scholarly journals Continuous Lake-Sediment Records of Glaciation in the Sierra Nevada between 52,600 and 12,50014C yr B.P

1998 ◽  
Vol 50 (2) ◽  
pp. 113-127 ◽  
Author(s):  
Larry V. Benson ◽  
Howard M. May ◽  
Ronald C. Antweiler ◽  
Terry I. Brinton ◽  
Michaele Kashgarian ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Lake Sediments ◽  
Sierra Nevada ◽  
Lake Sediment ◽  
Size Fraction ◽  
Alpine Glacier ◽  
Owens Lake ◽  
Clay Size Fraction

The chemistry of the carbonate-free clay-size fraction of Owens Lake sediments supports the use of total organic carbon and magnetic susceptibility as indicators of stadial–interstadial oscillations. Owens Lake records of total organic carbon, magnetic susceptibility, and chemical composition of the carbonate-free, clay-size fraction indicate that Tioga glaciation began ∼24,500 and ended by ∼13,60014C yr B.P. Many of the components of glacial rock flour (e.g., TiO2, MnO, BaO) found in Owens Lake sediments achieved maximum values during the Tioga glaciation when valley glaciers reached their greatest extent. Total organic carbon and SiO2(amorphous) concentrations reached minimum values during Tioga glaciation, resulting from decreases in productivity that accompanied the introduction of rock flour into the surface waters of Owens Lake. At least 20 stadial–interstadial oscillations occurred in the Sierra Nevada between 52,600 and 14,00014C yr B.P. Total organic carbon data from a Pyramid Lake sediment core also indicate oscillations in glacier activity between >39,500 and ∼13,60014C yr B.P. Alpine glacier oscillations occurred on a frequency of ≤1900 yr in both basins, suggesting that millennial-scale oscillations occurred in California and Nevada during most of the past 52,600 yr.

Climatic Oscillations 10,000–155,000 yr B.P. at Owens Lake, California Reflected in Glacial Rock Flour Abundance and Lake Salinity in Core OL-92

1997 ◽  
Vol 48 (3) ◽  
pp. 313-325 ◽  
Author(s):  
James L. Bischoff ◽  
Kirsten M. Menking ◽  
Jeffrey P. Fitts ◽  
John A. Fitzpatrick
Keyword(s):  
Sierra Nevada ◽  
Clay Fraction ◽  
Size Fraction ◽  
Glacial Cycle ◽  
Abrupt Decrease ◽  
Climatic Oscillations ◽  
Owens Lake ◽  
Clay Size Fraction ◽  
High Carbonate ◽  
Lake Salinity

Chemical analyses of the acid-soluble and clay-size fractions of sediment samples (1500-yr resolution) reveal oscillations of lake salinity and of glacial advances in core OL-92 back to 155,000 yr B.P. Relatively saline conditions are indicated by the abundance of carbonate and smectite (both pedogenic and authigenic), reflected by Ca, Sr, and Mg in the acid-soluble suite, and by Cs2O, excess MgO, and LOI (loss on ignition) in the clay-size fraction. Rock flour produced during glacial advances is represented by the abundance of detrital plagioclase and biotite in the clay-size fraction, the ratio of which remains essentially constant over the entire time span. These phases are quantitatively represented by Na2O, TiO2, Ba, and Mn in the clay fraction. The rock-flour record indicates two major ice-advances during the penultimate glacial cycle corresponding to marine isotope stage (MIS) 6, no major advances during the last interglaciation (entire MIS 5), and three major advances during the last glacial cycle (MIS 2, 3, and 4). The ages of the latter three correspond rather well to36Cl dates reported for Sierra Nevada moraines. The onset of the last interglaciation is shown by abrupt increases in authigenic CaCO3and an abrupt decrease in rock flour, at about 118,000 yr B.P. according to our time scale. In contrast, the boundary appears to be gradual in the δ18O record in which the change from light to heavy values begins at about 140,000 yrs B.P. The exact position of the termination, therefore, may be proxy-dependent. Conditions of high carbonate and low rock flour prevailed during the entire period from 118,000 yr B.P. until the glacial advance at 53,000 yr B.P. signaled the end of this long interglaciation.

scholarly journals Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. III. Distribution and kinetics of soil organic carbon in particle size fractions

Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 293 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Size Fraction ◽  
Organic C ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Clay Size Fraction ◽  
Sand Size

Distribution of soil organic carbon in sand-, silt- and clay-size fractions during cultivation for periods ranging from 20 to 70 years was studied in six major soils used for cereal cropping in southern Queensland. Particle-size fractions were obtained by dispersion in water using cation exchange resin, sieving and sedimentation. In the soils' virgin state no single particle-size fraction was found to be consistently enriched as compared to the whole soil in organic C in all six soils, although the largest proportion (48%) of organic C was in the clay-size fraction; silt and sand-size fractions contained remaining organic C in equal amounts. Upon cultivation, the amounts of organic C declined from all particle-size fractions in most soils, although the loss rates differed considerably among different fractions and from the whole soil. The proportion of the sand-size fraction declined rapidly (from 26% to 12% overall), whereas that of the clay-size fraction increased from 48% to 61% overall. The proportion of silt-size organic C was least affected by cultivation in most soils. It was inferred, therefore, that the sand-size organic matter is rapidly lost from soil, through mineralization as well as disintegration into silt-size and clay-size fractions, and that the clay fraction provides protection for the soil organic matter against microbial and enzymic degradation.

scholarly journals Mercury in Sediment Core Samples From Deep Siberian Ice-Rich Permafrost

2021 ◽  
Vol 9 ◽  
Author(s):  
Clara Rutkowski ◽  
Josefine Lenz ◽  
Andreas Lang ◽  
Juliane Wolter ◽  
Sibylle Mothes ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Susceptibility ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Total Nitrogen ◽  
The Arctic ◽  
Specific Magnetic Susceptibility ◽  
Shallow Soils

We determine Hg concentrations of various deposits in Siberia’s deep permafrost and link sediment properties and Hg enrichment to establish a first Hg inventory of late Pleistocene permafrost down to a depth of 36 m below surface. As Arctic warming is transforming the ice-rich permafrost of Siberia, sediment is released and increases the flux of particulates to the Arctic shelf seas through thawing coasts, lakeshores, and river floodplains. Heavy metals within soils and sediments are also released and may increasingly enter Arctic waters and the biological food chain. High levels of mercury (Hg) have been reported from shallow soils across the Arctic. Rapid thawing is now mobilizing sediment from deeper strata, but so far little is known about Hg concentrations in deep permafrost. Here, forty-one samples from sediment successions at seven sites and of different states of permafrost degradation on Bykovsky Peninsula (northern Yakutian coast) and in the Yukechi Alas region (Central Yakutia) were analyzed for Hg, total carbon, total nitrogen, and total organic carbon as well as grain-size distribution, bulk density, and mass specific magnetic susceptibility. We show average Hg concentrations of 9.72 ± 9.28 μg kg−1 in the deep sediments, an amount comparable to the few previous Arctic studies existing, and a significant correlation of Hg content with total organic carbon, total nitrogen, grain-size distribution, and mass specific magnetic susceptibility. Hg concentrations are higher in the generally sandier sediments of the Bykovsky Peninsula than in the siltier sediments of the Yukechi Alas. The ratio of Hg to total organic carbon in this study is 2.57 g kg−1, including samples with very low carbon content. We conclude that many deep permafrost sediments, some of which have been frozen for millennia, contain elevated concentrations of Hg and the stock of Hg ready to be released by erosion is of significance for the Arctic ecosystem. The Hg mobilized may accumulate on the way to or in the shallow sea, and where it enters into active biogeochemical cycles of aquatic systems it may concentrate in food webs. Our study highlights the need for better understanding Hg stocks and Hg release from permafrost.

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

2017 ◽  
Vol 77 (1) ◽  
Author(s):  
Shipei Dong ◽  
Zhuolun Li ◽  
Qiujie Chen ◽  
Zhiqiao Wei
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Lake Sediments ◽  
Surface Sediments ◽  
Northwest China ◽  
Wave Activity ◽  
Badain Jaran Desert ◽  
Lake Area ◽  
Autochthonous Organic Matter

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 km2) 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 a multiple and varied sources, a single proxy (TOC) cannot be used to reconstruct lake evolution.

scholarly journals REKAM SEDIMEN INTI UNTUK MEMPERKIRAKAN PERUBAHAN LINGKUNGAN DI PERAIRAN LERENG KANGEAN

2017 ◽  
Vol 14 (2) ◽  
Author(s):  
Yani Permanawati ◽  
Tri Prartono ◽  
Agus Saleh Atmadipoera ◽  
Rina Zuraida ◽  
Yuanpin Chang
Keyword(s):  
Principal Component Analysis ◽  
Magnetic Susceptibility ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Environmental Changes ◽  
Principal Component ◽  
Indonesian Throughflow ◽  
Core Sediment ◽  
Java Sea ◽  
Non Destructive

Sedimen inti dianalisis secara vertikal untuk memprediksi perubahan lingkungan saat sedimen terendapkan. Perairan segitiga Laut Jawa-Selat Makassar-Laut Flores (JMF) dilalui jalur arus lintas Indonesia/ARLINDO. Distribusi aliran ARLINDO yang masuk ke Selat Makassar terbagi dua arah aliran karena adanya Ambang Dewakang. Satu mengalir ke arah Tenggara melalui Laut Flores, sementara itu aliran lainnya bergerak ke arah Baratdaya menuju Selat Lombok melalui Laut Jawa. Penelitian ini menganalisis sedimen inti dari perairan Laut Jawa yang diwakili oleh Lereng Kangean. Metode penelitian menggunakan metode non-destructive yaitu pengamatan megaskopis dan pemindaian, dan metode destructive yaitu pencuplikan sistematis menggunakan 2 cm setiap interval 4 cm. Hasil cluster menunjukkan proses pengendapan tampak relatif seragam (88-0 cm) dari analisis sembilan variabel, antara lain: ukuran butir (mean) antara lempung–pasir sangat halus, kecerahan sedimen (L*) sekitar 40,14-44,17, kerentanan magnet (Magnetik Susceptibility/MS) sekitar 13,60-116,70, karbonat biogenik (BC) dari pengamatan mikroskopis sekitar 3-10%, karbonat sekitar 17,36-50,17%, Total Organic Carbon (TOC) sekitar 0,76-2,01%, C/N sekitar 9,11-13,57, ln K/Ti sekitar 0,58-1,09, dan ln Mn/Cl sekitar -4,97- -4,24. Interpretasi karakter sedimen dari hasil deskriptif Principal Component Analysis/PCA menunjukkan penciri utama/F1 sebesar 28,10% dicirikan oleh pengaruh kuat dari variabel MS, ln K/Ti, dan ln Mn/Cl, menggambarkan karakter sedimen dengan pengaruh yang kuat dari daratan. Kata kunci: analisis vertikal, perubahan lingkungan, arus lintas Indonesia, karakter sedimen, penciri utamaA core sediment was vertically analyzed to predict environmental changes of the sediments deposition. Triangle waters of Java Sea-Makassar Strait-Flores Sea (JMF) are traversed by the Indonesian Throughflow or ARLINDO. Distribution of  ARLINDO splited by morphological condition of the Dewakang Sill : Southeast ward of the Flores Sea and Southwest ward of the Lombok Strait through the Java Sea. The purpose of this study is to elaborate characteristics of the Kangean Slope’s core sediment corresponding to the Java Sea. The research method using non-destructive such as megaskopis and scanning method, and destructive such as sampling method which used 2 cm every interval 4 cm.  The cluster analysis showed that deposition process seemed of one kind (88-0 cm) by nine variables. They are : main of grain size between clay to lower very fine sand, lightness sediment (L*) about 40,14-44,17,  Magnetic Susceptibility (MS) about 13,60-116,70, biogenic carbonate (BC) by microscopic observation about 3-10%, carbonate about 17,36-50,17%, Total Organic Carbon (TOC) about 0,76-2,01%, C/N ratio about 9,11-13,57, ln K / Ti about 0,58-1,09, and  ln Mn / Cl about -4,97- -4,24. Sediment character by Principal Component Analysis/PCA showed principle component/F1 as 28,10% indicated Magnetic Susceptibility (MS) and ln K/Ti and ln Mn/Cl were the main character of the Kangean Slope’s sediment and suggested to very strong influence from mainland.Keywords:    vertically analysis, environmental changes, Indonesian throughflow, sediment character, principle component

CHARACTERISATION OF DISSOLVED ORGANIC CARBON (DOC) LEACHED FROM LEAVES IN WATER

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Markus Heryanto Langsa
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Total Organic Carbon ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Pyrolysis Gas Chromatography ◽  
Chromatography Mass Spectrometry ◽  
Pinus Radiate

<p>Penelitian ini bertujuan untuk menentukan senyawa organik khususnya organic karbon terlarut (DOC) dari dua spesies daun tumbuhan (<em>wandoo eucalyptus </em>and <em>pinus radiate, conifer</em>) yang larut dalam air selama periode 5 bulan leaching eksperimen. Kecepatan melarutnya senyawa organic ditentukan secara kuantitatif dan kualitatif menggunakan kombinasi dari beberapa teknik diantaranya Total Organic Carbon (TOC) analyser, Ultraviolet-Visible (UV-VIS) spektrokopi dan pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS).</p><p>Hasil analisis DOC dan UV menunjukkan peningkatan yang tajam dari kelarutan senyawa organic di awal periode pengamatan yang selanjutnya berkurang seiring dengan waktu secara eksponensial. Jumlah relatif senyawa organic yang terlarut tergantung pada luas permukaan, aktifitas mikrobiologi dan jenis sampel tumbuhan (segar atau kering) yang digunakan. Fluktuasi profil DOC dan UV<sub>254</sub> disebabkan oleh aktifitas mikrobiologi. Diperoleh bahwa daun kering lebih mudah terdegradasi menghasilkan senyawa organic dalam air dibandingkan dengan daun segar. Hasil pyrolysis secara umum menunjukkan bahwa senyawa hidrokarbon aromatic dan fenol (dan turunannya) lebih banyak ditemukan pada residue sampel setelah proses leaching kemungkinan karena adanya senyawa lignin atau aktifitas humifikasi mikrobiologi membuktikan bahwa senyawa-senyawa tersebut merupakan komponen penting dalam proses karakterisasi DOC.</p>

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