Search results for "ERT"
showing 10 items of 21537 documents
Differences in time and space use between two sympatric Acrocephalus warblers with similar diets
2016
Capsule: We found high diet overlap and different uses of space and time between Moustached Warblers Acrocephalus melanopogon and Reed Warblers Acrocephalus scirpaceus breeding in sympatry at a marshland in Spain. Aims: To study the degree of diet overlap between both species, their space use on a local scale and their breeding phenologies. Methods: We studied the breeding phenologies of the two species by standardized ringing activity. Spatial distribution was investigated by point counts. We determined diet composition from emetic samples and we collected invertebrates by standardized sweep-netting to estimate food availability. Results: Diet and prey selection were similar among species.…
Improving the analysis of biogeochemical patterns associated with internal waves in the strait of Gibraltar using remote sensing images
2018
High Amplitude Internal Waves (HAIWs) are physical processes observed in the Strait of Gibraltar (the narrow channel between the Atlantic Ocean and the Mediterranean Sea). These internal waves are generated over the Camarinal Sill (western side of the strait) during the tidal outflow (toward the Atlantic Ocean) when critical hydraulic conditions are established. HAIWs remain over the sill for up to 4 h until the outflow slackens, being then released (mostly) towards the Mediterranean Sea. These have been previously observed using Synthetic Aperture Radar (SAR), which captures variations in surface water roughness. However, in this work we use high resolution optical remote sensing, with the…
New insights into Late Devonian vertebrates and associated fauna from the Cuche Formation (Floresta Massif, Colombia)
2019
New vertebrate remains are reported from the Late Devonian (?Frasnian) Cuche Formation of northeastern Colombia, including a new taxon of antiarch placoderm (Colombialepis villarroeli, gen. et sp. nov., previously reported as Asterolepis) and a new taxon of arthrodiran placoderm (Colombiaspis rinconensis, gen. et sp. nov.). We also report evidence of a stegotrachelid actinopterygian, a diplacanthid acanthodian (cf. Florestacanthus morenoi), a second antiarch placoderm (Bothriolepis sp.), a putative megalichthyid, and a putative tristichopterid. The absence of typical Euramerican markers, e.g., Asterolepis and Strepsodus, in this assemblage suggests that faunal interchange between Euramerica…
Multilocus phylogenetics of smooth clam shrimps (Branchiopoda, Laevicaudata)
2021
International audience; Laevicaudatan branchiopods, also called ‘smooth clam shrimps’ or ’pea shrimps’, are rare crustaceans found exclusively in temporary, small freshwater bodies, which stay dry most of the year. Only 42 laevicaudatan species have been described so far, 90% of which belong to the genus Lynceus. The first multilocus phylogeny of the group is provided here, based on 15 Lynceus species from North and South America, Europe, Africa, Asia, Australia and New Caledonia and using nine molecular markers (two mitochondrial and seven nuclear genes, including newly designed primers). Genetic data suggest populations of Lynceus brachyurus from Europe and North America to represent a co…
The morphology, ontogeny, and inferred behaviour of the deep-sea echinoid Calymne relicta (Holasteroida).
2009
The deep-sea holasteroid Calymne relicta was first described from a few fragments discovered by the HMS ‘Challenger’ in the Bermuda abyssal plain more than a century ago. In addition to re-examining the type material, we describe herein new specimens from unpublished material collected between 3720 and 4860 m during three scientific expeditions that took place on both sides of the North Atlantic between 1966 and 1991. The new material includes juvenile and adult specimens in sufficiently good preservational state to allow a full redescription, including all types of appendages, some of which have never been described. These new observations confirm the atypical characteristics of C. relicta…
Possible amphi-Atlantic dispersal of Scyllarus lobsters (Crustacea: Scyllaridae): molecular and larval evidence
2017
14 pages, 6 figures, 1 table
Environmental controls on benthic food web functions and carbon resource use in subarctic lakes
2019
Climate warming and consequent greening of subarctic landscapes increase the availability of organic carbon to the detrital food webs in aquatic ecosystems. This may cause important shifts in ecosystem functioning through the functional feeding patterns of benthic organisms that rely differently on climatically altered carbon resources. Twenty-five subarctic lakes in Finnish Lapland across a tree line ecotone were analysed for limnological and optical variables, carbon (delta C-13) and nitrogen (delta N-15) stable isotope (SI) composition of surface sediment organic matter (OM) and fossil Chironomidae (Diptera) remains to examine environmental controls behind chironomid functional feeding g…
Parasitism and queen presence interactively shape worker behaviour and fertility in an ant host
2019
Parasites with complex life cycles regularly alter host traits in their own interest. In social hosts, phenotypic alterations induced by parasites can also affect uninfected group members. The tapeworm Anomotaenia brevis uses Temnothorax nylanderi ants as intermediate hosts, reducing host activity and behavioural repertoire, but increasing life span. Uninfected nestmates are less active and less aggressive and suffer from higher mortality. Next to parasites, the social environment, such as the queen, influences worker behaviour, reproduction and longevity. Here, we studied how tapeworm parasitism interacts with the queen to affect the behaviour and reproductive potential of ant workers. We …
Low temperature trumps high food availability to determine the distribution of intertidal mussels Perna perna in South Africa
2016
Explanations of species distributions often assume that the absence of a species is due to its inability to tolerate an environmental variable. Recent modelling techniques based on the dynamic energy budget (DEB) theory offer an effective way of identifying how interacting environmental parameters influence distributions through non-lethal effects on growth and development. The mussel Perna perna is an abundant ecosystem engineer around the coasts of Africa, South America and the Arabian peninsula, with an unexplained 1500 km lacuna in its distribution on the west coast of South Africa. We used a DEB approach to explain its distribution in southern Africa and test the hypothesis that this l…
Conifer Needles as Thermoplastic Composite Fillers: Structure and Properties
2016
This study describes the properties of thermoplastic polymer composites based on polyethylene (of low and high density) and ethylene-propylene copolymers using various types of conifer needles (pine, spruce, fir, and cedar) as fillers. For the needles, thermogravimetric analysis (TGA) and TGA/Fourier transform infrared spectroscopy (TGA/FTIR) were performed to investigate their structures and thermal resistance, as required for the composite processing methods. Moreover, structural differences were studied for the analyzed fillers and composite materials (FTIR). The results were compared with the values obtained for composites with conifer wood flour. Composites with conifer needles (pine) …