CARBONATE MINERALOGY OF LAKE SEDIMENTS AND SURROUNDING SOILS 1. BLACKSTRAP LAKE

1983 ◽  
Vol 63 (2) ◽  
pp. 245-257 ◽  
Author(s):  
K. GHEBRE-EGZIABHIER ◽  
R. J. ST. ARNAUD
Keyword(s):  
Lake Sediments ◽  
Lake Water ◽  
Ionic Concentration ◽  
Historical Background ◽  
Sediment Composition ◽  
Sand Fraction ◽  
Reservoir Sediment ◽  
Lake Deposits ◽  
Secondary Magnesium ◽  
Drainage Waters

The carbonate mineralogy of the Blackstrap Lake sediments in central Saskatchewan indicates that the lake deposits are composed of carbonatic minerals similar to those found in surrounding soils and glacial deposits. Textural differences reflect the transport of finer materials (silts and clay) from the adjacent eroding landscapes. In particular the persistence of dolomite in the silt fractions of the lake sediment is a good indication that part of the calcite together with the dolomite are derived from surrounding soils. The sediment sand fraction contains appreciable Mg-bearing calcite and mollusk shells of pure calcite. Changes in the ionic concentrations of the lake water indicate that dissolution-precipitation processes have affected sediment composition. The increased calcium carbonate equivalent percentages and the presence of secondary magnesium-bearing calcites in the lake sediments suggest that this is so, particularly since erosional processes could not account entirely for the differences observed between the sediments and surrounding soils. The presence of gypsum and the nature of the secondary calcites in the Blackstrap Reservoir sediment tie in well with the known historical background of the Reservoir. The increased ionic concentration of the lake water over the last 15 yr or so since the original inception of the Reservoir is attributed to the influx of drainage waters, evaporation and possibly the effects of groundwater entry from below. Key words: Mg-bearing calcite, dolomite, IAP, erosion

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.

scholarly journals Uranium-series isotopes from Eemian lake deposits, Hollerup, Denmark

1998 ◽  
Vol 44 ◽  
pp. 173-179
Author(s):  
C. Israelson ◽  
S. Bjorck ◽  
N. Noe Nygaard ◽  
C. J. Hawkesworth
Keyword(s):  
Ground Water ◽  
Lake Sediments ◽  
Sedimentary Facies ◽  
Organic Content ◽  
Time Interval ◽  
Decay Products ◽  
Large Spread ◽  
Isotope Study ◽  
Lake Deposits ◽  
High Organic Content

We report the results of a U-series isotope study on Eemian lake sediments from Hollerup, western Denmark. The purpose is to examine the possibility of dating these, and similar, sediments with the 238U-23"h method. Two sedimentary facies were studied; carbonate-present, and virtually carbonate-free but organic-rich sediments. All carbonate-present sediments (5-95%) have (230ThP38U) values higher than unity and relatively radiogenic (23"W232Th) values between 2 and 6.5, indicating postdeposition removal of U, probably by percolation of ground water. Carbonate-free sediments, but with high organic content (40-60%) had (230Th/238U) values lower than 1 and 'model ages' between 89 and 199 ky. The large spread in ages and variation in U content for these sediment samples that were deposited over a much shorter time interval, indicate a complex postdepositional migration pattern of U, probably involving several episodes of leaching and absorption of U from ground water. Our results suggest that lake sediments, such as those found in Hollerup, are vulnerable to mobilization of U and its decay products and care should be taken when interpreting U-series disequilibrium data from such sediments. Future studies will concentrate on sediments that have been more deeply buried andor are less compacted and sealed from percolation of oxidized groundwater.

Metabarcoding of modern sedimentary DNA from the Tibetan Plateau and Siberia as a training dataset for vegetation reconstructions

2021 ◽  
Author(s):  
Weihan Jia ◽  
Kathleen Stoof-Leichsenring ◽  
Sisi Liu ◽  
Kai Li ◽  
Sichao Huang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Lake Sediments ◽  
Plant Diversity ◽  
Lake Water ◽  
Aquatic Plant ◽  
Freshwater Ecosystems ◽  
The Tibetan Plateau ◽  
Plant Dna ◽  
Continental Scale ◽  
Dna Metabarcoding

<p>Lake sedimentary DNA (<em>sed</em>DNA) is an established tool to trace past changes in vegetation composition and plant diversity. However, little is known about the relationships between sedimentary plant DNA and modern vegetational and environmental conditions. In this study, we investigate i) the relationships between the preservation of sedimentary plant DNA and environmental variables, ii) the modern analogue of ancient plant DNA assemblages archived in lake sediments, and iii) the usability of sedimentary plant DNA for characterization of terrestrial and aquatic plant composition and diversity based on a large dataset of PCR-amplified plant DNA data retrieved from 259 lake surface sediments from the Tibetan Plateau and Siberia. Our results indicate the following: i) Lake-water electrical conductivity and pH are the most important variables for the preservation of plant DNA in lake sediments. We expect the best preservation conditions for sedimentary plant DNA in small deep lakes characterized by high water conductivities (≥100 μS cm<sup>-1</sup>) and neutral to slightly alkaline pH conditions (7–9). ii) Plant DNA metabarcoding is promising for palaeovegetation reconstruction in high mountain regions, where shifts in vegetation are solely captured by the <em>sed</em>DNA-based analogue matching and fossil pollen generally has poor modern analogues. However, the biases in the representation of some taxa could lead to poor analogue conditions. iii) Plant DNA metabarcoding is a reliable proxy to reflect modern vegetation types and climate characteristics at a sub-continental scale. However, the resolution of the <em>trn</em>L P6 loop marker, the incompleteness of the reference library, and the extent of <em>sed</em>DNA preservation are still the main limitations of this method. iv) Plant DNA metabarcoding is a suitable proxy to recover modern aquatic plant diversity, which is mostly affected by July temperature and lake-water conductivity. Ongoing warming might decrease macrophyte richness in the Tibetan Plateau and Siberia, and ultimately threaten the health of these important freshwater ecosystems. To conclude, sedimentary plant DNA presents a high correlation with modern vegetation and may therefore be an important proxy for reconstruction of past vegetation.</p>

Biogeochemistry of macrophytes, sediments and porewaters in thermokarst lakes of western Siberia in the discontinuous and continuous permafrost zone

2020 ◽  
Author(s):  
Rinat Manasypov ◽  
Oleg Pokrovsky ◽  
Liudmila Shirokova
Keyword(s):  
Trace Elements ◽  
Lake Sediments ◽  
Aquatic Plants ◽  
Lake Water ◽  
Western Siberia ◽  
The Arctic ◽  
Formation Mechanisms ◽  
Thermokarst Lakes ◽  
Continuous Permafrost ◽  
Thaw Lakes

<p>Despite high importance of macrophytes in shallow thaw lakes for control of major and trace nutrients in lake water, the chemical composition of different aquatic plants and trace element (TE) partitioning between macrophytes and lake water and sediments in the permafrost regions remain totally unknown. Here we sampled dominant macrophytes of thermokarst (thaw) lakes of discontinuous and continuous permafrost zones in Western Siberia Lowland (WSL) and we measured major and trace elements in plant biomass, lake water, lake sediments and sediment porewater. All 6 studies plants (Hippuris vulgaris L., Glyceria maxima (Hartm.) Holmb., Comarum palustre L., Ranunculus spitzbergensis Hadac, Carex aquatilis Wahlenb s. str., Menyanthes trifoliata L.), sizably accumulate macronutrients (Na, Mg, Ca), micronutrients (B, Mo, Nu, Cu, Zn, Co) and toxicants (As, Cd) relative to lake sediments. The accumulation of other trace elements including rare earth elements (REE) in macrophytes relative to pore waters and sediments was strongly species-specific. Under climate warmings scenario and the propagation of southern species northward, the accumulation of trace metals in aquatic plants of thermokarst lakes will produce preferential uptake of Cd, Pb, Ba from thermokarst lake water and sediments by the biomass of aquatic macrophytes. This may eventually diminish the transport of metal micronutrients from lakes to rivers and further to the Arctic Ocean.</p><p>Support from the RSF (RNF) grant 19-77-00073 “Experimental modeling of the formation mechanisms for elemental composition of water in thermokarst lakes of Western Siberia: vegetation effect”.</p>

Long-term changes in lake sediments and their infl uences on lake water quality in Japanese shallow lakes

2010 ◽  
Vol 177 (3) ◽  
pp. 177-188 ◽  
Author(s):  
Takehiko Fukushima ◽  
Koichi Kamiya ◽  
Yuichi Onda ◽  
Akio Imai ◽  
Kazuo Matsushige
Keyword(s):  
Water Quality ◽  
Lake Sediments ◽  
Shallow Lakes ◽  
Lake Water ◽  
Lake Water Quality ◽  
Long Term Changes

Carbon Isotope Composition of Lake Sediments in Relation to Lake Productivity and Radiocarbon Dating

1992 ◽  
Vol 37 (3) ◽  
pp. 333-345 ◽  
Author(s):  
Ramon Aravena ◽  
Barry G. Warner ◽  
Glen M. MacDonald ◽  
Karen I. Hanf
Keyword(s):  
Lake Sediments ◽  
Lake Sediment ◽  
Lake Water ◽  
Dissolved Inorganic Carbon ◽  
Isotope Composition ◽  
Hard Water ◽  
Lake Basin ◽  
Lake Productivity ◽  
Radiocarbon Dates ◽  
Organic Sediment

AbstractCarbon-13 profiles and radiocarbon dates were obtained from two Canadian kettle basins having similar geological and hydrological characteristics to develop criteria for evaluating the validity of radiocarbon dates on lake sediment from basins in calcareous terrain. Radiocarbon dates from a site in Alberta show a variable hard-water effect related to local hydrological changes during postglacial history of the lake basin, whereas radiocarbon dates from the other site in Ontario show no noticeable influence of old carbon during its history. These differences are mainly related to lake water residence time, which has influenced carbon isotopic exchange between atmospheric CO2 and dissolved inorganic carbon in lake water. δ13C values for bulk organic sediment and terrestrial and aquatic macrofossils reveal that the main component of lake sediment at both sites is autocthonous in origin. Furthermore, each site supported different submerged aquatic plant communities that used different sources of carbon for photosynthesis, thereby imprinting the organic sediments with a characteristic 13C composition. Both sites reflect a clear relationship between 13C values and paleoproductivity. This study shows the individualistic response of the developing lake system to the hydrology, lake biota, and local geology, and demonstrates the problem of using 13C in lake sediments as a single criterion to recognize the validity of radiocarbon dates of lake sediment without supporting paleoecological information.

Urban contamination sources reflected in inorganic pollution in urban lake deposits, Bergen, Norway

2015 ◽  
Vol 17 (4) ◽  
pp. 854-867 ◽  
Author(s):  
Malin Andersson ◽  
Ola Anfin Eggen
Keyword(s):  
Lake Sediments ◽  
Urban Lake ◽  
Chemical Changes ◽  
Modern City ◽  
Contamination Sources ◽  
Pristine Environment ◽  
Lake Deposits

The 7000 years transition from a pristine environment towards a modern city has brought a number of chemical changes and effects to urban lake sediments in Bergen.

scholarly journals Lake Sediments from the Kashmir Himalayas: Inverted 14C Chronology and Its Implications

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 561-565 ◽  
Author(s):  
Sheela Kusumgar ◽  
D. P. Agrawal ◽  
Narendra Bhandari ◽  
R. D. Deshpande ◽  
Alok Raina ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Lake Sediments ◽  
Sedimentation Rate ◽  
Catchment Area ◽  
Inversion Layer ◽  
The Core ◽  
Manasbal Lake ◽  
Mineral Magnetic ◽  
Lake Deposits

We have measured 14C, 210Pb and 137Cs profiles in two representative cores from Manasbal Lake, Kashmir, India. The sedimentation rate derived from 210Pb and 137Cs in the upper part of the core is in the range of 3.4 to 5.5 mm yr−1. In contrast, 14C ages show an inversion at depths >20 cm. These results are attributed to the erosion of the ubiquitous 10–20-m-thick loess mantle, based on the similarity of 14C ages of the inversion layer in the sediments and the paleosols present in the catchment area. Frequency-dependent mineral magnetic susceptibility (χfd), carbon to nitrogen ratios and pigment concentrations in the profile show a significant amount of allochthonous component in the lake deposits and support the conclusion that the 14C dates do not reflect the chronology of the in-situ lake sedimentation but episodic deposition of the surrounding loess. Thus, 14C serves as a useful tracer to understand source components of the sediments.

Precipitation Loading of Acid and Heavy Metals to a Small Acid Lake near Sudbury, Ontario

1977 ◽  
Vol 34 (5) ◽  
pp. 649-658 ◽  
Author(s):  
R. J. Beamish ◽  
J. C. Van Loon
Keyword(s):  
Heavy Metals ◽  
Lake Sediments ◽  
Lake Water ◽  
Atmospheric Fallout ◽  
Annual Change ◽  
Bulk Precipitation ◽  
Ph Change ◽  
Manganese Zinc ◽  
Measured Change ◽  
High Concentrations

The pH of Lumsden Lake was closely related to the measured amount of acid entering the lake from bulk precipitation. In 1972 it was estimated that an excess of 2135 kg of H2SO4 was added to the lake from the atmosphere. The predicted annual change in lake pH was from 5.2 to 4.8 and the actual measured change was from 5.2 to 4.7. In 1973 an estimated excess of 1271 kg of H2SO4 was added to the lake from the atmosphere. The predicted annual pH change was from 4.8 to 4.7 and there was no net change in the lake pH in 1973.Lumsden Lake also had high concentrations of sulfate, manganese, zinc, and nickel in comparison with remote or "unpolluted" lakes. High concentrations of manganese and possibly some zinc in the lake appeared to result from increased mobilization from the lake sediments or watershed or both as the pH decreased. Atmospheric fallout also contributed substantial quantities of nickel and copper to the watershed, some of which appeared to be retained in the lake water. The high concentrations of lead in the precipitation were not retained in the lake.

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