Search results for "Sediment"

Sondeo de l'Albufera de Pego (Valencia): micropaleontología y biofacies

1988

LA ANTIGUA ALBUFERA DE PEGO (VALENCIA-ESPAÑA) ES UN INTERESANTE PALEOSISTEMA DONDE LAS BIOFACIES REGISTRAN UNA HIDRODINAMICA SEDIMENTARIA DE ORIGEN MIXTO O PARALICO. EL GRADO DE INCIDENCIA Y ANTAGONISMO DE LAS AGUAS CONTINENTALES Y MARINAS QUEDA REGISTRADO EN FORAMINIFEROS, OSTRACODOS, MICROMOLUSCOS Y RESTOS VEGETALES, CUYA EVOLUCION CUANTITATIVA Y MORFOLOGICA, A TRAVES DEL SONDEO, REFLEJA NO SOLO EL GRADO DE EURIHALINIDAD DE LOS ORGANISMOS, SINO TAMBIEN LOS DIVERSOS EPISODIOS LITORALES DEL WURM II-III HASTA EL HOLOCENO, PASANDO POR LA TRANSGRESION FLANDRIENSE. (A)

Estudio sedimentológico de los depósitos de inundación en la Ribera del Xúqer (Valencia), en octubre de1982

2013

As a result of the sedimentological study of a series of deposits corresponding to the exceptional flood in the Xuquer River in October 1982, we analyze the behaviour of fluvial dynamics. The sedimentary response enables us lo perceive certain differences between the deposits analyzed, bUI these do not completely adjust to the genetic patterns considered in the classic Geomorphology as the producers ofthe traits ofvertical growth generated during floods.

STOP 2: Late-glacial and postglacial environmental changes, Lake Āraiši, Vidzeme Upland

2014

STOP 5: Veselava end moraine, north-western Vidzeme Upland

2014

How do the 1982/83 and 1997/98 El Niños rank in a geological record from Peru?

2007

Two very strong El Nino events during the years 1982/83 and 1997/98 caused dramatic economical and social damages worldwide. However, it is quite uncertain how these events rank in a long-term perspective and how frequent events of similar magnitude were in the past. Very-high-resolution proxy data for flood events in the El Nino key region of Peru are presented. Strong flood events in the hyper-arid northern and northern central Peru coastal desert occur during El Nino events. The flood data are derived from a laminated marine sediment core. The proxy data reveal that both modern events were recorded as the strongest sediment discharges in the 106KL flood record over the last millennium. S…

STOP 3: Late-glacial and early postglacial environmental processes and the history of the River Triečupīte valley and surroundings, in the foreland o…

2014

A diagenetic control on the Early Triassic Smithian-Spathian carbon isotopic excursions recorded in the marine settings of the Thaynes Group (Utah, U…

2016

17 pages; International audience; n the aftermath of the end-Permian mass extinction, Early Triassic sediments record some of the largest Phanerozoic carbon isotopic excursions. Among them, a global Smithian-negative carbonate carbon isotope excursion has been identified, followed by an abrupt increase across the Smithian–Spathian boundary (SSB; ~250.8 Myr ago). This chemostratigraphic evolution is associated with palaeontological evidence that indicate a major collapse of terrestrial and marine ecosystems during the Late Smithian. It is commonly assumed that Smithian and Spathian isotopic variations are intimately linked to major perturbations in the exogenic carbon reservoir. We present p…

Dendrochemical assessment of mercury releases from a pond and dredged-sediment landfill impacted by a chlor-alkali plant.

2016

International audience; Although current Hg emissions from industrial activities may be accurately monitored, evidence of past releases to the atmosphere must rely on one or more environmental proxies. We used Hg concentrations in tree cores collected from poplars and willows to investigate the historical changes of Hg emissions from a dredged sediment landfill and compared them to a nearby control location. Our results demonstrated the potential value of using dendrochemistry to record historical Hg emissions from past industrial activities.

Ecotoxicity assessment of boreal lake sediments affected by metal mining: Sediment quality triad approach complemented with metal bioavailability and…

2019

Highlights • Ecological risk assessment of metal-contaminated boreal lakes and sediments. • Sediment Quality Triad complemented with bioavailability and body residue studies. • Toxicity studies for natural sediments with several organisms and endpoints • Adverse effects observed. High variation on results between different methods. • Standard toxicity tests not suitable for testing, too low pH hampers the results. There are several methods for studying metal-contaminated freshwater sediments, but more information is needed on which methods to include in ecological risk assessment. In this study, we compliment the traditional Sediment Quality Triad (SQT) approach – including information on c…

Vertical stratification of bacteria and archaea in sediments of a small boreal humic lake

2019

ABSTRACT Although sediments of small boreal humic lakes are important carbon stores and greenhouse gas sources, the composition and structuring mechanisms of their microbial communities have remained understudied. We analyzed the vertical profiles of microbial biomass indicators (PLFAs, DNA and RNA) and the bacterial and archaeal community composition (sequencing of 16S rRNA gene amplicons and qPCR of mcrA) in sediment cores collected from a typical small boreal lake. While microbial biomass decreased with sediment depth, viable microbes (RNA and PLFA) were present all through the profiles. The vertical stratification patterns of the bacterial and archaeal communities resembled those in mar…