Spatial variability and the controlling mechanisms of surface sediments from Nam Co, central Tibetan Plateau, China

Wang, Junbo; Zhu, Liping; Wang, Yong; Ju, Jianting; Daut, Gerhard; Li, Minghui

doi:10.1016/j.sedgeo.2015.01.011

Cited by 29 publications

(16 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4 ), and attributed it to different living environments instead of metabolic MIF during growth, because in vivo MIF was not supported theoretically or experimentally until now 11 12 13 44 50 51 . In this study, the adult G. namensis and G. waddelli mostly occupy the main lakes except migrating for spawning from May to July every year or every two years 61 , and the juveniles usually stay in tributaries before 5 years of age where the water depth is lower (Nam Co Lakes: 2 to 93 m 28 ; tributaries: 1–2 m) and the size of its MHg pool is much smaller. Because light penetration depths were similar between tributaries and lakes based on their close DOC concentrations 62 , the intraspecies variations of Hg isotopes were probably caused by different sizes of MHg pool.…”

Section: Discussionmentioning

confidence: 79%

“…1 ). The geological setting and limnology of the Nam Co Lake have been studied due to its large size and important role in hydrogeology on the TP, but Yamdrok Lake was not studied before 25 27 28 . Sediment and biotic samples from the bottom to the top trophic positions were collected and processed for analysis of Hg concentrations and nitrogen, carbon, and Hg stable isotopes.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Linking mercury, carbon, and nitrogen stable isotopes in Tibetan biota: Implications for using mercury stable isotopes as source tracers

Zhang

Wang

2016

Sci Rep

View full text Add to dashboard Cite

Tibetan Plateau is located at a mountain region isolated from direct anthropogenic sources. Mercury concentrations and stable isotopes of carbon, nitrogen, and mercury were analyzed in sediment and biota for Nam Co and Yamdrok Lake. Biotic mercury concentrations and high food web magnification factors suggested that Tibetan Plateau is no longer a pristine site. The primary source of methylmercury was microbial production in local sediment despite the lack of direct methylmercury input. Strong ultraviolet intensity led to extensive photochemical reactions and up to 65% of methylmercury in water was photo-demethylated before entering the food webs. Biota displayed very high Δ199Hg signatures, with some highest value (8.6%) ever in living organisms. The δ202Hg and Δ199Hg in sediment and biotic samples increased with trophic positions (δ15N) and %methylmercury. Fish total length closely correlated to δ13C and Δ199Hg values due to dissimilar carbon sources and methylmercury pools in different living waters. This is the first mercury isotope study on high altitude lake ecosystems that demonstrated specific isotope fractionations of mercury under extreme environmental conditions.

show abstract

Section: Discussionmentioning

confidence: 79%

mentioning

confidence: 99%

Linking mercury, carbon, and nitrogen stable isotopes in Tibetan biota: Implications for using mercury stable isotopes as source tracers

Zhang

Wang

2016

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Since Al and Fe are thought to be of allochthonous origin in lacustrine systems (Wen et al, 2008;Wündsch et al, 2018), their significant correlation with water depth (r = 0.87 and 0.81, respectively; α < 0.05; Table 1) indicates the high accumulation of allochthonous material within the deep zones of basins A and B. According to Anderson et al (2008, and references cited therein), sediment accumulation mostly occurs below a mud deposition boundary depth which is further described by Wang et al (2015) as the sediment accumulation zone that is least influenced by wind-driven turbulences and other processes. Thus, this accumulation zone provides the best suited sediments for paleoenvironmental studies, and for Lake Khar Nuur, a distinct sediment focussing occurs in the accumulation zones in the two basins A and B (Anderson et al, 2008;Lehman, 1975;Wang et al, 2015).…”

Section: Grain Size and Elementsmentioning

confidence: 92%

“…aluminium (Al), iron (Fe)] distribution which is directly related to transport mechanisms and transport energies and indicate allochthonous input into the lake (Håkanson & Jansson, 1983;Mclaren & Bowles, 1985;Wen et al, 2008;Wündsch et al, 2018). Both proxies can be used to trace sediment focussing in deeper parts of the lake below the mud deposition boundary (Anderson et al, 2008;Lehman, 1975;Wang et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

The spatial distribution of sedimentary compounds and their environmental implications in surface sediments of Lake Khar Nuur (Mongolian Altai)

Strobel

Struck

Zech

et al. 2021

Earth Surf Processes Landf

View full text Add to dashboard Cite

Lake sediments are valuable natural archives to reconstruct paleoclimate and paleoenvironmental changes which consist of inorganic and organic sediment compounds of allochthonous origin from the catchment and of autochthonous production in the lake. However, for robust paleo-reconstructions it is important to develop a better understanding about sedimentation processes, the origin of inorganic and organic sediment compounds and their distribution within the lake. In this context, modern process studies provide important insights, although environmental and anthropological changes can affect the spatial distribution of sediment compounds through time. Therefore, in this study the spatial distribution of grain size and geochemical proxies in 52 surface sediment samples from Lake Khar Nuur, a small high-altitude lake in the Mongolian Altai with a small and anthropogenically used hydrological catchment, is investigated. The results show a distinct sediment focussing in the two deep basins of the lake, which therefore act as accumulation zones. In those accumulation zones, total organic carbon (TOC), total nitrogen (N) and their isotopic composition (δ 13 C TOC , δ 15 N) as well as n-alkanes indicate that organic sediment compounds are a mixture of both allochthonous and autochthonous origin. While the recent catchment vegetation consists of grasses/herbs and the shrub Betula nana (L.) with distinct differences in their n-alkane homologue patterns, those differences are not reflected in the sediment surface samples which rather indicates that grass-derived n-alkanes become preferentially incorporated in the lake. Extensive anthropogenic activity such as grazing and housing in the southern part of the catchment causes soil erosion which is well reflected by high TOC, N and sulphur (S) contents and 15 N depleted δ 15 N values at the central southern shore, i.e. increased allochthonous sediment input by anthropogenically-induced soil erosion. Overall, the surface sediments of Lake Khar Nuur origin from allochthonous and autochthonous sources and are focussed in the accumulation zones of the lake, while their distribution is both environmentally and anthropogenically driven.

show abstract

“…Moreover, the spatial distributions of elements in lake sediments, a powerful indicator of past environmental conditions (Chawchai et al, ; Sahoo et al, ; Tanaka et al, ; Xiao et al, ), can reveal the provenance of sediments and the weathering intensity of their source areas (Allen et al, ; Jin et al, ; Kříbek et al, ). Thus, temporal changes in lake sediment chemical composition have been the focus of many sedimentology and paleoclimatology studies (L. Chen et al, ; Day et al, ; J. Wang et al, ).…”

Section: Introductionmentioning

confidence: 99%

Environmental Significance of the Chemical Composition of Sediments in Groundwater‐Recharged Lakes of the Badain Jaran Desert, NW China

Chen

Zou

et al. 2019

Geochem Geophys Geosyst

View full text Add to dashboard Cite

For lakes in desert hinterlands that are not recharged by river runoff, sediment is input solely by wind transport; however, the mechanisms that control the spatial variations in geochemical characteristics of sediments in such lakes remain unclear. Moreover, it remains uncertain whether some element ratios can be used as proxies for environmental characteristics. In this study, 100 surface sediment samples were collected from five lakes in the hinterland of the Badain Jaran Desert, NW China, and examined for their major, trace and rare earth element contents and mineral assemblages. Chemical composition and mineral components of the sediments differed significantly between lakes with different total dissolved solids (TDS). Geochemical characteristics of the lake sediments and their spatial variations are influenced by eolian sands, saline minerals, and sediment sorting. Eolian sands dominate the immobile and nonsoluble elements, whereas authigenic minerals are important in influencing variations in the mobile and soluble elements. Sediment sorting is reflected in the spatial variation of the sediment chemical composition. The positive relationship between the SiO 2 /Ti of sediment and lake area indicates that changes in the SiO 2 /Ti ratio can reveal approximate lake area. The Na 2 O/K 2 O ratio in sediments can reveal the TDS of salt lakes more effectively than can the Rb/Sr ratio. However, the key factors and mechanisms governing the chemical composition of sediments at different brine evolution stages vary among lakes with different TDS levels, which should be carefully considered when interpreting the environmental significance of the chemical composition as a proxy for paleoenviroment change.

show abstract

Spatial variability and the controlling mechanisms of surface sediments from Nam Co, central Tibetan Plateau, China

Cited by 29 publications

References 47 publications

Linking mercury, carbon, and nitrogen stable isotopes in Tibetan biota: Implications for using mercury stable isotopes as source tracers

Linking mercury, carbon, and nitrogen stable isotopes in Tibetan biota: Implications for using mercury stable isotopes as source tracers

The spatial distribution of sedimentary compounds and their environmental implications in surface sediments of Lake Khar Nuur (Mongolian Altai)

Environmental Significance of the Chemical Composition of Sediments in Groundwater‐Recharged Lakes of the Badain Jaran Desert, NW China

Contact Info

Product

Resources

About