Search results for "Sediment"

Roots Characteristics of a flexible and mature vegetation: Preliminary results of experimental investigation in a meandering laboratory flume

2018

Vegetation controls sediment dynamics and affects the kinematic characteristics of flow in rivers. The uprooting mechanism is strongly affected by mechanical properties, morphology and branching of the roots system. This work presents preliminary results of experimental work conducted in a laboratory meandering flume. The work aims to investigate how the geometrical and mechanical characteristics of the roots of a real, flexible and mature vegetation could vary along the bend. Results show that both the geometrical and the mechanical characteristics of the roots assume higher/lower values in peculiar sections of the bend suggesting that they could be affected by the kinematic characteristic…

Erosión costera y cambio ambiental en el humeral de Cabanes-Torreblanca (Castelló). Datos para una gestión sostenible

2014

A progressive increase in salinity and marine influence, related to local subsidence characterize the evolution of the lagoon of Cabanes Torreblanca. Relative sea level rise, caused saltwater intrusion and landward migration of the barrier. This barrier is recessive (60-20 m in the last 50 years) and its current processes show a sedimentary deficit that can lead to rapid and irreversible changes. The information shown by this research can help to achieve a sustainable management.

Metals in sediments of lakes in Latvia

1995

Abstract The concentrations and speciation forms of Pb, Cu, Ni, Cd, Zn, and Mn have been determined in sediments from 49 lakes thoroughout Latvia to study the impact of different pollutant sources and to estimate the background pollution level. Regional variation in pollutant distributions of Pb, Cu, and Cd concentrations is due to anthropogenic load. The enrichment of metals in the top layer of sediments is an estimate of the environmental pollution level. In regions with no known pollution sources, this enrichment was not typical. Another factor that determines metal concentrations in sediments is the organic matter production and sedimentation in eutrophic water bodies.

River-bed erosion due to changing boundary conditions: performance of a protective measure

2018

Abstract. Due to the introduction of man-made sediment barriers along a river, the amount of sediment load entering the downstream river reach is different to that leaving the reach, and erosion processes occur downstream of the barrier itself. Designers are often required to take into account the scouring process and to include adequate protective measures against the local scour. This paper addresses the performance of bio-engineering protective measures against the erosion process. In particular, a green carpet, realized with real flexible vegetation, has been used as the protective measure against erosion processes downstream of a rigid bed. Analyses are based on experimental work carri…

Experimental Analysis of Velocity Distribution in a Coarse-Grained Debris Flow: A Modified Bagnold’s Equation

2020

Today, Bagnold&rsquo

Bacterial Diversity in a Dynamic and Extreme Sub-Arctic Watercourse (Pasvik River, Norwegian Arctic)

2020

Microbial communities promptly respond to the environmental perturbations, especially in the Arctic and sub-Arctic systems that are highly impacted by climate change, and fluctuations in the diversity level of microbial assemblages could give insights on their expected response. 16S rRNA gene amplicon sequencing was applied to describe the bacterial community composition in water and sediment through the sub-Arctic Pasvik River. Our results showed that river water and sediment harbored distinct communities in terms of diversity and composition at genus level. The distribution of the bacterial communities was mainly affected by both salinity and temperature in sediment samples, and by oxygen…

Development of temperature and oxygen gradients during the formation of ice cover in a deep boreal lake

2008

Autochthonous organic matter promotes DNRA and suppresses N2O production in sediments of the coastal Baltic Sea

2021

Coastal environments are nitrogen (N) removal hot spots, which regulate the amount of land-derived N reaching the open sea. However, mixing between freshwater and seawater creates gradients of inorganic N and bioavailable organic matter, which affect N cycling. In this study, we compare nitrate reduction processes between estuary and offshore archipelago environments in the coastal Baltic Sea. Denitrification rates were similar in both environments, despite lower nitrate and carbon concentrations in the offshore archipelago. However, DNRA (dissimilatory nitrate reduction to ammonium) rates were higher at the offshore archipelago stations, with a higher proportion of autochthonous carbon. Th…

STOP 12: Late-glacial and Holocene development of Lake Rāzna as recorded by biostratigraphy

2014

Synsedimentary collapse on a carbonate platform margin (lower Barremian, southern Vercors, SE France)

2004

International audience; A large area of synsedimentary collapse covering about 25 km2 has been identified within Lower Barremian carbonate platform strata of the Southern Vercors (Vocontian Basin, SE France). New observations of the prograding/aggrading strata of the Cirque d'Archiane and the Glandasse Plateau reveal the presence of a disturbed zone, showing tilted and imbricated blocks as well as slump features. Measurements and analysis on these synsedimentary distorted strata suggest that they compose a slide which slipped on the Barremian slope. The occurence of two coarse bioclastic grainstone beds on the eastern side of the Archiane Valley, in a distal hemipelagic context, suggests th…