Isotopes in Lake Sediments

Leng, Melanie J.; Lamb, Angela L.; Heaton, Timothy H.; Marshall, James D.; Wolfe, Brent B.; Jones, Matthew D.; Holmes, Jonathan A.; Arrowsmith, Carol

doi:10.1007/1-4020-2504-1_04

Cited by 135 publications

(145 citation statements)

References 112 publications

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“…We analysed bulk organic carbon isotopes (d 13 C org ), total organic carbon (TOC), total nitrogen (TN), and C/N (atomic) ratio to explore environmental changes within the palaeo-lake. Before measuring the d 13 C org and TOC values, we followed the procedure described in Leng et al [34] to remove carbonates from the samples by immersing them in 10 % HCl until complete degassing of CO 2 . The values of d 13 C org and TOC were measured in the Isotope Laboratory of GeoZentrum Nordbayern, Friedrich Alexander Universität Erlangen Nürnberg, using a CE 1110 Elemental analyser connected online to a ThermoFisher Delta V plus mass spectrometer.…”

Section: Geochemical Samples and Methodsmentioning

confidence: 99%

“…The values of d 13 C org are primarily controlled by the isotopic composition of the carbon source during photosynthesis [34,35,52]; an increase in the isotopic composition of the source of carbon (such as atmospheric or aqueous CO 2 ) produces an increase in d 13 C org [34,35]. When primary productivity is high, d 13 C org values increase because C 3 plants preferentially absorb 12 C during photosynthesis, leaving the remaining carbon enriched in 13 C if the carbon source is not replenished [35].…”

Section: Environmental Significance Of Geochemical Proxiesmentioning

confidence: 99%

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Lake geochemistry reveals marked environmental change in Southwest China during the Mid Miocene Climatic Optimum

Lebreton-Anberrée

et al. 2016

Science Bulletin

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The Mid-Miocene Climatic Optimum (MMCO; *15-17 Ma) was one of the short-term climatic warm events that punctuated the Cenozoic long-term cooling trend. Because there are very few terrestrial records of this event, most of our understanding comes from marine cores. In this report, we first present new palaeomagnetic data that revises the dating of our 400 m-thick lacustrine section in Wenshan (Yunnan), previously thought to be Late Miocene. These new data suggest an older age, ca. 15.2-16.5 Ma, coinciding with the MMCO. We measured d 13 C on bulk organic matter (d 13 C org ), total organic carbon (TOC), total nitrogen (TN) and C/N ratios at a high sample resolution to: (1) reconstruct the palaeoenvironmental changes in the lake catchment area, and (2) infer mechanisms responsible for these changes. Our results show that all four geochemical parameters demonstrate that a strong environmental change occurred around the middle of the section, shortly after the C5Cn/C5Br geomagnetic reversal and the Early/Middle Miocene boundary at 15.97 Ma. We propose that the environmental shift may be due to a combination of a change in climate, which became cooler, together with a change in organic matter cycling within the lake. This study provides a new insight into the MMCO and demonstrates that although the MMCO was generally a warm event, it was also a time of climatic instability and abrupt environmental changes.Keywords Yunnan Á Mid-Miocene Climatic Optimum Á Bulk organic carbon isotopes (d 13 C org ) Á C/N ratio Á TOC Electronic supplementary material The online version of this article

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Section: Geochemical Samples and Methodsmentioning

confidence: 99%

Section: Environmental Significance Of Geochemical Proxiesmentioning

confidence: 99%

Lake geochemistry reveals marked environmental change in Southwest China during the Mid Miocene Climatic Optimum

Lebreton-Anberrée

et al. 2016

Science Bulletin

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“…We consequently attribute the formation of the carbonate laminae primarily to evaporation, although the influence of algal photosynthesis cannot be ruled out (Leng et al 2006;Li and Ku 1997;.…”

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confidence: 92%

First lacustrine varve chronologies from Mexico: impact of droughts, ENSO and human activity since AD 1840 as recorded in maar sediments from Valle de Santiago

et al. 2009

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We present varve chronologies for sediments from two maar lakes in the Valle de Santiago region (Central Mexico): Hoya La Alberca (AD 1852(AD -1973 and Hoya Rincón de Parangueo (AD 1839(AD -1943. These are the first varve chronologies for Mexican lakes. The varved sections were anchored with tephras from Colima (1913) and Paricutín (1943Paricutín ( /1944 and 210 Pb ages. We compare the sequences using the thickness of seasonal laminae and element counts (Al, Si, S, Cl, K, Ti, Mn, Fe, and Sr) determined by micro X-ray fluorescence spectrometry. The formation of the varve sublaminae is attributed to the strongly seasonal climate regime. Limited rainfall and high evaporation rates in winter and spring induce precipitation of carbonates (high Ca, Sr) enriched in 13 C and 18 O, whereas rainfall in summer increases organic and clastic input (plagioclase, quartz) with high counts of lithogenic elements (K, Al, Ti, and Si). Eolian input of Ti occurs also in the dry season. Moving correlations (5-yr windows) of the Ca and Ti counts show similar development in both sequences until the 1930s. Positive correlations indicate mixing of allochthonous Ti and autochthonous Ca, while negative correlations indicate their separation in sublaminae. Negative excursions in the correlations correspond with historic and reconstructed droughts, El Niño events, and This paper is dedicated to our colleague and friend Jim Luhr,

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“…Environmental changes can affect the isotopic composition of organic matter, the amount of organic matter produced within lakes, the relative contribution of autochthonous and allochthonous organic matter, and the transport processes leading to the incorporation of organic matter into lake sediments. Therefore, analysis of d 13 C of bulk sedimentary organic matter (SOM) can potentially provide information on past changes in climate, productivity, origin of organic matter, pollution, and in-lake carbon cycling (Leavitt et al 2006;Leng et al 2005;Meyers and LallierVergès 1999). It is difficult, however, to reconstruct limnological changes in different compartments (benthic, pelagic) of a lake based on d 13 C of SOM only, since variations in d 13 C of SOM may reflect variations in the isotopic composition of organic matter within the lake as well as in the lake catchment.…”

Section: Introductionmentioning

confidence: 99%

Taxon-specific δ13C analysis of chitinous invertebrate remains in sediments from Strandsjön, Sweden

et al. 2014

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Taxon-specific stable carbon isotope (d 13 C) analysis of chitinous remains of invertebrates can provide valuable information about the carbon sources used by invertebrates living in specific habitats of lake ecosystems (for example, sediments, water column, or aquatic vegetation). This is complementary to d 13 C of sedimentary organic matter (SOM), which provides an integrated signal of organic matter produced in a lake and its catchment, and of diagenetic processes within sediments. In a sediment record from Strandsjön (Sweden) covering the past circa 140 years, we analyzed SOM geochemistry (d 13 C, C:N atomic , organic carbon content) and d 13 C of chitinous invertebrate remains in order to examine whether taxon-specific d 13 C records could be developed for different invertebrate groups and whether these analyses provide insights into past changes of organic carbon sources for lacustrine invertebrates available in benthic and planktonic compartments of the lake. Invertebrate taxa included benthic chironomids (Chironomus, Chironomini excluding Chironomus, Tanytarsini, and Tanypodinae), filter-feeders on suspended particulate organic matter (Daphnia, Plumatella and Cristatella mucedo), and Rhabdocoela. d 13 C of chironomid remains indicated periodic availability of 13 C-depleted carbon sources in the benthic environment of the lake as d 13 C values of the different chironomid taxa fluctuated simultaneously between -34.7 and -30.5 % (VPDB). Daphnia and Bryozoa showed parallel changes in their d 13 C values which did not coincide with variations in d 13 C of chironomids, though, and a 2-3 % decrease since circa AD 1960. The decrease in d 13 C of Daphnia and Bryozoa could indicate a decrease in phytoplankton d 13 C as a result of lower lake productivity, which is in accordance with historical information about the lake that suggests a shift to less eutrophic conditions after AD 1960. In contrast, Rhabdocoela cocoons were characterized by relatively high d 13 C values (-30.4 to -28.2 %) that did not show a strong temporal trend, which could be related to the predatory feeding mode and wide prey Author's personal copy spectrum of this organism group. The taxon-specific d 13 C analyses of invertebrate remains indicated that different carbon sources were available for the benthic chironomid larvae than for the filter-feeding Daphnia and bryozoans. Our results therefore demonstrate that taxon-specific analysis of d 13 C of organic invertebrate remains can provide complementary information to measurements on bulk SOM and that d 13 C of invertebrate remains may allow the reconstruction of past changes in carbon sources and their d 13 C in different habitats of lake ecosystems.

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Isotopes in Lake Sediments

Cited by 135 publications

References 112 publications

Lake geochemistry reveals marked environmental change in Southwest China during the Mid Miocene Climatic Optimum

Lake geochemistry reveals marked environmental change in Southwest China during the Mid Miocene Climatic Optimum

First lacustrine varve chronologies from Mexico: impact of droughts, ENSO and human activity since AD 1840 as recorded in maar sediments from Valle de Santiago

Taxon-specific δ13C analysis of chitinous invertebrate remains in sediments from Strandsjön, Sweden

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