scholarly journals An In Situ Analyzer for Two-Dimensional Fe(II) Distribution in Sediment Pore Water Based on Ferrozine Coloration and Computer Imaging Densitometry

ACS Omega ◽  
2020 ◽  
Vol 5 (49) ◽  
pp. 31551-31558
Author(s):  
Mingjie Ma ◽  
Honghui Wang ◽  
Jin Xu ◽  
Yongming Huang ◽  
Dongxing Yuan ◽  
...  
Keyword(s):  
Pore Water ◽  
Two Dimensional ◽  
Sediment Pore Water ◽  
Water Based

In situ measurement of dissolved Fe(ii) in sediment pore water with a novel sensor based on C18-ferrozine concentration and optical imaging detection

2019 ◽  
Vol 11 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Chengrong Guo ◽  
Mingjie Ma ◽  
Dongxing Yuan ◽  
Yongming Huang ◽  
Kunning Lin ◽  
...  
Keyword(s):  
Optical Imaging ◽  
Pore Water ◽  
In Situ Measurement ◽  
Sensor System ◽  
Sediment Pore Water ◽  
Imaging Detection

A novel sensor system, which integrated sampling, enrichment, and in situ measurement of dissolved Fe(ii) in sediment pore water, was developed.

Distributions of Ferrous Iron and Sulfide in an Anoxic Hypolimnion

1984 ◽  
Vol 41 (2) ◽  
pp. 286-293 ◽  
Author(s):  
Robert B. Cook
Keyword(s):  
Pore Water ◽  
Solubility Product ◽  
Iron Sulfide ◽  
Water Flux ◽  
Sediment Pore Water ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Anoxic Hypolimnion ◽  
Decomposition Of Organic Matter

In the anoxic hypolimnion of Lake 227, Experimental Lakes Area, northwestern Ontario, ΣH2S exhibits a mid-depth maximum, while Fe2+ increases with depth. At the mid-depth ΣH2S maximum and below, saturation with respect to amorphous FeS is reached, and the concentration of ΣH2S is limited by the high Fe2+ concentrations, in accord with the FeS solubility product. Values for pKsp[Formula: see text] for FeS determined from the ΣH2S maximum and below averaged 3.16 in 1979 and agree well with other in situ and laboratory measurements. In the top 10 cm of sediment, pore water ΣH2S and Fe2+ are in equilibrium with amorphous FeS. Analyses of cores confirms the existence of an iron sulfide phase. Fe2+, which is produced in the pore water from the decomposition of organic matter, increases to concentrations at which siderite may form, although the presence of siderite has not been verified. Comparison of calculated pore water fluxes of Fe2+ with the observed increase of Fe2+ in the anoxic hypolimnion reveals that about 90% of the observed flux originates at the sediment–water interface, while the remainder is derived from pore water flux.

scholarly journals COMPARISON OF TWO SAMPLING METHODS (CORER AND IN SITU SEDIMENT SIPPER METHODS) FOR THE PORE WATER OF SEDIMENT

2018 ◽  
Vol 29 ◽  
pp. 1-11
Author(s):  
Muswerry Muchtar
Keyword(s):  
Pore Water ◽  
Sampling Methods ◽  
Sampling Techniques ◽  
Sediment Depth ◽  
Sediment Pore Water ◽  
Advantages And Disadvantages ◽  
Phosphate Nitrate ◽  
Vertical Variations

Effect of two sampling techniques (i.e. corer and sipper samplers) of sediment pore water on measured concentrations of phosphate, nitrate and ammonia was examined. The concentrations of nitrate and ammonia in relation to sediment depth (vertical variations) collected by corer and sipper sampler do not show significant differences, while for phosphate concentrations significant differences occurred. The advantages   and disadvantages of both techniques are discussed.

Determination of tracer gas contents in sediment pore water of gas hydrate area by two-dimensional gas chromatography

2011 ◽  
Vol 29 (1) ◽  
pp. 70-74
Author(s):  
Hu WANG ◽  
Qunhui YANG ◽  
Fuwu JI ◽  
Huaiyang ZHOU ◽  
Xiang XUE
Keyword(s):  
Gas Chromatography ◽  
Pore Water ◽  
Gas Hydrate ◽  
Two Dimensional ◽  
Tracer Gas ◽  
Sediment Pore Water

A novel device for in situ point measurements of fluorescent tracers in sediment pore water

2021 ◽  
Vol 148 ◽  
pp. 103827
Author(s):  
Anja Höhne ◽  
Karl Mellerowicz ◽  
Oliver Lischtschenko ◽  
Jörg Lewandowski
Keyword(s):  
Pore Water ◽  
Fluorescent Tracers ◽  
Sediment Pore Water ◽  
Novel Device

Effects of Sampling Technique on the Determination of Major and Trace Elements on Sediment Pore Water

1996 ◽  
Vol 31 (4) ◽  
pp. 709-724 ◽  
Author(s):  
Jose M. Azcue ◽  
Fernando Rosa
Keyword(s):  
Pore Water ◽  
Sampling Technique ◽  
Major And Trace Elements ◽  
Sediment Pore Water ◽  
In Situ Techniques ◽  
Sampling Artifacts ◽  
Almost All ◽  
Dialysis Technique

Abstract Pore water samples obtained by squeezing, centrifuging followed by filtration, and in situ dialysis were compared. The effects of the three methods on the measured concentrations of eight elements (Ca, Fe, K, Mg, Mn, Na, Si and Sr) were studied. Iron and Mn proved to be extremely sensitive to oxygen exposure. Immediate centrifugation followed by filtration under nitrogen yield very similar results for almost all the elements as the in situ dialysis technique. The squeezing technique was the most susceptible to handling variables such as pressure-, oxygen- and temperature-related changes. Whenever possible, we recommend the use of in situ techniques that minimize the sampling artifacts. However, the choice of the technique for sampling sediment pore water should be dictated by the objectives of the study.

REY distribution and concentration in bottom seawater and oxic pore water in the CCZ, NE Pacific: pilot study on the application of a DGT passive sampling method in deep sea environments

2020 ◽  
Author(s):  
Katja Schmidt ◽  
Sophie Anna Luise Paul ◽  
Cornelia Kriete
Keyword(s):  
Trace Elements ◽  
Trace Metal ◽  
Pore Water ◽  
Deep Sea ◽  
Passive Sampling ◽  
Sampling Method ◽  
Passive Samplers ◽  
Sediment Pore Water ◽  
Ce Anomaly

<p>Sampling and analysis of trace elements in open seawater and in sediment pore water in the deep sea is challenging due to small sample volumes and matrix effects. Here we evaluate an alternative method using the technique of diffusive gradients in thin films (DGT passive samplers), focussing on rare earth elements and yttrium (REY). DGT measures the labile fraction of metals in situ by fixing them on a Chelex resin after diffusion through a gel layer, providing a diffusive flux and averaged in situ concentrations of elements during the time of deployment. As the accumulated element concentrations increase with exposure time to solution, long-term deployment times overcome low trace metal concentrations in seawater and pore water. So far, no deep-sea applications of passive samplers are yet reported.</p><p>Sampling was performed in bottom seawater and surface sediments in the German licence area for manganese nodule exploration in the Clarion Clipperton Zone (CCZ, research cruise SO268 in April/May 2019), deployment times ranged from 12 hours in sediments to 4 weeks in open seawater.</p><p>Seawater DGT’s were deployed 0.5 m to 8 m above the seafloor. PAAS-normalized REY show the typical seawater pattern, with increase from LREE to HREE, a strong negative Ce anomaly, a kink from Gd to Tb, and a pronounced positive Y/Ho anomaly. The pattern and calculated concentrations agree very well with reported dissolved REY (<0.2 µm) for Pacific deep water (Alibo and Nozaki, 1999). Sediment DGT sticks were deployed in cores taken with a multicorer and cover the first 15 cm of the sediment. They provide in situ high-resolution profiles of trace metal fluxes and were analysed in 0.5 cm to 2 cm segments. We observe smooth PAAS-normalized patterns with negative Ce anomaly, an increase from LREE to MREE, and a slight decrease from Tb to Lu, sometimes accompanied by a small positive Y/Ho anomaly. The calculated concentrations generally increase with depth. Paul et al (2019) previously described very similar distribution patterns for CCZ sediment pore water and suggested Mn and Fe phases as the REY source. The pore water REY patterns clearly differ from bottom seawater already in the first centimetres of surface sediment– this sharp shift demonstrates that the dissolved pore water REY pool in the sediment surface is controlled by fluid-mineral equilibria.</p><p>The DGT passive sampling method may provide an additional tool to investigate biogeochemical processes at the deep-sea sediment-water interface and in the open ocean, and to monitor effects of anthropogenic disturbances at the seafloor on benthic trace element fluxes. We will discuss uncertainties of concentration calculation resulting from diffusion coefficients and from non-steady state conditions in pore water, and the comparability of DGT-derived distribution pattern and concentrations with results from physically filtered water. The DGT labile fraction is thought to represent the bioavailable fraction of trace elements and may also include colloids and nanoparticles (NPCs).</p><p> </p><p>Alibo and Nozaki, 1999: Geochimica et Cosmochimica Acta 63, pp. 363-372.</p><p>Paul et al, 2019: Geochimica et Cosmochimica Acta 251, pp. 56-72.</p>

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