Суперечності розвитку сучасного регіоналізму: чинники, детермінанти та механізми

A mass-balanced trophic model was developed for the coral reef lagoon of Uvea atoll (New Caledonia) using the Ecopath software. The model accounts for both pelagic and soft-bottom communities to describe the whole trophic structure and biomass flows in the shallowest part of the atoll lagoon. Phytoplankton production approximately equals the benthic primary production. Benthic biomass accounts for more than 80% of the total living biomass in the shallow lagoon. The benthic domain requires input of food from the pelagic system (mainly zooplankton) and from adjacent areas to sustain the biomass of predatory fishes. Predation pressure was found to be a major force structuring the food web, but it is also suggested that water circulation within the lagoon influences the amount of primary resources, such as plankton, benthic microphytes and detritus

Trophic signature of coral reef fish assemblages : towards a potential indicator of ecosystem disturbance

Face to the increasing anthropogenic disturbances that affect coral reef ecosystems, it becomes urgent to define appropriate ecological indicators for monitoring purposes. One useful approach is to search for a simplified description of the structure of biological communities that are highly diverse and complex on coral reefs. To this end, we propose to represent the trophic structure of coral reef fish assemblages by using fractional trophic levels assigned to each fish species. Fish abundance trophic spectra (i.e., the distributions of fish abundance per trophic level) were established for the fringing reefs of two bays located in the city of Noumea (New Caledonia). The comparison of these trophic spectra revealed a similar trophic structure in the two bays, in spite of contrasted levels of fish abundance due to habitat damages. The embayment degree was characterized by changes in the fish trophic structure, reflecting a decreasing influence of urban and industrial wastes discharged in the bottom of the bays. This case of study shows the interest of using fractional trophic levels for the description of highly diverse biological communities. The trophic level-based approach offers new prospects in the search for ecological indicators, by characterizing the structure of biological communities by trophic signatures which testify to the disturbance level affecting their environment

Late-acting self-incompatible system, preferential allogamy and delayed selfing in the heteromorphic invasive populations of <i>Ludwigia grandiflora subsp. hexapetala</i>

International audienc

A review of selected indicators of particle, nutrient and metal inputs in coral reef lagoon systems

This review presents environmental and biological indicators of the impact of three major categories of inputs in coral reef lagoons i.e. particles, nutrients and metals. Information was synthesized to extract well established indicators together with some interesting new concepts currently under development, and to provide the reader with an assessment of their respective advantages and drawbacks. The paper has been organized according to the capacity of three categories of indicators to respond either in a specific or a non specific way to a given source of input. The first section focuses on abiotic indicators which main interest is to respond instantaneously and in a truly specific way to a given source of input. The second and third sections present informations on bioindicators either at the sub-individual level or at the individual to community level, indicator specificity generally decreasing as a direct function of biological or ecological complexity. This review showed that even though significant work has already been done on coral reef ecosystems, much more scientific studies are still needed to answer the growing local demands for simple and truly validated tools to be used in environmental surveys. It is further stressed that, due to the biological and environmental diversity of coral reef lagoons, a preliminary step of on-site validation must be considered as an absolute prerequisite when indicators are planned to be used in the frame of a local environmental monitoring programme

CO2 supply from the North Sea and the Baltic Sea to the North Atlantic Ocean - evidence for the continental shelf pump

Coastal and marginal seas are thought to act as a continental shelf pump transporting CO2 from the atmosphere to the open oceans. The CO2 uptake in coastal seas is triggered by high biological activity increasing the CO2 concentrations of their waters which finally are transported to the open ocean. The North Sea and Baltic Sea located in north-west Europe are connected via the Skagerrak where the Baltic Sea water first enters the North Sea. The North Sea the provides then link to the North Atlantic Ocean. Carbon budgets for the Baltic Sea and the North Sea will be presented in order to provide evidence that in both seas the transfer of CO2, i.e. the continental shelf pump, acts in two different, but characteristic pattern. The Baltic Sea as a brackish water system collects river water and one might even call it as an estuarine system in a broader sense. Two major drainage areas provide the fresh water supply to the Baltic Sea: The Scandinavian shield supply CO2 –poor waters and the north-east European continent CO2 –rich waters. During the transport of Baltic Sea water to the North Sea the CO2 concentrations increase continuously. Riverine inputs in part control primary production in the Baltic Sea, however the major control mechanism is the winter nutrient concentrations. These are established by an interaction of production, remineralisation, export and riverine and atmospheric inputs on decadal time scale because of the residence time of the Baltic Sea water of approximately 25years. The Baltic Sea thus acts as a continental shelf pump for atmospheric CO2 which injects CO2-rich water to the Atlantic Ocean (injection pump). In contrast the North Sea water is renewed once to twice per year most notably by water from the North Atlantic Ocean. The major control mechanism of the biological activity in the North Sea are thus the continuous (and - in comparison to the Baltic Sea - high) nutrient inputs for the North Atlantic Ocean. For the CO2 export from the North Sea to the Atlantic Ocean this means that the water is enriched by CO2 during its 6-12 month travel through the North Sea. Having in mind that almost no burial occurs in the North Sea, the North Sea acts as a continental shelf pump for atmospheric CO2 by increasing the CO2 concentrations in the Atlantic waters while they are bypassing through the North Sea (bypass-pump)

The antimalarial MMV688533 provides potential for single-dose cures with a high barrier to

The emergence and spread of Plasmodium falciparum resistance to first-line antimalarials creates an imperative to identify and develop potent preclinical candidates with distinct modes of action. Here, we report the identification of MMV688533, an acylguanidine that was developed following a whole-cell screen with compounds known to hit high-value targets in human cells. MMV688533 displays fast parasite clearance in vitro and is not cross-resistant with known antimalarials. In a P. falciparum NSG mouse model, MMV688533 displays a long-lasting pharmacokinetic profile and excellent safety. Selection studies reveal a low propensity for resistance, with modest loss of potency mediated by point mutations in PfACG1 and PfEHD. These proteins are implicated in intracellular trafficking, lipid utilization, and endocytosis, suggesting interference with these pathways as a potential mode of action. This preclinical candidate may offer the potential for a single low-dose cure for malaria

The antimalarial MMV688533 provides potential for single-dose cures with a high barrier to

The emergence and spread of Plasmodium falciparum resistance to first-line antimalarials creates an imperative to identify and develop potent preclinical candidates with distinct modes of action. Here, we report the identification of MMV688533, an acylguanidine that was developed following a whole-cell screen with compounds known to hit high-value targets in human cells. MMV688533 displays fast parasite clearance in vitro and is not cross-resistant with known antimalarials. In a P. falciparum NSG mouse model, MMV688533 displays a long-lasting pharmacokinetic profile and excellent safety. Selection studies reveal a low propensity for resistance, with modest loss of potency mediated by point mutations in PfACG1 and PfEHD. These proteins are implicated in intracellular trafficking, lipid utilization, and endocytosis, suggesting interference with these pathways as a potential mode of action. This preclinical candidate may offer the potential for a single low-dose cure for malaria

Experimentation de tubercules de petits calibres en plein champ

National audienc

Using an association of cultivars to simulate early generation selection in potato

National audienc

Invasive water primroses in France become a weed problem in meadows

Invasive water primroses in France become a weed problem in meadows. International Conference on Ecological Science