during the Middle Holocene (8.4 to 4 cal. ka BP). The following main features are highlighted: 1. The rapid shift from the LGM arid conditions to the African Humid Period (AHP) started at about 15 cal. ka BP. AHP extends until 8.4 cal. ka BP, and we suggest that the Ethiopian African Monsoon maximum between 12 and 8 cal. ka BP is responsible for a larger Blue/Atbara Nile sediment load and freshwater input into the Eastern Mediterranean Sea. 2. The transition between the AHP and the arid Late Holocene is gradual and occurs in two main phases between 8.4 and 6.5 cal. ka BP and 6.5 to 3.2 cal. ka BP. We suggest that the main rain belt shifted southward from 8.4 to ~4 cal. ka BP and was responsible for progressively reduced sediment load and freshwater input into the eastern Mediterranean Sea. 3. The aridification along the Nile catchments occurred from ~4 to 2 cal. ka BP. A dry period, which culminates at 3.2 cal. ka BP, and seems to coincide with a re-establishment of increased oceanic primary productivity in the western Mediterranean Sea. We postulate that the decrease in thermo-haline water Mediterranean circulation could be part of a response to huge volumes of fresh-water delivered principally by the Nile River from 12 to 8.4 cal. ka BP in the eastern Mediterranean. We propose that the large hydrological change in Ethiopian latitude could be a trigger for the 8.2 ka cooling event recorded in high latitude. Revel R., Colin C., Bernasconi S., Combourieu-Nebout N., Ducassou E., Grousset F.E., Rolland Y., Migeon S., Brunet P., Zhaa Y., Bosch D., Mascle J.,. "21,000 years of Ethiopian African moonsoon variability recorded in sediments of the western Nile deep sea fan", Regional Environmental Change,
ISSN: 1436-3798

hal-00836300
https://hal.archives-ouvertes.fr/hal-00836300

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
Abstract Numerous freshwater species are consumed or exploited through artisanal fisheries in the rivers of the islands of Guadeloupe, French West Indies. Autochthonous production of organic matter is limited in these flowing rivers and is mainly represented by scarce filamentous green algae and an abundant epilithic biofilm growing on wet stones in the river bed. Stable isotope analysis was used to quantify the relative importance of biofilm and other riverine allochthonous and autochthonous food sources in the diet of tropical shrimps (Palaemonidae, Atyidae and Xiphocarididae) and fishes (Gobiidae and Eleotridae) consumed by the local people. The epilithic biofilm was exploited by most species, constituted an important source of autochthonous carbon and was an important source of organic matter production at the base of freshwater food webs in Caribbean rivers. Biofilm percentages in the diet reached 32% for molluscs, 85% for atyid shrimps, 29% for xiphocaridid shrimps, 14% for palaemonid shrimps and 13% for fish. Assessment of biofilm in nine rivers showed that blue and red cyanobacteria were quantitatively dominant with a moderately rich diatom flora. These results address the interactions between river biofilm and Caribbean freshwater fauna where trophic links between consumers and their potential resources have poorly been documented.
ISSN: 0969-997X

hal-00744809
https://hal.univ-antilles.fr/hal-00744809
DOI : 10.1111/j.1365-2400.2010.00767.x

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
A strong non linear relationship between nitrate and organic matter (assessed by dissolved organic carbon, DOC) has been recently demonstrated by Taylor and Townsend (2010), namely for freshwaters. In this context, our study explores this relation from the behavior of sets of normalized UV spectra (same area under each spectrum) of different water samples showing a hidden isosbestic point (HIP) around 225 nm. This HIP is linked to the existence of a simple relation between nitrate and DOC, the proportions of which vary according to the sampling location and environmental factors. In a second step, a simple linear model is proposed for nitrate-DOC relationship (α⋅NO3+β⋅DOC=1) and a validation is proposed for more than 150 samples of different Brittany rivers and lakes. For samples of the largest watershed, a complementary exploitation from data acquired during the different campaigns confirmed the seasonal evolution between spring (high nitrate/low DOC) and autumn (high DOC/low nitrate). Further investigation on other freshwater samples is needed in order to improve the limits of this linear model.
ISSN: 0045-6535

hal-01063932
https://hal.archives-ouvertes.fr/hal-01063932
DOI : 10.1016/j.chemosphere.2014.03.034
PUBMED : 24875878

Éditeur(s) : HAL CCSD Cambridge University Press (CUP)
Résumé : Nodulated legume trees comprised 43% of the stand basal area in the low, most frequently flooded microsites, and 23% in higher, drier microsites in a tropical freshwater swamp forest in French Guiana. Dinitrogen fixation in Pterocarpus officinalis, Hydrochorea corymbosa and Inga pilosula was confirmed by acetylene reduction assay (ARA), presence of leghaemoglobin in nodules and the N-15 natural abundance method. The results for Zygia cataractae were inconclusive but suggested N-2 fixation in drier microsites. Nodulated Inga disticha had a N-15-to-N-14 ratio similar to non-N-2-fixing trees, but ARA indicated nitrogenase activity and leghaemoglobin was present in nodules. All bacterial strains were identified as Bradyrhizobium spp. according to the partial 16S rDNA sequences, and they were infective in vitro in the model species Macroptilium atropurpuretan. About 35-50% of N in the leaves of P. officinalis, H. corymbosa and I. pilosula was fixed from the atmosphere. Dinitrogen fixation was estimated to contribute at least 8-13% and 1728% to whole-canopy N in high and low microsites, respectively. Symbiotic N, fixation appears to provide both a competitive advantage to legume trees under N-limited, flooded conditions and an important N input to neotropical freshwater swamp forests.
ISSN: 0266-4674

hal-01189191
https://hal.archives-ouvertes.fr/hal-01189191
PRODINRA : 13151
DOI : 10.1017/S0266467403006059

Éditeur(s) : Copernicus Gesellschaft Mbh
Résumé : From 10 to 8 ka BP (thousand years before present), paleoclimate records show an atmospheric and oceanic cooling in the high latitudes of the Southern Hemisphere. During this interval, temperatures estimated from proxy data decrease by 0.8 degrees C over Antarctica and 1.2 degrees C over the Southern Ocean. In order to study the causes of this cooling, simulations covering the early Holocene have been performed with the climate model of intermediate complexity LOVECLIM constrained to follow the signal recorded in climate proxies using a data assimilation method based on a particle filtering approach. The selected proxies represent oceanic and atmospheric surface temperature in the Southern Hemisphere derived from terrestrial, marine and glaciological records. Two mechanisms previously suggested to explain the 10-8 ka BP cooling pattern are investigated using the data assimilation approach in our model. The first hypothesis is a change in atmospheric circulation, and the second one is a cooling of the sea surface temperature in the Southern Ocean, driven in our experimental setup by the impact of an increased West Antarctic melting rate on ocean circulation. For the atmosphere hypothesis, the climate state obtained by data assimilation produces a modification of the meridional atmospheric circulation leading to a 0.5 degrees C Antarctic cooling from 10 to 8 ka BP compared to the simulation without data assimilation, without congruent cooling of the atmospheric and sea surface temperature in the Southern Ocean. For the ocean hypothesis, the increased West Antarctic freshwater flux constrainted by data assimilation (+100 mSv from 10 to 8 ka BP) leads to an oceanic cooling of 0.7 degrees C and a strengthening of Southern Hemisphere westerlies (+6 %). Thus, according to our experiments, the observed cooling in Antarctic and the Southern Ocean proxy records can only be reconciled with the reconstructions by the combination of a modified atmospheric circulation and an enhanced freshwater flux.
Climate Of The Past (1814-9324) (Copernicus Gesellschaft Mbh), 2013 , Vol. 9 , N. 2 , P. 887-901

Droits : Author(s) 2013. CC Attribution 3.0 License.
http://archimer.ifremer.fr/doc/00181/29203/27584.pdf
DOI:10.5194/cp-9-887-2013
http://archimer.ifremer.fr/doc/00181/29203/

Éditeur(s) : HAL CCSD Biopress Limited
Résumé : International audience
Obligately epizoic diatoms (Bacillariophyta) on vertebrates were first described from cetaceans, but turtles, both freshwater and marine, also host very specific floras. Several scrapings of juvenile Chelonia mydas have allowed the description of two new diatom taxa whose valves are asymmetrical about the transapical axis, Tripterion societatis sp. nov. and Chelonicola caribeana sp. nov. These taxa are very small and show some morphological plasticity. Such plasticity might suggest their inclusion in genera with slightly different characteristics from Tripterion and Chelonicola as originally delimited. Based on our observations, an emended diagnosis is proposed for Chelonicola.
ISSN: 2159-8347

hal-01500418
https://hal.archives-ouvertes.fr/hal-01500418
DOI : 10.1080/0269249X.2017.1299042

Éditeur(s) : HAL CCSD American Chemical Society
Résumé : International audience
Cyanobacterial toxins and pesticides regularly impact freshwaters. Microcystin-LR is one of the most toxic and common cyanobacterial toxins whereas glyphosate is the active ingredient of a widely use herbicide. As filter feeders, freshwater mussels are particularly exposed. Like many native bivalve species, Unio pictorum suffers from a continuous decline in Europe. In order to get a deeper insight of its response to contaminants, U. pictorum was exposed to either 10 μg L(-1) of microcystin-LR or 10 μg L(-1) of glyphosate or a mixture of both. Proteins of the digestive glands were extracted and analyzed by DIGE. Gel analysis revealed 103 spots with statistical variations, and the response seems to be less toward glyphosate than to microcystin-LR. Specific spots have variations only when exposed to the mixture, showing that there is an interaction of both contaminants in the responses triggered. The proteins of 30 spots have been identified. They belong mostly to the cytoskeleton family, but proteins of the oxidative pathway, detoxification, and energetic metabolism were affected either by glyphosate or microcystin-LR or by the mixture. These results demonstrate the importance to study contaminants at low concentrations representative of those found in the field and that multicontaminations can lead to different response pathways.
ISSN: 1535-3893

hal-00877711
https://hal.archives-ouvertes.fr/hal-00877711
DOI : 10.1021/pr4006316
PUBMED : 23972258

Éditeur(s) : HAL CCSD Kluwer Academic Publishers
Résumé : International audience
The interlocking leaves of tank-forming bromeliads (Bromeliaceae) collect rainwater and detritus, thus creating a freshwater habitat for specialized organisms. Their abundance and the possibility of quantifying communities with accuracy give us unparalleled insight into how changes in local to regional environments influence community diversity in small water bodies. We sampled 365 bromeliads (365 invertebrate communities) along a southeastern to northwestern range in French Guiana. Geographic locality determined the species pool for bromeliad invertebrates, and local environments determined the abundance patterns through the selection of traits that are best adapted to the bromeliad habitats. Patterns in community structure mostly emerged from patterns of predator species occurrence and abundance across local-regional environments, while the set of detritivores remained constant. Water volume had a strong positive correlation with invertebrate diversity, making it a biologically relevant measure of the pools' carrying capacity. The significant effects of incoming detritus and incident light show that changes in local environments (e.g., the conversion of forest to cropping systems) strongly influence freshwater communities. Because changes in local environments do not affect detritivores and predators equally, one may expect functional shifts as sets of invertebrates with particular traits are replaced or complemented by other sets with different traits.
Hydrobiologia

hal-00845572
https://hal.archives-ouvertes.fr/hal-00845572

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Exposure to disturbance is rarely considered in marine protected area planning. Typically, representing and replicating the habitat types present within protected areas is used to spread the risk of protecting frequently disturbed sites. This was the approach used during the 2004 re-zoning of the Great Barrier Reef Marine Park (GBRMP) via the Representative Areas Program. Over 10 years later, we examine whether the risk was spread by mapping exposure of coral reefs in the GBRMP to four disturbances that cause coral mortality: bleaching, tropical cyclones, crown-of-thorns starfish outbreaks, and freshwater inundation. Our objectives were to: (1) assess whether no-take areas include a range of disturbance regimes, and (2) identify coral reef areas with lower relative exposure. At least 13% and an average of 31% of reef locations in each of 11 exposure classes are included within no-take areas. A greater proportion of low-exposure areas are within no-take areas than high-exposure areas (34.2% vs. 28.3%). The results demonstrate the value of risk spreading when exposure data are not available while also showing that regularly assessing exposure increases capacity for adaptive, resilience-based reef management.
ISSN: 1755-263X

Droits : http://creativecommons.org/licenses/by/
hal-01225201
https://hal-univ-perp.archives-ouvertes.fr/hal-01225201
https://hal-univ-perp.archives-ouvertes.fr/hal-01225201/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01225201/file/Maynard_et_al-2015-Conservation_Letters.pdf
DOI : 10.1111/conl.12198

Éditeur(s) : HAL CCSD Society of Environmental Toxicology and Chemistry Press (SETAC)
Résumé : International audience
Tributyltin (TBT) and triphenyltin (TPT) are emblematic endocrine disruptors, which have been mostly studied in gonochoric prosobranchs. Although both compounds can simultaneously occur in the environment, they have mainly been tested separately for their effects on snail reproduction. Because large discrepancies in experimental conditions occurred in these tests, the present study aimed to compare the relative toxicity of TBT and TPT under similar laboratory conditions in the range of 0 ng Sn/L to 600 ng Sn/L. Tests were performed on the simultaneous hermaphrodite Lymnaea stagnalis, a freshwater snail in which effects of TPT were unknown. Survival, shell length, and reproduction were monitored in a 21-d semistatic test. Frequency of abnormal eggs was assessed as an additional endpoint. Triphenyltin hampered survival while TBT did not. Major effects on shell solidity and reproduction were observed for both compounds, reproductive outputs being more severely hampered by TBT than by TPT. Considering the frequency of abnormal eggs allowed increasing test sensitivity, because snail responses to TBT could be detected at concentrations as low as 19 ng Sn/L. However, the putative mode of action of the 2 compounds could not be deduced from the structure of the molecules or from the response of apical endpoints. Sensitivity of L. stagnalis to TBT and TPT was compared with the sensitivity of prosobranch mollusks with different habitats and different reproductive strategies.
Environmental Toxicology and Chemistry

hal-00877955
https://hal.archives-ouvertes.fr/hal-00877955
DOI : 10.1002/etc.2200
PUBMED : 23450754