Search results for "Nutrient"

Organic Fertilization in Traditional Mediterranean Grapevine Orchards Mediates Changes in Soil Microbial Community Structure and Enhances Soil Fertil…

2016

Soil microbial populations and their functions related to nutrient cycling contribute substantially to the regulation of soil fertility and the sustainability of agroecosystems. A field experiment was performed to assess the medium-term effect of a mineral fertilizer and two organic fertilization systems with different nitrogen sources on the soil microbial community biomass, structure, and composition (phospholipid fatty acids, pattern, and abundance), microbial activity (basal respiration, dehydrogenase, protease, urease, β-glucosidase, and total amount of phosphomonoesterase activities), and physical (aggregate stability) and chemical (total organic C, total N, available P and water-solu…

Decomposer communities in contaminated soil: Is altered community regulation a proper tool in ecological risk assessment of toxicants?

1997

Abstract Effects of patchy soil contamination on decomposer organisms, their community regulation and nutrient mineralization were studied in a microcosm experiment. Coniferous forest soil was patchily contaminated with three concentrations of sodiumpentachlorophenate PCP (0, 50 and 500 mg PCP kg−1 of dry soil). Abundance of microbes, enchytraeids, nematodes, small oribatids and predatory mites were reduced by the PCP. Direct toxicity of PCP and lowered microbial biomass seemed to affect animal community composition in the most contaminated patches. Some large oribatids which seemed to be tolerant to PCP increased their numbers in the most contaminated patches. Although predatory mites suff…

Soil animals and ecosystem processes: How much does nutrient cycling explain?

2008

Summary Trophic-dynamic hypotheses have been extensively tested by manipulating the presence of soil animals in experimental laboratory microcosms. Soil animals typically have pronounced effects on microbial populations, nutrient cycling and plant growth. However, because often only the total effect has been reported, the relative importance of feeding interactions versus non-trophic effects remains obscure. Using simple calculations based on mass conservation I argue that the observed faunal effect on microbes and system functioning is often larger than can be explained by trophic dynamics and nutrient cycling. Non-trophic effects may help to explain why microcosm experiments have failed t…

Macrofungi as ecosystem resources: Conservation versus exploitation

2013

Fungi are organisms of significant importance not only for the crucial roles they undertake in nature but also for many human activities that are strictly dependent on them. Indeed, fungi possess fundamental positions in ecosystems functioning including nutrient cycles and wood decomposition. As concerns human-related activities, edible and non-edible mushrooms are also involved and/or exploited in forestry, pharmaceutical industry and food production; hence, nowadays they represent a major economic source worldwide. In order to maintain and improve their strategic importance, several conservation strategies, such as habitat preservation, are needed. This article reports several contributio…

Soil-Water Interactions Unveiled by Fast Field Cycling NMR Relaxometry

2017

isotracer: An R package for the analysis of tracer addition experiments

2021

AbstractTracer addition experiments, particularly using isotopic tracers, are becoming increasingly important in a variety of studies aiming at characterizing the flows of molecules or nutrients at different levels of biological organization, from the cellular and tissue levels, to the organismal and ecosystem levels.We present an approach based on Hidden Markov Models (HMM) to estimate nutrient flow parameters across a network, and its implementation in the R package isotracer.The isotracer package is capable of handling a variety of tracer study designs, including continuous tracer drips, pulse experiments, and pulse-chase experiments. It can also take into account tracer decay when radio…

Leaf life span and the mobility of "non-mobile" mineral nutrients - The case of boron in conifers

2002

Nutrient conservation is considered important for the adaptation of plants to infertile environments. The importance of leaf life spans in controlling mean residence time of nutrients in plants has usually been analyzed in relation to nutrients that can be retranslocated within the plant. Longer leaf life spans increase the mean residence time of all mineral nutrients, but for non-mobile nutrients long leaf life spans concurrently cause concentrations in tissues to increase with leaf age, and consequently may reduce non-mobile nutrient use efficiency. Here we analyze how the role of leaf life span is related to the mobility of nutrients within the plant. We use optimality concepts to derive…

Impact of HPP on the bioaccessibility/bioavailability of nutrients and bioactive compounds as a key factor in the development of food processing

2020

Abstract High-pressure processing (HPP) technology has great potential for manipulating the structure and functionality of the components present in food matrices, therefore considerably affecting their bioaccessibility and bioavailability. Without knowledge of the principles and mechanisms responsible for these modifications, this technology’s potential is still not fully understood and justified from a nutritional point of view. This chapter presents the results of some of the main studies carried out to date to assess the impact of HPP on the bioaccessibility and bioavailability of nutrients and bioactive compounds of different food matrices.

Seasonal succession of phytoplankton in an ice-free pond warmed by a thermal power plant

1982

In a pond receiving warmed cooling waters from a thermal power plant, the physical and chemical properties of the water, phytoplankton, periphyton and zooplankton were monitored on a weekly sampling schedule. In winter the phytoplankton growth was limited by poor light conditions. In mid-February a rapid phytoplankton growth started, simultaneously with increasing light energy, high nutrient concentrations and small herbivorous zooplankton populations. The increase of phytoplankton biomass was stopped by lack of free nutrients and silica at the end of March. From May until August the phytoplankton standing crop was mainly regulated by herbivorous zooplankton. The autumnal maximum of phytopl…

Subfossil chironomid assemblages in deep, stratified European lakes: relationships with temperature, trophic state and oxygen

2010

Summary 1. The distributions of subfossil remains of chironomid larvae in 28 large, deep and stratified lakes in Europe were examined in surface sediments along a latitudinal transect ranging from northern Sweden to southern Italy. 2. Canonical correspondence analysis (CCA) showed that summer surface water and July air temperature, as well as total phosphorus (TP) concentrations, hypolimnetic oxygen availability and conductivity were statistically significant (P < 0.05) explanatory variables explaining between 11 and 14% of the variance in the chironomid data. 3. Owing to the spatial scale covered by our study, many environmental variables were covarying. Temperature, TP concentration and o…