Search results for "Calcareous"

Post-fire hydrological response and suspended sediment transport of a terraced Mediterranean catchment

2017

In July 2013, a wildfire severely affected the western part of the island of Mallorca (Spain). During the first three post-fire hydrological years, when the window of disturbance tends to be more open, the hydrological and sediment delivery processes and dynamics were assessed in a representative catchment intensively shaped by terracing that covered 37% of its surface area. A nested approach was applied with two gauging stations (covering 1.2 km2 and 4.8 km2) built in September 2013 that took continuous measurements of rainfall, water and sediment yield. Average Suspended Sediment Concentration (1,503 mg l-1) and the maximum peak (33,618 mg l-1) were two orders of magnitude higher than tho…

A new Neoplatyura Malloch from Finland (Diptera, Keroplatidae).

2014

The genus Neoplatyura Malloch is globally represented by 50 species, of which four are European species. In this article a new European Neoplatyura from Finland is described. The new species, Neoplatyura noorae Salmela, sp. n. is a dark brown species with tibial bristles arranged in rows. The new species is here reported from seven localities in Finnish Lapland. Based on available data, the new species occurs in mires, especially in calcareous rich fens.

230Th/U-dating of carbonate deposits from ancient aqueducts

2016

Abstract Carbonate deposits in aqueducts, known as calcareous sinter, can reach a considerable thickness and are commonly annually laminated. Environmental and palaeoclimate proxies measured in calcareous sinter samples, such as stable oxygen and carbon isotopes and trace elements, can provide important high-resolution information on hydrological conditions, temperature, and local precipitation in the catchment area of an aqueduct. In order to utilize the proxy data for palaeoclimate reconstruction, the sinter deposits must be dated by annual laminae counting and more precisely by 230 Th/U-dating. The major problem of 230 Th/U-dating of calcareous sinter in aqueducts is the relatively large…

Double pulse laser induced breakdown spectroscopy applied to natural and artificial materials from cultural heritages. A comparison with micro-X-ray …

2009

Facilitated transport of diuron and glyphosate in high copper vineyard soils.

2007

6 pages; International audience; The fate of organic herbicides applied to agricultural fields may be affected by other soil amendments, such as copper applied as a fungicide. The effect of copper on the leaching of diuron and glyphosate through a granitic and a calcareous soil was studied in the laboratory using sieved-soil columns. Each soil was enriched with copper sulfate to obtain soil copper concentrations of 125, 250, 500, and 1000 mg kg(-1). Glyphosate leaching was influenced by soil pH and copper concentration, whereas diuron leaching was not. In the calcareous soil, glyphosate leaching decreased as copper levels increased from 17 mg kg(-1) (background) to 500 mg kg(-1). In the gra…

Occurrence and regional distribution of calcareous concretions in the rat pineal gland.

1978

Serial sections of 90 Sprague-Dawley rat brains with the pineal in situ were scanned to determine the occurrence and regional distribution of calcareous concretions within the pineal gland and its surrounding leptomeningeal tissue. In 90% of the cases examined concretions were found in varying number and appearance, predominantly lying in the dorsal region of the pineal gland and in the distal portion of the pineal stalk. Discussing the hypothesis advanced by Lukaszyk and Reiter (1975) that the origin of pineal concretions may be related to a neurosecretory process involving a pineal carrier protein, called neuroepiphysin, it is thought that, in view of the intra- and extra-pineal occurrenc…

Suborbital climate variability during Marine Isotopic Stage 5 in the central Mediterranean basin: evidence from calcareous plankton record

2006

Abstract New faunal and floral records from Ocean Drilling Project Hole 963A, resolved at ∼80-year spacing, provide evidence of suborbital scale climate variability in the central Mediterranean Sea throughout Marine Isotope Stage (MIS) 5. Cold events in the central Mediterranean Sea, indicated by low abundances of warm species and high abundances of cold species, are also evident in a planktonic foraminifera paleoclimatic curve. They have been linked to NGRIP Greenland ice core “C” events and appear correlative with similar sub-millennial climate fluctuations identified in the North Atlantic region and in the Alboran Basin (Westernmost Mediterranean). Low-resolution benthic and planktonic O…

Variability in the vertical structure of the water column and paleoproductivity reconstruction in the central-western Mediterranean during the Late P…

2008

Abstract A sedimentary sequence spanning Marine Isotope Stage (MIS) 6 to MIS 2 in core LC07, recovered in the central Mediterranean, has been investigated in order to produce a high-resolution paleoceanographic reconstruction. The changes in productivity deduced from calcareous plankton relative abundances and independently confirmed by the Ba XS fluctuations are linked to the stability of the water column which is mainly controlled by the water mass temperature. During glacial intervals, productivity was generally enhanced. Oligotrophic and warmer water masses with a deepened seasonal thermocline can be inferred for most of MIS5. The magnetic properties of the sediment show increased occur…

Biocalcite, a multifunctional inorganic polymer: Building block for calcareous sponge spicules and bioseed for the synthesis of calcium phosphate-bas…

2014

Calcium carbonate is the material that builds up the spicules of the calcareous sponges. Recent results revealed that the calcium carbonate/biocalcite-based spicular skeleton of these animals is formed through an enzymatic mechanism, such as the skeleton of the siliceous sponges, evolutionarily the oldest animals that consist of biosilica. The enzyme that mediates the calcium carbonate deposition has been identified as a carbonic anhydrase (CA) and has been cloned from the calcareous sponge species Sycon raphanus. Calcium carbonate deposits are also found in vertebrate bones besides the main constituent, calcium phosphate/hydroxyapatite (HA). Evidence has been presented that during the init…

Holocene climate variability of the Western Mediterranean: Surface water dynamics inferred from calcareous plankton assemblages

2020

A high-resolution study (centennial scale) has been performed on the calcareous plankton assemblage of the Holocene portion of the Ocean Drilling Program Site 976 (Alboran Sea) with the aim to identify the main changes in the surface water dynamic. The dataset also provided a seasonal foraminiferal sea surface water temperatures (SSTs), estimated using the modern analog technique SIMMAX 28, and it was compared with available geochemical and pollen data at the site. Three main climate shifts were identified as (1) the increase in abundance of Syracosphaera spp. and Turborotalita quinqueloba marks the early Holocene humid phase, during maximum summer insolation and enhanced river runoff. It i…