scholarly journals Stable water isotopes in pore water of Jurassic argillaceous rocks as tracers for solute transport over large spatial and temporal scales

2007 ◽  
Vol 43 (4) ◽  
Author(s):  
T. Gimmi ◽  
H. N. Waber ◽  
A. Gautschi ◽  
A. Rübel
2018 ◽  
Author(s):  
Carolina Cárcamo ◽  
Iván Vargas-Cordero ◽  
Francisco Fernandoy ◽  
Umberta Tinivella ◽  
Diego López-Acevedo ◽  
...  

Abstract. Gas hydrate occurrences along the Chilean margin has been documented, but the processes associated to fluid escapes originated by gas hydrate dissociation yet are unknown. Here, we report morphologies growing related to fluid migration in the continental shelf offshore western Lebu (37 °S) by analysing mainly geochemical features. In this study oxygen and deuterium stable water isotopes in pore water were measured. Knowledge was completed by analysing bathymetric data, biological and sedimentological data. From bathymetric interpretation a positive relief at 127 m below sea level was recognised; it is oriented N55 °E and characterised by five peaks. Moreover, enrichment values for δ18O (from 0.0 to 1.8 ‰) and δD (from 0.0 to 5.6 ‰) were obtained. These are typical values related to hydrate melting during coring and post-sampling. The evident orientation of positive relief could be associated with faults and fractures reported by others authors, in which these structures constitute pathways for fluid migration from deep to shallow zones. Finally, benthic foraminifera observed in the core sample can be associated to seep areas. On the basis of theoretical modelling, we conclude that the positive relief correspond to mud growing processes related to gas hydrates dissociation and represent a key area to investigate fluid migration processes.


Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 563
Author(s):  
Wiebe Förster ◽  
Jan C. Scholten ◽  
Michael Schubert ◽  
Kay Knoeller ◽  
Nikolaus Classen ◽  
...  

The eutrophic Lake Eichbaumsee, a ~1 km long and 280 m wide (maximum water depth 16 m) dredging lake southeast of Hamburg (Germany), has been treated for water quality improvements using various techniques (i.e., aeration plants, removal of dissolved phosphorous by aluminum phosphorous precipitation, and by Bentophos® (Phoslock Environmental Technologies, Sydney, Australia), adsorption) during the past ~15 years. Despite these treatments, no long-term improvement of the water quality has been observed and the lake water phosphorous content has continued to increase by e.g., ~670 kg phosphorous between autumn 2014 and autumn 2019. As no creeks or rivers drain into the lake and hydrological groundwater models do not suggest any major groundwater discharge into the lake, sources of phosphorous (and other nutrients) are unknown. We investigated the phosphorous fluxes from sediment pore water and from groundwater in the water body of the lake. Sediment pore water was extracted from sediment cores recovered by divers in August 2018 and February 2019. Diffusive phosphorous fluxes from pore water were calculated based on phosphorus gradients. Stable water isotopes (δ2H, δ18O) were measured in the lake water, in interstitial waters in the banks surrounding the lake, in the Elbe River, and in three groundwater wells close to the lake. Stable isotope (δ2H, δ18O) water mass balance models were used to compute water inflow/outflow to/from the lake. Our results revealed pore-water borne phosphorous fluxes between 0.2 mg/m2/d and 1.9 mg/m2/d. Assuming that the measured phosphorous fluxes are temporarily and spatially representative for the whole lake, about 11 kg/a to 110 kg/a of phosphorous is released from sediments. This amount is lower than the observed lake water phosphorous increase of ~344 kg between April 2018 and November 2018. Water stable isotope (δ2H, δ18O) compositions indicate a water exchange between an aquifer and the lake water. Based on stable isotope mass balances we estimated an inflow of phosphorous from the aquifer to the lake of between ~150 kg/a and ~390 kg/a. This result suggests that groundwater-borne phosphorous is a significant phosphorous source for the Eichbaumsee and highlights the importance of groundwater for lake water phosphorous balances.


2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Zarai Besma ◽  
Walter Christian ◽  
Michot Didier ◽  
Montoroi Jean Pierre ◽  
Hachicha Mohamed

2008 ◽  
Vol 1 (2) ◽  
pp. 81-88 ◽  
Author(s):  
C. Zevenbergen ◽  
W. Veerbeek ◽  
B. Gersonius ◽  
S. Van Herk

2021 ◽  
Author(s):  
Christopher Johannes Diekmann ◽  
Matthias Schneider ◽  
Peter Knippertz ◽  
Andries Jan de Vries ◽  
Stephan Pfahl ◽  
...  

2015 ◽  
Vol 120 ◽  
pp. 51-60 ◽  
Author(s):  
Yuval ◽  
Meytar Sorek–Hamer ◽  
Amnon Stupp ◽  
Pinhas Alpert ◽  
David M. Broday

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