Search results for "Sediment"

Flotsam samples can help explain the δ13C and δ15N values of invertebrate resting stages in lake sediment

2018

Abstract The stable isotopic composition of chitinous remains of Cladocera (water fleas) and freshwater Bryozoa (moss animals) preserved in lake sediment records can provide supporting insights into past environmental and ecosystem changes in lakes. Here we explore whether analyses of these remains isolated from lake flotsam can provide information on the driving variables affecting the isotopic composition of these remains. We collected flotsam in 53 lakes and found enough material in 33 lakes to measure the stable carbon and nitrogen isotope ratios (expressed as δ13C and δ15N values, respectively) of resting stages. These values were compared with lake characteristics, water chemistry mea…

Flotsam samples can help explain the δ13C and δ15N values of invertebrate resting stages in lake sediment

2018

The stable isotopic composition of chitinous remains of Cladocera (water fleas) and freshwater Bryozoa (moss animals) preserved in lake sediment records can provide supporting insights into past environmental and ecosystem changes in lakes. Here we explore whether analyses of these remains isolated from lake flotsam can provide information on the driving variables affecting the isotopic composition of these remains. We collected flotsam in 53 lakes and found enough material in 33 lakes to measure the stable carbon and nitrogen isotope ratios (expressed as δ13C and δ15N values, respectively) of resting stages. These values were compared with lake characteristics, water chemistry measurements…

Dobór metody oceny czystości mikrobiologicznej powietrza w zakładach przemysłu spożywczego

2016

Organismi unicellulari "spie" dell'inquinamento dell'ambiente marino.

2008

Classificazione sistematica e distribuzione dei foraminiferi bentonici recenti nei sedimenti marini delle coste siciliane.

2012

Evaluating the Effectiveness of Forest Crop to Mitigate Erosion Using a Sediment Delivery Distributed Model

1998

In this paper sediment yield data, measured from 1978 to 1997 in a small experimental Calabrian basin reafforested with Eucalyptus trees (Eucalyptus occidentalis Engl.), and RUSLE (Revised Universal Soil Loss Equation) coupled with a sediment delivery distributed model are used to evaluate the antierosive effects of this forest cover. At first, the soil loss measureinents carried out in two experimental plots, located in the basin, are used to evaluate the crop and management factor C of RUSLE far Eucalyptus coppice. The reliability of the selected C factor value is verified by comparing, at an event scale, the measured and the calculated sediment yield values at the basin outlet. Then, a M…

Approche d'un territoire de montagne : occupations humaines et contexte pédo-sédimentaire des versants du col du Petit-Saint-Bernard, de la Préhistoi…

2014

As part of a multi-year programme, survey campaigns have been carried out on both slopes of the Petit-Saint-Bernard pass (2188 m, western Alps), at an altitude of between 750 and 3000 m. The method employed abandons ground-based surveying in favour of multiple manual surveys carried out on selected topographic contexts down to the base of the Holocene fill. The results obtained document the longterm development of the pedo-sedimentary dynamic and the occupation of the different altitude stages. The significance of the archaeological data collected is discussed in relation to the state of knowledge in a comparison area including the neighbouring valleys of the western Alps, to existing settl…

Possible influence of Zoophycos bioturbation on radiocarbon dating and environmental interpretation

2002

Abstract In paleoenvironmental studies of marine sediments bioturbation is often neglected and/or only treated as a diffusion-like process affecting only the uppermost sediment with decreasing intensity with depth. Deep dwelling animals, like the Zoophycos producing animal, however, affect the sediment composition by transporting material over vertical distances of up to 1 m below the seafloor. In Arabian Sea sediment cores 70KL, 64KL and 57KL a significant downward transport of particles by Zoophycos can be observed. Within the Zoophycos burrows the faunal composition of both planktonic and benthic foraminiferal assemblages as well as the isotopic signature of foraminiferal carbonate diffe…

On the formation of laminated sediments on the continental margin off Pakistan: the effects of sediment provenance and sediment redistribution

2001

Abstract The sedimentary processes and sediment sources contributing to the formation of laminated sediments along the upper slope off Pakistan are unravelled using inorganic bulk sediment geochemistry of 43 surface cores from the Pakistani continental margin and additional geochemical and Pb and Nd-isotope data for different types of layers. An important process everywhere along the margin is redeposition of fluvial-derived detritus from the shelf onto the slope. This process is of considerably higher intensity along the Makran margin than on the Indus margin. Trace element enrichment related to early diagenesis or surface productivity, which is commonly detectable in bulk sediment composi…

New lithostratigraphy for the Cantabrian Mountains: A common tectono-stratigraphic evolution for the onset of the Alpine cycle in the W Pyrenean real…

2019

The Pyrenean-Cantabrian Orogen arose through the collision of the Iberian and Eurasian plates, mostly in Cenozoic times. This orogen comprises two main mountain ranges, the Pyrenees to the east, and the Cantabrian Mountains to the west. To date, the early Alpine tectono-sedimentary phases preserved in the Cantabrian Mountains, of Permian and Triassic age, have been considered independently from the same phases in neighbouring basins of SW Europe, and even from the eastern part of the same orogeny (the Pyrenean orogeny). In consequence, the beginning of the Alpine cycle in the Cantabrian Mountains has been interpreted within a specific geodynamic context, far from the general evolutionary ph…