Hydrological changes and Holocene climate variations in NW China, inferred from lake sediments of Juyanze palaeolake by factor analyses

Hartmann, Kai; Wünnemann, Bernd

doi:10.1016/j.quaint.2007.06.037

Cited by 101 publications

(60 citation statements)

References 44 publications

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“…Water sources are mainly groundwater, summer rainfalls, and sporadic runoff from small branches of the lower reaches of the Heihe River. In this region, the mean annual precipitation is <50 mm, and evaporation is roughly 2,000-2,500 mm/y (47)(48)(49). In the laboratory, 1 μL of the original lake water was diluted into 100 μL of sterilized half-strength R 2 A medium, and the dilution was plated directly onto half-strength R 2 A agar plates (SI Appendix, Table S1).…”

Section: Phylogeny Of Photosynthesis Genes In Gemmatimonadetes Andmentioning

confidence: 99%

Functional type 2 photosynthetic reaction centers found in the rare bacterial phylum Gemmatimonadetes

Zeng

Feng

Medová

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

208

253

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Photosynthetic bacteria emerged on Earth more than 3 Gyr ago. To date, despite a long evolutionary history, species containing (bacterio)chlorophyll-based reaction centers have been reported in only 6 out of more than 30 formally described bacterial phyla: Cyanobacteria, Proteobacteria, Chlorobi, Chloroflexi, Firmicutes, and Acidobacteria. Here we describe a bacteriochlorophyll a-producing isolate AP64 that belongs to the poorly characterized phylum Gemmatimonadetes. This red-pigmented semiaerobic strain was isolated from a freshwater lake in the western Gobi Desert. It contains fully functional type 2 (pheophytin-quinone) photosynthetic reaction centers but does not assimilate inorganic carbon, suggesting that it performs a photoheterotrophic lifestyle. Full genome sequencing revealed the presence of a 42.3-kb-long photosynthesis gene cluster (PGC) in its genome. The organization and phylogeny of its photosynthesis genes suggests an ancient acquisition of PGC via horizontal transfer from purple phototrophic bacteria. The data presented here document that Gemmatimonadetes is the seventh bacterial phylum containing (bacterio)chlorophyllbased phototrophic species. To our knowledge, these data provide the first evidence that (bacterio)chlorophyll-based phototrophy can be transferred between distant bacterial phyla, providing new insights into the evolution of bacterial photosynthesis.anoxygenic photosynthesis | horizontal gene transfer | bacterial pigments | aerobic photoheterotroph | fluorescence imaging system

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Section: Phylogeny Of Photosynthesis Genes In Gemmatimonadetes Andmentioning

confidence: 99%

Functional type 2 photosynthetic reaction centers found in the rare bacterial phylum Gemmatimonadetes

Zeng

Feng

Medová

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

208

253

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“…Total organic carbon (ToC) content in lake sediments is one of the proxies used for the analysis of lake basin ecological environments (Mackay et al, 2012), including the effective humidity (An et al, 1993;Long et al, 2010;Li et al, 2016b), precipitation (Xu et al, 2006;An et al, 2012), runoff (hartmann and Wünnemann, 2009), and has been widely used in paleoenvironmental studies (Ji et al, 2005;Xu et al, 2007;Liu et al, 2013;Kołaczek et al, 2014). in previous studies, ToC contents in surface sediments have been interpreted mainly to reflect climate factors that influence terrestrial plant growth or the input processes of terrestrial organic matter to lakes and rivers (Ji et al, 2005;Xu et al, 2007;Kołaczek et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Total organic carbon and its environmental significance for the surface sediments in groundwater recharged lakes from the Badain Jaran Desert, northwest China

Dong

Chen

et al. 2017

J Limnol

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Total organic carbon (ToC) content in lake sediments is typically used for the reconstruction of paleoenvironments. it remains uncertain, however, whether these sediment variables in lakes supplied by groundwater in the hinterland of the Badain Jaran Desert are applicable. Moreover, it is still uncertain whether the ToC content in these lakes can be used as a proxy to identify past climatic change and environmental evolution studies. in this study, the spatial distributions of the ToC contents and C/n ratios were analyzed for 109 surface sediment samples collected from five lakes without runoff recharge. The results revealed that the ToC content of the lake surface sediments was extremely low (0.03% -1.01%) and consisted of both allochthonous organic matter carried by wind, as well as autochthonous organic matter generated in the lakes. Within a lake, spatial differences in the amount of ToC found in surface sediments may be caused by several processes including bathymetry topography and wind-induced wave activity. in addition, wind-induced wave activity produces a higher ToC content, which is more pronounced in larger lakes (>0.21 km 2 ) with longer fetches. By contrast, in smaller lakes, organic matter accumulates in the deeper waters, but can be affected by many factors. it is therefore necessary to consider lake area when applying the ToC content of lake sediments for the reconstruction of a paleolake evolution. Furthermore, because the ToC content of lake sediments in hyper-arid regions is extremely low, and the organic matter may have multiple and varied sources, a single proxy (ToC) cannot be used to reconstruct lake evolution.

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“…Extremely low run off occurred between 8900 and 8100 cal BP. Compared with the early Holocene wet climate, the mid to late Holocene local rainfall was less pronounced and displays a general decreasing trend towards complete desiccation of the lake (Hartmann and Wunnemann, 2009). A two-meter deep hole (39.83°N, 102.47°E, Alashan) above 15 m than Lake Huhejilin water surface indicate that the lake level of Huhejilin was at least 15 m higher from about 8,000 to 7,000 cal BP than at present (Yang, 2001).…”

Section: Evidences From Desert Plains (Gobi) and Alluvial Sedimentationmentioning

confidence: 92%

“…The eastern Juyanze palaeolake in the east edge of the Ejina Basin (Figure 13d) (41.75-42°N, 101.5-102°E) provides evidence of a complex hydrological pattern during the Holocene (Hartmann and Wunnemann, 2009). Lithological, geochemical and mineral data of sedimentary cores from the lake indicate remarkable difference between the early Holocene and mid to late Holocene lake formation.…”

Section: Evidences From Desert Plains (Gobi) and Alluvial Sedimentationmentioning

confidence: 98%

“…The maximum dimension of the Guaizihu Lake and Juyanze basins is about 60×60 km. These ancient lake basins have now thoroughly dried up in the natural environment, and the area of recent day playas, which are assumed to show evidence of higher lake levels in the past or even the existence of a palaeolake Hartmann and Wunnemann, 2009), cover an area of about 15,000 km 2 . Viewing from remote-sensing images, these lakes were apparently the terminal lakes of the Roushui River (Figure 13).…”

Section: 13desert Gorgesmentioning

confidence: 99%

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Climate-Driven Landformof the Ejina Basin (NW China) in Central Asia and Its Paleoenvironmental Implications

Zhu¹

2015

ESR

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Though neotectonic activity is believed to be the major factor in the evolution of the topography of the Ejina Basin in Central Asia, detailed documentation and analysis of climatic landscape features and their environmental implications are lacking. The present study is a site-specific documentation of landforms developed in the wide part of the Ejina Basin, with the aim to identify the climatic landforms based on the method of climatic geomorphology and to evaluate its landscape evolution and response to palaeoclimate changes. The morphodynamics of older landscapes are recognized by making comparison with the present climate and its corresponding landscapes. Clear evidences testifying the basin-scale shifting and transformation of different morphoclimatic zones in the basin are observed, which prove that the main geomorphic unit is changed from an alluvial-lacustrine plain to a desert plain. The coexistence of diverse landscapes and the consequent geomorphodiversity in the basin should be a compound result of surficial processes other than glaciations. The climate and hydrological conditions of the basin during the last glaciation and during the Early Holocene were much better than at present, possibly having an average annual precipitation ranged between 60~350 mm on the basin during ca. 39-23 ka BP but great fluctuations during Holocene. The periods of lower aridity during the late Pleistocene in the bain could be induced by an increase of the westerlies and a weakening of the Asian winter monsoon on the arid areas of the central Asia.

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Hydrological changes and Holocene climate variations in NW China, inferred from lake sediments of Juyanze palaeolake by factor analyses

Cited by 101 publications

References 44 publications

Functional type 2 photosynthetic reaction centers found in the rare bacterial phylum Gemmatimonadetes

Functional type 2 photosynthetic reaction centers found in the rare bacterial phylum Gemmatimonadetes

Total organic carbon and its environmental significance for the surface sediments in groundwater recharged lakes from the Badain Jaran Desert, northwest China

Climate-Driven Landformof the Ejina Basin (NW China) in Central Asia and Its Paleoenvironmental Implications

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