Lead-210 chronology of the Scandinavian SWAP sites

1990 ◽  
Vol 327 (1240) ◽  
pp. 239-242 ◽  
Keyword(s):  
Land Use ◽  
Sediment Accumulation ◽  
Past Century ◽  
The Past ◽  
Enhanced Dissolution ◽  
Surface Water Acidification ◽  
Constant Rate ◽  
Minor Losses ◽  
Lead 210 ◽  
Atmospheric Inputs

In the Surface Water Acidification Project (SWAP) sediment profiles from five Scandinavian sites were analysed for 210 Pb by using refined isotope dilution alpha spectrometry. The 210 Pb parameters of these lakes were very similar to those obtained for protected forest lakes with no land-use activities. These data demonstrated almost exclusive atmospheric inputs and an internal deposition regulated by the organic fractionation and the grain-size distribution in the sediments. Preliminary speciation experiments showed minor losses of 210 (≤ 5%) through enhanced dissolution of fulvic compounds at acid conditions (pH ≥ 4). The sediment accumulation rates (constant rate of unsupported 210 Pb supply (CRS) model) of the lakes gradually increased, by at least a factor of three, over the past century although 210 Pb parameters did not show any strong signs of enhanced land-use activities. This is perhaps caused by more efficient preservation of the sediments through humic precipitation under more acid conditions.

scholarly journals Assessing potential landscape service trade-offs driven by urbanization in Switzerland

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Madleina Gerecke ◽  
Oskar Hagen ◽  
Janine Bolliger ◽  
Anna M. Hersperger ◽  
Felix Kienast ◽  
...  
Keyword(s):  
Land Use ◽  
Urban Expansion ◽  
Land Use Changes ◽  
Landscape Management ◽  
Past Century ◽  
Landscape Services ◽  
The Past ◽  
Trade Offs ◽  
Land Surfaces ◽  
Landscape Information

Abstract Landscapes have been changing at an increasing pace over the past century, with countless consequences for humans and their surrounding environments. Information on past and future land use change and the resulting alteration of landscape service provisioning are valuable inputs for policy making and planning. Land use transitions in Switzerland (2009–2081) were simulated using statistical models informed by past land use changes as well as environmental and socio-economic data (1979–2009). By combining land use types with additional contextual landscape information, eight landscape services, based on both (semi-)natural and artificial landscapes, were quantified and investigated on how they would evolve under projected land use changes. Investigation of land use transitions showed region-dependent trends of urban expansion, loss of agricultural area, and forest regrowth. Landscapes cannot accommodate all services simultaneously, and this study sheds light on some competing landscape services, in particular (i) housing at the expense of agriculture and (ii) vanishing recreation opportunities around cities as city limits, and thus housing and job provisioning, expand. Model projections made it possible to pinpoint potential trade-offs between landscape services in a spatially explicit manner, thereby providing information on service provision losses and supporting planning. While future changes are presented as extrapolations of the patterns quantified in the past, policy changes might cause deviation from the projections presented here. A major challenge is to produce socio-economic and policy scenarios to inform projections that will differ from current landscape management. Given that urban sprawl is affecting many land surfaces globally, the approach used here could be generalized to other countries in similar situations.

Changes in the bird fauna of Uttara Kannada, India, in relation to changes in land use over the past century

1990 ◽  
Vol 52 (1) ◽  
pp. 37-48 ◽  
Author(s):  
R.J. Ranjit Daniels ◽  
N.V. Joshi ◽  
Madhav Gadgil
Keyword(s):  
Land Use ◽  
Past Century ◽  
The Past ◽  
Bird Fauna

scholarly journals Sedimentation rates in the Lake Qattinah using 210Pb and 137Cs as geochronometer

2014 ◽  
Vol 41 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Eskander Alhajji ◽  
Iyas Ismail ◽  
Mohammad Al-Masri ◽  
Nouman Salman ◽  
Mohammad Al-Haleem ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Past Century ◽  
Sedimentation Rates ◽  
Accumulation Rates ◽  
210Pb And 137Cs ◽  
The Past ◽  
Activity Concentrations ◽  
210Pb Activity ◽  
Constant Rate ◽  
210Pb Method

Abstract The constant rate of supply (CRS) of excess 210Pb model was successfully applied to assess 210Pb data of two sediment cores from the lake Qattinah, Syria. Gamma spectrometry was used to determine 137Cs and 210Pb activity concentrations. The bottom of the cores was 210Pb-dated to years 1907 and 1893. The accumulation rates were determined using 210Pb method and found to vary similarly in both cores from 0.10 ± 0.01 to 3.78 ± 0.57 kg m−2 y−1 during the past century. 137Cs was used as an in-dependent chronometer. The two distinct peaks observed on the 137Cs record of both cores, corresponding to 1965 and 1986, have allowed a successful validation of the CRS model.

Lead-210 and Pollen Geochronologies on Lake Superior Sediments

1975 ◽  
Vol 5 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Kenneth W. Bruland ◽  
Minoru Koide ◽  
Carl Bowser ◽  
Louis J. Maher ◽  
Edward D. Goldberg
Keyword(s):  
Average Rate ◽  
Lake Superior ◽  
Ragweed Pollen ◽  
Past Century ◽  
Sedimentation Rates ◽  
Human Settlement ◽  
The Past ◽  
Lead 210

AbstractRates of sedimentation in two Lake Superior deposits were determined by both ragweed pollen and 210Pb geochronologies. The former yields an average rate over the time since the first appearance of enhanced concentrations of the pollen as a consequence of human settlement. Sedimentation rates derived on these two bases can be brought into accord if the first appearance of ragweed pollen in the sediments was around 1830 and if the sedimentation rates have been uniform over the past century.

Extreme floods in the Meuse river over the past century: aggravated by land-use changes?

2005 ◽  
Vol 30 (4-5) ◽  
pp. 267-276 ◽  
Author(s):  
Min Tu ◽  
Michael J. Hall ◽  
Pieter J.M. de Laat ◽  
Marcel J.M. de Wit
Keyword(s):  
Land Use ◽  
Land Use Changes ◽  
Past Century ◽  
Extreme Floods ◽  
The Past ◽  
Meuse River

scholarly journals Mapping dynamics of agricultural land use in the dry steppe zone of the Northern Кazakhstan

2021 ◽  
Vol 27 (4) ◽  
pp. 5-18
Author(s):  
Tatiana Vorobyova ◽  
Yelaman Smagulov
Keyword(s):  
Land Use ◽  
Agricultural Land ◽  
Arable Land ◽  
Steppe Zone ◽  
Agricultural Landscapes ◽  
Agricultural Land Use ◽  
Past Century ◽  
The Past ◽  
Northern Kazakhstan ◽  
Dry Steppe

The agricultural use of land resources in the dry steppe regions of Northern Kazakhstan has undergone significant changes over the past century and continues to change at the present time. The middle position in the region is occupied by the Akmola region, one of the leading agricultural regions, where 9.3 % of the country’s gross agricultural output is produced. The main branches of agriculture in the region are grain farming and dairy and beef cattle breeding. The study of the change in the ratio of the areas of arable and pasture lands, the changes that have occurred in the state of agricultural landscapes as a result of long-term use is important for the further development of the agricultural industry in the region. Using the example of the Astrakhan district of the Akmola region, typical for the dry steppe zone, an analysis of changes in the structure of agricultural land from 1953 to 2020 was carried out. with the help of a series of digital maps compiled from detailed maps of scientific reference atlases of Northern Kazakhstan in 1964, 1970, remote sensing data of different times, archival materials and data of modern statistics. The resulting maps visualize significant changes in cropland areas within the study area over the past 70 years. Seven main periods were identified, during which the most significant changes in the structure of land use occurred as a result of political, economic and natural factors. During the years of development of virgin and fallow lands, the highest rates of increase in arable land were observed, which continued on a smaller scale until 1990. The period from 1991-1999 characterized by a large-scale reduction of arable land and abandonment of pastures. This was followed by two periods of gradual restoration of the use of arable and rangelands. Compiled comprehensive map of the dynamics of agricultural land use from 1988 to 2020 made it possible to identify spatial and temporal patterns in changes in the structure of agricultural land use, to determine to which specific natural types of lands the abandoned lands belonged and to which restored ones. Spatial analysis showed that over the past 30, more than half of the area’s area has not changed the type of land use. The results obtained are used to select the optimal ratio of arable and pasture lands in the structure of agricultural land use, as well as to develop a strategy for the rational use of agricultural land in the zone of risky farming.

scholarly journals Early land use and centennial scale changes in lake-water organic carbon prior to contemporary monitoring

2015 ◽  
Vol 112 (21) ◽  
pp. 6579-6584 ◽  
Author(s):  
Carsten Meyer-Jacob ◽  
Julie Tolu ◽  
Christian Bigler ◽  
Handong Yang ◽  
Richard Bindler
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Lake Water ◽  
Past Century ◽  
The Past ◽  
Catchment Disturbance ◽  
Millennial Time Scale ◽  
Carbon Concentrations ◽  
Early Land

Organic carbon concentrations have increased in surface waters across parts of Europe and North America during the past decades, but the main drivers causing this phenomenon are still debated. A lack of observations beyond the last few decades inhibits a better mechanistic understanding of this process and thus a reliable prediction of future changes. Here we present past lake-water organic carbon trends inferred from sediment records across central Sweden that allow us to assess the observed increase on a centennial to millennial time scale. Our data show the recent increase in lake-water carbon but also that this increase was preceded by a landscape-wide, long-term decrease beginning already A.D. 1450–1600. Geochemical and biological proxies reveal that these dynamics coincided with an intensification of human catchment disturbance that decreased over the past century. Catchment disturbance was driven by the expansion and later cessation of widespread summer forest grazing and farming across central Scandinavia. Our findings demonstrate that early land use strongly affected past organic carbon dynamics and suggest that the influence of historical landscape utilization on contemporary changes in lake-water carbon levels has thus far been underestimated. We propose that past changes in land use are also a strong contributing factor in ongoing organic carbon trends in other regions that underwent similar comprehensive changes due to early cultivation and grazing over centuries to millennia.

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