100 research outputs found

    Dataset of characteristic remanent magnetization and magnetic properties of early Pliocene sediments from IODP Site U1467 (Maldives platform)

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    This data article describes data of magnetic stratigraphy and anisotropy of isothermal remanent magnetization (AIRM) from "Magnetic properties of early Pliocene sediments from IODP Site U1467 (Maldives platform) reveal changes in the monsoon system" [1]. Acquisition of isothermal magnetization on pilot samples and anisotropy of isothermal remanent magnetization are reported as raw data; magnetostratigraphic data are reported as characteristic magnetization (ChRM).info:eu-repo/semantics/publishedVersio

    Toward Human-Carnivore Coexistence: Understanding Tolerance for Tigers in Bangladesh

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    Fostering local community tolerance for endangered carnivores, such as tigers (Panthera tigris), is a core component of many conservation strategies. Identification of antecedents of tolerance will facilitate the development of effective tolerance-building conservation action and secure local community support for, and involvement in, conservation initiatives. We use a stated preference approach for measuring tolerance, based on the ‘Wildlife Stakeholder Acceptance Capacity’ concept, to explore villagers’ tolerance levels for tigers in the Bangladesh Sundarbans, an area where, at the time of the research, human-tiger conflict was severe. We apply structural equation modeling to test an a priori defined theoretical model of tolerance and identify the experiential and psychological basis of tolerance in this community. Our results indicate that beliefs about tigers and about the perceived current tiger population trend are predictors of tolerance for tigers. Positive beliefs about tigers and a belief that the tiger population is not currently increasing are both associated with greater stated tolerance for the species. Contrary to commonly-held notions, negative experiences with tigers do not directly affect tolerance levels; instead, their effect is mediated by villagers’ beliefs about tigers and risk perceptions concerning human-tiger conflict incidents. These findings highlight a need to explore and understand the socio-psychological factors that encourage tolerance towards endangered species. Our research also demonstrates the applicability of this approach to tolerance research to a wide range of socio-economic and cultural contexts and reveals its capacity to enhance carnivore conservation efforts worldwide

    Cyclic anoxia and organic rich carbonate sediments within a drowned carbonate platform linked to Antarctic ice volume changes: Late Oligocene-early Miocene Maldives

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    This paper reports on the newly discovered occurrence of thick sequences (∌100 m) of Late Oligocene and Early Miocene (∌24.9 to ∌20 Ma) interbedded organic-rich sediments (sapropels) and pelagic (organic poor) carbonates at Sites U1466 and U1468 drilled in the Maldives archipelago during the International Ocean Discovery Program (IODP) Expedition 359. This occurrence is unusual in that this sequence is located > 1000 m above the surrounding ocean floor within an inter-atoll basin and not linked to any known global oceanic events. Total organic content reaches as high as 35% in the darker layers, while the interbedded carbonates have concentrations of less than 0.1%. Trace elements characteristic of anoxic waters, such as Mo, V, Cr, U, and Pb, correlate positively with concentrations of organic carbon. Nitrogen isotopic data show no evidence that the intervals of high total organic carbon are related to enhanced productivity driven by upwelling. Instead, high organic carbon is associated with intervals of anoxia. We propose that sea-level fluctuations linked to changes in Antarctic ice volume restricted exchange with the open ocean causing bottom waters of the inter-atoll basin to become anoxic periodically. The architecture of the platform at the end of the Oligocene, combined with the global sea-level highstand, set the stage for orbitally-driven sea-level changes producing cyclic deposition of sapropels. The proposed mechanism may serve as an analogue for other occurrences of organic carbon-rich sediments within carbonate platform settings.</p

    Carbonate delta drift: a new sediment drift type

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    Based on high-resolution reflection seismic and core data from IODP Expedition 359 we present a new channel-related drift type attached to a carbonate platform slope, which we termed delta drift. Like a river delta, it is comprised of several stacked lobes and connected to a point source. The delta drifts were deposited at the exit of two gateways that connect the Inner Sea of the Maldives carbonate platform with the open ocean. The channels served as conduits focusing and accelerating the water flow; Entrained material was deposited at their mouth where the flows relaxed. The lobe-shaped calcareous sediment drifts must have formed under persistent water through flow. Sediment supply was relatively high and continuous, resulting in an average sedimentation rate of 17 cm ka−1. The two delta drifts occupy 342 and 384 km2, respectively; with a depositional relief of approximately 500 m. They have a sigmoidal clinoform reflection pattern with a particular convex upward bending of the foresets. In the Maldives the drift onset marks the transition from a sea-level controlled to a progressively current dominated depositional regime. This major event occurred in the Serravallian about 13 Ma ago, leading to the partial drowning of the carbonate platform and the creation of shallow seaways. The initial bank-enclosed topography resembles an “empty bucket” geometry which is rapidly filled by the drift sediments that aggrade and prograde into the basin. Thereby the depositional environment of the delta drifts changes from deep water (>500) to shallow-water conditions at their topsets, indicated by the overall coarsening upward trend in grain size and the presence of shallow water large benthic foraminifers at their top

    Magnetic properties of early Pliocene sediments from IODP Site U1467 (Maldives platform) reveal changes in the monsoon system

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    We report a study of the magnetic stratigraphy and the anisotropy of isothermal remanent magnetization of Pliocene sediments from International Ocean Discovery Program (IODP) Site U1467 drilled in the Maldives platform (Indian Ocean) during Exp. 359. Magnetic stratigraphy gives a precise record of geomagnetic reversals of the early Pliocene from approximately 5.3 Ma to 3.1 Ma providing a detailed age model in an interval where the biostratigraphic record is scarce. We use the anisotropy of isothermal remanent magnetization (AIRM) to investigate the statistical orientation of fine magnetic particles and provide data on the strength and direction of bottom currents during the early Pliocene. The strength of bottom currents recorded by the AIRM, shows a prominent increase at the top of Chron C3n.1n (about 4.2 Ma), and the current direction (NE - SW) is consistent with that of modern instrumental measurements. Since bottom currents in the Maldives are driven by the monsoon, we speculate that the 4.2 Ma increase of bottom currents could mark the onset of the present-day setting, probably related to the coeval uplift phase of the Himalayan plateau

    Systemic retention of ingested cantharidin by frogs

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    Frogs (Rana pipiens) fed on blister beetles (Meloidae) or cantharidin, retain cantharidin systemically. After cessation of feeding, they void the compound relatively quickly. Systemic cantharidin does not protect frogs against ectoparasitic feeding by leeches (Hirudo medicinalis) or predation by snakes (Nerodia sipedon). As suggested by our data, and from reports in the early literature, ingestion of cantharidin-containing frogs can pose a health threat to humans.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43540/1/49_2005_Article_BF01325229.pd