Deforestation for oil palm alters the fundamental balance of the soil N cycle

This abstract contains mathematical characters (see download

Enrichment of Phosphate on Ferrous Iron Phases during Bio-Reduction of Ferrihydrite *

The reduction of less stable ferric hydroxides and formation of ferrous phases is critical for the fate of phosphorus in anaerobic soils and sediments. The interaction between ferrous iron and phosphate was investigated experimentally during the reduction of synthetic ferrihydrite with natural organic materials as carbon source. Ferrihydrite was readily reduced by dissimilatory iron reducing bacteria (DIRB) with between 52 % and 73 % Fe(III) converted to Fe(II) after 31 days, higher than without DIRB. Formation of ferrous phases was linearly coupled to almost complete removal of both aqueous and exchangeable phosphate. Simple model calculations based on the incubation data suggested ferrous phases bound phosphate with a molar ratio of Fe(II):P between 1.14- 2.25 or a capacity of 246- 485 mg·P·g −1 Fe(II). XRD analysis indicated that the ratio of Fe(II): P was responsible for the precipitation of vivianite (Fe3(PO4)2·8H2O), a dominant Fe(II) phosphate mineral in incubation systems. When the ratio of Fe(II):P was more than 1.5, the precipitation of Fe(II) phosphate was soundly crystallized to vivianite. Thus, reduction of ferric iron provides a mechanism for the further removal of available phosphate via the production of ferrous phases, with anaerobic soils and sediments potentially exhibiting a higher capacity to bind phosphate than some aerobic systems

Hydromorphological control of phosphorus in a large free-flowing gravel bed river: the Garonne river (France)

The objective of this paper is to relate phosphorus (P) transport dynamics and hydromorphological characteristics of a large human-influenced river, the River Garonne within a sector receiving the waste water of a sewage treatment plant for a population of 600 000. Two studies were conducted in 1997 and 1999 during two different hydrological conditions at low-flow periods. The 1997 study was carried out on an 18-km stretch with discharges varying between 33 and 53 m3/s and with very small fluctuations. The 1999 study concerned a longer stretch of 47 km, divided into four smaller reaches, and with discharges fluctuating rapidly from 40 to 108 m3/s. Downstream of the sewage treatment plant, total phosphorus (TP) concentrations ranged from 0.19 to 0.27 mg/L and were mainly in the dissolved form: between 60 and 78% of TP was dissolved reactive phosphorus (DRP). P concentrations were significantly lower upstream of the sewage treatment plant. By a mass-balance approach, we estimated that the sewage treatment plant represents more than half the input (between 59 and 67%) of the studied sector. TP dynamic is linked to suspended solids for discharges above 60 m3/s. During established low-flow period in the 1997 study (<60 m3/s), 22 and 27% of TP and DRP were retained by the river bed. In the 1999 study, under different low-water period hydraulic conditions, we calculate that particulate P retention occurred in two reaches among the four under study and only for discharges below 60 m3/s. We show that for established discharges below 60 m3/s, there is an active uptake of transported P by functional compartments (i.e. the hyporheic zone and the periphyton). During the low-water period with relatively high hydraulic fluctuations, and for discharges >60 m3/s, P retention is controlled as expected by suspended matter dynamics

Coupling 3D groundwater modeling with CFC-based age dating to classify local groundwater circulation in an unconfined crystalline aquifer

International audienceNitrogen pollution of freshwater and estuarine environments is one of the most urgent environmental crises. Shallow aquifers with predominantly local flow circulation are particularly vulnerable to agricultural contaminants. Water transit time and flow path are key controls on catchment nitrogen retention and removal capacity, but the relative importance of hydrogeological and topographical factors in determining these parameters is still uncertain. We used groundwater dating and numerical modeling techniques to assess transit time and flow path in an unconfined aquifer in Brittany, France. The 35.5 km2 study catchment has a crystalline basement underneath a ∼60 m thick weathered and fractured layer, and is separated into a distinct upland and lowland area by an 80 m-high butte. We used groundwater discharge and groundwater ages derived from chlorofluorocarbon (CFC) concentration to calibrate a free-surface flow model simulating groundwater flow circulation. We found that groundwater flow was highly local (mean travel distance = 350 m), substantially smaller than the typical distance between neighboring streams (∼1 km), while CFC-based ages were quite old (mean = 40 years). Sensitivity analysis revealed that groundwater travel distances were not sensitive to geological parameters (i.e. arrangement of geological layers and permeability profile) within the constraints of the CFC age data. However, circulation was sensitive to topography in the lowland area where the water table was near the land surface, and to recharge rate in the upland area where water input modulated the free surface of the aquifer. We quantified these differences with a local groundwater ratio (rGW-LOCAL), defined as the mean groundwater travel distance divided by the mean of the reference surface distances (the distance water would have to travel across the surface of the digital elevation model). Lowland, rGW-LOCAL was near 1, indicating primarily topographical controls. Upland, rGW-LOCAL was 1.6, meaning the groundwater recharge area is almost twice as large as the topographically-defined catchment for any given point. The ratio rGW-LOCAL is sensitive to recharge conditions as well as topography and it could be used to compare controls on groundwater circulation within or between catchments

Experimental investigation of relevant road surface descriptors for tire-road noise measurements on low-absorbing road surfaces

Aufgrund von geräuschsenkenden Maßnahmen der Automobilindustrie ist der Kontakt zwischen Reifen und Straße heute die wichtigste Geräuschquelle außerhalb des Fahrzeugs. Diese Tendenz wird sich mit der Verbreitung von Elektrofahrzeugen noch verstärken. Mit zunehmender Forderung von Bevölkerung und Politik nach einer Reduzierung des Verkehrslärms wird die Regelung für die Reifen- und Fahrzeugzulassung regelmäßig verschärft. Daher sind weitere Untersuchungen über den Einfluss der Eigenschaften der Fahrbahnoberfläche auf die Geräuschemission von Reifen und Fahrzeugen erforderlich. Ziel dieser Arbeit ist es, die relevanten Fahrbahneigenschaften zu identifizieren, um das Reifen-Fahrbahn-Geräusch von frei rollenden Reifen mit einem systematischen Ansatz zu mindern. Da die Verwendung offenporiger Asphalte bereits als effiziente Maßnahme zur Reduzierung des Reifenrollgeräusches bekannt ist, konzentriert sich diese Arbeit auf kompakte Straßenoberflächen mit geringer Schallabsorption. Zunächst werden die Mechanismen, die Reifen-Fahrbahngeräusche erzeugen, sowie die wichtigsten Forschungsergebnisse über den Einfluss der Reifen- und der Straßeneigenschaften auf die Reifen-Fahrbahngeräusche vorgestellt. Nachdem die notwendigen theoretischen Grundlagen zum Verständnis dieser Arbeit vermittelt wurden, werden die verschiedenen Methoden zur akustischen Analyse der Wechselwirkung zwischen Fahrbahnoberfläche und Reifen vorgestellt. Diese Methoden werden in zwei Gruppen unterteilt: die Mess- und die statistischen Methoden. Die Anwendung statistischer Methoden auf die Messung der Fahrbahnoberfläche und des Reifenfahrgeräusches bietet mehrere Vorteile. Erstens können multidimensionale Daten auf Skalare reduziert werden, so dass die Anzahl der als Eingabe verwendeten Parameter minimiert wird. Dann können die wichtigsten Straßenbelagsparameter identifiziert werden, um das Reifen-Fahrbahngeräusch und einige seiner Entstehungsmechanismen wie die Rillenresonanz zu reduzieren. Am Ende wird eine Analyse durchgeführt, um festzustellen, ob die Definition der Homologationsprüfstrecke nach der Norm ISO 10844 vollständig genug ist oder ob zusätzliche Parameter benötigt werden, um die Geräuschvarianz zwischen verschiedenen, der Norm entsprechenden Prüfstrecken zu erklären. Anhand aller gesammelten Informationen kann eine optimale Straßenbelagsgestaltung vorgenommen werden, um die Reifen-Fahrbahn-Geräusche bei Homologationstests, aber auch bei normalen Rollbedingungen auf öffentlichen Straßen zu reduzieren

Approaches for assessing the impacts of the Rural Development Programmes in the context of multiple intervening factors

The Common Monitoring and Evaluation Framework (CMEF) provides a single framework for monitoring and evaluation of all EU Rural Development Programmes (RDP) in the current programming period (2007-2013). It provides continuity from previous periods and constitutes a significant simplification as regards assessment of results and impacts, while at the same time offering greater flexibility to Member States. The European Evaluation Network for Rural Development has published a Working Paper on Approaches for assessing the impacts of the Rural Development Programmes in the context of multiple intervening factors. The aim of the Working Paper is to inspire and to encourage programme evaluators, not to restrict or constrain them. From a methodological perspective, the three common socio-economic impact indicators of the CMEF (economic growth, employment creation, labour productivity) are more closely related than the four common environmental impact indicators (reversing biodiversity decline, maintenance of High Nature Value faming and forestry, improvement in water quality, contribution to combating climate change).assessment of impacts, Rural Development Programmes, policy evaluation, EU policy, Agricultural and Food Policy,

Low flow controls on benthic and hyporheic macroinvertebrate assemblages during supra-seasonal drought

Despite the widely accepted importance of the hyporheic zone as a habitat for stream macroinvertebrates during floods, few data exist regarding community composition and distribution during periods of low flow or drought in perennial streamsi Integrating research on hyporheic invertebrates with results from a long-term study of a U K river provided the opportunity to examine how surface and hyporheic macroinvertebrate communities respond to inter-annual variability in river flow and periods of groundwater drought. Changes in the riverine macroinvertebrate community associated with low flow included a reduction in species richness and the number of individuals per sample, particularly aquatic insects. The hyporheic community was characterized by a relatively homogeneous composition during a period of severe low flow, punctuated by short-term changes associated with variation in water temperature rather than changes in discharge. We present a conceptual model of the processes influencing benthic and hyporheic invertebrates under low-flow conditions. Previous studies have seldom integrated these two assemblages and their interactions. The model presented highlights the potential importance of surface water and hyporheic zone linkages for riverine invertebrate communities under a range of flow conditions

Experimental investigation of relevant road surface descriptors for tire-road noise measurements on low-absorbing road surfaces

Ihrer Arbeit in der Originalsprache: This work aims at identifying relevant road surface characteristics to mitigate tire-road noise of free-rolling tires using a systematic approach. As using open porous roads is already known as an efficient measure to reduce tire rolling noise, this study will focus on compact road surfaces which have a low acoustic absorption. Measurements on standardized ISO 10844 test tracks and on public roads are used to study the norm\u27s representativity and its completeness

Experimental investigation of relevant road surface descriptors for tire-road noise measurements on low-absorbing road surfaces

Ihrer Arbeit in der Originalsprache: This work aims at identifying relevant road surface characteristics to mitigate tire-road noise of free-rolling tires using a systematic approach. As using open porous roads is already known as an efficient measure to reduce tire rolling noise, this study will focus on compact road surfaces which have a low acoustic absorption. Measurements on standardized ISO 10844 test tracks and on public roads are used to study the norm's representativity and its completeness

Signature proteins that are distinctive of alpha proteobacteria

BACKGROUND: The alpha (α) proteobacteria, a very large and diverse group, are presently characterized solely on the basis of 16S rRNA trees, with no known molecular characteristic that is unique to this group. The genomes of three α-proteobacteria, Rickettsia prowazekii (RP), Caulobacter crescentus (CC) and Bartonella quintana (BQ), were analyzed in order to search for proteins that are unique to this group. RESULTS: Blast analyses of protein sequences from the above genomes have led to the identification of 61 proteins which are distinctive characteristics of α-proteobacteria and are generally not found in any other bacteria. These α-proteobacterial signature proteins are generally of hypothetical functions and they can be classified as follows: (i) Six proteins (CC2102, CC3292, CC3319, CC1887, CC1725 and CC1365) which are uniquely present in most sequenced α-proteobacterial genomes; (ii) Ten proteins (CC1211, CC1886, CC2245, CC3470, CC0520, CC0365, CC0366, CC1977, CC3010 and CC0100) which are present in all α-proteobacteria except the Rickettsiales; (iii) Five proteins (CC2345, CC3115, CC3401, CC3467 and CC1021) not found in the intracellular bacteria belonging to the order Rickettsiales and the Bartonellaceae family; (iv) Four proteins (CC1652, CC2247, CC3295 and CC1035) that are absent from various Rickettsiales as well as Rhodobacterales; (v) Three proteins (RP104, RP105 and RP106) that are unique to the order Rickettsiales and four proteins (RP766, RP192, RP030 and RP187) which are specific for the Rickettsiaceae family; (vi) Six proteins (BQ00140, BQ00720, BQ03880, BQ12030, BQ07670 and BQ11900) which are specific to the order Rhizobiales; (vii) Four proteins (BQ01660, BQ02450, BQ03770 and BQ13470) which are specific for the order Rhizobiales excluding the family Bradyrhizobiaceae; (viii) Nine proteins (BQ12190, BQ11460, BQ11450, BQ11430, BQ11380, BQ11160, BQ11120, BQ11100 and BQ11030 which are distinctive of the Bartonellaceae family;(ix) Six proteins (CC0189, CC0569, CC0331, CC0349, CC2323 and CC2637) which show sporadic distribution in α-proteobacteria, (x) Four proteins (CC2585, CC0226, CC2790 and RP382) in which lateral gene transfers are indicated to have occurred between α-proteobacteria and a limited number of other bacteria. CONCLUSION: The identified proteins provide novel means for defining and identifying the α-proteobacteria and many of its subgroups in clear molecular terms and in understanding the evolution of this group of species. These signature proteins, together with the large number of α-proteobacteria specific indels that have recently been identified , provide evidence that all species from this diverse group share many unifying and distinctive characteristics. Functional studies on these proteins should prove very helpful in the identification of such characteristics