scholarly journals Sedimentological characteristics of ice-wedge polygon terrain in Adventdalen (Svalbard). Environmental and climatic implications for the Late Holocene

2014 ◽  
Vol 6 (1) ◽  
pp. 1191-1225
Author(s):  
M. Oliva ◽  
G. Vieira ◽  
P. Pina ◽  
P. Pereira ◽  
M. Neves ◽  
...  
Keyword(s):  
Organic Matter Content ◽  
Soil Formation ◽  
Matter Content ◽  
Valley Bottom ◽  
Radiocarbon Dates ◽  
Climate Conditions ◽  
Fluvial Terraces ◽  
Ice Wedge ◽  
Homogeneous Composition ◽  
Climatic Severity

Abstract. Ice-wedges are widespread periglacial features in the landscape of Adventalen, Svalbard. The networks of ice-wedges have created areas with well-developed polygonal terrains in the lowest fluvial terraces in this valley. We have examined the sedimentological characteristics of the northern and southern banks of the Advent river for palaeoenvironmental purposes. The base of two sedimentary sections reported radiocarbon dates of 3.3 and 3.9 ka cal BP, respectively. The northern site is constituted by three very different lithostratigraphical units, which suggests that their formation should be related to different environmental and climate conditions. By contrast, the southern section shows a rather homogeneous composition, with no significant variations in grain size and organic matter content. In both cases the uppermost sediments are constituted by a thick aeolian deposit. According to our data, warmer climate conditions may have prevailed during the Mid Holocene until 3.3 ka cal BP with widespread peat formation in the valley bottom. Subsequently, a period with alternating soil formation and aeolian sedimentation took place from 3 to 2.5 ka cal BP, probably due to increasing climatic severity. During the last millennium a long-term cooling trend has favoured aeolian deposition in the lowest Adventalen valley.

scholarly journals Sedimentological characteristics of ice-wedge polygon terrain in Adventdalen (Svalbard) – environmental and climatic implications for the late Holocene

Solid Earth ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 901-914 ◽  
Author(s):  
M. Oliva ◽  
G. Vieira ◽  
P. Pina ◽  
P. Pereira ◽  
M. Neves ◽  
...  
Keyword(s):  
Organic Matter Content ◽  
Soil Formation ◽  
Matter Content ◽  
Valley Bottom ◽  
Radiocarbon Dates ◽  
Climate Conditions ◽  
Fluvial Terraces ◽  
Ice Wedge ◽  
Homogeneous Composition ◽  
Climatic Severity

Abstract. Ice wedges are widespread periglacial features in the landscape of Adventdalen, Svalbard. The networks of ice wedges have created areas with well-developed polygonal terrains in the lowest fluvial terraces in this valley. We have examined the sedimentological characteristics of the northern and southern banks of the Advent river for palaeoenvironmental purposes. The base of two sedimentary sections reported radiocarbon dates of 3.3 and 3.9 ka BP, respectively. The northern site is constituted by three very different lithostratigraphical units, which suggests that their formation should be related to different environmental and climate conditions. By contrast, the southern section shows a rather homogeneous composition, with no significant variations in grain size and organic matter content. In both cases the uppermost sediments are constituted by a thick aeolian deposit. According to our data, warmer climate conditions may have prevailed during the mid Holocene until 3.3 ka BP with widespread peat formation in the valley bottom. Subsequently, a period with alternating soil formation and aeolian sedimentation took place from 3 to 2.5 ka BP, probably due to increasing climatic severity. During the last millennium a long-term cooling trend has favoured aeolian deposition in the lowest part of Adventdalen.

scholarly journals Initial limnological observations at five small lakes in southern Pacific Costa Rica

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
Sally P. Horn ◽  
Erik N. Johanson ◽  
Kurt A. Haberyan ◽  
Mathew S. Boehm ◽  
Jessie L. Johanson ◽  
...  
Keyword(s):  
Costa Rica ◽  
Environmental History ◽  
Global Climate ◽  
Sediment Cores ◽  
Organic Matter Content ◽  
Plant Macrofossils ◽  
Matter Content ◽  
Radiocarbon Dates ◽  
Natural Lakes ◽  
Lake Formation

Costa Rica has hundreds of lakes, many of which have never been described or sampled by limnologists. Here we summarize initial observations of five small (0.2–1.7ha) lakes located at low elevation (365–490m) in the cantón of Buenos Aries. We collected basic limnological data and samples during visits in 2013 and 2014, and compiled environmental and archaeological data for their surroundings as a contribution to the documentation of lake diversity in Costa Rica, and to support parallel investigations of indicators of environmental history preserved in the sediments of the lakes. Lagunas Carse, Los Mangos, Danta, and Ojo de Agua all appear to owe their origin to landslide events, while Laguna Junquillo is an artificial impoundment. Radiocarbon dates on plant macrofossils near the bases of sediment cores from three of the natural lakes provide minimum ages for lake formation; results indicate that Laguna Los Mangos formed over 4 100 years ago, while Laguna Danta formed prior to 1 320 CE and Laguna Carse formed ca. 1 550 CE, near the time of the Spanish Conquest. More than two dozen archaeological sites are located within 1–3Km of the natural lakes, documenting pre-Columbian human occupation and likely use of lake resources. Lake water temperatures and water chemistry were in keeping with observations at lakes throughout Costa Rica. All five lakes are probably polymictic lakes that turn over frequently; none evinced stratification. The surface lake sediments showed similar organic matter content (22,1–28,8%), with values falling near the middle of the range of lakes previously sampled in Costa Rica. Phytoplankton samples included taxa previously reported from small lowland lakes, but differed between lakes and included dominant taxa that were subdominant or uncommon at other lakes surveyed. Our investigation adds to knowledge of lake characteristics and diversity in Costa Rica, and provides benchmarks for assessing future changes in these lakes and their watersheds resulting from human activity, natural disturbances, and regional and global climate change.

scholarly journals Spatial Variability of the Physicochemical Properties of Soils from Seasonally Flooded Forest Fragments on a Tropical Plain

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Marcus Vinicius Moreira Barbosa ◽  
Taynara Augusta Fernandes ◽  
Guilherme Benko Siqueira ◽  
Flávia Lucila Tonani de Siqueira ◽  
Paula Benevides de Morais
Keyword(s):  
Chemical Reactions ◽  
Organic Matter Content ◽  
Soil Formation ◽  
Dry Season ◽  
Matter Content ◽  
Soil Conditions ◽  
Forest Fragments ◽  
Low Oxygen ◽  
Flood Pulses ◽  
Seasonally Flooded

Flooded ecosystems are conditioned to seasonal floods that promote specific soil conditions, such as low oxygen, hydromorphism, and peculiar chemical reactions. These environments are dependent on flood pulses that determine specific ecological conditions. Ipucas are seasonally flooded discontinuous forest patches that occur exclusively in the Araguaia Plain in Central Brazil. They are located 0.40 to 1.20 m lower than the surrounding plain, which promotes an accumulation of rainwater for five to six months of the year, being entirely or partially dry during the dry season. The aim of this study was to evaluate the horizontal (centre and edge) and vertical (depths: 0–0.20 m and 0.20–0.40 m) variability of physicochemical parameters in Ipucas soils, attempting to establish the importance of flood pulses and the leaching of surrounding areas in soil formation and composition. Samples were collected during the dry season in three Ipucas of similar size and circularity using a Dutch auger. The results reveal that flood pulses promote the deposition of sediments eroded from the surrounding plain, homogenizing the characteristics of the surface soil, from the edge to the centre of the Ipucas. However, biogeochemical processes, also linked to temporary flooding, account for the differences between the surface and deeper soil horizons because anoxic conditions during flooding promote chemical reactions characteristic of anaerobic environments, modifying the pH and organic matter content, in addition to the gleying of soils subjected to flooding, which are then covered by sediments after the dry season. Finally, Ipucas soils are susceptible to anthropic changes and are dependent on seasonal flood pulses.

A 40,000-yr record of environmental change from Burial Lake in Northwest Alaska

2010 ◽  
Vol 74 (1) ◽  
pp. 156-165 ◽  
Author(s):  
Mark B. Abbott ◽  
Mary E. Edwards ◽  
Bruce P. Finney
Keyword(s):  
Lake Level ◽  
Organic Matter Content ◽  
Lacustrine Sediments ◽  
Matter Content ◽  
Radiocarbon Dates ◽  
Fine Grained ◽  
Shrub Tundra ◽  
Northern Alaska ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractBurial Lake in northwest Alaska records changes in water level and regional vegetation since ∼ 39,000 cal yr BP based on terrestrial macrofossil AMS radiocarbon dates. A sedimentary unconformity is dated between 34,800 and 23,200 cal yr BP. During all or some of this period there was a hiatus in deposition indicating a major drop in lake level and deflation of lacustrine sediments. MIS 3 vegetation was herb-shrub tundra; more xeric graminoid-herb tundra developed after 23,200 cal yr BP. The tundra gradually became more mesic after 17,000 cal yr BP. Expansions of Salix then Betula, at 15,000 and 14,000 cal yr BP, respectively, are coincident with a major rise in lake level marked by increasing fine-grained sediment and higher organic matter content. Several sites in the region display disrupted sedimentation and probable hiatuses during the last glacial maximum (LGM); together regional data indicate an arid interval prior to and during the LGM and continued low moisture levels until ∼ 15,000 cal yr BP. AMS 14C dates from Burial Lake are approximately synchronous with AMS 14C dates reported for the Betula expansion at nearby sites and sites across northern Alaska, but 1000–2000 yr younger than bulk-sediment dates.

SURFICIAL REARRANGEMENT AND CRACKING IN SWELLING CLAY SOILS OF THE GLACIAL LAKE REGINA BASIN IN SASKATCHEWAN

1985 ◽  
Vol 65 (2) ◽  
pp. 317-327 ◽  
Author(s):  
A. R. MERMUT ◽  
D. F. ACTON
Keyword(s):  
Subsurface Layer ◽  
Organic Matter Content ◽  
Soil Classification ◽  
Matter Content ◽  
Clay Soils ◽  
Glacial Lake ◽  
Swelling Clay ◽  
Radiocarbon Dates ◽  
Swelling Clays ◽  
Soil Age

A pipeline trench across the Glacial Lake Regina basin provided an opportunity to examine the nature of soil development in heavy textured swelling clays in Saskatchewan. Radiocarbon dates showed a steep age versus depth gradient within the upper 1 m of these soils, and an abrupt change of gradient at this depth. Granular surface structure, deep and wide cracking, slickensides, weak horizon development, and gradual changes in organic matter content were the major characteristics of these soils. The dark-colored subsurface layer in the depressional position appeared to represent a former surface which was buried by accretion of materials from upper slopes. The characteristic morphological features signify the need to re-examine the classification of these soils in the Canadian System of Soil Classification. Key words: Organic 14C dates, soil age, paleosols, swelling clay soils, Holocene soils

scholarly journals Geophysical estimation of shallow permafrost distribution and properties in an ice-wedge polygon-dominated Arctic tundra region

Geophysics ◽  
2016 ◽  
Vol 81 (1) ◽  
pp. WA247-WA263 ◽  
Author(s):  
Baptiste Dafflon ◽  
Susan Hubbard ◽  
Craig Ulrich ◽  
John Peterson ◽  
Yuxin Wu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
High Resolution ◽  
Water Content ◽  
Organic Matter Content ◽  
Matter Content ◽  
The Arctic ◽  
Soil Organic Matter Content ◽  
Ice Wedge ◽  
Ice Content

Shallow permafrost distribution and characteristics are important for predicting ecosystem feedbacks to a changing climate over decadal to century timescales because they can drive active layer deepening and land surface deformation, which in turn can significantly affect hydrologic and biogeochemical responses, including greenhouse gas dynamics. As part of the U.S. Department of Energy Next-Generation Ecosystem Experiments-Arctic, we have investigated shallow Arctic permafrost characteristics at a site in Barrow, Alaska, with the objective of improving our understanding of the spatial distribution of shallow permafrost, its associated properties, and its links with landscape microtopography. To meet this objective, we have acquired and integrated a variety of information, including electric resistance tomography data, frequency-domain electromagnetic induction data, laboratory core analysis, petrophysical studies, high-resolution digital surface models, and color mosaics inferred from kite-based landscape imaging. The results of our study provide a comprehensive and high-resolution examination of the distribution and nature of shallow permafrost in the Arctic tundra, including the estimation of ice content, porosity, and salinity. Among other results, porosity in the top 2 m varied between 85% (besides ice wedges) and 40%, and was negatively correlated with fluid salinity. Salinity directly influenced ice and unfrozen water content and indirectly influenced the soil organic matter content. A relatively continuous but depth-variable increase in salinity led to a partially unfrozen saline layer (cryopeg) located below the top of the permafrost. The cryopeg environment could lead to year-round microbial production of greenhouse gases. Results also indicated a covariability between topography and permafrost characteristics including ice-wedge and salinity distribution. In addition to providing insight about the Arctic ecosystem, through integration of lab-based petrophysical results with field data, this study also quantified the key controls on electric resistivity at this Arctic permafrost site, including salinity, porosity, water content, ice content, soil organic matter content, and lithologic properties.

scholarly journals Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization

2008 ◽  
Vol 32 (5) ◽  
pp. 2027-2035 ◽  
Author(s):  
Eduardo da Silva Matos ◽  
Eduardo de Sá Mendonça ◽  
Paulo César de Lima ◽  
Marino Salgarello Coelho ◽  
Renato Faria Mateus ◽  
...  
Keyword(s):  
Biomass Production ◽  
Green Manure ◽  
Organic Matter Content ◽  
Minas Gerais ◽  
Matter Content ◽  
The Other ◽  
Southeastern Brazil ◽  
N Availability ◽  
Climate Conditions ◽  
Coffee Plantations

The use of green manure may contribute to reduce soil erosion and increase the soil organic matter content and N availability in coffee plantations in the Zona da Mata, State of Minas Gerais, in Southeastern Brazil. The potential of four legumes (A. pintoi, C. mucunoides, S. aterrimum and S. guianensis) to produce above-ground biomass, accumulate nutrients and mineralize N was studied in two coffee plantations of subsistence farmers under different climate conditions. The biomass production of C. mucunoides was influenced by the shade of the coffee plantation. C. mucunoides tended to mineralize more N than the other legumes due to the low polyphenol content and polyphenol/N ratio. In the first year, the crop establishment of A. pintoi in the area took longer than of the other legumes, resulting in lower biomass production and N2 fixation. In the long term, cellulose was the main factor controlling N mineralization. The biochemical characteristics, nutrient accumulation and biomass production of the legumes were greatly influenced by the altitude and position of the area relative to the sun.

scholarly journals Ecological and geological determination of the initial pedogenesis on devastated lands in the Kryvyi Rih Iron Mining & Metallurgical District (Ukraine)

2019 ◽  
Vol 28 (4) ◽  
pp. 738-746 ◽  
Author(s):  
Vasyl M. Savosko ◽  
Yuriy V. Lykholat ◽  
Yulia V. Bielyk ◽  
Tetiana Y. Lykholat
Keyword(s):  
Organic Matter Content ◽  
Correlation Coefficients ◽  
Soil Formation ◽  
Matter Content ◽  
Parent Material ◽  
Waste Rock ◽  
Time Duration ◽  
Initial Soil ◽  
Iron Mining ◽  
Low Levels

In our time, a very urgent problem is the cessation of negative impacts on the environment and the return to the practical use of the territories of devastated lands. In  this regard, it is important to find out the basic laws of primary soil formation in the area of these man-made neoplasms. The initial soil formation conditions were analyzed on 19 experimental sites which represent the main varieties of devastated land in the Kryvyi Rih Iron Mining and Metallurgical District (Central Ukraine): (i) waste rock dumps of old iron mines (old name “Forges”), (ii) tailing storage facility of underground iron mines, (iii) waste rock dumps of the Iron Ore Mining and Dressing Plant, (iv) waste rock dumps of the Granite Quarry Plant. It was established that on the devastated lands in Kryvyi Rih District, the initial soil formation occurs in very difficult conditions. Therefore, over 25- 100 years only very primitive soils were formed. The following features are inherent to them: (1) primitive soil profile (thickness 10-100 mm), (2) low levels of soil organic substance content (9.5-11.5 %), (3) alkaline indicators of the soil solution (pHH2O – 8.08-8.92, pHKCl  – 7.42-8.23), (4) low levels of cation exchange capacity (6.34-8.47 mMol /100 g). By results of correlation calculations, among the factors of soil formation time (duration of soil formation) and input of plant ash elements’ fall are characterized by the maximum number of statistically significant correlation coefficients and their numerical values. In terms of chemical composition of the technosol, the values of organic matter content and exchangeable acidity (pHKCl) were the most predictable soil formation factors. Generally physical / chemical characteristics of geological rocks (as parent material) and time were the two most important factors in determining the initial pedogenesis on devastated lands in the Kryvyi Rih Iron Mining & Metallurgical District (Ukraine).

HEAVY METAL SPECIATION IN BOTTOM SEDIMENTS OF THE VYSHNEVOLOTSKY RESERVOIR

2018 ◽  
pp. 46-54
Author(s):  
O. A. Lipatnikova
Keyword(s):  
Heavy Metal ◽  
Organic Matter ◽  
Bottom Sediments ◽  
Metal Speciation ◽  
Organic Matter Content ◽  
Water Reservoir ◽  
Matter Content ◽  
Heavy Metal Speciation ◽  
Mobile Forms ◽  
Manganese Hydroxides

The study of heavy metal speciation in bottom sediments of the Vyshnevolotsky water reservoir is presented in this paper. Sequential selective procedure was used to determine the heavy metal speciation in bottom sediments and thermodynamic calculation — to determine ones in interstitial water. It has been shown that Mn are mainly presented in exchangeable and carbonate forms; for Fe, Zn, Pb и Co the forms are related to iron and manganese hydroxides is played an important role; and Cu and Ni are mainly associated with organic matter. In interstitial waters the main forms of heavy metal speciation are free ions for Zn, Ni, Co and Cd, carbonate complexes for Pb, fulvate complexes for Cu. Effects of particle size and organic matter content in sediments on distribution of mobile and potentially mobile forms of toxic elements have been revealed.

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