Search results for "Clad"
showing 10 items of 495 documents
Contrasting Patterns in Chironomid (Chironomidae) Communities of Shallow and Deep Boreal Lakes Since the 1960s
2016
Chironomids have been widely used as indicators of trophic conditions of lakes due to their species-specific environmental requirements. In order to understand resilience and deterioration of aquatic ecosystems due to increases and/or decreases in external loading, recent chironomid community and water chemistry data of seven southern Finnish lakes with varying anthropogenic pressures and bathymetric properties were compared with similar data from the 1960s. Altogether 64 taxa were found. At present, the most numerous taxa are Procladius spp., Chironomus f.l. plumosus, Chironomus f.l. salinarius, Stictochironomus f.l. psammophilus, Benthalia spp., Tanytarsus spp. and Cladotanytarsus. In fou…
Effects of the filter-feeding benthic bivalve corbicula fluminea on plankton community and water quality in aquatic ecosystems: A mesocosm study
2021
The influence of filter-feeding bivalves on plankton communities, nutrients, and water quality in a given aquatic ecosystem is so profound that they can be considered ecosystem engineers. In a 70-day mesocosm experiment, we tested the hypothesis that Corbicula fluminea would change plankton community structure by reducing small zooplankton and large phytoplankton and improve water quality by reducing nutrients. We monitored levels of nitrogen and phosphorus, organic suspended solids (OSS), and light at the sediment surface. Within the plankton, phytoplankton biomass (as Chl a, >
Survival of an Endangered OrchidLiparis loeseliiin Habitats with Different Water Level Fluctuations
2018
Liparis loeselii (L.) Rich. is an endangered orchid species which occurs in wetland habitats. For successful conservation of this orchid it is necessary to recognize its adaptive traits and special habitat requirements. Therefore, we examined morphological and anatomical traits in relation to the water level, cover of vascular plants and seed viability of L. loeselii in habitats with different water level fluctuations. Field studies of L. loeselii were carried out in nine localities and four habitat types: alkaline fen, calcareous fen with Cladium mariscus, transition mire and quaking bog. The fluctuations of seasonal water level were defined in the range from dry substrate to short time fl…
Lake restoration influences nutritional quality of algae and consequently Daphnia biomass
2020
AbstractFood quality is one of the key factors influencing zooplankton population dynamics. Eutrophication drives phytoplankton communities toward the dominance of cyanobacteria, which means a decrease in the availability of sterols and long-chain polyunsaturated fatty acids (EPA and DHA). The effects of different restoration measures on the nutritional quality of the phytoplankton community and subsequent impacts on zooplankton biomass have rarely been considered. We analyzed the nutritional quality of phytoplankton in the eutrophic Lake Vesijärvi in southern Finland over a 37-year period, and studied the impacts of two restoration measures, biomanipulation and hypolimnetic aeration, on th…
Fossorial but widespread: the phylogeography of the common spadefoot toad (Pelobates fuscus), and the role of the Po Valley as a major source of gene…
2007
International audience; Pelobates fuscus is a fossorial amphibian that inhabits much of the European plain areas. To unveil traces of expansion and contraction events of the species' range, we sequenced 702 bp of the mitochondrial cytochrome b gene. To infer the population history we applied phylogeographical methods, such as nested clade phylogeographical analysis (NCPA), and used summary statistics to analyse population structure under a neutral model of evolution. Populations were assigned to different drainage systems and we tested hypotheses of explicit refugial models using information from analysis of molecular variance, nucleotide diversity, effective population size estimation, NCP…
Adaptive radiation in the fossil record: a case study among Jurassic ammonoids
2013
15 pages; International audience; Evolutionary radiations have been extensively studied especially in the fossil record and in the context of postcrisis recoveries. The concept of adaptive radiation that emerges from this very broad topic explicitly involves the effect of adaptation driven by ecological opportunity and is considered to be of the foremost importance. It is essential to be able to detect adaptive radiation because it points up factors that predispose a clade to radiate. Adaptive radiation has received much attention in recent decades based mostly on studies dealing with recent clades, but data from the fossil record are still scarce. This study begins to fill this gap with th…
Notulae to the Italian alien vascular flora: 2
2016
In this contribution, new data concerning the Italian distribution of alien vascular flora are presented. It includes new records, exclusions and confirmations for Italy or for Italian administrative regions for taxa in the genera Ageratum, Aster, Buddleja, Cedrus, Centranthus, Cephalotaxus, Clerodendrum, Cotoneaster, Cyperus, Honorius, Lantana, Ligustrum, Morus, Muscari, Oenothera, Opuntia, Platycladus, Plumbago, Pseudotsuga, Sedum, Sporobolus, Stachys, Ulmus and Yucca. A nomen novum, Stachys talbotii, is proposed as a replacement name for Sideritis purpurea.
The evolution, diversity and host associations of rhabdoviruses
2015
Metagenomic studies are leading to the discovery of a hidden diversity of RNA viruses, but new approaches are needed predict the host species these poorly characterised viruses pose a risk to. The rhabdoviruses are a diverse family of RNA viruses that includes important pathogens of humans, animals and plants. We have discovered the sequences of 32 new rhabdoviruses through a combination of our own RNA sequencing of insects and searching public sequence databases. Combining these with previously known sequences we reconstructed the phylogeny of 195 rhabdovirus sequences producing the most in depth analysis of the family to date. In most cases we know nothing about the biology of the viruses…
Optimisation of refractory coatings realised with cored wire addition using a high-power diode laser
2005
Laser; Cladding; Refractory alloys; Factorial experiments; International audience; The objective or our research was to obtain refractory alloys using the high-power diode laser (HPDL) coating technique. After optimisation using factorial experiments, two different cladding regimes were clearly distinguished. It was also shown that a very narrow transition zone exists between the two regimes, and, inside this zone, clad layers having a satisfactory compromise between the response functions (surface aspect and cavity presence) were obtained. The main objective of our study, namely, the control of the operating parameters (geometrical and kinematical) to realise adequate coatings, without cav…
The protein and microRNA cargo of extracellular vesicles from parasitic helminths – current status and research priorities
2020
Helminth parasites have a remarkable ability to persist within their mammalian hosts, which is largely due to their secretion of molecules with immunomodulatory properties. Although the soluble components of helminth secretions have been extensively studied, the discovery that helminths release extracellular vesicles (EVs) has added further complexity to the host-parasite interaction. Whilst several studies have begun to characterise the molecules carried by helminth EVs, work aimed at investigating their biological functions has been hindered by a lack of helminth-specific EV markers. To begin to address this, we summarised helminth EV literature to date. With a focus on the protein and mi…