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2. A study of heavy metals and radionuclides in Scottish freshwater loch sediments

Author

Bryant, Charlotte L.

Subjects
551.9
Abstract

Heavy metals (Fe, Mn, Pb, Zn, Cu, Cd, Co and Ni) and radionuclides 210Pb, 134Cs and 137Cs were studied in the sediments of Scottish freshwater lochs (acidified Round Loch of Glenhead, oligotrophic/mesotrophic Loch Lomond, eutrophic Loch Leven and Balgavies Loch and Loch Coire nan Arr in the remote north-west) to compare metal behaviour and associations in the different systems. Metal concentrations were determined in acid digested and sequentially extracted sediment and sediment porewaters. Radionuclide concentrations were measured to investigate sedimentation processes. Redox cycling of Fe and Mn was important in all the lochs. In Balgavies Loch, porewater data for Fe and Mn were related to redox conditions at the time of sampling, whereas the solid phase concentrations were still changing in response to recent water column stratification. The association of Fe with organic matter was additionally important in surface sediment of Round Loch and Loch Coire nan Arr. Mn behaviour in Round Loch was also influenced by surface water acidification via post-depositional leaching of Mn from the sediment and/or a pH-related decrease in the efficiency of Mn sedimentation, resulting in increasing Mn concentration with depth. Post-depositional mobility of Pb was not evident, despite the association of Pb with Fe oxides/hydroxides in sediments from all the lochs. This was supported by low, or non-detectable, porewater Pb concentrations and little change with depth in the relative concentrations of Pb in each fraction. Zn was generally more labile than Pb and, in Loch Coire nan Arr and Balgavies Loch, redox related release of Zn from the sediment and short-range mobility was apparent. In Round Loch, Zn concentrations, decreasing sharply towards the sediment surface, were explained by historical trends in pollutant Zn deposition to the loch, as well as a pH-related decrease in the efficiency of Zn deposition to the sediment.

Published
1993

9. Relationships between riverine and terrestrial dissolved organic carbon: Concentration, radiocarbon signature, specific UV absorbance

Author

Tipping, Edward, primary, Elias, Jessica L., additional, Keenan, Patrick O., additional, Helliwell, Rachel C., additional, Pedentchouk, Nikolai, additional, Cooper, Richard J., additional, Buckingham, Sarah, additional, Gjessing, Egil, additional, Ascough, Philippa, additional, Bryant, Charlotte L., additional, and Garnett, Mark H., additional

Published
2022
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10. A Complete Terrestrial Radiocarbon Record for 11.2 to 52.8 kyr B.P.

Author

Ramsey, Christopher Bronk, Staff, Richard A., Bryant, Charlotte L., Brock, Fiona, Kitagawa, Hiroyuki, van der Plicht, Johannes, Schlolaut, Gordon, Marshall, Michael H., Brauer, Achim, Lamb, Henry F., Payne, Rebecca L., Tarasov, Pavel E., Haraguchi, Tsuyoshi, Gotanda, Katsuya, Yonenobu, Hitoshi, Yokoyama, Yusuke, Tada, Ryuji, and Nakagawa, Takeshi

Published
2012
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14. Relationships between riverine and terrestrial dissolved organic carbon: Concentration, radiocarbon signature, specific UV absorbance

Author

Tipping, Edward, Eliasa, Jessica L., Keenan, Patrick O., Helliwell, Rachel C., Pedentchouk, Nikolai, Cooper, Richard J., Buckingham, Sarah, Gjessing, Egil, Ascough, Philippa, Bryant, Charlotte L., and Garnett, Mark H.

Subjects
Environmental Engineering, Rivers, Environmental Chemistry, Hydrology, Dissolved Organic Matter, Pollution, Waste Management and Disposal, Ecology and Environment, Carbon, Carbon Cycle, Environmental Monitoring
Abstract

The transfer of dissolved organic carbon (DOC) from land to watercourses plays a major role in the carbon cycle, and in the transport and fate of associated organic and inorganic contaminants. We investigated, at global scale, how the concentrations and properties of riverine DOC depend upon combinations of terrestrial source solutions. For topsoil, subsoil, groundwater and river solutions in different Köppen-Geiger climatic zones, we compiled published and new values of DOC concentration ([DOC]), radiocarbon signature (DO14C), and specific UV absorbance (SUVA). The average value of each DOC variable decreased significantly in magnitude from topsoil to subsoil to groundwater, permitting the terrestrial sources to be distinguished. We used the terrestrial data to simulate the riverine distributions of each variable, and also relationships between pairs of variables. To achieve good matches between observed and simulated data, it was necessary to optimise the distributions of water fractions contributed by each of the three terrestrial sources, and also to reduce the mean input terrestrial [DOC] values, to about 60% of the measured ones. One possible explanation for the required lowering of the modelled terrestrial [DOC] values might be unrepresentative sampling of terrestrial DOC, including dilution effects; another is the loss of DOC during riverine transport. High variations in simulated riverine DOC variables, which match observed data, are due predominantly to variations in source solution values, with a lesser contribution from the different combinations of source waters. On average, most DOC in rivers draining catchments with forest and/or grass-shrub land cover comes in similar amounts from topsoil and subsoil, with about 10% from groundwater. In rivers draining croplands, subsoil and groundwater solutions are the likely dominant DOC sources, while in wetland rivers most DOC is from topsoil.

Published
2021

22. Evidence for a bi-partition of the Younger Dryas Stadial in East Asia associated with inversed climate characteristics compared to Europe

Author

Schlolaut, Gordon, primary, Brauer, Achim, additional, Nakagawa, Takeshi, additional, Lamb, Henry F., additional, Tyler, Jonathan J., additional, Staff, Richard A., additional, Marshall, Michael H., additional, Bronk Ramsey, Christopher, additional, Bryant, Charlotte L., additional, and Tarasov, Pavel E., additional

Published
2017
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23. Long-term macronutrient stoichiometry of UK ombrotrophic peatlands

Author

Schillereff, Daniel N., primary, Boyle, John F., additional, Toberman, Hannah, additional, Adams, Jessica L., additional, Bryant, Charlotte L., additional, Chiverrell, Richard C., additional, Helliwell, Rachel C., additional, Keenan, Patrick, additional, Lilly, Allan, additional, and Tipping, Edward, additional

Published
2016
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25. Integration of the Old and New Lake Suigetsu (Japan) Terrestrial Radiocarbon Calibration Data Sets

Author

Staff, Richard A., Schlolaut, Gordon, Christopher Bronk Ramsey, Brock, Fiona, Bryant, Charlotte L., Kitagawa, Hiroyuki, Plicht, Johannes, Marshall, Michael H., Brauer, Achim, Lamb, Henry F., Payne, Rebecca L., Tarasov, Pavel E., Haraguchi, Tsuyoshi, Gotanda, Katsuya, Yonenobu, Hitoshi, Yokoyama, Yusuke, Nakagawa, Takeshi, Suigetsu 2006 Project, and Isotope Research

Subjects
010506 paleontology, Archeology, 010504 meteorology & atmospheric sciences, Calibration (statistics), Borehole, 550 - Earth sciences, Scale (descriptive set theory), 01 natural sciences, KYR BP, law.invention, law, AGE CALIBRATION, Radiocarbon dating, Geomorphology, 0105 earth and related environmental sciences, Varve, Sediment, Macrofossil, LATE-GLACIAL CHRONOLOGY, CAL BP, RECORD, Data set, YR BP, General Earth and Planetary Sciences, Physical geography, Geology
Abstract

The varved sediment profile of Lake Suigetsu, central Japan, offers an ideal opportunity from which to derive a terrestrial record of atmospheric radiocarbon across the entire range of the 14C dating method. Previous work by Kitagawa and van der Plicht (1998a,b, 2000) provided such a data set; however, problems with the varve-based age scale of their SG93 sediment core precluded the use of this data set for 14C calibration purposes. Lake Suigetsu was re-cored in summer 2006, with the retrieval of overlapping sediment cores from 4 parallel boreholes enabling complete recovery of the sediment profile for the present “Suigetsu Varves 2006” project (Nakagawa et al. 2012). Over 550 14C determinations have been obtained from terrestrial plant macrofossils picked from the latter SG06 composite sediment core, which, coupled with the core's independent varve chronology, provides the only non-reservoir-corrected 14C calibration data set across the 14C dating range.Here, physical matching of archive U-channel sediment from SG93 to the continuous SG06 sediment profile is presented. We show the excellent agreement between the respective projects' 14C data sets, allowing the integration of 243 14C determinations from the original SG93 project into a composite Lake Suigetsu 14C calibration data set comprising 808 individual 14C determinations, spanning the last 52,800 cal yr.

Published
2013

29. Progress in AMS target production in sub-milligram samples at the NERC Radiocarbon Laboratory

Author

Ertunc, Tanya, Xu, Sheng, Bryant, Charlotte L., Maden, Colin, Murray, Callum, Currie, Margaret, and Freeman, Stewart T.

Abstract

Recent progress in graphite target production for sub-milligram environmental samples in our facility is presented.\ud We describe an optimized hydrolysis procedure now routinely used for the preparation of CO2 from inorganic samples,\ud a new high-vacuum line dedicated to small sample processing (combining sample distillation and graphitization units),\ud as well as a modified graphitization procedure. Although measurements of graphite targets as small as 35 µg C have been\ud achieved, system background and measurement uncertainties increase significantly below 150 µg C. As target lifetime can\ud become critically short for targets

Published
2005

32. Diatom-inferred late Pleistocene and Holocene palaeolimnological changes in the Ioannina basin, northwest Greece

Author

Jones, Timothy D., primary, Lawson, Ian T., additional, Reed, Jane M., additional, Wilson, Graham P., additional, Leng, Melanie J., additional, Gierga, Merle, additional, Bernasconi, Stefano M., additional, Smittenberg, Rienk H., additional, Hajdas, Irka, additional, Bryant, Charlotte L., additional, and Tzedakis, P. C., additional

Published
2012
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33. A Complete Terrestrial Radiocarbon Record for 11.2 to 52.8 kyr B.P.

Author

Bronk Ramsey, Christopher, primary, Staff, Richard A., additional, Bryant, Charlotte L., additional, Brock, Fiona, additional, Kitagawa, Hiroyuki, additional, van der Plicht, Johannes, additional, Schlolaut, Gordon, additional, Marshall, Michael H., additional, Brauer, Achim, additional, Lamb, Henry F., additional, Payne, Rebecca L., additional, Tarasov, Pavel E., additional, Haraguchi, Tsuyoshi, additional, Gotanda, Katsuya, additional, Yonenobu, Hitoshi, additional, Yokoyama, Yusuke, additional, Tada, Ryuji, additional, and Nakagawa, Takeshi, additional

Published
2012
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34. Toward establishing precise 40Ar/39Ar chronologies for Late Pleistocene palaeoclimate archives: an example from the Lake Suigetsu (Japan) sedimentary record

Author

Smith, Victoria C., primary, Mark, Darren F., additional, Staff, Richard A., additional, Blockley, Simon P.E., additional, Ramsey, Christopher Bronk, additional, Bryant, Charlotte L., additional, Nakagawa, Takeshi, additional, Han, Kim Kyu, additional, Weh, Alexander, additional, Takemura, Keiji, additional, and Danhara, Toru, additional

Published
2011
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36. Accurate increment identification and the spatial extent of the common signal in five Arctica islandica chronologies from the Fladen Ground, northern North Sea

Author

Butler, Paul G., primary, Richardson, Christopher A., additional, Scourse, James D., additional, Witbaard, Rob, additional, Schöne, Bernd R., additional, Fraser, Nicole M., additional, Wanamaker, Alan D., additional, Bryant, Charlotte L., additional, Harris, Ian, additional, and Robertson, Iain, additional

Published
2009
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42. The multiple chronological techniques applied to the Lake Suigetsu SG06 sediment core, central Japan.

Author

Staff, Richard A., Nakagawa, Takeshi, Schlolaut, Gordon, Marshall, Michael H., Brauer, Achim, Lamb, Henry F., Bronk Ramsey, Christopher, Bryant, Charlotte L., Brock, Fiona, Kitagawa, Hiroyuki, Plicht, Johannes, Payne, Rebecca L., Smith, Victoria C., Mark, Darren F., Macleod, Alison, Blockley, Simon P. E., Schwenninger, Jean‐Luc, Tarasov, Pavel E., Haraguchi, Tsuyoshi, and Gotanda, Katsuya

Subjects
GEOLOGICAL time scales, RADIOCARBON dating, OPTICALLY stimulated luminescence dating, LAKE sediments, DATA analysis, FLOODS
Abstract

The varved sediment of Lake Suigetsu (central Japan) provides a valuable opportunity to obtain high-resolution, multi-proxy palaeoenvironmental data across the last glacial/interglacial cycle. In order to maximize the potential of this archive, a well-constrained chronology is required. This paper outlines the multiple geochronological techniques being applied - namely varve counting, radiocarbon dating, tephrochronology (including argon-argon dating) and optically stimulated luminescence ( OSL) - and the approaches by which these techniques are being integrated to form a single, coherent, robust chronology. Importantly, we also describe here the linkage of the floating Lake Suigetsu ( SG06) varve chronology and the absolute ( Int Cal09 tree-ring) time scale, as derived using radiocarbon data from the uppermost (non-varved) portion of the core. This tie-point, defined as a distinct (flood) marker horizon in SG06 (event layer B-07-08 at 1397.4 cm composite depth), is thus derived to be 11 255 to 11 222 Int Cal09 cal. years BP (68.2% probability range). [ABSTRACT FROM AUTHOR]

Published
2013
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43. NEW 14C DETERMINATIONS FROM LAKE SUIGETSU, JAPAN: 12,000 TO 0 CAL BP.

Author

Staff, Richard A., Ramsey, Christopher Bronk, Bryant, Charlotte L., Brock, Fiona, Payne, Rebecca L., Schlolaut, Gordon, Marshall, Michael H., Brauer, Achim, Lamb, Henry F., Tarasov, Pavel, Yokoyama, Yusuke, Haraguchi, Tsuyoshi, Gotanda, Katsuya, Yonenobu, Hitoshi, and Nakagawa, Takeshi

Subjects
RADIOCARBON dating, CALIBRATION, FOSSIL plants, LAKES
Abstract

Calibration is a fundamental stage of the radiocarbon (14C) dating process if one is to derive meaningful calendar ages from samples' 14C measurements. For the first time, the IntCal09 calibration curve (Reimer et al. 2009) provided an internationally ratified calibration data set across almost the complete range (0 to 50,000 cal BP) of the 14C timescale. However, only the last 12,550 cal yr of this record are composed of terrestrial data, leaving approximately three quarters of the 14C timescale necessarily calibrated via less secure, marine records (incorporating assumptions pertaining to the temporally variable "marine reservoir effect"). The predominantly annually laminated (varved) sediment profile of Lake Suigetsu, central Japan, offers an ideal opportunity to derive an extended terrestrial record of atmospheric 14C across the entire range of the method, through pairing of 14C measurements of terrestrial plant macrofossil samples (extracted from the sediment) with the independent chronology provided through counting of its annual laminations. This paper presents new data (182 14C determinations) from the upper (largely non-varved) 15 m of the Lake Suigetsu (SG06) sediment strata. These measurements provide evidence of excellent coherence between the Suigetsu 14C data and the IntCal09 calibration curve across the last ~12,000 cal yr (i.e. the portion of IntCal based entirely on terrestrial data). Such agreement demonstrates that terrestrial plant material picked from the Lake Suigetsu sediment provides a reliable archive of atmospheric 14C, and therefore supports the site as being capable of providing a high-resolution extension to the "wholly terrestrial" (i.e. non-reservoir-corrected) calibration curve beyond its present 12,550 cal BP limit. [ABSTRACT FROM AUTHOR]

Published
2011

44. Toward establishing precise 40Ar/39Ar chronologies for Late Pleistocene palaeoclimate archives: an example from the Lake Suigetsu (Japan) sedimentary record

Author

Smith, Victoria C., Mark, Darren F., Staff, Richard A., Blockley, Simon P.E., Ramsey, Christopher Bronk, Bryant, Charlotte L., Nakagawa, Takeshi, Han, Kim Kyu, Weh, Alexander, Takemura, Keiji, and Danhara, Toru

Subjects
*ARGON, *PALEOCLIMATOLOGY, *SEDIMENTS, *ARCHIVES, *TEPHROCHRONOLOGY, *VOLCANIC ash, tuff, etc.
Abstract

Abstract: The varved Suigetsu (SG06) sediment core is potentially one of the most important and well-constrained mid-latitude palaeoclimate archives, recording continuous deposition during the last ∼150 kyrs. Numerous visible and non-visible volcanic ash layers form unique age markers within SG06. These ash layers are too fine and crystal-poor to be directly dated using the 40Ar/39Ar technique so the tephra were correlated to proximal volcanic deposits using their glass shard compositions. A high-precision 40Ar/39Ar sanidine age of 10.0 ± 0.3 ka (1σ, n = 34, MSWD = 0.71, p = 0.89) was obtained for the SG06-1288 (U-Oki) proximal tephra (Ulleungdo U4). 40Ar/39Ar yields a precision of ±3% near the younger limit of the method, with improved precision possible for older SG06 samples. Such 40Ar/39Ar ages for tephra layers can provide invaluable tie-points within the Lake Suigetsu SG06 sequence, giving independent verification of the core’s varve chronology, allowing for the calibration of cosmogenic nuclide production, and providing a precise chronology beyond the varve limit. [Copyright &y& Elsevier]

Published
2011
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