Dissolved oxygen as an eutrophication factor in Dal Lake
Dal Lake ; Eutrophisation ; Géographie de l'Asie ; Hydrobiochimie ; Inde ; Jammu and Kashmir ; Lac ; Milieu dulçaquatique ; Oxygène dissous
This paper helps us to understand the fact that the oxygen status of water, measured in terms of either level of dissolved oxygen or bio-chemical oxygen demand is perhaps the best indicator of health of an aquatic ecosystem. - (PLK)
The Greenland Ice Sheet Project 2 (GISP2) oxygen isotope record, with its high-resolution detail, yields crucial information on past climate change. Here the AA. present high-resolution GISP2 oxygen isotope records and mention some of their climatic
During studies of oxygen isotope : temperature relationships for tree rings in the Canadian Rockies, the AA. noted differences in oxygen isotope ratios between samples from compression wood and normal radii in the same stem. This paper briefly
Oxygen isotope constraints on surface ocean temperatures
Donnée substitutive ; Foraminifère ; Géographie physique ; Isotopes de l'oxygène ; Paléoclimatologie ; Quaternaire zone chaude ; Température de surface de l'océan
Published oxygen isotope results from benthic and planktonic foraminifera are used to constrain the extent to which surface ocean temperatures in the tropics changed between glacial and inter-glacial time. The possible impacts of bioturbation
and of the redistribution of oxygen isotopic ratios within the sea, putting aside the oxygen isotope results, are consistent with the CLIMAP project conclusion that tropical ocean temperatures remained within ca. 2oC of their present value.
Ross ice shelf oxygen isotopes and West Antarctic climate history
Antarctique ; Barrière de Ross ; Carotte de glace ; Glace ; Géographie des régions polaires ; Isotopes de l'oxygène ; Paléoclimatologie ; Quaternaire supérieur ; Ross Ice Shelf
The Ross Ice Shelf oxygen isotopic profile at station J-9 covers at least the last 30,000 yr.
Le foyer de plasma d'oxygène permet de séparer de petits échantillons de sédiments clastiques à partir des filtres à basse température sans altération physique ou chimique. Cette technique est appropriée à l'examen des sédiments éoliens alpins et
Oxygen and strontium isotope relationships in the British late Caledonian granites
Analyse isotopique ; Calédonien ; Cristallin ; England ; Ere primaire ; Granite ; Géographie de l'Europe ; Magma ; Oxygène ; Royaume-Uni ; Scotland ; Strontium
Oxygen and strontium isotope data for 25late Caledonian granite plutons emplaced between 435and 390Myr indicate that the parent magmas were hybrids, derived from partial fusion of mantle-like material and varying proportions of a crustal component.
This paper describes the isotopic fractionations and shows that variations of the oxygen isotopic composition of foraminifera along deep sea cores are generally a continental ice volume index and thus a worldwide oceanic stratigraphic marker
. Specific applications of oxygen isotopes related either to past temperature changes or local sea water isotopic composition variations are presented.
The aim of this paper is to empirically determine a fractionation equation that relates the δ18 O of local meteoritic waters to the composition of tooth phosphate in present-day arvicolines; select the most adequate relationship between the oxygen
Algue ; Allemagne ; Biomasse ; Chlorophylle ; Cours d'eau ; Elbe ; Estuaire ; Modèle ; Oxygène ; Pollution ; Pollution de l'eau ; Qualité de l'eau
Algae ; Biomass ; Chlorophyll ; Estuary ; Germany ; Model ; Oxygen ; Pollution ; Stream ; Water pollution ; Water quality
Depuis la réunification allemande, les fermetures industrielles dans l'ex-RDA ont permis de diminuer la pollution de l'Elbe qui affectait le taux d'oxygène de ce fleuve. Depuis l'été 1991, l'amélioration de la qualité de l'eau s'est traduite par un
développement des algues et par un taux d'ammonium inférieur à 0,1 mg/l N. Cela a entraîné une augmentation de la concentration en oxygène et des concentrations croissantes de biomasse consommatrice d'oxygène. Cependant, les déficits en oxygène se produisent
Using iron metal rods to infer oxygen status in seasonally saturated soils
Agropédologie ; Biogéochimie ; Eau du sol ; Etats-Unis ; Oxygène ; Propriétés du sol ; Sol ; Technique de recherche ; Texas
Agropedology ; Biogeochemistry ; Oxygen ; Research technique ; Soil ; Soil properties ; Soil water ; Texas ; United States of America
Since monitoring oxygen in soils is expensive and time consuming, the aim of this research was to develop an inexpensive, non-intrusive, simple field technique to infer or estimate the oxygen status in soils. Zero-valent iron rods (polished nails
) were placed in 3 soil toposequences and the surface coatings formed by oxidation were compared to measured oxygen concentrations taken every three weeks for one year. This research may have implications in hydric soil determination, horticultural
Changes in solar constant over an 11 yr cycle suggest a certain, but limited, degree of solar forcing of climate. The high-resolution climate (oxygen isotope) record of the Greenland GISP2 (Greenland Ice Sheet Project 2) ice core has been analyzed
for solar (and volcanic) influences. The atmospheric C 14 record is used as a proxy of solar change and compared to the oxygen isotope profile in the GISP2 ice core. Solar forcing during the surprisingly strong 1470 yr climate cycle of the 11,000-75,000 yr
Asian part of Russia ; Deuterium ; Holocene ; Ice wedge ; Isotope analysis ; Oxygen 18 ; Palaeo-environment ; Palaeoclimate ; Periglacial features ; Pleistocene ; Quaternary ; Siberia
Late Quaternary permafrost deposits on Big Lyakhovsky Island (New Siberian Islands, Russian Arctic) were studied with the aim of reconstructing the palaeoclimatic and palaeoenvironmental conditions of northern Siberia. Hydrogen and oxygen stable
ice wedges ever analysed for hydrogen and oxygen isotopes.
Chlorophyll ; Index ; Lake ; Oxygen ; Phosphate ; Reservoir ; Temperate zone ; Typology ; Water stratification
Discussion de l'application possible de données sur la distribution verticale d'oxygène dissous dans les lacs et les lacs artificiels stratifiés pour l'évaluation de leur état trophique. Corrélations statistiques entre la concentration moyenne
verticalement pondérée et les indicateurs les plus courants de l'état trophique de réservoirs (transparence de l'eau, concentrations en phosphore total et en chlorophylle a daans l'eau. Les types trophqies de réservoirs sont classés suivant l'indice d'oxygène.
Regional atmospheric circulation change in the North Pacific during the Holocene inferred from lacustrine carbonate oxygen isotopes, Yukon Territory, Canada
The AA. analyzed oxygen isotopes in sediment cores from Jellybean Lake, located in the southern Yukon interior, to improve the detail and resolution of the regional climatic history and investigate mechanisms for Holocene climatic change. Holocene
changes in North Pacific atmospheric circulation inferred from Jellybean Lake oxygen isotopes correspond with late Holocene glacial advances in the St. Elias Mountains, changes in North Pacific salmon abundance, and shifts in atmospheric circulation over