scholarly journals Late Quaternary environmental and climatic changes in central Europe as inferred from the composition of organic matter in annually laminated maar lake sediments

2004 ◽  
Vol 5 (11) ◽  
pp. n/a-n/a ◽  
Author(s):  
Andreas Fuhrmann ◽  
Thomas Fischer ◽  
Andreas Lücke ◽  
Achim Brauer ◽  
Bernd Zolitschka ◽  
...  
Keyword(s):  
Organic Matter ◽  
Lake Sediments ◽  
Central Europe ◽  
Late Quaternary ◽  
Climatic Changes ◽  
Maar Lake

scholarly journals A late Quaternary record of eolian silt deposition in a maar lake, St. Michael Island, western Alaska

2003 ◽  
Vol 60 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Daniel R. Muhs ◽  
Thomas A. Ager ◽  
Josh Been ◽  
J. Platt Bradbury ◽  
Walter E. Dean
Keyword(s):  
Lake Sediments ◽  
Late Quaternary ◽  
Geochemical Data ◽  
Unexpected Finding ◽  
The Holocene ◽  
Tundra Vegetation ◽  
Shrub Tundra ◽  
Loess Deposition ◽  
Maar Lake ◽  
Glacial Time

AbstractRecent stratigraphic studies in central Alaska have yielded the unexpected finding that there is little evidence for full-glacial (late Wisconsin) loess deposition. Because the loess record of western Alaska is poorly exposed and not well known, we analyzed a core from Zagoskin Lake, a maar lake on St. Michael Island, to determine if a full-glacial eolian record could be found in that region. Particle size and geochemical data indicate that the mineral fraction of the lake sediments is not derived from the local basalt and is probably eolian. Silt deposition took place from at least the latter part of the mid-Wisconsin interstadial period through the Holocene, based on radiocarbon dating. Based on the locations of likely loess sources, eolian silt in western Alaska was probably deflated by northeasterly winds from glaciofluvial sediments. If last-glacial winds that deposited loess were indeed from the northeast, this reconstruction is in conflict with a model-derived reconstruction of paleowinds in Alaska. Mass accumulation rates in Zagoskin Lake were higher during the Pleistocene than during the Holocene. In addition, more eolian sediment is recorded in the lake sediments than as loess on the adjacent landscape. The thinner loess record on land may be due to the sparse, herb tundra vegetation that dominated the landscape in full-glacial time. Herb tundra would have been an inefficient loess trap compared to forest or even shrub tundra due to its low roughness height. The lack of abundant, full-glacial, eolian silt deposition in the loess stratigraphic record of central Alaska may be due, therefore, to a mimimal ability of the landscape to trap loess, rather than a lack of available eolian sediment.

scholarly journals Traces of sunlight in the organic matter biogeochemistry of two shallow subarctic lakes

2021 ◽  
Author(s):  
Marttiina V. Rantala ◽  
Carsten Meyer-Jacob ◽  
E. Henriikka Kivilä ◽  
Tomi P. Luoto ◽  
Antti. E. K. Ojala ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Lake Sediments ◽  
Lake Water ◽  
Human Impacts ◽  
Global Environmental Change ◽  
Carbon Export ◽  
Subarctic Lakes ◽  
Carbon Regulation ◽  
In Situ Experiments

AbstractGlobal environmental change alters the production, terrestrial export, and photodegradation of organic carbon in northern lakes. Sedimentary biogeochemical records can provide a unique means to understand the nature of these changes over long time scales, where observational data fall short. We deployed in situ experiments on two shallow subarctic lakes with contrasting light regimes; a clear tundra lake and a dark woodland lake, to first investigate the photochemical transformation of carbon and nitrogen elemental (C/N ratio) and isotope (δ13C, δ15N) composition in lake water particulate organic matter (POM) for downcore inferences. We then explored elemental, isotopic, and spectral (inferred lake water total organic carbon [TOC] and sediment chlorophyll a [CHLa]) fingerprints in the lake sediments to trace changes in aquatic production, terrestrial inputs and photodegradation before and after profound human impacts on the global carbon cycle prompted by industrialization. POM pool in both lakes displayed tentative evidence of UV photoreactivity, reflected as increasing δ13C and decreasing C/N values. Through time, the tundra lake sediments traced subtle shifts in primary production, while the woodland lake carried signals of changing terrestrial contributions, indicating shifts in terrestrial carbon export but possibly also photodegradation rates. Under global human impact, both lakes irrespective of their distinct carbon regimes displayed evidence of increased productivity but no conspicuous signs of increased terrestrial influence. Overall, sediment biogeochemistry can integrate a wealth of information on carbon regulation in northern lakes, while our results also point to the importance of considering the entire spectrum of photobiogeochemical fingerprints in sedimentary studies.

The first Permian scorpionfly from Germany (Insecta, Panorpida: Protomeropidae)

2021 ◽  
Vol 4 (3) ◽  
Author(s):  
MARKUS J. POSCHMANN ◽  
ANDRÉ NEL
Keyword(s):  
Central Europe ◽  
Black Shale ◽  
New Genus ◽  
Climatic Changes ◽  
Late Carboniferous ◽  
Early Permian ◽  
New Genus And Species

A new genus and species, Glanomerope virgoferroa gen. et sp. nov., the first Permian record of a scorpionfly from Germany, is described from the Niedermoschel black shale, Meisenheim Formation, Lower Rotliegend of the Saar-Nahe basin. It is assigned to the Protomeropidae, the oldest known family of the holometabolous superorder Panorpida, ranging from the Bashkirian-Moscovian (Late Carboniferous) to the Roadian. It confirms that this family was very diverse in Central Europe during the Early Permian. Protomeropidae possibly became extinct in the course of major climatic changes that progressively affected the supercontinent Pangea after the Artinskian, although generally these changes seem to have more severely affected some other insects such as the palaeopteran Dictyoneuridae than holometabolous groups.

scholarly journals Separation and 14C Dating of Pure Pollen from Lake Sediments: Nanofossil AMS Dating

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 557-560 ◽  
Author(s):  
Austin Long ◽  
Owen K. Davis ◽  
Jeanne de Lanois
Keyword(s):  
Organic Matter ◽  
Lake Sediments ◽  
Mono Lake ◽  
Bulk Sediment ◽  
Clean Room ◽  
14C Dating ◽  
Ams Dating

We have developed and tested a practical device for manually separating pollen from pollen concentrates in sufficient quantity for AMS 14C dating. It is a combination of standard, commercially available equipment handled in a clean room by an individual trained to recognize pollen. A typical example requires about 15–20 h of hand-picking under the microscope. We show the usefulness of this procedure with results on a mid-Holocene segment from a core from Mono Lake. Sediments from this hardwater lake contain pollen and finely disseminated organic matter, but no macrofossils. The pollen dated ca. 1000 yr younger than the bulk sediment. The sediment “date” is most likely affected by incorporation of limestone-derived carbon, and is erroneously old.

scholarly journals Trace metal distribution in pristine permafrost-affected soils of the Lena River Delta and its Hinterland, Northern Siberia, Russia

2013 ◽  
Vol 10 (2) ◽  
pp. 2205-2244 ◽  
Author(s):  
I. Antcibor ◽  
S. Zubrzycki ◽  
A. Eschenbach ◽  
L. Kutzbach ◽  
D. Bol'shiyanov ◽  
...  
Keyword(s):  
Trace Elements ◽  
Organic Matter ◽  
Trace Metal ◽  
Climatic Changes ◽  
River Delta ◽  
Metal Distribution ◽  
Background Concentrations ◽  
Lena River ◽  
Trace Metal Distribution ◽  
Lena River Delta

Abstract. Soils are an important compartment of ecosystems and have the ability to immobilize chemicals preventing their movement to other environment compartments. Predicted climatic changes together with other anthropogenic influences on Arctic terrestrial environments may affect biogeochemical processes enhancing leaching and migration of trace elements in permafrost-affected soils. This is especially important since the Arctic ecosystems are considered to be very sensitive to climatic changes as well as to chemical contamination. This study characterizes background levels of trace metals in permafrost-affected soils of the Lena River Delta and its hinterland in northern Siberia (73.5° N–69.5° N) representing a remote region far from evident anthropogenic trace metal sources. Investigations on total element contents of iron (Fe), arsenic (As), manganese (Mn), zinc (Zn), nickel (Ni), copper (Cu), lead (Pb), cadmium (Cd), cobalt (Co) and mercury (Hg) in different soil types developed in different geological parent materials have been carried out. The highest concentrations of the majority of the measured elements were observed in soils belonging to ice-rich permafrost sediments formed during the Pleistocene (ice-complex) in the Lena River Delta region. Correlation analyses of trace metal concentrations and soil chemical and physical properties at a Holocene estuarine terrace and two modern floodplain levels in the southern-central Lena River Delta (Samoylov Island) showed that the main factors controlling the trace metal distribution in these soils are organic matter content, soil texture and contents of iron and manganese-oxides. Principal Component Analysis (PCA) revealed that soil oxides play a significant role in trace metal distribution in both top and bottom horizons. Occurrence of organic matter contributes to Cd binding in top soils and Cu binding in bottom horizons. Observed ranges of the background concentrations of the majority of trace elements were similar to background levels reported for other pristine arctic areas and did not exceed mean global background concentrations examined for the continental crust as well as for the world's soils.

Glacial advances in southeastern Tibet during late Quaternary and their implications for climatic changes

2010 ◽  
Vol 218 (1-2) ◽  
pp. 58-66 ◽  
Author(s):  
Zhou Shangzhe ◽  
Wang Jie ◽  
Xu Liubing ◽  
Wang Xiaoli ◽  
Patrick M. Colgan ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Climatic Changes ◽  
Southeastern Tibet

Biomarkers, Including Botryococcenes, in Maar Lake Sediments from Vietnam Record Fluctuations in Phytoplankton Dynamics

2019 ◽  
Author(s):  
Kelsey E. Doiron ◽  
Arndt Schimmelmann ◽  
Huang Nguyen-Văn ◽  
Duong Nguyen-Thùy ◽  
Simon C. Brassell
Keyword(s):  
Lake Sediments ◽  
Phytoplankton Dynamics ◽  
Maar Lake

scholarly journals Analysis of Wastewater Generated in Greenhouse Soilless Tomato Cultivation in Central Europe

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2538 ◽  
Author(s):  
Artur Mielcarek ◽  
Joanna Rodziewicz ◽  
Wojciech Janczukowicz ◽  
Artur Dobrowolski
Keyword(s):  
Organic Matter ◽  
Chemical Oxygen Demand ◽  
Central Europe ◽  
Oxygen Demand ◽  
Complete Recovery ◽  
Qualitative Composition ◽  
Coconut Fiber ◽  
High Concentration ◽  
North Eastern ◽  
Soilless Cultivation

Soilless plantations under cover constitute a significant part of horticulture. This study aimed at determining the qualitative composition of wastewater generated from the soilless cultivation of tomato under cover. This is important for managing the wastewater, which may be recirculated to allow the or employ a partial or complete recovery of minerals. Two plantations located in north-eastern Poland, which differed in the type of substratum (coconut fiber or rockwool), were studied. The generated wastewater was characterized by a low content of organic matter and a high concentration of total nitrogen (TN), total phosphorus (TP), and salinity (EC). Over 99% of the TN was constituted by nitrates. The chemical oxygen demand (COD) changed from 50.07 to 75.82 mgO2·L−1 (greenhouse 1), and from 37.35 to 78.12 mgO2·L−1 (greenhouse 2); the content of TN changed from 403.59 to 614.89 mgN·L−1 (greenhouse 1), and from 270.00 to 577.40 mgN·L−1 (greenhouse 2); that of TP changed from 35.44 to 78.00 mgP·L−1 (greenhouse 1), and from 54.10 to 104.00 mgP·L−1 (greenhouse 2); and the EC changed from 3.53 to 6.93 mS·cm−1 (greenhouse 1), and from 4.94 to 6.94 mS·cm−1 (greenhouse 2). No statistically significant correlations were noted between TN and TP, or between TP and EC.

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