Resultats de dragages et essai de stratigraphie des bancs de Galice,et des montagnes de Porto et de Vigo (marge occidentale Iberique)

Dredged samples have been studied to establish the stratigraphy as well as the probable paleogeographic evolution of the sedimentary cover of Galicia Bank, and Vigo and Porto Seamounts. The sedimentation appears to have been neritic up to the Late Jurassic. These structural features evolved separately from the Iberic continental margin in Late Jurassic to Early Cretaceous times. Part of the sediments is made of calpionellid limestones, which is indicative of open marine conditions in this area of the Atlantic at that time. This also suggests the establishment of marine connections between this area and the “Mésogée”. These open marine conditions would have persisted since the Early Cretaceous.     

Importations et remaniements de thanatofaunes dans les sables de la plate-forme profonde des approches occidentales de la Manche

Macro- and micro-faunas are reported from six gravity cores collected at a mean depth of 150 m in the surficial deposits of the Kaiser sand bank in the Southern Western Channel Approaches. These are bivalves (mainly), gastropods, echinids, crustaceans and foraminifers. These fauna present a very rich association of numerous, well preserved species from various ecological settings. Such an association is commonly reported from the continental shelf of the last transgressive cycle. In addition, the sediment comprises two imported faunal associations. The first one corresponds to thanatocaenoses of Pliocene/lowermost Pleistocene and Weichselian age, reworked respectively from the underlying celtic incised valley fills and the Celtic Sand Banks. The absence of Quaternary fauna prior to the Weichselian suggests that the introduction of Pliocene sources occurred during the last climatic cycle. The second stage of importation took place after the last transgression in the Western Channel, and corresponds to the enrichment of the sediment in coastal fauna derived from western Brittany by the the predominant ebb tidal current. The variations of taxonomic diversity from core to core suggest a sediment transport around the bank that matches the one deduced from the study of tidal bedforms. At the present day, the wave action is highlighted by accumulation of species of the same shape, size and density inside storm beds. However, the survival within these beds of very small, juvenile shells indicate that each storm reworking was short in duration.     

Distribution des terres rares dans les fractions de sediments et nodules de Fe et Mn associes en l'ocean Indien

The REE distribution in size fractions of sediments and associated ferromanganese nodules from the Indian Ocean was studied. Bulk-sample patterns of sediments result from the combination of coarsest fractions depleted in Ce and fine fractions enriched in Ce. Ce depletion of the coarsest fractions is related to biogenic silica; on the contrary, REE distribution patterns of fine fractions are closely similar to those of associated ferromanganese nodules. The Ce excess in fine fractions is probably of continental origin, but it could also be derived from submarine weathering of volcanic glass or related to Ce oxydation in the marine environment. In fine fractions Ce is probably in its tetravalent state, hence it can easily be scavenged by fine clays and oxyhydroxydes. Trivalent REE can be incorporated in nodules, partly by occlusion of fine clays or oxyhydroxydes and partly by surface to surface transfer as was proposed by Ehrlich (1968). Comparison between REE patterns of fine-sized fractions, nodules and seawater also supported adsorption as a possible mechanism governing the incorporation of REE of sediments and nodules from seawater. Light REE are probably incorporated as oxyhydroxyde complexes, whereas heavy REE are markedly fractionated with increasing atomic number. This fractionation reflects the complexed form of the heavy REE in seawater.     

Contribution a l'etude chimique du materiel dissous et particulaire de l'estuaire de la riviere rimouski

Temperature, pH, total alkalinity, dissolved oxygen, silicate, nitrate, phosphate and the Mn, Fe and Al contents of suspended particulate matter (SPM) were measured in the Rimouski River estuary as functions of chlorinity during the period May—September 1980.At any given time, total alkalinity (TA) is conservative within the estuary with respect to chlorinity. However, the total alkalinity (TA) of the freshwater is related to river flow. This is attributed to dilution of the river water with bicarbonate-poor rainwater.Generally, pH follows the same pattern observed for TA in freshwater. Dissolved oxygen is usually more concentrated in freshwater and decreases linearly with increasing chlorinity. Freshwater is always saturated or supersaturated with respect to O₂. Seasonal fluctuations are attributed to temperature variations.There is no evidence for removal of soluble silicate from the freshwater entering the sea. The concentration of silicate in the freshwater is strongly influenced by rainfall. Soil leaching, conditioned by high rainfall increases the concentration of soluble silicate in freshwater. Nitrate behaves similarly whereas phosphate is complicated by the presence of sewage.Analysis of the Mn, Fe and Al contained in the SPM indicates dilution of river-borne particles rich in Mn by others less rich in this element. A decrease in Mn content with increasing chlorinity and SPM concentration as well as increasing concentrations of SPM with increasing chlorinity indicate that the composition is controlled primarily by physical mixing of material from two sources rather than by chemical processes. Within the analytical precision the Fe/Al ratio does not vary with the chlorinity.     

Financing marine conservation tourism: Governing entrance fees in Raja Ampat,Indonesia

Worldwide, the growth of marine tourism is creating opportunities for financing marine protected areas (MPAs), but what these financial arrangements look like and how they can be governed at larger scales, and in equitable and transparent ways, is unclear. This paper examines the governance arrangement of two region-wide successive entrance fee systems established since 1997 in Raja Ampat, Indonesia, to finance a network of MPAs delineated under the auspices of two big international non-governmental organizations (NGO), namely Raja Ampat Entrance Fee and Raja Ampat Ecosystem Service Stewardship Fee. These two successive entrance fee systems can be viewed as payment for environmental services (PES) arrangements. The PES-like entrance fee arrangements improved in terms of participation, transparency and equity. In the second scheme, local communities in Raja Ampat were involved in the design of the disbursement of the community fund, and the criteria for disbursement became more clear and transparent. However, in both schemes there is no clear connection between the distribution of the funds and activities that improve environmental services provision (conditionality). In addition, the latter scheme is still facing equity challenges as some communities with customary rights over marine tourism hotspots are asking for additional user-fees from tourists and tourism operators.     

Incidence de la cinetique de decroissance de la temperature apres le choc thermique sur les modifications d'activite des esterases et les possibilites de survie de Scolelepis (malacoceros) fuliginosa (annelide polychete)

Scolelepis fuliginosa reared in the laboratory at 13°C were put through 10-min thermal shocks at 16°C and 18°C and were then submitted to either a slow or a rapid temperature reduction. After the thermal shock, a posterior fragment of each specimen was cut off at intervals, until six days. Samples were submitted to electrophoresis on polyacrylamide gel, esterase activity being determined with α-naphthyl acetate.Enzymograms show that thermal shocks act on esterases in decreasing the activity of the main fractions. Immediate effects result in a very precocious enzymic response; more long-term effects depend on the maximum temperature, the animal's sex and the kinetics of the post-shock thermal reduction.Females are more sensitive than males. For a given Δt, esterase changes are greater and more long-lasting. After a 16°C Δt, a rapid decrease in temperature prevents the loss of activity of the middle and fast fractions in males and delays, by about 10 h, the alteration of female esterases. After 18°C ΔT, loss of activity of the middle and fast fractions occurs in less than 1 h, independently of the thermal kinetics, but survival is only possible—solely for males—with a rapid decrease in temperature which also delays females' deaths by between 24 and 48 h.In conclusion, a rapid decrease in temperature gives organisms a better resistance to thermal shock, as determined by esterase activity and controls the lethality of a high Δt.