Search results for "feature"

The role ofSphagnummosses in the methane cycling of a boreal mire

2010

Peatlands are a major natural source of atmospheric methane (CH4). Emissions from Sphagnum-dominated mires are lower than those measured from other mire types. This observation may partly be due to methanotrophic (i.e., methane-consuming) bacteria associated with Sphagnum. Twenty-three of the 41 Sphagnum species in Finland can be found in the peatland at Lakkasuo. To better understand the Sphagnum-methanotroph system, we tested the following hypotheses: (1) all these Sphagnum species support methanotrophic bacteria; (2) water level is the key environmental determinant for differences in methanotrophy across habitats; (3) under dry conditions, Sphagnum species will not host methanotrophic ba…

The impact of long-term water level draw-down on microbial biomass : A comparative study from two peatland sites with different nutrient status

2017

We examined the effects of long-term (51 years) drainage on peat microbial communities using phospholipid fatty acid (PLFA) analysis. We analysed the peat profiles of natural and adjacent drained fen and bog sites. Viable microbes (i.e. microbial PLFA) were present in relatively large amounts even in the deepest peat layers of both peatland sites, a finding that warrants further investigation. Microbial biomass was generally higher in the fen than in the bog. Microbial community structure (indexed from PLFA) differed between the fen and bog sites and among depths. Although we did not exclude other factors, the effect of drainage on the total microbial biomass and community structure was not…

Stable carbon isotopic composition of peat columns, subsoil and vegetation on natural and forestry-drained boreal peatlands.

2018

We studied natural and forestry-drained peatlands to examine the effect of over 34 years lowered water table on the δ13C values of vegetation, bulk peat and subsoil. In the seven studied sites, δ13C in the basal peat layer was 1.1 and 1.2 ‰ lower than that of the middle-layer and surface layer, respectively. Furthermore, there was a positive correlation between the δ13C values of the basal and surface peat layers, possibly due to carbon (C) recycling within the peat column. In the same mire complex, natural fen peat δ13C values were lower than those of the nearby bog, possibly due to the dominance of vascular plants on fen and the generally larger share of recycled C in the fens than in the…

A synthesis of methane emissions from 71 northern, temperate, and subtropical wetlands

2014

Wetlands are the largest natural source of atmospheric methane. Here, we assess controls on methane flux using a database of approximately 19 000 instantaneous measurements from 71 wetland sites located across subtropical, temperate, and northern high latitude regions. Our analyses confirm general controls on wetland methane emissions from soil temperature, water table, and vegetation, but also show that these relationships are modified depending on wetland type (bog, fen, or swamp), region (subarctic to temperate), and disturbance. Fen methane flux was more sensitive to vegetation and less sensitive to temperature than bog or swamp fluxes. The optimal water table for methane flux was consi…

Water quality in cutaway peatland lakes in Seda mire, Latvia

2011

Remediation of industrially-milled peatland is an important task in the sustainable management of natural resources. Several approaches for wetland restoration, depending on local climatic and hydrological conditions, topography, physico-chemical properties of peat, as well as peat mining techniques, have been developed worldwide. However, most of the restoration activities include regulation of hydrological regime and surface topography in order to reintroduce typical bog vegetation, especially, Sphagnum cover, and to restore the peatland’s ecosystem close to its original conditions (Gorham and Rochefort, 2003; Farrell and Doyle, 2003; Lamers et al., 2002). In many countries, a significant…

Exploring the mechanisms by which reindeer droppings induce fen peat methane production

2021

Abstract Peatlands, especially fens, are known to emit methane. Reindeer (Rangifer tarandus) use mires mainly as spring and summer pastures. In this work we observed that adding reindeer droppings to fen peat increased the potential methane production by 40%. This became apparent when droppings originating from reindeer kept in pen or pasture in winter were added to methanogenic fen peat samples. The droppings introduced Methanobacteriaceae (Methanobrevibacter; > 90% of the mcrA MiSeq reads) to the peat, which was originally populated by Methanosarcinaceae, Methanosaetaceae, Methanoregulaceae, Methanobacteriaceae, Methanomassiliicoccaceae, Methanocellaceae and Methanomicrobiaceae. The origi…

Age and mineralogy of supergene uranium minerals — Tools to unravel geomorphological and palaeohydrological processes in granitic terrains (Bohemian …

2010

Abstract Uranyl phosphates (torbernite, autunite, uranocircite, saleeite) and hydrated uranyl silicates (normal and beta-uranophane) found in various erosion levels and structures in the Late Variscan granites at the western edge of the Bohemian Massif, Germany, were the target of mineralogical investigations and age dating, using conventional and more advanced techniques such as Laser-Ablation-Inductive-Coupled-Plasma Mass Spectrometry (LA-ICP-MS). Supergene U minerals have an edge over other rock-forming minerals for such studies, because of their inherent ‘clock’ and their swift response to chemical and physical environmental changes on different scales. Uraniferous phoscretes and silcre…

Hyperspectral system for early detection of rottenness caused by Penicillium digitatum in mandarins

2008

Abstract Nowadays, the detection of fruit infected with Penicillium sp. fungi on packing lines is carried out manually under ultraviolet illumination. Ultraviolet sources induce visible fluorescence of essential oils, present in the skin of citrus and which are released by the action of fungi, thus increasing the contrast between sound and rotten skin. This work analyses a set of techniques aimed at detecting rotten citrus without the use of UV lighting. The techniques used include hyperspectral image acquisition, pre-processing and calibration, feature selection and segmentation using linear and non-linear methods for classification of fruits. Different methods such as correlation analysis…

Cover Feature: Single Peptide Backbone Surrogate Mutations to Regulate Angiotensin GPCR Subtype Selectivity (Chem. Eur. J. 47/2020)

2020

Melt evolution beneath a rifted craton edge: 40Ar/39Ar geochronology and Sr-Nd-Hf-Pb isotope systematics of primitive alkaline basalts and lamprophyr…

2016

A new high-precision Ar-40/Ar-39 anorthoclase feldspar age of 176.7 +/- 0.5 Ma (2-sigma) reveals that small-volume alkaline basaltic magmatism occurred at the rifted SW margin of the Baltic Shield in Scania (southern Sweden), at a time of global plate reorganization associated with the inception of Pangea supercontinent break-up. Our combined elemental and Sr-Nd-Hf-Pb isotope dataset for representative basanite and nephelinite samples (>8 wt.% MgO) from 16 subvolcanic necks of the 30 by 40 km large Jurassic volcanic field suggests magma derivation from a moderately depleted mantle source (Sr-87/(86)Sri = 0.7034-0.7048; epsilon Nd-i = +4.4 to +5.2; epsilon Hf-i = +4.7 to +8.1; Pb-206/(204)Pb…