scholarly journals Subsurface Water Oceans on Icy Satellites: Chemical Composition and Exchange Processes

2010 ◽  
pp. 483-508 ◽  
Author(s):  
Frank Sohl ◽  
Mathieu Choukroun ◽  
Jeffrey Kargel ◽  
Jun Kimura ◽  
Robert Pappalardo ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Subsurface Water ◽  
Icy Satellites ◽  
Exchange Processes

scholarly journals Subsurface Water Oceans on Icy Satellites: Chemical Composition and Exchange Processes

2010 ◽  
Vol 153 (1-4) ◽  
pp. 485-510 ◽  
Author(s):  
Frank Sohl ◽  
Mathieu Choukroun ◽  
Jeffrey Kargel ◽  
Jun Kimura ◽  
Robert Pappalardo ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Subsurface Water ◽  
Icy Satellites ◽  
Exchange Processes

scholarly journals Chemical composition of groundwaters in the Hornsund region, southern Spitsbergen

2012 ◽  
Vol 44 (1) ◽  
pp. 117-130 ◽  
Author(s):  
Tomasz Olichwer ◽  
Robert Tarka ◽  
Magdalena Modelska
Keyword(s):  
Chemical Composition ◽  
Ion Exchange ◽  
Shallow Groundwater ◽  
Mineralogical Composition ◽  
Deep Groundwater ◽  
Exchange Processes ◽  
Groundwater Circulation ◽  
Initial Chemical Composition ◽  
The University ◽  
Intermediate System

Chemical composition of groundwaters was investigated in the region of the Hornsund fjord (southern Spitsbergen). The investigations were conducted during polar expeditions organized by the University of Wroclaw in two summer seasons of 2003 and 2006. Three zones of groundwater circulation: suprapermafrost, intrapermafrost and subpermafrost, were identified in areas of perennial permafrost in the region of Hornsund. The zone of shallow circulation occurs in non-glaciated (suprapermafrost) and subglacial areas. In this zone, the chemical composition of groundwater originates from initial chemical composition of precipitation, mineralogical composition of bedrock, oxidation of sulphides and dissolution of carbonates. The intermediate system of circulation is connected with water flow inside and below perennial permafrost (intrapermafrost and subpermafrost). In this zone, the chemical composition of groundwater is mainly controlled by dissolution of carbonates, ion exchange processes involving Ca2+ substitution by Na+, and oxidation of sulphides under oxygen-depleted conditions. The subpermafrost zone (deep groundwater circulation) occurs in deep-tectonic fractures, which are likely conduits for the descent of shallow groundwater to deeper depths. In this zone, the groundwater shows lower mineralization comparing to intrapermafrost zone and has a multi-ion nature Cl–HCO3–Na-Ca–Mg.

scholarly journals REMOTE SENSING OBSERVATIONS AND NUMERICAL SIMULATION FOR MARTIAN LAYERED EJECTA CRATERS

2018 ◽  
Vol XLII-3 ◽  
pp. 865-870
Author(s):  
L. Li ◽  
Z. Yue ◽  
C. Zhang ◽  
D. Li
Keyword(s):  
Remote Sensing ◽  
Numerical Simulation ◽  
Morphological Characteristics ◽  
Subsurface Water ◽  
Icy Satellites ◽  
Martian Surface ◽  
Water Ice ◽  
Topographic Features ◽  
Model Setup ◽  
Basaltic Crust

To understand past Martian climates, it is important to know the distribution and nature of water ice on Mars. Impact craters are widely used ubiquitous indicators for the presence of subsurface water or ice on Mars. Remote sensing observations and numerical simulation are powerful tools for investigating morphological and topographic features on planetary surfaces, and we can use the morphology of layered ejecta craters and hydrocode modeling to constrain possible layering and impact environments. The approach of this work consists of three stages：Firstly, the morphological characteristics of the Martian layered ejecta craters are performed based on Martian images and DEM data. Secondly, numerical modeling layered ejecta are performed through the hydrocode iSALE (impact-SALE). We present hydrocode modeling of impacts onto targets with a single icy layer within an otherwise uniform basalt crust to quantify the effects of subsurface H<sub>2</sub>O on observable layered ejecta morphologies. The model setup is based on a layered target made up of a regolithic layer (described by the basalt ANEOS), on top an ice layer (described by ANEOS equation of H<sub>2</sub>O ice), in turn on top of an underlying basaltic crust. The bolide is a 0.8&amp;thinsp;km diameter basaltic asteroid hitting the Martian surface vertically at a velocity of 12.8&amp;thinsp;km/s. Finally, the numerical results are compared with the MOLA DEM profile in order to analyze the formation mechanism of Martian layered ejecta craters. Our simulations suggest that the presence of an icy layer significantly modifies the cratering mechanics, and many of the unusual features of SLE craters may be explained by the presence of icy layers. Impact cratering on icy satellites is significantly affected by the presence of subsurface H<sub>2</sub>O.

Micro scale exchange processes between surface and subsurface water

2002 ◽  
Vol 269 (1-2) ◽  
pp. 3-10 ◽  
Author(s):  
Stefan Vollmer ◽  
Francisco de los Santos Ramos ◽  
Helge Daebel ◽  
Gregor Kühn
Keyword(s):  
Subsurface Water ◽  
Micro Scale ◽  
Exchange Processes

Detection, Analysis, and Mapping of Surface Material from Europa

2020 ◽  
Author(s):  
William Goode ◽  
Sascha Kempf ◽  
Juergen Schmidt
Keyword(s):  
Chemical Composition ◽  
Dust Particles ◽  
Surface Material ◽  
Detection Analysis ◽  
Spacecraft Trajectory ◽  
Exchange Processes ◽  
Subsurface Ocean ◽  
Chemical Measurements ◽  
Geological Features

&lt;p&gt;Europa Clipper, NASA&amp;#8217;s next flagship mission launching in 2024, will closely study Jupiter&amp;#8217;s icy ocean moon in order to determine if it has conditions favorable for life. Among the nine scientific instruments will be the Surface Dust Analyzer (SUDA), a state-of-the-art instrument for in situ chemical analysis of dust grains. During a series of close flybys of Europa (~25 to 100 km at closest approach), SUDA will collect and measure the chemical composition of thousands of ice and dust particles ranging from ~200 nm to 100 microns in radius, which will be direct samples from Europa&amp;#8217;s surface. This is possible due to the flux of interplanetary micrometeoroids impacting the surface producing a cloud of ejecta particles, which SUDA detects and analyzes. Knowing the spacecraft trajectory, instrument pointing, and particle velocity through the instrument aperture, SUDA&amp;#8217;s in situ chemical measurements will be linked to their site of origin on Europa&amp;#8217;s surface near the spacecraft ground-track, thereby offering geological context for chemical composition. This method implements established models of impact ejecta dynamics and derives distributions for each measurement&amp;#8217;s site of origin on the surface using Monte Carlo simulations. These studies are especially useful for evaluating the science return for particular tour designs since we can simulate SUDA&amp;#8217;s effectiveness at mapping the composition of geologically interesting areas. With well targeted flybys by Europa Clipper, SUDA will be help constrain the chemical composition of surface material originating from various geological features, particularly those characterized by non-icy materials. This will enhance our understanding of the exchange processes between the icy surface and subsurface ocean as well as assess the habitability of Europa.&lt;/p&gt;

scholarly journals Geochemical Processes Controlling Ionic Composition of Water in the Catchments of Lakes Saana and Saanalampi in the Kilpisjärvi Area of North Scandinavia

Geosciences ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 174
Author(s):  
Valle Raidla ◽  
Enn Kaup ◽  
Sigrid Hade ◽  
Jüri Ivask ◽  
Alvar Soesoo
Keyword(s):  
Chemical Composition ◽  
Chemical Weathering ◽  
Stream Water ◽  
Ionic Composition ◽  
Subsurface Water ◽  
Chemical Components ◽  
Geochemical Processes ◽  
Rock Composition ◽  
Local Soil ◽  
Arctic Conditions

The study focuses on chemical composition of stream and subsurface water in the catchments of two small arctic alpine lakes in the Kilpisjärvi area (northwest Finland). Differences and changes in chemical components of both water types are followed in order to detect spatial variability and impact of environmental factors. To achieve this, ion compositions of subsurface water and streams were measured at 12 sites in the catchments of Lakes Saana and Saanalampi during four years (2008–2010, and again in 2017). In the Lake Saanalampi catchment, the salinity of stream water (7.0 to 12.7 μS·cm−1) corresponded to that of snow. In the catchment of Lake Saana, however, the conductivity in stream water was much higher (40 to 220 μS·cm−1), connected mainly to the increase of SO42− and less with Mg2+ and Ca2+ contents, especially in the western part of the Saana catchment. These results demonstrate that arctic conditions do not preclude intense chemical weathering where conditions are favourable. Although chemical composition of the soil fluid does not match the geochemical signal from the local soil, rock composition, especially the presence of pyrite, is the main controller of chemical weathering rates of the rocks on the area. This supports earlier views that the character of precipitation mostly controls water chemistry of local lakes in the Kilpisjärvi area.

scholarly journals The copper content in the organs and tissues of Mytilus galloprovincialis Lamarck, 1819 and the flow of its sedimentary deposition into bottom sediments in the farms of the Black Sea aquaculture

2018 ◽  
Vol 3 (4) ◽  
pp. 64-75 ◽  
Author(s):  
N. V. Pospelova ◽  
V. N. Egorov ◽  
N. S. Chelyadina ◽  
M. V. Nekhoroshev
Keyword(s):  
Chemical Composition ◽  
Copper Content ◽  
Water Environment ◽  
The Black Sea ◽  
Content Change ◽  
Exchange Processes ◽  
Mussel Farms ◽  
Copper Exchange ◽  
Mussel Farm

The role of mussels in formation of water chemical composition is determined by the peculiarities of sorption and trophodynamic processes. Copper is a vital element, but of ten metals the toxic effect of which was tested for the survival of mussel and oyster embryos, copper is following mercury. Studying the regularities of copper content change during mussel ontogeny allows to determine both sanitary and hygienic risks of mussel product use during the mollusks cultivation in mariculture and the biogeochemical role in the formation of the chemical composition of the marine water near mussel farms. The purpose of this work is to determine the copper content in the organs and tissues of the mussels during seasonal course of mollusks ontogenesis, to analyze the degree of copper assimilation along the food path of mineral nutrition using the mathematical model and empirical data and to assess the influence of marine farms on the copper exchange processes in the coastal ecosystem. The mollusks were collected from the mussel farm located in the external roadstead of Sevastopol. Studying the copper content in the environment – mussel – biodeposition system, a method of atomic absorption spectroscopy with electrothermal atomization was used. A general model illustrating the process of copper exchange between the mussels and the water environment is presented. Equations for determining the degree of assimilation of metal from food (q) and the limiting coefficient of food accumulation of metal (Кп) are proposed based on the results of measurements of its concentrations in the mussels’ diet, soft tissue and their biodeposition without using radioactive trace elements. The values of the copper removal by the mussel farm were calculated. The role of cultivated mollusks in the heavy metals precipitation was shown.

Phytoplankton communities influence the dissolved organic matter composition of the sea-surface microlayer

2020 ◽  
Author(s):  
Lea Oeljeschlaeger ◽  
Nils Hintz ◽  
Jutta Niggemann ◽  
Oliver Wurl ◽  
Thorsten Dittmar
Keyword(s):  
Boundary Layer ◽  
Organic Matter ◽  
Chemical Composition ◽  
Solid Phase ◽  
Sea Surface ◽  
Surface Microlayer ◽  
Exchange Processes ◽  
Sea Surface Microlayer ◽  
Phytoplankton Communities ◽  
External Forces

&lt;p&gt;The sea surface microlayer (SML) is the boundary layer at the ocean and atmosphere interface and plays a crucial role in air-sea gas exchange processes and global climate. It is enriched in dissolved organic matter (DOM) compared to the underlying water, but the chemical composition of this material has&amp;#160;been&amp;#160;insufficiently&amp;#160;studied. For improved understanding of the exchange processes it is of utmost importance knowing the molecular composition of the SML. Studying the microlayer is very challenging due to its thinness and strong influence of external forces as wind, UV light and atmospheric deposition on the chemical and microbial composition. The complex and dynamic nature of the microlayer and the enrichment of hydrophobic substances led to the assumption that we find unique chemical composition and distinct compound groups. SML samples of the Indo-Pacific Ocean from R/V Falkor cruise FK161010 (October 2016) were studied with respect to molecular composition of DOM. We analyzed solid-phase extracted DOM with high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). The results were compared to the underlying water (ULW, 1m depth). We found similar molecular DOM composition in the ULW, whereas microlayer extracts were more variable and diverse. This can be related to the influence of changing weather conditions during the cruise on the SML. To reveal molecular changes without interfering external forces, a 5-week indoor mesocosm experiment with induced marine phytoplankton blooms was conducted. A modified solid-phase extraction approach was used to chemically fractionate the microlayer DOM prior to molecular analysis. Our experiment showed that the DOM enrichment in the SML is linked to different phytoplankton communities. In addition, it revealed that depending on the predominant community the DOM concentration can be even depleted in the SML compared to the ULW. Based on the outcome of our field and laboratory studies we conclude that molecular level analysis of surface microlayers is essential to understand the chemical diversity of this highly dynamic boundary layer.&lt;/p&gt;

Geochemical investigation of weathering processes in a forested headwater catchment: mass-balance weathering fluxes

2008 ◽  
Vol 72 (1) ◽  
pp. 65-69 ◽  
Author(s):  
B. F. Jones ◽  
J. S. Herman
Keyword(s):  
Chemical Composition ◽  
Surface Water ◽  
Ground Water ◽  
Mass Balance ◽  
Mineral Weathering ◽  
Subsurface Water ◽  
Balance Model ◽  
Compositional Variation ◽  
Weathering Profile ◽  
Solute Fluxes

AbstractGeochemical research on natural weathering has often been directed towards explanations of the chemical composition of surface water and ground water resulting from subsurface water-rock interactions. These interactions are often defined as the incongruent dissolution of primary silicates, such as feldspar, producing secondary weathering products, such as clay minerals and oxyhydroxides, and solute fluxes (Meunier and Velde, 1979). The chemical composition of the clay-mineral product is often ignored. However, in earlier investigations, the saprolitic weathering profile at the South Fork Brokenback Run (SFBR) watershed, Shenandoah National Park, Virginia, was characterized extensively in terms of its mineralogical and chemical composition (Piccoli, 1987; Pochatila et al., 2006; Jones et al., 2007) and its basichydrology. O’Brien et al. (1997) attempted to determine the contribution of primary mineral weathering to observed stream chemistry at SFBR. Mass-balance model results, however, could provide only a rough estimate of the weathering reactions because idealized mineral compositions were utilized in the calculations. Making use of detailed information on the mineral occurrence in the regolith, the objective of the present study was to evaluate the effects of compositional variation on mineral-solute mass-balance modelling and to generate plausible quantitative weathering reactions that support both the chemical evolution of the surface water and ground water in the catchment, as well as the mineralogical evolution of the weathering profile.

Development of a new mathematical model for subsurface water quality management

2002 ◽  
Vol 45 (9) ◽  
pp. 301-307 ◽  
Author(s):  
D.B. Das ◽  
V. Nassehl
Keyword(s):  
Water Quality ◽  
Water Quality Management ◽  
Dynamical Behaviour ◽  
Subsurface Water ◽  
Complex Flow ◽  
Porous Flow ◽  
Transition Zones ◽  
Aspect Ratios ◽  
Exchange Processes ◽  
Soil Flow

The interfaces between free (e.g., groundwater) and porous (e.g., soil) flow zones in the subsurface represent important transition zones across which many important transfer/exchange processes occur. The understanding of these interactive phenomena and the way these regions behave in combination is, therefore, critical for management of subsurface water quality. Indispensable to this is numerical modelling and simulation as they can handle complex flow domains and minimise the analysis cost and time. In the present work, the hydrodynamic conditions for a combined free and porous flow domain in the subsurface are analysed. An investigation into the fluid dynamical behaviour for different aspect ratios of the domains is of most interest.

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