Stable-isotope (H, O, and Si) evidence for seasonal variations in hydrology and Si cycling from modern waters in the Nile Basin: implications for interpreting the Quaternary record

Cockerton, Helen E.; Street-Perrott, F. Alayne; Leng, Melanie J.; Barker, Philip A.; Horstwood, Matthew; Pashley, Vanessa

doi:10.1016/j.quascirev.2012.12.005

Cited by 54 publications

(42 citation statements)

References 110 publications

(37 reference statements)

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“…Since the first data of DSi in freshwaters by De La Rocha (De La Rocha et al, 2000), δ 30 Si has been analyzed from a number of rivers (and lakes) across the world including the Congo River and tributaries Hughes et al, 2011), the Tana River (Hughes et al, 2012), the Yellow and Yangtze Rivers (Ding et al, 2004(Ding et al, , 2011, the Kalix River in Sweden (Engström et al, 2010), Swiss alpine rivers (Georg et al, 2006), and most recently from the Nile River (Cockerton et al, 2013), the Amazon river and tributaries , areas of central Siberia (Pokrovsky et al, 2013;Panizzo et al, 2017) and the Ganges (Fontorbe et al, 2013;Frings et al, 2015). The range in δ 30 Si from freshwaters, thus far analyzed, now stands at −0.17 to +4.66‰ (Figure 1).…”

Section: Riversmentioning

confidence: 99%

“…All the work published on the major catchment/riverine systems (e.g., Cockerton et al, 2013) highlight the complexity of lake/drainage basin systems, and clearly illustrate that both Si concentrations and δ 30 Si are closely controlled by a mixture of weathering/erosion processes [regulated by the wider climate system (De La Rocha et al, 2000;Opfergelt and Delmelle, 2012)], aquatic productivity and catchment soil, vegetation. Studies of the Congo Basin, for example, have shown that δ 30 Si DSi is mainly regulated by the intensity of silicate weathering/secondary mineral formation across the drainage basin with spatial variations further driven by the type of weathering regime and the extent to which clays are dissolved by organic matter ).…”

Section: Riversmentioning

confidence: 99%

“…These abiotic processes are then superimposed by seasonal biological processes, in particular by diatom biomineralization in the dry season, which exports significant amounts of Si out of the water column (Hughes et al, 2011). Other examples also account for the downstream increase in Nile River δ 30 Si to the progressive uptake of DSi by diatoms and other Si-accumulating organisms (Cockerton et al, 2013). Indeed, Cockerton et al (2013) showed significant seasonal variations in δ 30 Si from freshwaters, with higher δ 30 Si in the dry season (+1.54 to +4.66‰) than the wet season (+0.48 to +3.45‰) due to reduced mobilization of dissolved Si from the catchment relative to its aquatic demand.…”

Section: Riversmentioning

confidence: 99%

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A Review of the Stable Isotope Bio-geochemistry of the Global Silicon Cycle and Its Associated Trace Elements

et al. 2018

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Section: Riversmentioning

confidence: 99%

Section: Riversmentioning

confidence: 99%

Section: Riversmentioning

confidence: 99%

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A Review of the Stable Isotope Bio-geochemistry of the Global Silicon Cycle and Its Associated Trace Elements

et al. 2018

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“…L. Victoria and lakes Kyoga and Albert link via River Nile; L. George is associated to L. Edward via a large flowing water mass, Kazinga Channel and L. Edward to L. Albert through River Semliki (Green 2009;Byrnes 2010;Cockerton et al 2013), (also see Fig. 1).…”

Section: Study Areas/locationsmentioning

confidence: 99%

Anthropogenic impacts on the contextual morphological diversification and adaptation of Nile tilapia (Oreochromis niloticus, L. 1758) in East Africa

et al. 2018

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Nile tilapia occurs naturally in East Africa where it's an economically important species. Many of the natural populations of Nile tilapia have been affected by anthropogenic activities including translocations, associated with programmes aimed at enhancing capture fisheries and aquaculture productivity. Using geometric morphometric analyses, we tested the hypothesis that such anthropogenic activities have augmented admixture among natural populations of Nile tilapia and influenced the geographical distribution of morphological variation within the species. Our expectation was that Nile tilapia shape divergent might be consistent with reportedly anthropogenic activities in nonnative environments. To test this hypothesis, we analyzed the shapes of 490 individuals from thirteen populations; three farms, six natives and four nonnative natural populations. Our analysis revealed that the most pronounced shape diversification was observed in seven populations; three nonnatives (Victoria, Kyoga and Sindi farm) and four natives (Albert, River Nile, George and Turkana). The features responsible for the observed morphotypes were mainly related to the orientation of the anterior region of the fish and may be due to diversifying selection in response to new environmental pressures (for nonnative populations), admixture or drift. Shape change in the nonnative high-altitude populations was unexpectedly conserved, suggesting recent introductions which may have not resulted in admixture or there was strong selection against change in the traits measured. On the other hand, the recorded morphotypic clusters explained the possible genetic link to their putative ancestral home. Our results were partially consistent with our prediction that the nonnative populations exhibited divergent morphotypes. We recommend further investigations with molecular genetics for followup of these findings.

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“…De la https://doi.org/10.1016/j.gca.2018.03.015 0016-7037/Ó 2018 Elsevier Ltd. All rights reserved. Rocha et al, 2000;Ding et al, 2004Ding et al, , 2011Georg et al, 2006a;Hughes et al, 2013;Cockerton et al, 2013;Vandevenne et al, 2015;Steinhoefel et al, 2017), and residual clays and iron oxides with negative values (down to d 30 Si $ À2.5‰; e.g. Ziegler et al, 2005aZiegler et al, , 2005bDelstanche et al, 2009;Opfergelt et al, 2010;Steinhoefel et al, 2011;Opfergelt and Delmelle, 2012).…”

Section: Introductionmentioning

confidence: 99%

The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology

Bayon

Delvigne

Ponzevera

et al. 2018

Geochimica et Cosmochimica Acta

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The d 30 Si stable isotopic composition of silicon in soils and fine-grained sediments can provide insights into weathering processes on continents, with important implications on the Si budget of modern and past oceans. To further constrain the factors controlling the distribution of Si isotopes in sediments, we have analysed a large number (n = 50) of separate size-fractions of sediments and suspended particulate materials collected near the mouth of rivers worldwide. This includes some of the world's largest rivers (e.g. Amazon, Congo, Mackenzie, Mississippi, Murray-Darling, Nile, Yangtze) and rivers from the case study areas of the Congo River Basin and Northern Ireland. Silt-size fractions exhibit a mean Si isotopic composition (d 30 Si = À0.21 ± 0.19‰; 2 s.d.) similar to that previously inferred for the upper continental crust. In contrast, clay-size fractions display a much larger range of d 30 Si values from À0.11‰ to À2.16‰, which yield a global d 30 Si clay of À0.57 ± 0.60‰ (2 s.d.) representative of the mean composition of the average weathered continental crust. Overall, these new data show that the Si isotopic signature transported by river clays is controlled by the degree of chemical weathering, as inferred from strong relationships with Al/Si ratios. At a global scale, the clay-bound Si isotopic composition of the world's largest river systems demonstrates a link with climate, defining a general correlation with mean annual temperature (MAT) in corresponding drainage basins. While the distribution of Si isotopes in river sediments also appears to be influenced by the tectonic setting, lithological effects and sediment recycling from former sedimentary cycles, our results pave the way for their use as paleo-weathering and paleo-climate proxies in the sedimentary record.

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Stable-isotope (H, O, and Si) evidence for seasonal variations in hydrology and Si cycling from modern waters in the Nile Basin: implications for interpreting the Quaternary record

Abstract: Seasonal variations in hydrology and Si cycling in the Nile Basin were investigated using stable-isotope (H, O, and Si) compositions and dissolved Si (DSi) concentrations of surface waters, as a basis for interpreting lacustrine diatom sequences. δ

Cited by 54 publications

References 110 publications

A Review of the Stable Isotope Bio-geochemistry of the Global Silicon Cycle and Its Associated Trace Elements

A Review of the Stable Isotope Bio-geochemistry of the Global Silicon Cycle and Its Associated Trace Elements

Anthropogenic impacts on the contextual morphological diversification and adaptation of Nile tilapia (Oreochromis niloticus, L. 1758) in East Africa

The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology

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