scholarly journals Tracking climate signals in varved lake sediments: research strategy and key sites for comprehensive process studies in the Masurian Lakeland

2017 ◽  
Vol 17 (3) ◽  
pp. 159-166 ◽  
Author(s):  
Wojciech Tylmann ◽  
Paulina Głowacka ◽  
Agnieszka Szczerba
Keyword(s):  
High Resolution ◽  
Lake Sediments ◽  
Sediment Cores ◽  
Monitoring Program ◽  
Sediment Traps ◽  
Research Strategy ◽  
Meteorological Conditions ◽  
Lake Basin ◽  
Climate Signals ◽  
Process Studies

AbstractLake sediments are excellent archives of environmental and climate change. Especially important are varved sediments which can provide high-resolution (annual) records of those changes. Process studies including limnological measurements, particle flux monitoring and analyses of sediment structures give an opportunity to explain relationships between meteorological conditions, in-lake processes and varve formation. In our study, three lakes were selected in the Masurian Lakeland: Lake Żabińskie, Łazduny and Rzęśniki. These relatively small and deep lakes contain well preserved biogenic varves. The lakes are influenced by the same meteorological conditions but differ in terms of their catchment size, land use, hydrology, lake basin morphology and trophic status. To explore the relationships between different parameters and preservation/transformation of climate signals in the sediments we started systematic limnological measurements in the water column of these lakes, water sampling for hydrochemical analyses, monitoring of modern sedimentation using sediment traps and analysis of topmost varves from short sediment cores. With this comprehensive and high-resolution monitoring program scheduled for at least four years we are going to verify the potential of varves to track short-term meteorological phenomena in lake sediments.

Tsunami hazard from lacustrine mass wasting in Lake Tekapo, New Zealand

2018 ◽  
Vol 477 (1) ◽  
pp. 413-426 ◽  
Author(s):  
Joshu J. Mountjoy ◽  
Xiaoming Wang ◽  
Susi Woelz ◽  
Sean Fitzsimons ◽  
Jamie D. Howarth ◽  
...  
Keyword(s):  
High Resolution ◽  
Sediment Cores ◽  
Lake Basin ◽  
Diverse Range ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Tectonically Active ◽  
Tsunami Risk ◽  
Western Shore ◽  
The Impact

AbstractLacustrine-tsunami risk from landslides can be significant yet for most locations globally the hazard remains unquantified. Lake Tekapo, in the tectonically active mountain belt of New Zealand's South Island, has been chosen to develop surveying and modelling techniques to assess the hazard from landslide tsunamis. Lake Tekapo is ideal for this study due to the high sedimentation rates, steep surrounds and the proximity to active faulting that indicate a high landslide potential. The shoreline tourist settlement and hydropower infrastructure mean the impact of any tsunami could be significant. In 2016 a survey was carried out to collect high-resolution (1 m grid) EM2040 multibeam bathymetry, high-resolution seismic reflection data (Boomer and chirp) and 6 m long sediment cores. These data reveal a diverse range of sedimentary processes in response to high sediment input and numerous landslides with varied styles of emplacement. For example, a one-off landslide initiated 40 m above the shoreline with debris deposits that have runout onto the lake floor to 100 m water depth contrasts with the Cass River delta on the western shore that has failed multiple times during the lake-basin infilling history. Landslide-generated tsunami scenarios are used to determine the relative hazard at different regions of the lake to guide development of a probabilistic tsunami model.

scholarly journals Seasonal climate signals preserved in biochemical varves: insights from novel high-resolution sediment scanning techniques

2021 ◽  
Vol 17 (5) ◽  
pp. 2055-2071
Author(s):  
Paul D. Zander ◽  
Maurycy Żarczyński ◽  
Wojciech Tylmann ◽  
Shauna-kay Rainford ◽  
Martin Grosjean
Keyword(s):  
High Resolution ◽  
Meteorological Conditions ◽  
Additive Models ◽  
Formation Processes ◽  
Seasonal Climate ◽  
Climate Proxy ◽  
Climate Signals ◽  
Paleoclimate Reconstructions ◽  
Annual Resolution ◽  
Very High

Abstract. Varved lake sediments are exceptional archives of paleoclimatic information due to their precise chronological control and annual resolution. However, quantitative paleoclimate reconstructions based on the biogeochemical composition of biochemical varves are extremely rare, mainly because the climate–proxy relationships are complex and obtaining biogeochemical proxy data at very high (annual) resolution is difficult. Recent developments in high-resolution hyperspectral imaging (HSI) of sedimentary pigment biomarkers combined with micro X-ray fluorescence (µXRF) elemental mapping make it possible to measure the structure and composition of varves at unprecedented resolution. This provides opportunities to explore seasonal climate signals preserved in biochemical varves and, thus, assess the potential for annual-resolution climate reconstruction from biochemical varves. Here, we present a geochemical dataset including HSI-inferred sedimentary pigments and µXRF-inferred elements at very high spatial resolution (60 µm, i.e. > 100 data points per varve year) in varved sediments of Lake Żabińskie, Poland, over the period 1966–2019 CE. We compare these data with local meteorological observations to explore and quantify how changing seasonal meteorological conditions influenced sediment composition and varve formation processes. Based on the dissimilarity of within-varve multivariate geochemical time series, we classified varves into four types. Multivariate analysis of variance shows that these four varve types were formed in years with significantly different seasonal meteorological conditions. Generalized additive models (GAMs) were used to infer seasonal climate conditions based on sedimentary variables. Spring and summer (MAMJJA) temperatures were predicted using Ti and total C (Radj2=0.55; cross-validated root mean square error (CV-RMSE) = 0.7 ∘C, 14.4 %). Windy days from March to December (mean daily wind speed > 7 m s−1) were predicted using mass accumulation rate (MAR) and Si (Radj2=0.48; CV-RMSE = 19.0 %). This study demonstrates that high-resolution scanning techniques are promising tools to improve our understanding of varve formation processes and climate–proxy relationships in biochemical varves. This knowledge is the basis for quantitative high-resolution paleoclimate reconstructions, and here we provide examples of calibration and validation of annual-resolution seasonal weather inference from varve biogeochemical data.

scholarly journals Seasonal climate signals preserved in biochemical varves: insights from novel high-resolution sediment scanning techniques

2021 ◽  
Author(s):  
Paul D. Zander ◽  
Maurycy Żarczyński ◽  
Wojciech Tylmann ◽  
Shauna-kay Rainford ◽  
Martin Grosjean
Keyword(s):  
High Resolution ◽  
Meteorological Conditions ◽  
Additive Models ◽  
Formation Processes ◽  
Seasonal Climate ◽  
Climate Proxy ◽  
Climate Signals ◽  
Paleoclimate Reconstructions ◽  
Annual Resolution ◽  
Very High

Abstract. Varved lake sediments are exceptional archives of paleoclimatic information due to their precise chronological control and annual resolution. However, quantitative paleoclimate reconstructions based on the biogeochemical composition of biochemical varves are extremely rare mainly because the climate-proxy relationships are complex, and obtaining biogeochemical proxy data at very high (annual) resolution is difficult. Recent developments in high-resolution hyperspectral imaging (HSI) of sedimentary pigment biomarkers combined with micro X-ray fluorescence (μXRF) elemental mapping make it possible to measure the structure and composition of varves at unprecedented resolution. This provides opportunities to explore (seasonal) climate signals preserved in biochemical varves and, thus, assess the potential for annual resolution climate reconstruction from biochemical varves. Here, we present a geochemical dataset including HSI-inferred sedimentary pigments and uXRF-inferred elements at very high spatial resolution (60 μm, i.e. > 100 data points per varve year) in varved sediments of Lake Żabińskie, Poland over the period 1966–2019 CE. We compare this data with local meteorological observations to explore and quantify how changing seasonal meteorological conditions influenced sediment composition and varve formation processes. Based on the dissimilarity of within-varve multivariate geochemical time series, we classified varves into four types. Multivariate analysis of variance shows that these four varve types were formed in years with significantly different seasonal meteorological conditions. Generalized additive models (GAMs) were used to infer seasonal climate conditions based on sedimentary variables. Spring and summer (MAMJJA) temperature were predicted using Ti and total C (R2adj = 0.55; cross-validated root mean square error (CV-RMSE) = 0.7 °C, 14.4%). Windy days from March to December (mean daily wind speed > 7 m/s) were predicted using mass accumulation rate (MAR) and Si (R2adj = 0.48; CV-RMSE = 19.0%). This study demonstrates that high-resolution scanning techniques are promising tools to improve our understanding of varve formation processes and climate-proxy relationships in biochemical varves. This knowledge is the basis for quantitative high-resolution paleoclimate reconstructions, and here we provide examples of calibration and validation of annual resolution seasonal weather inference from varve biogeochemical data.

Searching for weather in varves: use of ultra-high-resolution scanning techniques to reconstruct seasonal meteorological conditions

2021 ◽  
Author(s):  
Paul Zander ◽  
Maurycy Żarczyński ◽  
Wojciech Tylmann ◽  
Shauna-kay Rainford ◽  
Martin Grosjean
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Lake Sediments ◽  
Predictive Power ◽  
Accumulation Rate ◽  
Meteorological Data ◽  
Meteorological Conditions ◽  
Additive Models ◽  
Geochemical Data ◽  
Formation Processes

<p>Varved lake sediments are recognized as valuable archives of paleoclimatic information due to their precise chronological control. However, paleoclimate reconstructions based on the composition of biochemical varves are relatively rare (Zolitschka et al., 2015). We applied novel high-resolution scanning techniques to the varved sediments of Lake Żabińskie, Poland to obtain spatially resolved geochemical data at a resolution of 60 μm covering the period 1966-2019. Relative abundances of elements were measured in resin-embedded sediment slabs using a Bruker M4 Tornado micro-XRF scanner. Chloropigments-<em>a</em> and bacteriopheopigments-<em>a</em> were measured on a wet sediment core using a Specim Hyperspectral core scanner (Butz et al., 2015). The high resolution of the scanning data, and the relatively thick well-preserved varves (average thickness = 6.4 mm), enables a close examination of seasonal scale sediment composition and varve formation processes. Time series of geochemical variables within each varve year were classified into 4 varve type groups based on the dissimilarity measure ψ for multivariate time series (Benito and Birks, 2020; Gordon and Birks, 1974). Based on a Multivariate Analysis Of Variance test, these groups of years experienced significant (p<0.05) differences in seasonal meteorological conditions, particularly wind speed and temperature.  Additionally, a correlation analysis on mean annual geochemical values from the aforementioned scanning techniques and conventional CNS analysis, and seasonal meteorological data revealed significant (p<0.05) correlations with windiness and temperature. Based on these relationships, we applied generalized additive models to predict spring and summer (MAMJJA) temperature and number of windy days (spring through fall), yielding models with significant predictive power. Based on model selection, the variables with the most predictive power for spring and summer temperature were Ti (negative correlation) and total C. The variables with the most predictive power for windiness were Si, sediment accumulation rate, and varve type. This study highlights the usefulness of high-resolution scanning techniques to improve our understanding of varve formation processes and relationships between varve composition and climate variables in biochemical varves.</p><p> </p><p><strong>References</strong></p><p>Benito, B. M. and Birks, H. J. B.: distantia: an open‐source toolset to quantify dissimilarity between multivariate ecological time‐series, Ecography (Cop.)., 43(5), 660–667, doi:10.1111/ecog.04895, 2020.</p><p>Butz, C., Grosjean, M., Fischer, D., Wunderle, S., Tylmann, W. and Rein, B.: Hyperspectral imaging spectroscopy: a promising method for the biogeochemical analysis of lake sediments, J. Appl. Remote Sens., 9(1), 096031, doi:10.1117/1.jrs.9.096031, 2015.</p><p>Gordon, A. D. and Birks, H. J. B.: Numerical methods in Quaternary palaeoecology: II. Comparison of pollen diagrams, New Phytol., 73(1), 221–249, doi:10.1111/j.1469-8137.1974.tb04621.x, 1974.</p><p>Zolitschka, B., Francus, P., Ojala, A. E. K. and Schimmelmann, A.: Varves in lake sediments - a review, Quat. Sci. Rev., 117, 1–41, doi:10.1016/j.quascirev.2015.03.019, 2015.</p>

scholarly journals Application of Corrected Methods for High-Resolution XRF Core Scanning Elements in Lake Sediments

2020 ◽  
Vol 10 (22) ◽  
pp. 8012
Author(s):  
Xiaonan Zhang ◽  
Hucai Zhang ◽  
Fengqin Chang ◽  
Umar Ashraf ◽  
Wei Peng ◽  
...  
Keyword(s):  
High Resolution ◽  
Water Content ◽  
Lake Sediments ◽  
Lake Sediment ◽  
Sediment Cores ◽  
Xrf Core Scanner ◽  
Calibration Methods ◽  
Xrf Scanning ◽  
The Impact ◽  
Log Ratio

Contemporary studies emphasize theoretical and analytical aspects of monitoring water quality within lacustrine settings. The X-ray fluorescence (XRF) core scanner provides the most rapid, non-destructive high-resolution elemental measurements for unprocessed sediments. However, the analytical precision of measured elemental composition may be offset due to water content and inhomogeneities in the physical properties of the sediment. A range of calibration approaches developed specifically for converting XRF scanning intensities to element fractions has been made available. Here, two lake sediment-cores retrieved from southwest China were used to evaluate the performance of various calibration methods. In particular, the influence of sediment properties on XRF scanning intensities was assessed by redundancy analyses (RDA) and the generalized additive model (GAM). The results demonstrate that for fine-grained sediments, the impact of grain size results in only minor deviations in the XRF scanning intensities. Water content of the lake sediment was shown to be the most important factor influencing the XRF scanning intensities, especially for light elements (e.g., Al to Fe). Significant decreases in XRF scanning intensities may occur when sediment water content is greater than 47%. We recommend testing the element fractions obtained via conventional techniques throughout the core and applying the multivariate log-ratio calibration for high-resolution XRF scanning elements within lake sediments.

scholarly journals Effects of Macrofaunal Recolonization on Biogeochemical Processes and Microbiota—A Mesocosm Study

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1599
Author(s):  
Annika Fiskal ◽  
Aixala Gaillard ◽  
Sebastien Giroud ◽  
Dejan Malcic ◽  
Prachi Joshi ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Bottom Water ◽  
Surface Sediments ◽  
Sediment Cores ◽  
Lake Basin ◽  
Sediment Properties ◽  
Chironomid Larvae ◽  
Sediment Reworking ◽  
Mesocosm Experiments ◽  
Tubificid Worms

Macroinvertebrates are widespread in lake sediments and alter sedimentary properties through their activity (bioturbation). Understanding the interactions between bioturbation and sediment properties is important given that lakes are important sinks and sources of carbon and nutrients. We studied the biogeochemical impact of macrofauna on surface sediments in 3-month-long mesocosm experiments conducted using sediment cores from a hypoxic, macrofauna-free lake basin. Experimental units consisted of hypoxic controls, oxic treatments, and oxic treatments that were experimentally colonized with chironomid larvae or tubificid worms. Overall, the presence of O2 in bottom water had the strongest geochemical effect and led to oxidation of sediments down to 2 cm depth. Relative to macrofauna-free oxic treatments, chironomid larvae increased sediment pore water concentrations of nitrate and sulfate and lowered porewater concentrations of reduced metals (Fe2+, Mn2+), presumably by burrow ventilation, whereas tubificid worms increased the redox potential, possibly through sediment reworking. Microbial communities were very similar across oxic treatments; however, the fractions of α-, β-, and γ-Proteobacteria and Sphingobacteriia increased, whereas those of Actinobacteria, Planctomycetes, and Omnitrophica decreased compared to hypoxic controls. Sediment microbial communities were, moreover, distinct from those of macrofaunal tubes or feces. We suggest that, under the conditions studied, bottom water oxygenation has a stronger biogeochemical impact on lacustrine surface sediments than macrofaunal bioturbation.

Organochlorine pollutant analysis of contaminated and uncontaminated lake sediments by high resolution gas chromatography

Chemosphere ◽  
1981 ◽  
Vol 10 (8) ◽  
pp. 945-956 ◽  
Author(s):  
H. Buchert ◽  
S. Bihler ◽  
P. Schott ◽  
H.P. Röper ◽  
H.-J. Pachur ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
High Resolution ◽  
Lake Sediments ◽  
High Resolution Gas Chromatography ◽  
Organochlorine Pollutant

High-resolution radiocarbon dating to reconstruct last century environmental changes in the pacific island of Espiritu Santo

2021 ◽  
Author(s):  
Giorgia Camperio ◽  
Caroline Welte ◽  
S. Nemiah Ladd ◽  
Matthew Prebble ◽  
Nathalie Dubois
Keyword(s):  
High Resolution ◽  
Radiocarbon Dating ◽  
Environmental Changes ◽  
Accumulation Rate ◽  
Sediment Cores ◽  
Volcanic Eruptions ◽  
High Accumulation ◽  
Sedimentary Records ◽  
The Pacific ◽  
Rapid Accumulation

<p>Espiritu Santo is one of the 82 islands of the archipelago of Vanuatu and is the largest, highest, and most biodiverse of the insular country. Climatic changes linked to El Niño and extreme events such as cyclones and volcanic eruptions are a daily challenge in this remote area. These events can be recorded in sedimentary archives. Here we present a multi-proxy investigation of sediment cores retrieved from two small lakes located on the West coast of Espiritu Santo. Although the records span the last millennium, high-resolution radiocarbon dating of macrofossils reveals a rapid accumulation of sediment in the past 100 years. The high accumulation rate coupled with the high-resolution dating of freshwater sediments allows us to compare the <sup>14</sup>C bomb curve with the biogeochemical proxies of the sedimentary records. The results can then be validated against written and oral historical records linked with the societal perception of recent environmental changes in this vulnerable ecosystem.</p><div> <div title="Translate selected text"></div> <div title="Play"></div> <div title="Copy text to Clipboard"></div> </div>

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