Search results for "Oceanography"
showing 10 items of 1567 documents
New insights into submarine tailing disposal for a reduced environmental footprint: Lessons learnt from Norwegian fjords
2021
Submarine tailing disposal (STD) in fjords from land-based mines is common practice in Norway and takes place in other regions worldwide. We synthesize the results of a multidisciplinary programme on environmental impacts of STDs in Norwegian fjords, providing new knowledge that can be applied to assess and mitigate impact of tailing disposal globally, both for submarine and deep-sea activities. Detailed geological seafloor mapping provided data on natural sedimentation to monitor depositional processes on the seafloor. Modelling and analytical techniques were used to assess the behaviour of tailing particles and process-chemicals in the environment, providing novel tools for monitoring. To…
Byers Peninsula: A reference site for coastal, terrestrial and limnetic ecosystem studies in maritime Antarctica
2009
Abstract This article describes the development of an international and multidisciplinary project funded by the Spanish Polar Programme on Byers Peninsula (Livingston Island, South Shetlands). The project adopted Byers Peninsula as an international reference site for coastal and terrestrial (including inland waters) research within the framework of the International Polar Year initiative. Over 30 scientists from 12 countries and 26 institutions participated in the field work, and many others participated in the processing of the samples. The main themes investigated were: Holocene changes in climate, using both lacustrine sediment cores and palaeo-nests of penguins; limnology of the lakes, …
Changes to processes in estuaries and coastal waters due to intense multiple pressures:an introduction and synthesis
2015
From the 2013 ECSA conference ‘Estuaries and Coastal Areas in Times of Intense Change’ a theme emerged that has ended up being the focus of this Special Issue of Estuarine Coastal and Shelf Science, namely ‘Changes to processes in estuaries and coastal waters due to intense multiple pressures’. Manyparts of the world are continuing to experience unprecedented rates of economic growth, and those responsible for managing coastal and estuarine areas must respond accordingly. At the same time, global climate change and sea level rise are also continuing, placing new or more intense pressures on coastal areas that must be dealt with in ways that are as far as possible managed as a result of good…
Vertical distribution of planktonic rotifers in a karstic meromictic lake
1993
Vertical distribution of planktonic rotifers is described in relation to temperature and oxygen in Lake La Cruz, a single-doline, closed karstic lake (121 m diameter and 25 m maximum depth) which shows iron meromixis. Samples were taken by peristaltic pumping at 10 cm depth intervals in the oxycline zone from June 1987 to September 1988. A model of rotifer vertical structure in stratified lakes is proposed. Rotifers concentrate their populations at the depths with intense gradients. As stratification develops some rotifer populations show a downward migration following the thermocline and some others show an upward migration following the oxycline. The production-respiration balance in the …
Impact of Holocene climate variability on lacustrine records and human settlements in South Greenland
2015
Due to its sensitivity to climate changes, south Greenland is a particularly suitable area to study past global climate changes and their influence on locale Human settlements. A paleohydrological investigation was therefore carried out on two river-fed lakes: Lake Qallimiut and Little Kangerluluup, both located close to the Labrador Sea in the historic farming center of Greenland. Two sediment cores (QAL-2011 and LKG-2011), spanning the last four millennia, were retrieved and showed similar thin laminae, described by high magnetic susceptibility and density, high titanium and TOC / TN atomic ratio, and coarse grain size. They are also characterized either by inverse grading followed by nor…
Potential and limits of combining studies of coarse- and fine-grained sediments for the coastal event history of a Caribbean carbonate environment
2013
The coastal deposits of Bonaire, Leeward Antilles, are among the most studied archives for extreme-wave events (EWEs) in the Caribbean. Here we present more than 400 electron spin resonance (ESR) and radiocarbon data on coarse-clast deposits from Bonaire’s eastern and western coasts. The chronological data are compared to the occurrence and age of fine-grained extremewave deposits detected in lagoons and floodplains. Both approaches are aimed at the identification of EWEs, the differentiation between extraordinary storms and tsunamis, improving reconstructions of the coastal evolution, and establishing a geochronological framework for the events. Although the combination of different method…
A geochemical traverse along the “Sperchios Basin – Evoikos Gulf” graben (Central Greece): Origin and evolution of the emitted fluids
2014
The studied area is a 130 km long fast spreading graben in Central Greece. Its complex geodynamical setting includes both the presence of a subduction slab at depth responsible for the recent (Quaternary) volcanic activity in the area and the western termination of a tectonic lineament of regional importance (the North-Anatolian fault). A high geothermal gradient is made evident by the presence of many thermal springs with temperatures from 19 to 82 °C, that discharge along the normal faults bordering the graben. In the period 2004–2012, 58 gas and 69 water samples were collected and their chemical and isotopic analysis revealed a wide range of compositions. Two main groups of thermal water…
Orbitally modulated black shale deposition in the upper Albian Amadeus Segment (central Italy): a multi-proxy reconstruction
2003
Abstract The upper Albian Amadeus Segment, which falls within Oceanic Anoxic Event 1c, exhibits cyclical alternations of marls/black shales and carbonate-rich beds that record evidence of orbital climate and sedimentary dynamics. A combined micropalaeontological (planktic and benthic foraminifera, and palynomorphs) and geochemical (stable isotopes, clay mineralogy, and major element distribution) investigation allowed recognition of a remarkable influence of continental material within the black shales. Moreover, the palaeoproductivity record is characterised by a non-linear response to the orbital forcing. The micropalaeontological and geochemical record suggests that upper Albian bedded c…
EPR dating of shells from Malhada Marsh, Rio de Janeiro, Brazil
2020
The formation of the coastal plain of the Brazilian sea is mainly due to the fluctuation of relative sea level in the past. Armacao dos Buzios or simply Buzios is a municipality in the microregion of lakes, in the state of Rio de Janeiro. In this region there is a lowland area about two meters above current sea level. This lowland area is also known as coastal plain of Una River. It is expected that during the Holocene period the sea level reached a maximum about 2.5 meters above the current level. During that time billions of mollusks lived and proliferated in the shallow waters around the coastal plain of the Una River. As they died their shells formed a layer in the soil including Malhad…
Palaeogeographical relationships between Alpine and Jura glaciers during the two last Pleistocene glaciations
1992
Abstract Two main moraine complexes are usually defined in the northwestern Alpine piedmont: the External Moraine Complex (EMC) dated to the penultimate glaciation (“Riss” sensu lato) and the Internal Moraine Complex (IMC) dated to the last glaciation (“Wurm”). Until recently the prevalent concept was that these two complexes had been built by glaciers originating in the central Alpine zone. This paper presents a new palaeogeographical diagram, based on mapping and petrographical studies of these two moraine complexes, and especially on the relationships between Alpine and Jura tills. We reach the following conclusions. 1. (1) The Jura glaciers were independent of the Alpine glaciers during…