Combined use of stable isotopes and hydrochemical characteristics to determine streamflow sources in the Jonkershoek catchment, South Africa

2020 ◽  
Vol 56 (3) ◽  
pp. 238-259
Author(s):  
Retang A. Mokua ◽  
Julia Glenday ◽  
Jacobus Nel ◽  
Mike Butler
Keyword(s):  
South Africa ◽  
Stable Isotopes ◽  
Hydrochemical Characteristics ◽  
Combined Use

scholarly journals Contamination of the Bushveld Complex (South Africa) magmas by basinal brines: Stable isotopes in phlogopite from the UG2 chromitite

Geology ◽  
2021 ◽  
Author(s):  
Haoyang Zhou ◽  
Robert B. Trumbull ◽  
Ilya V. Veksler ◽  
Ilya N. Bindeman ◽  
Johannes Glodny ◽  
...  
Keyword(s):  
South Africa ◽  
Stable Isotopes ◽  
Hydrogen Isotope ◽  
Bushveld Complex ◽  
Isotope Ratios ◽  
Second Step ◽  
Merensky Reef ◽  
Oxygen Isotope Ratios ◽  
Abundant Evidence ◽  
Hydrogen Isotope Ratios

There is abundant evidence for significant H2O in evolved melts from the platinum-rich UG2 chromitite and the Merensky Reef of the Bushveld Complex (South Africa), but there is no consensus about the source of H2O. We report triple-oxygen and hydrogen isotope ratios of interstitial, late-magmatic phlogopite from three localities of the UG2 layer. The phlogopite yielded δD values of –43‰ to –23‰, which is >30‰ higher than previously known from Bushveld rocks and far above the mantle values of ~–75‰. The phlogopite triple-oxygen isotope ratios are the first to be reported for Bushveld rocks, with values of Δ′17O0.5305 (17O excess relative to the reference line 0.5305) from –0.069‰ to –0.044‰ (δ18O 5.2‰–6.2‰). The oxygen data support existing models of as much as 30%–40% contamination of mantlederived magmas in the lower to middle crust. However, the high δ values require a second step of contamination, which we attribute to brines from the marine sediments in the Transvaal Basin at the emplacement level.

A lonely dot on the map: Exploring the climate signal in tree-ring density and stable isotopes of clanwilliam cedar, South Africa

2021 ◽  
Vol 69 ◽  
pp. 125879
Author(s):  
Tom De Mil ◽  
Matthew Meko ◽  
Soumaya Belmecheri ◽  
Edmund February ◽  
Matthew Therrell ◽  
...  
Keyword(s):  
South Africa ◽  
Stable Isotopes ◽  
Tree Ring ◽  
Climate Signal ◽  
Ring Density

scholarly journals Hydrochemical characteristics of aquifers near Sutherland in the Western Karoo, South Africa

2001 ◽  
Vol 241 (1-2) ◽  
pp. 91-103 ◽  
Author(s):  
S Adams ◽  
R Titus ◽  
K Pietersen ◽  
G Tredoux ◽  
C Harris
Keyword(s):  
South Africa ◽  
Hydrochemical Characteristics

scholarly journals Stable isotope analysis spills the beans about spatial variance in trophic structure in a fish host – parasite system from the Vaal River System, South Africa

2019 ◽  
Author(s):  
Beric M. Gilbert ◽  
Milen Nachev ◽  
Maik A. Jochmann ◽  
Torsten C. Schmidt ◽  
Daniel Köster ◽  
...  
Keyword(s):  
South Africa ◽  
Stable Isotopes ◽  
Stable Isotope ◽  
Feeding Strategy ◽  
Isotope Analysis ◽  
Isotope Enrichment ◽  
Host Fish ◽  
Vaal River ◽  
Spatial Differences ◽  
Stable Isotope Enrichment

Abstract BackgroundStable isotope analysis offers a unique tool for comparing trophic interactions and food web architecture in ecosystems. This approach is based on analysis of the stable isotope ratios of carbon (13 C/ 12 C) and nitrogen (15 N/ 14 N) in organisms. Studies comparing stable isotope enrichment in hosts and parasites have shown that parasites are variably enriched in stable isotopes relative to the host.MethodsSharptooth catfish (Clarias gariepinus) were collected from six sites along the Vaal River, South Africa and were assessed for ectoparasites and endoparasites. Lamproglena clariae (Copepoda), Tetracampus ciliotheca and Proteocephalus glanduligerus (Cestoda), and larval Contracaecum sp. (Nematoda) were collected from the gills, intestine and mesenteries, respectively. Signatures of δ 13 C and δ 15 N were analysed in host muscle tissue and parasites using bulk stable isotope analysis.ResultsStable isotope enrichment was variable between parasites and the host fish, with L. clariae and the host sharing similar δ 15 N signatures and the endoparasites being depleted in both δ 13 C and δ 15 N relative to the host. Spatial differences in enrichment of stable isotopes were also identified. Fish and parasites collected from below the Vaal River Barrage were more enriched in the 15 N isotope than hosts and parasites collected from other sites. The opposite was identified for 13 C isotope fractionation.ConclusionDifferences in stable isotope enrichment in parasites infecting C. gariepinus could be related to the feeding strategy of each parasite species collected. Enrichment of δ 15 N in L. clariae would relate to the micropredatory nature of this parasite, which feeds on whole blood of the host fish. Depleted isotope levels in endoparasites could relate to their absorptive feeding strategy on metabolic by-products of the host. Spatial differences in both host and parasite tissues identified likely resulted from differences in the diet of the host and related with availability of prey items for the host fish.

scholarly journals Comment on “A comparison of catchment travel times and storage deduced from deuterium and tritium tracers using StorAge Selection functions” by Rodriguez et al. (2021)

2021 ◽  
Vol 25 (12) ◽  
pp. 6333-6338
Author(s):  
Michael Kilgour Stewart ◽  
Uwe Morgenstern ◽  
Ian Cartwright
Keyword(s):  
Stable Isotopes ◽  
Travel Time ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Travel Times ◽  
Catchment Hydrology ◽  
Important Development ◽  
Combined Use ◽  
And Storage

Abstract. The combined use of deuterium and tritium to determine travel time distributions (TTDs) in streams is an important development in catchment hydrology (Rodriguez et al., 2021). This comment takes issue with Rodriguez et al.'s assertion that the truncation hypothesis may not hold for catchments in general, i.e. that the use of stable isotopes alone may not lead to underestimation of travel times or storage compared to tritium. We discuss reasons why the truncation hypothesis may not appear to hold for the catchment studied by Rodriguez et al. (2021) but could still apply to the majority of catchments. We also discuss more generally future applications of tritium in Northern Hemisphere and Southern Hemisphere catchments.

scholarly journals Determining Water Isotope Compositions for the IAEA WICO and North West Villages, South Africa

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2801
Author(s):  
Joseph Mathuthu ◽  
Naomi Dikeledi Mokhine ◽  
Namhla Mkiva ◽  
Samuel Che Nde ◽  
Ingrid Dennis ◽  
...  
Keyword(s):  
South Africa ◽  
Stable Isotopes ◽  
Isotope Composition ◽  
Underground Water ◽  
Cavity Resonance ◽  
North West ◽  
The North ◽  
North West Province ◽  
Patterns And Processes ◽  
Water Isotope

Deuterium (2H) and oxygen 18 (18O) stable isotopes in water are the key indicators of hydrological and ecological patterns and processes. The water isotopes δ2H and δ18O have been employed widely as tracers in hydrological and ecological research, as they are integrated into geological and biological systems in a predictable manner. The aim of this study was to determine the water isotope composition of the International Atomic Energy Agency’s (IAEA) Water Isotope Inter-laboratory Comparison (WICO) samples and to determine the Local Meteoric Water Line for North West Province (NWP) villages in South Africa. The IAEA WICO 2020 samples were obtained from the IAEA, Vienna, and borehole water samples from selected villages in the North West province of South Africa were randomly collected to investigate the relationship between the stable isotopes (18O and 2H) and the climate in underground water aquifers. A cavity ring-down spectroscopy analyzer with laser-current-tuned cavity resonance, Picarro L2140-i, was used to measure triple water–isotope ratios with high precision. The IAEA WICO results obtained for the d-excess were in a satisfactory range and the margins of error were close to those required by the IAEA. The δ2H values ranged between −33.00‰ and −8.00‰, while the δ18O values ranged between −5.50‰ and −2.00‰. The results of this work have shown that our water science and management lab is capable of undertaking inter-laboratory comparisons for the IAEA.

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