21,470 research outputs found
Observations of non-compliance behaviour by tourists to a voluntary code of conduct: A pilot study of turtle tourism in the Exmouth region, Western Australia
No full textThis paper reports on the results of a pilot study of observations of non-compliance behaviour by tourists to a voluntary code of conduct based on marine turtles attempting to nest in the Ningaloo Marine Park, Western Australia. The study used focal-animal sampling to record the response of marine turtles to non-compliance behaviour of tourist groups. Results of observations indicated that 77% of tourist groups breached the code of conduct, with 51% of these breaches resulting in a disturbance to marine turtles attempting to nest. The key aspects of the code of conduct that were breached included: shining light on the turtle; being closer than three metres from a turtle; and not staying behind the turtle at all times. The greatest disturbance to marine turtles was from tourists groups shining their torches on the turtles. This work demonstrates the need for further research into disturbance of turtles by tourists and the effectiveness of voluntary codes of conduct
Sea turtles and the environmental management of industrial activities in North West Western Australia
No full textThe nesting demographics of sea turtles using beaches within the Barrow, Lowendal, Montebello (B-L-M) island complex on the North West Shelf of Western Australia were examined in the context of their spatial and temporal distribution and potential for exposure to industrially based artificial light sources. The distribution of overnight turtle tracks throughout the island complex confirmed high density nesting of Chelonia mydas (green turtles) on deep, sandy and high energy beaches and Natator depressus (flatback turtles) on deep, sandy and low energy beaches, while Eretmochelys imbricata (hawksbill turtle) tracks were most visible on shallow, sandy beaches adjacent to near shore coral reef habitat. The three species exhibited a summer nesting peak. Hawksbill turtles commenced nesting in September and continued through to January, green turtles commenced in November and decreased in March. Flatback turtles displayed the most constrained nesting season reported to date in Australia with 86% of the animals visits recorded in December and January only. Nesting population sizes estimated for the three species suggest that on a national scale the B-L-M complex is a moderately large green turtle and a large flatback rookery site. The hawksbill rookery is large on an international scale. While none of the green turtle nesting beaches fell within a 1.5 km radius of industrially based artificial light sources an estimated 42% of nesting flatback turtles and 12% of nesting hawksbill turtles were potentially exposed to these light sources.
Testing of green turtle and hawksbill hatchling response to different wavelengths of light indicate that hatchlings from the B-L-M region respond to low wavelength much like hatchlings tested in North America (Witherington 1992a). Flatback hatchlings displayed a similar preference for low wavelength light however their responses to discrete light wavelengths between 400 nm and 700 nm suggest that this species may not discriminate well between wavelengths that lie between 450 nm and 550 nm. This response may be related to the rapid attenuation of visible light that occurs in the turbid near shore habitats favoured by this species.
Field based arena studies carried out to investigate hatchling behaviour on nesting beaches with light types commonly used in industrial settings found green turtle and flatback hatchlings are significantly attracted to these lights compared to controls. Lights that emit strongly in the low wavelength range (i.e. metal halide and fluorescent) caused hatchling misorientation at lower intensities than the test light that emitted relatively poorly in this range (high pressure sodium vapour). Hawksbill hatchlings tested in situ under the influence of actual oil and gas onshore and offshore facility based lighting were disrupted from the most direct line to the ocean by these light emissions. Emergence fan mapping methods that measure hatchling orientation on nesting beaches were refined and are proposed as an alternative monitoring tool for use on beaches that are logistically difficult to access for large scale experimental orientation studies. The hatchling behaviour was clearly complicated by beach topography and moon phase.
Satellite tracking of post nesting female green and hawksbill turtles from North West Shelf rookeries has identified the Western Australian location of migratory corridors and foraging grounds for these species while Scott Reef turtles migrate from their south Timor Sea rookery to Northern Territory waters. Green turtle nesting on Barrow Island and Sandy Island (Scott Reef) forage at feeding grounds 200 - 1000 km from their nesting beaches. Hawksbill turtles nesting at Varanus Island and Rosemary Islands forage at locations 50 - 450 km from their nesting beaches. While all of the nesting beaches within the B-L-M island complex are protected under the Barrow-Montebello Marine Conservation Reserves, the only foraging ground similarly protected is the Northern Territory foraging ground used by Scott Reef green turtles. None of the foraging grounds used by North West Shelf green or hawksbill turtles is currently protected by conservation reserves
A new stem turtle from the Middle Jurassic of the Isle of Skye, Scotland, and a reassessment of basal turtle relationships
No full textA recent phylogenetic analysis of turtle interrelationships suggests that the Middle Jurassic
was a crucial time period for understanding the evolution of crown-group turtles. However, turtle
material of this age is scarce worldwide. Here, a new stem turtle, Eileanchelys waldmani, from the
Middle Jurassic (Bathonian) of the Isle of Skye, Scotland, is described and compared to other
basal species. With cranial and postcranial remains of several individuals, this is the most
comprehensive Middle Jurassic turtle material known to date. Eileanchelys waldmani documents an
intermediate stage in the evolution of early turtles between the Early Jurassic Kayentachelys aprix
and the crown-group. Whereas most stem turtles are interpreted as terrestrial forms, taphonomic
evidence suggests that E. waldmani may have been aquatic (freshwater), indicating that basal turtles
were ecologically more diverse than previously thought.
This new material provides the basis for a reassessment of other Middle Jurassic turtle
remains from the UK, especially revisions of material from Kirtlington and Stonesfield
(Oxfordshire). The material from Kirtlington is attributed to Paracryptodira and represents the
earliest occurrence of this group. The name 'Protochelys blakii', which had been proposed for the
Stonesfield remains, is considered to be a nomen dubium as this material lacks diagnostic features.
However, this material is remarkable as it consists of fossilised epidermal scales from the carapace.
A new phylogeny is proposed, resulting from a cladistic analysis of a revised and updated
version of a previously published data set. Nineteen new species are included in order to achieve a
more thorough representation of basal turtle taxa. Heckerochelys romani and Condorchelys antiqua are
found to be more basal than Eileanchelys waldmani. Chengyuchelyids (Middle Jurassic of China)
may be stem turtles more basal than Kallokibotion bajazidi. Naomichelys speciosa is closely related to
meiolaniids and Mongolochelys efremovi, while Siamochelys peninsularis is nested within
xinjiangchelyids
TURTLE: A real-time UML profile supported by a formal validation toolkit
No full textAbstract The paper presents a UML 1.5 profile named TURTLE (Timed UML and RT-LOTOS Environment) endowed with a formal semantics given in terms of RT-LOTOS. TURTLE relies on UML's extensibility mechanisms to enhance class and activity diagrams. Class diagrams are extended with specialized classes named Tclasses, which communicate and synchronize through gates. Also, associations between Tclasses are attributed by a composition operator (Parallel, Synchro, Invocation, Sequence, or Preemption) which provides them with a formal semantics. TURTLE extends UML activity diagrams with synchronization actions and temporal operators (deterministic delay, non deterministic delay, time-limited offer, and time-capture). The real-time dimension of TURTLE has been further improved by the addition of two composition operators, Periodic and Suspend, as well as suspendable delay, latency, and time-limited offer operators at the activity diagram level. Core characteristics of TURLE are supported by TTool - the TURTLE toolkit -, which includes a diagram editor, a RT-LOTOS code generator and a result analyzer. The toolkit reuses RTL, a RT-LOTOS validation tool offering debug-oriented simulation and exhaustive analysis. TTool hides RT-LOTOS to the end-user and allows him/her to directly check TURTLE modeling against logical errors and timing inconsistencies. Besides the foundations of the TURTLE profile, the paper also discusses its application in the context of space-based embedded software
Timing requirement description diagrams for real-time system verification
No full textTURTLE is a real-time UML profile introduced a few years ago to address the analysis, design and deployment of time-constrained systems. The profile has a formal semantics. Further, it is supported by an open source toolkit: TTool. The latter enables formal verification of TURTLE models without specific knowledge of mathematical notations or formal languages. This paper proposes to extend TURTLE to cover the requirement capture phase, to check a model against formally expressed temporal requirements, and to achieve temporal requirement traceability. TURTLE is extended with SysML requirement diagrams. Non-formal and formal requirements are both handled. Timing Requirement Description Diagrams are introduced to formally express temporal requirements. TRDDs are based on UML Timing Diagrams. A Hybrid Power Management Unit of a Hybrid Vehicle serves as example
Conflicts about Living Marine Resources in Southeast Asian and Australian Waters: Turtles and Dugong as Cases
No full textThis paper considers conflicts that arise and socioeconomic problems involved in managing fugitive resources, especially transborder or transfrontier ones when economic development occurs. To do this it concentrates on the situation of turtles and of dugong in Southeast Asian and Australian waters. Particular attention is given to turtle farming and to zoning as conservation strategies and the use of marine parks for resource management. Questions are raised about the responsibilities of developed countries such as Australia for conserving species that migrate to less developed countries.Environmental Economics and Policy, International Development, International Relations/Trade, Resource /Energy Economics and Policy,
Minor metabolomic disturbances induced by glyphosate-isopropylammonium exposure at environmentally relevant concentrations in an aquatic turtle, Pelodiscus sinensis
No full textThe ecotoxicological and environmental impacts of glyphosate-based herbicides have received considerable attention due to their extensive use globally. However, the potential for adverse effects in cultured non-fish vertebrate species are commonly ignored. In this study, effects on growth, indicators of functional performance, gut microbial diversity, liver antioxidant responses and metabolite profiles were evaluated in soft-shelled turtle hatchlings (Pelodiscus sinensis) exposed to different concentrations of glyphosate-isopropylammonium (0, 0.02, 0.2, 2 and 20 mg/L). No significant changes in growth or functional performance (food intake, swimming speed), gut microbiota, and liver antioxidant responses (SOD and CAT activities, MDA content) were observed in exposed turtles. However, hepatic metabolite profiles revealed distinct perturbations that primarily involved amino acid metabolism in turtles exposed to environmentally relevant concentrations. Overall, our results suggested that metabolite profiles may be more sensitive than phenotypic or general physiological endpoints and gut microbiota profiling, and indicate a potential mechanism of hepatotoxicity caused by glyphosate-isopropylammonium based on untargeted metabolomics analysis. Furthermore, the toxicity of glyphosate at environmentally relevant concentrations might be relatively minor in aquatic turtle species.No Full Tex
Release and elementary mechanisms of nitric oxide in hair cells
No full textThe enzyme nitric oxide (NO) synthase, that produces the signaling molecule NO, has been identified in several cell types in the inner ear. However, it is unclear whether a measurable quantity of NO is released in the inner ear to confer specific functions. Indeed, the functional significance of NO and the elementary cellular mechanism thereof are most uncertain. Here, we demonstrate that the sensory epithelia of the frog saccule release NO and explore its release mechanisms by using self-referencing NO-selective electrodes. Additionally, we investigated the functional effects of NO on electrical properties of hair cells and determined their underlying cellular mechanism. We show detectable amounts of NO are released by hair cells (>50 nM). Furthermore, a hair-cell efferent modulator acetylcholine produces at least a threefold increase in NO release. NO not only attenuated the baseline membrane oscillations but it also increased the magnitude of current required to generate the characteristic membrane potential oscillations. This resulted in a rightward shift in the frequency-current relationship and altered the excitability of hair cells. Our data suggest that these effects ensue because NO reduces whole cell Ca(2+) current and drastically decreases the open probability of single-channel events of the L-type and non L-type Ca(2+) channels in hair cells, an effect that is mediated through direct nitrosylation of the channel and activation of protein kinase G. Finally, NO increases the magnitude of Ca(2+)-activated K(+) currents via direct NO nitrosylation. We conclude that NO-mediated inhibition serves as a component of efferent nerve modulation of hair cells
Marine letter and it's effects on the nesting population of Turtles, Chelones bay, northern Cyprus.
No full textNot availabl
A global assessment of microplastic abundance and characteristics on marine turtle nesting beaches.
No full textSandy coastal beaches are an important nesting habitat for marine turtles and a known sink for plastic pollution. Existing methodologies for monitoring the spatiotemporal patterns of abundance and composition of plastic are, however, disparate. We engaged a global network of marine turtle scientists to implement a large-scale sampling effort to assess microplastic abundance in beach sediments on marine turtle nesting beaches. Sand samples were collected from 209 sites spanning six oceans, microplastics (1-5 mm) were extracted through stacked sieves, visually identified, and a sub-sample verified via Fourier-transform infrared spectroscopy. Microplastics were detected in 45 % (n = 94) of beaches and within five ocean basins. Microplastic presence and abundance was found to vary markedly within and among ocean basins, with the highest proportion of contaminated beaches found in the Mediterranean (80 %). We present all data in an accessible, open access format to facilitate the extension of monitoring efforts and empower novel analytical approaches.The authors thank the UK Global Challenges Resource Fund (GCRF) (Grant number: NE/V005448/1) and the Natural Environment Research Council (Grant number: NE/V009354/1) which has enabled this international collaboration. We also thank and are grateful to everyone who assisted in the collection and shipment of the samples. We thank Dr. Jennifer Lynch from the National Institute of Standards & Technology (NIST) for collecting and processing of the Hawaiian beach samples. José C. Báez was financially supported by the project ‘Plan Complementario de I + D + i en el área de Biodiversidad (PCBIO),’ funded by the European Union within the framework of the Recovery, Transformation and Resilience Plan – NextGenerationEU, by the Spanish Ministry of Science, Innovation and Universities, and by the Regional Government of Andalusia. For the purpose of open access, the author has applied a ‘Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission. The manuscript was improved as a result of the input of the editor and two anonymous reviewers
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