Agrocampus Ouest

About: Agrocampus Ouest is a education organization based out in Rennes, France. It is known for research contribution in the topics: Population & Soil water. The organization has 2160 authors who have published 3219 publications receiving 75606 citations. The organization is also known as: Institut supérieur des sciences agronomiques, agroalimentaires, horticoles et du paysage & Higher Institute for agricultural sciences, food industry, horticulture and landscape management.

Projecting changes in the distribution and productivity of living marine resources: A critical review of the suite of modelling approaches used in the large European project VECTORS

Abstract: We review and compare four broad categories of spatially-explicit modelling approaches currently used to understand and project changes in the distribution and productivity of living marine resources including: 1) statistical species distribution models, 2) physiology-based, biophysical models of single life stages or the whole life cycle of species, 3) food web models, and 4) end-to-end models Single pressures are rare and, in the future, models must be able to examine multiple factors affecting living marine resources such as interactions between: i) climate-driven changes in temperature regimes and acidification, ii) reductions in water quality due to eutrophication, iii) the introduction of alien invasive species, and/or iv) (over-)exploitation by fisheries Statistical (correlative) approaches can be used to detect historical patterns which may not be relevant in the future Advancing predictive capacity of changes in distribution and productivity of living marine resources requires explicit modelling of biological and physical mechanisms New formulations are needed which (depending on the question) will need to strive for more realism in ecophysiology and behaviour of individuals, life history strategies of species, as well as trophodynamic interactions occurring at different spatial scales Coupling existing models (eg physical, biological, economic) is one avenue that has proven successful However, fundamental advancements are needed to address key issues such as the adaptive capacity of species/groups and ecosystems The continued development of end-to-end models (eg, physics to fish to human sectors) will be critical if we hope to assess how multiple pressures may interact to cause changes in living marine resources including the ecological and economic costs and trade-offs of different spatial management strategies Given the strengths and weaknesses of the various types of models reviewed here, confidence in projections of changes in the distribution and productivity of living marine resources will be increased by assessing model structural uncertainty through biological ensemble modelling

Transit time distributions, legacy contamination and variability in biogeochemical 1/fα scaling: how are hydrological response dynamics linked to water quality at the catchment scale?

Abstract: In spite of recent progress, hydrological processes underlying observed water quality response patterns, such as the emergence of near-chemostatic conditions and fractal 1/f(alpha) scaling of stream chemistry, are not completely understood. Analysing hydrological and Cl- tracer data for two intensely managed, hydrologically contrasting yet biogeochemically similar catchments we tested if (1) a semi-distributed, conceptual model can simultaneously reproduce catchment scale hydrological and biogeochemical responses, (2) legacy stores, allowing for long-term storage of nutrient inputs can be identified and (3) a model can reproduce 1/f(alpha) scaling. Further we analysed (4) transit (TTD) and residence time distributions (RTD) and the associated response dynamics of legacy stores, to explore (5) what controls fluctuations in the scaling exponent a, thereby establishing a process based link between 1/f(alpha) scaling, legacy stores and age distributions. We found that the model could reproduce the variable hydrological and the stable Cl- responses. This was possible through Cl- accumulation in hydrologically passive legacy stores that are mainly associated with the groundwater store, where Cl- age is well above 2000 days, one magnitude above the Cl- age in other components, such as the root zone (similar to 200 d). The results indicate that legacy stores can cause stable nutrient concentrations in streams for several decades after the end of nutrient input. It was further found that the model could reproduce fractal scaling of stream Cl- in both catchments, with higher values of alpha for the catchment with the smaller legacy store and faster response (alpha = -0.88 vs -1.29). Further analysing the spectral properties of model components, it was found that the parts of the system with less storage are characterized by higher values of alpha. This suggests a plausible processes-based link between the fluctuations of alpha, legacy stores and RTDs: the smaller the legacy store and the higher the flow contribution from faster responding system components, the higher alpha, suggesting that fractal scaling may potentially not be a universally emerging property of the biogeochemical response in streams.

Light Signaling in Bud Outgrowth and Branching in Plants.

Abstract: Branching determines the final shape of plants, which influences adaptation, survival and the visual quality of many species. It is an intricate process that includes bud outgrowth and shoot extension, and these in turn respond to environmental cues and light conditions. Light is a powerful environmental factor that impacts multiple processes throughout plant life. The molecular basis of the perception and transduction of the light signal within buds is poorly understood and undoubtedly requires to be further unravelled. This review is based on current knowledge on bud outgrowth-related mechanisms and light-mediated regulation of many physiological processes. It provides an extensive, though not exhaustive, overview of the findings related to this field. In parallel, it points to issues to be addressed in the near future.