Éditeur(s) : University of Florida ( Gainesville, Fla. )
Résumé : (Thesis) Thesis (Ph.D.)--University of Florida, 1984.
(Bibliography) Include bibliographic references (leaves 119-125).
Vita.
Dominican Republic
UF

ACN7945
11908433
0030497226
http://ufdc.ufl.edu/UF00102795/00001

Éditeur(s) : Taylor and Francis
Résumé : A new sand-dwelling dinoflagellate species, Cabra reticulata sp. nov., is described from sandy habitats in the south of Brittany (northwestern France). This new species possesses the characteristics of the 'unusual' genus, Cabra Murray et Patterson. The thecal plate formula is Po Pt 3' 1a 4'' 'x' 3c ?s 5''' 1'''' (or alternatively interpreted as Po Pt 4' 0a 4'' 'x' 3c ?s 5''' 1''''). Because of the strong lateral compression, cells of C. reticulata are frequently seen laterally and have a polygonal shape, with three prominent antapical pointed flanges and a dorsal spine in the anterior part of the hypotheca. The cingulum is ascending and incomplete. The thecal surface is ornamented with strong reticulations forming polygonal areolae, which differs from C. matta Murray et Patterson, the type species of the genus. In addition to their different size and shape, a detailed study of C. reticulata by scanning electron microscopy also revealed several different plate features. Plates of the cingulum, c1 and c3, have no reticulations and are ornamented with shallow round areolae, while c2 is only faintly reticulated. Plate 1'''' is also characteristic because dorsally it forms a prominent pointed flange and ventrally bears a peculiar small area of densely arranged pores or tiny areolae. A similar finding has previously been described in Roscoffia capitata Balech. In the description of the genus, it was suggested that Cabra is closely related to species of the genus Roscoffia, and our observations strengthen this hypothesis. Prior to this study, C. reticulata was probably observed in the Virgin Islands, Caribbean Sea, but was tentatively identified as Thecadinium sp. and not fully described. Thus, C. reticulata appears to be present on both sides of the Atlantic Ocean and to occupy benthic habitats in temperate and tropical areas.
European journal of phycology (0967-0262) (Taylor and Francis), 2009-08 , Vol. 44 , N. 3 , P. 415-423

Droits : 2009 Informa plc, Taylor & Francis
http://archimer.ifremer.fr/doc/2009/publication-6804.pdf
DOI:10.1080/09670260902883271
http://archimer.ifremer.fr/doc/00000/6804/

Éditeur(s) : HAL CCSD Editions Paralia CFL
Résumé : The wave-dominated beach barrier of Villeneuve-Lès-Maguelone extends between Palavas and Frontignan (Gul f of Lions, northernmost Me diterranean Sea), along a slightly natural sandy protected area char acterized by typical and well-expressed morphologies. In the nearshore, the sea bottom shows one or two approximately rectilinear sand bars. In 2010-2011, we pe rformed a 6 month-long monitoring (autumn 2010/late spring 2011) of a 500 meter-long se gment along this sand barrier. We used RTK D-GPS offering centimeter resolution to acquire sets of elevation data on the beach and the upper shoreface. The study is innovative because a full morphologic monitoring was performed each time the wave/ wind conditions changed significantly. These changes were tracked in real-time thanks to a set of hydrodynamic equipments deployed at sea, including well-known DREAL buoys. We identify from well- documented data: (1) a beach reconstruction cycle at the shorelin e after a moderate storm event (wave height at 3-4 m) and (2) how a sand bar in the nearshore migrates to the shoreline and drives the shoreline shift.
ISSN: 1760-8716

hal-00854402
https://hal.archives-ouvertes.fr/hal-00854402
DOI : 10.5150/jngcgc.2012.023-C

Éditeur(s) : HAL CCSD Elsevier
Résumé : SUBSURF
Statistical sequential analysis was performed on a series of sediment cores collected from the Têt prodelta in the Gulf of Lions, northwestern Mediterranean Sea, between October 2003 and October 2004. Seabed changes during that period were correlated to hydrodynamic conditions (waves and currents) and river discharge. Low sediment supply prevents full preservation of new sediment strata on this low-accumulation prodelta located on a microtidal, storm-dominated inner shelf. Severe meteorological events caused a rapid succession of erosion and deposition phases. For example, the December 2003 flood and storm produced a flood layer deposit that persisted for 2 months with only slight transformations due to early diagenesis and/or bioturbation, until a new storm event eroded this layer. A typical sedimentary sequence was observed for the secular deposits composed of a 10-cm-thick sandy layer overlaying siltyclayey layers. These characteristic features were used to analyse the last millennia sedimentary record of the Têt prodelta. The low preservation of freshly deposited sediments and variable sedimentation rates during the last millennia period yield a sedimentary sequence formed by the outcropping of muddy prodeltaic units intersected by heterogeneous siltysandy units similar to those formed under present day hydrodynamic conditions. No flood layer was found related to catastrophic flooding of the last century in the sedimentary record. The Little Ice Age ( 1550–1850 AD) probably favoured the formation of a well-developed muddy prodelta in the mouth of the Têt River. Later on, the decrease of sediment supply by rivers due to climate change and/or human activities (damming, irrigation), and the increase of the number of high-energy storms reaching the coast, induced a coarsening of the top sediment layer on this prodelta. This modern change of the substrate is also observed in the composition of benthic biota found in the substrate
ISSN: 0025-3227

hal-00407662
https://hal.archives-ouvertes.fr/hal-00407662
DOI : 10.1016/j.margeo.2007.04.009

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
We analyze the kinematics of fault tip folding at the front of a fold-and-thrust wedge using a sandbox experiment. The analog model consists of sand layers intercalated with low-friction glass bead layers, deposited in a glass-sided experimental device and with a total thickness h = 4.8 cm. A computerized mobile backstop induces progressive horizontal shortening of the sand layers and therefore thrust fault propagation. Active deformation at the tip of the forward propagating basal décollement is monitored along the cross section with a high-resolution CCD camera, and the displacement field between pairs of images is measured from the optical flow technique. In the early stage, when cumulative shortening is less than about h/10, slip along the décollement tapers gradually to zero and the displacement gradient is absorbed by distributed deformation of the overlying medium. In this stage of detachment tip folding, horizontal displacements decrease linearly with distance toward the foreland. Vertical displacements reflect a nearly symmetrical mode of folding, with displacements varying linearly between relatively well defined axial surfaces. When the cumulative slip on the décollement exceeds about h/10, deformation tends to localize on a few discrete shear bands at the front of the system, until shortening exceeds h/8 and deformation gets fully localized on a single emergent frontal ramp. The fault geometry subsequently evolves to a sigmoid shape and the hanging wall deforms by simple shear as it overthrusts the flat ramp system. As long as strain localization is not fully established, the sand layers experience a combination of thickening and horizontal shortening, which induces gradual limb rotation. The observed kinematics can be reduced to simple analytical expressions that can be used to restore fault tip folds, relate finite deformation to incremental folding, and derive shortening rates from deformed geomorphic markers or growth strata.
ISSN: 2169-9313

hal-00138061
https://hal.archives-ouvertes.fr/hal-00138061
https://hal.archives-ouvertes.fr/hal-00138061/document
https://hal.archives-ouvertes.fr/hal-00138061/file/Bernard_et_al-2007-Journalsur Geophysical_Research__Solid_Earth_%281978-2012%29.pdf
DOI : 10.1029/2005JB004149

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Maguelone shore extends along the northern coast of the Gulf of Lions, west of the Rhone Delta and east of high-gradient coastal streams that have provided most of the clastic sediments to the Gulf of Lions margin since the early Miocene. This 10 km-wide area is constituted by a small coastal watershed (15 km long) in low-lying carbonate hills, a kilometre-wide marsh, a sandy beach barrier and a shoreface experiencing local low sedimentation rates. This onshore-offshore transition zone is a key area to understand the relationships between erosion, by-pass, deposition and preservation processes. Unlike the neighbouring Rhone deposits that display numerous thick deltaic sequences related to a continuous sediment flux, the Maguelone shore exhibits peculiar sedimentary bodies. The analysis of about 250 km of new VHR seismic profiles acquired over the study area, 9 short cores and outcrops data allowed us to determine the three-dimensional high-resolution geometry of the coastal system tracts from Quaternary to present-day. This revealed dominant denudation processes in the Upstream catchments associated with the formation of incised valleys during Quaternary lowstands. In addition, this study investigates the erosion and deposition mechanisms controlled by littoral hydrodynamics that have been taken place on this shore since the last transgression. In particular, metre-high and hundreds of metre-long sandy bodies constructed by alongshore hydrodynamics were identified and their effect on the morphodynamics of the whole littoral system is discussed. The Maguelone shore can be used as an experimental study for onshore/offshore dynamics under the influence of microtidal wave/current hydrodynamics and very low river-derived sediment flux during a eustatic cycle. Geometry of system tracts across flood plain to shoreface is usually considered to be controlled by relative sea-level changes, and is successfully analysed with 2D sequence stratigraphy cross-shore models. It is observed that in areas like the Maguelone shore, traditional sequence stratigraphy methods might not be fully relevant and need to integrate alongshore hydrodynamical processes.
ISSN: 0025-3227

hal-00421060
https://hal.archives-ouvertes.fr/hal-00421060
DOI : 10.1016/j.margeo.2009.06.008

Éditeur(s) : HAL CCSD Cambridge University Press (CUP)
Résumé :  
Although the potential contribution to tropical tree species coexistence of niche differentiation along light gradients has receivedmuch attention, the degree to which species perform differentially along soil resource gradients remains unclear. To examine differential growth response to soil resources, we grew seedlings of nine tropical tree species at 6.0% of full sun for 12mo in a factorial design of two soil types (clay and white sand), two phosphate fertilization treatments (control and addition of 100mgP kg−1) and two watering treatments (field capacity and water limitation to one-third field capacity). Species differedmarkedly in biomass growth rate, but this hierarchy was almost completely conserved across all eight treatments. All species grew more slowly in sand than clay soils, and no species grew faster with phosphate additions. Only Eperua grandiflora and E. falcata showed significant growth increases in the absence of water limitation. Faster-growing species were characterized by high specific leaf area, high leaf allocation and high net assimilation rate but not lower root allocation. Slower-growing species exhibited greater plasticity in net assimilation rate, suggesting that tolerance of edaphic stress in these species is related more to stomatal control than to whole-plant carbon allocation. Although relative growth rate for biomass was correlatedwith both its physiological and morphological components, interspecific differences were best explained by differences in net assimilation rate across six of the eight treatments. A suite of traits including high assimilation and high specific leaf area maintains rapid growth rate of faster-growing species across awide gradient of soil resources, but the lack of plasticity they exhibit may compromise their survival in the poorest soil environments.
ISSN: 0266-4674

hal-01032086
https://hal.archives-ouvertes.fr/hal-01032086
DOI : 10.1017/S0266467406003439

Éditeur(s) : HAL CCSD
Résumé : International audience
Studying the ecology of Leishmania parasites is essential for understanding and controlling the epidemiology of the diseases they cause. Despite their abundance and diversity in neotropical forests, few studies have been conducted to investigate the potential involvement of Chiroptera in the Leishmania pathogenic complexes. However, phlebotomine sand flies are known to colonize the same anthropized habitat, are attracted to bats, and are able to transmit trypanosomatids. Thus, 216 bats representing 29 species were sampled in the field in different primary and secondary forests of French Guiana where human cutaneous leishmaniases have been reported, together with 62 non-volant mammals. A series of 411 tissue samples representing 47 mammalian species were cultured and screened for the presence of Leishmania spp. by a genus-specific polymerase chain reaction. All 278 individuals surveyed were negative. Thus, bats do not appear to be involved in the Lishmania parasitic cycles in the Guyanas.
The American journal of tropical medicine and hygiene

halsde-00339305
https://hal.archives-ouvertes.fr/halsde-00339305

Éditeur(s) : HAL CCSD Coastal Education and Research Foundation
Résumé : The present work concerns cuspate spits: slightly symmetrical geomorphic features growing along the shoreline in shallow waters. We develop a new formulation for the dynamics of cuspate spits. Our approach relies on classical paradigms such as a conservation law to the shoreface scale and an explicit formula for alongshore sediment transport. We derive a non-linear diffusion equation and a fully explicit solution for the growth of cuspate spits. From this general expression, we found interesting applications to quantify shoreline dynamics in the presence of cuspate spits. In particular, we point out a simple method for the datation of a cuspate spit given a limited number of input parameters. Furthermore, we develop a method to quantify the mean alongshore diffusivity along a shoreline perturbed by well-defined cuspate spits of known sizes. Finally, we introduce a formal relationship between the geometric characteristics (amplitude, length) of cuspate spits, which reproduce the self-similarity of these geomorphic features.
ISSN: 0749-0208

hal-01234952
https://hal.archives-ouvertes.fr/hal-01234952
DOI : 10.2112/SI70-009.1

Éditeur(s) : HAL CCSD
Résumé : International audience
o abstract
Coastal Engineering Proceedings

hal-01426586
https://hal.archives-ouvertes.fr/hal-01426586

Éditeur(s) : HAL CCSD Société géologique de France
Résumé : A study combining very high resolution seismic and sediment core data has been carried out on the Thau lagoon (Mediterranean coast, microtidal setting, SE France) in order to understand more clearly the dynamics and Holocene chronology of its closure through the different stages of its filling. One main seismic unit (U2) has been defined into the infill, above the rocky basement (U0) and a composite unit U1, which is interpreted as remnants of Pleistocene fluvial terraces or/and to early marine Holocene deposits. Unit U2, that reaches locally 9 m in thickness, rests conformably on U1 in the central part of the lagoon and onlaps U0 or U1 close to the edge of the lagoon. It is divided in two sub-units, U2-1 and U2-2. U2-2 rests paraconformably on U2-1 in the central part of the lagoon where the infill is the thickest, while a marked erosional unconformity is observed between U2-1 and U2-2 on topographic highs of the basement and on the seaward edge of the lagoon. A total of seven elementary sequences have been observed in U2-1 and U2-2.;According to core data, U2 consists in a series of mud-dominated sequences, with shell fragments dispersed at the base. The vertical distribution of the fauna into U2-1 and U2-2 reveals a lagoonal environment. However in U2-1, marine species are more abundant in the south of the lagoon. C-14 AMS dating provides three ages: similar to 6000 cal yr B.P. in the lower part of U2-1 on CAL1, 5400 cal yr B.P. just above the boundary between U2-1 and U2-2 on CAL4, similar to 3000 cal yr B.P. in the middle of U2-2 on CAL4.;A scenario to explain the lagoon infill stratigraphy and geometry is proposed. The beginning of the lagoon infill occurred with the initiation of the barrier construction, as soon as the sea-level rise slowed down significantly, i.e. between 7000-6000 yr B.P. The sediment-fill began into the back-barrier system, with a high rate of sedimentation for U2-1, according to the radiocarbon data. At 5400 yr B.P., the barrier is assumed to be totally closed leading to the deposition of the fully lagoonal U2-2 succession. The unconformity between U2-1 and U2-2 is interpreted as the result of a rapid landward retreat of the barrier. This severe retreat could be related to climate forcing and/or brutal change in sediment discharge driven by the Rhone River, which is the main sediment source of the longshore drift. In this scenario, the last sub-unit, U2-2, represents most of the late Holocene infill. In this framework, the elementary sequences observed in U2-2 could be related to high frequency climate changes of about 1000-1500 years periodicity according to C-14 dates.
EISSN: 1777-5817

hal-00486386
https://hal.archives-ouvertes.fr/hal-00486386
DOI : 10.2113/gssgfbull.181.2.197

Éditeur(s) : HAL CCSD Cambridge University Press
Résumé : International audience
The reproduction of Rhinecanthus aculeatus (Linnaeus,1758), a tropical Indo-Pacific reef fish, occurs aroundthe full and new moon (Kuwamura 1997). Spawningbegins 16 to 45 min before the sunrise. The courtshipsbegin 7 to 27 min before the spawning. A specific behaviourof the courtships is when the male places itsrostrum against the caudal peduncle of the female(Kuwamura 1997).Observations have been recorded in the lagoon ofTiahura [shallow sandy area (0.5 - 2 m deep) withalgae Hypnea spinella (C.Agardh) Kützing, 1847 -Moorea, French Polynesia; 17°29′27′ S, 149°53′32″O]in March and April 2015. Fifteen R. aculeatus (fivemales and ten females) lived in this area where themales have territories, which included the subterritoriesof the females. During video-recorded courtships,in addition to the behaviour described byKuwamura (the nuzzling), two new behaviours havebeen observed: circling and touching. During the circling,the male and the female swim to the surface inprogressively larger circles (Fig. 1). The circling behaviourhas been observed in other Balistidae such asPseudobalistes flavimarginatus (Rüppell, 1829) andBalistapus undulatus (Park, 1797) (Lobel andJohannes 1980). During the touching, the abdomensof the male and the female’s touch each other withoutgametes emission (Fig. 2). The touching has been reportedfor Xanthichthys mento (Jordan and Gilbert1882) (Kawase 2003).Although Balistidae present different reproductivestrategies, they have common reproduction features,such as the time and the day of hatching andspawning (Kawase 2003). Our observations are innovativebecause the courtship of R. aculeatus is morecomplicated than previously described. This resultsuggests, thus, that Balistidae have also some commoncourtship behaviour features. These behaviours mayfacilitate the release of gametes, as with the nuzzling(Kuwamura 1997) or can convince the partner to mate.We do not know if these patterns are phylogeneticallyrelated. But as the egg care strategy of Balistidae (biparentalvs maternal) appears to be related to the distributionof food and breeding sites, more than by thephylogeny (Kuwamura 1997), more studies on thistopic will be useful to better understand the establishement of these behaviours.
EISSN: 1755-2672

hal-01562097
https://hal-univ-perp.archives-ouvertes.fr/hal-01562097
DOI : 10.1007/s12526-016-0464-7