scholarly journals Occurrence and distribution of glycerol dialkyl glycerol tetraethers in lake water column: A review

2021 ◽  
Vol 33 (5) ◽  
pp. 1334-1349
Author(s):  
Li Jingjing ◽  
◽  
Yang Huan ◽  
Zheng Fengfeng ◽  
Gao Chao ◽  
...  
Keyword(s):  
Water Column ◽  
Lake Water ◽  
Glycerol Dialkyl Glycerol Tetraethers

scholarly journals A 900-year New England temperature reconstruction from <i>in situ</i> seasonally produced branched glycerol dialkyl glycerol tetraethers (brGDGTs)

2018 ◽  
Author(s):  
Daniel R. Miller ◽  
M. Helen Habicht ◽  
Benjamin A. Keisling ◽  
Isla S. Castañeda ◽  
Raymond S. Bradley
Keyword(s):  
New England ◽  
Water Column ◽  
Lacustrine Sediments ◽  
Temperature Reconstruction ◽  
Early Spring ◽  
Pollen Record ◽  
The North ◽  
The North Atlantic Oscillation ◽  
Glycerol Dialkyl Glycerol Tetraethers

Abstract. Paleotemperature reconstructions are essential for distinguishing anthropogenic climate change from natural variability. An emerging method in paleoclimatology is the use of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in lacustrine sediments to reconstruct temperature, but their application is hindered by a limited understanding of their sources, seasonal production, and transport. We report seasonally resolved measurements of brGDGT production within the water column, in catchment soils and in a sediment sequence from a small, deep inland lake in Maine, USA. BrGDGT distributions in the water column are distinct from catchment soils but similar to the distributions in lake sediments, suggesting that (1) brGDGTs are produced within the lake and (2) this in situ production dominates the downcore sedimentary signal. Seasonally, depth-resolved measurements indicate that the dominant production of brGDGTs occurs in late fall/early spring and at intermediate depths (18–30 meters) in the water column. We apply these observations to help interpret a 900-year-long brGDGT-based temperature reconstruction and find that it shows similar trends to a pollen record from the same site and to regional and global syntheses of terrestrial temperatures over the last millennium. However, the record also shows higher-frequency variability than has previously been captured by such an archive in the Northeastern United States, potentially attributed to the North Atlantic Oscillation and volcanic/solar activity. This is the first brGDGT- based multi-centennial paleoreconstruction from this region and contributes to our understanding of the production and fate of brGDGTs in lacustrine systems.

Radioactivity measurements in the atmosphere and water column of Rogoznica Lake (central Adriatic)

2021 ◽  
Author(s):  
Ivana Tucaković ◽  
Sarah Mateša ◽  
Ivana Coha ◽  
Marija Marguš ◽  
Milan Čanković ◽  
...  
Keyword(s):  
Water Column ◽  
Long Range ◽  
Lake Water ◽  
Dry Deposition ◽  
Long Range Transport ◽  
Atmospheric Input ◽  
Air Masses ◽  
Activity Concentrations ◽  
Range Transport ◽  
Radionuclide Activity

&lt;p&gt;Croatian Science Foundation MARRES project (MARine lake (Rogoznica) as a model for EcoSystem functioning in a changing environment) aims to investigate the unique environment (slow exchange of seawater with the sea; atmospheric input is the only source of freshwater) of the marine lake which is an example of highly stratified (permanent anoxia bellow 9 m depth), and by climate changes affected marine system in the middle of the eastern Adriatic coast (43.53&amp;#176; N, 15.95&amp;#176; E). The area of the lake is characterized by the extensive tourism and mariculture, and the low impact of local industrial activities. It is also affected by the combined influence of long-range transport of air masses and local emissions (open-fire events).&lt;/p&gt;&lt;p&gt;An important part of the project is focused on the exchange and interaction between atmosphere, water column and sediment by measuring the atmospheric input (wet and dry deposition) of sulphur compounds, organic carbon, trace metals and radionuclides (Be-7, Pb-210).&lt;/p&gt;&lt;p&gt;This work for the first time will present the current state of the measurements of radioactivity in the Rogoznica lake area, including samples of aerosol particulate matter, PM2.5 &lt; 2.5 um, rainwater and lake water column. Namely, the concentrations of Be-7 and Pb-210 in PM2.5 are measured to determine and correlate the dynamics of particle transport, meteorological information, especially origin of air masses and seasonal variation of PM2.5. While presence of Be-7 indicates the recent wet or dry deposition from the upper parts of the atmosphere, Pb-210 may be used as a tracer for continental air masses. Therefore, it can also indicate the influence of the pollution induced by human activity. Regarding that, special attention will be paid to compare results before and during the Covid-19 lockdown periods.&lt;/p&gt;&lt;p&gt;So far, preliminary results do not show significant difference in PM2.5 masses and measured radionuclide activity concentrations for the lockdown period. Be-7 and Pb-210 were regularly detected in aerosols collected on a glass fiber filters during a one-week sampling periods with the air flow rate of 2.3 m&lt;sup&gt;3&lt;/sup&gt;/h. Their activity concentrations are determined by gamma spectrometry using High Purity Germanium detectors. The results are found to be correlated with PM2.5 masses, ranging from 2.9 to 12.2 Bq/m&lt;sup&gt;3&lt;/sup&gt; for Be-7 and from 0.5 to 2.5 Bq/m&lt;sup&gt;3&lt;/sup&gt; for Pb-210. First analyses show that the highest values can be related to the long-range transport of air masses and to the recorded near open-fire event. As expected, Be-7 is also detected in almost every rainwater sample (event), with the activity concentration up to 5.6 Bq/L, while low activities of Pb-210 are detected only sporadically. Related to that, Be-7 is detected in lake water column as well, but only in the surface layer and in samples collected during, or immediately after the rain events.&amp;#160;&lt;/p&gt;&lt;p&gt;Dynamics and seasonal variation of radionuclide activity concentrations in here studied samples will be discussed, and the relationships with some meteorological parameters (temperature, wind speed, relative humidity, precipitation level) as well as local and long-range transport and physico-chemical conditions in the lake water column will be established.&lt;/p&gt;

scholarly journals Authigenic formation of Ca–Mg carbonates in the shallow alkaline Lake Neusiedl, Austria

2020 ◽  
Vol 17 (7) ◽  
pp. 2085-2106
Author(s):  
Dario Fussmann ◽  
Avril Jean Elisabeth von Hoyningen-Huene ◽  
Andreas Reimer ◽  
Dominik Schneider ◽  
Hana Babková ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Water Column ◽  
Community Composition ◽  
Pore Water ◽  
Lake Water ◽  
Bacterial Community Composition ◽  
Anoxic Sediment ◽  
Alkaline Lake ◽  
Core Depth ◽  
Dolomite Formation

Abstract. Despite advances regarding the microbial and organic-molecular impact on nucleation, the formation of dolomite in sedimentary environments is still incompletely understood. Since 1960, apparent dolomite formation has been reported from mud sediments of the shallow, oligohaline and alkaline Lake Neusiedl, Austria. To trace potential dolomite formation or diagenetic alteration processes in its deposits, lake water samples and sediment cores were analyzed with respect to sediment composition, hydrochemistry and bacterial community composition. Sediments comprise 20 cm of homogenous mud with 60 wt % carbonate, which overlies dark-laminated consolidated mud containing 50 wt % carbonate and plant debris. Hydrochemical measurements reveal a shift from oxic lake water with pH 9.0 to anoxic sediment pore water with pH 7.5. A decrease in SO42- with a concomitant increase in ΣH2S and NH4+ from 0 to 15 cm core depth indicates anaerobic heterotrophic decomposition, including sulfate reduction. The bacterial community composition reflects the zonation indicated by the pore water chemistry, with a distinct increase in fermentative taxa below 15 cm core depth. The water column is highly supersaturated with respect to (disordered) dolomite and calcite, whereas saturation indices of both minerals rapidly approach zero in the sediment. Notably, the relative proportions of different authigenic carbonate phases and their stoichiometric compositions remain constant with increasing core depth. Hence, evidence for Ca–Mg carbonate formation or ripening to dolomite is lacking within the sediment of Lake Neusiedl. As a consequence, precipitation of high-magnesium calcite (HMC) and protodolomite does not occur in association with anoxic sediment and sulfate-reducing conditions. Instead, analytical data for Lake Neusiedl suggest that authigenic HMC and protodolomite precipitate from the supersaturated, well-mixed aerobic water column. This observation supports an alternative concept to dolomite formation in anoxic sediments, comprising Ca–Mg carbonate precipitation in the water column under aerobic and alkaline conditions.

Understanding the physical and biological controls on microplastic transport in lakes.

2020 ◽  
Author(s):  
Hassan Elagami ◽  
Sven Frei ◽  
Jan-Pascal Boos ◽  
Benjamin Gilfedder
Keyword(s):  
Water Column ◽  
Lake Water ◽  
Extracellular Polymeric Substances ◽  
Field Experiments ◽  
Settling Velocity ◽  
Theoretical Calculations ◽  
Systematic Investigation ◽  
Microbial Colonization ◽  
Natural Systems ◽  
Terrestrial Environments

&lt;p&gt;Microplastics (MPs) have been found ubiquitously in oceanic and terrestrial environments.&amp;#160; As the production and consumption of plastic polymers increases the amount of plastic evading accepted disposal pathways and entering natural systems is also expected to increase. To date the focus of plastic and MP research in particular has been on the ocean, there has recently been a rapid increase in interest in MP levels and distribution in terrestrial systems. However, the focus of existing studies has mostly been on the quantification and distribution of MP contamination in the sediment or on the water column of rivers and lakes. The aim of this project is to investigate the fundamental physical and biological influences on the transport of microplastics (MPs) in lake systems. In particular, we will focus on an understanding of the migration and distribution of MPs, and a systematic investigation on transport and sedimentation of MP in the lake water column. Lab and field experiments are planned to investigate the behavior of different MPs polymers, shapes and sizes under different conditions and determine how this influence the MP transport.&lt;/p&gt;&lt;p&gt;The settling velocity of MPs in stationary water was measured in the laboratory using particle image velocimetry (PIV) which was then compared to manual timing of the sinking velocity. The trajectories of the settling MPs have also been tracked during weak turbulences. In addition, the results were compared with theoretical calculations.&lt;/p&gt;&lt;p&gt;To investigate microbial colonization and biofilm formation on the surface of MPs, samples were exposed on a natural lake environment for varying time periods. The colonization of MP surfaces by microorganisms and their excretion of extracellular polymeric substances (EPS) were examined by laser microscopic techniques and subsequently the effect of the microbiological colonization of settling velocity was determined. In this work we show that the transport of MP is complex, as it is influenced by plastic type, shape, and biological colonization as well as the hydrodynamic conditions in the lake water column.&lt;/p&gt;

scholarly journals Quantifying nitrate dynamics in an oligotrophic lake using Δ<suP>17</sup>O

2011 ◽  
Vol 8 (3) ◽  
pp. 687-702 ◽  
Author(s):  
U. Tsunogai ◽  
S. Daita ◽  
D. D. Komatsu ◽  
F. Nakagawa ◽  
A. Tanaka
Keyword(s):  
Water Column ◽  
Lake Water ◽  
Mixing Ratio ◽  
Active Nitrogen ◽  
Isotopic Compositions ◽  
Stable Isotopic ◽  
Atmospheric Nitrate ◽  
Oligotrophic Water ◽  
Rapid Removal ◽  
Continuous Feeding

Abstract. The stable isotopic compositions of nitrate, including the 17O anomalies (Δ17O), were determined twice in 1 yr (June and August 2007) in the oligotrophic water column of Lake Mashu, Japan. These data were then used to quantify the geochemical dynamics of nitrate in the lake, by using the deposition rate of the atmospheric nitrate onto the entire catchment area of the lake. The total amount of nitrate in the lake water decreased from 4.2 to 2.1 Mmol during the period between the observations, while the average Δ17O values remained uniform at +2.5‰. The Δ17O values corresponded to an small and uniform mixing ratio of atmospheric nitrate to total nitrate of 9.7 ± 0.8%. These results indicate that 0.52 ± 0.34 Mmol of the remineralized nitrate was fed into the water column through nitrification, while 2.6 ± 0.4 Mmol of nitrate was simultaneously removed from the water column by assimilation, during the period between the observations. The lake water dissolved nitrate was characterized by rapid removal through assimilation during summer until it was almost completely removed from the euphotic layer, as well as continuous feeding into the lake through nitrification (3.2 ± 0.3 Mmol a−1) and deposition (0.35 ± 0.2 Mmol a−1), regardless of the seasons. The 15N-depleted nitrogen isotopic compositions of nitrate were as low as −6.5‰ in June, which also indicates that in-lake nitrification is the major source of nitrate in the lake and suggests that there is low potential for denitrification in and around the lake. Atmospheric nitrate deposited into the lake will be assimilated quickly, having a mean residence time of 1.2 ± 0.1 yr. In addition, more than 90% of the assimilated nitrate will be remineralized to nitrate and re-assimilated via active nitrogen cycling in the lake.

scholarly journals EFFECTS OF THERMODYNAMICAL PROCESSES ON RADIOCESIUM BEHAVIOR IN LAKE TAPELIAI / TERMODINAMINIŲ PROCESŲ ĮTAKA RADIOCEZIO ELGSENAI TAPELIŲ EŽERE

2012 ◽  
Vol 3 (6) ◽  
pp. 95-100
Author(s):  
Anastasija Moisejenkova ◽  
Aloyzas Girgždys ◽  
Nikolaj Tarasiuk
Keyword(s):  
Lake Sediments ◽  
Water Column ◽  
Lake Water ◽  
Sediment Surface ◽  
Main Process ◽  
Complex Data ◽  
Data Set ◽  
Activity Concentrations ◽  
Lake Bottom ◽  
Integrated Study

The article presents the results of the integrated study of radiocesium behavior in Lake Tapeliai using not only conventional data on radiocesium activity concentrations in lake water and sediments but also a complex data set on seasonal variations and vertical profiles of standard water variables. Radiocesium activity concentrations in lake water as well as the vertical structure of the water column considerably depend on the inflows of the colored waters from the swampy watershed of the lake enriched in radiocesium. The global fallouts are mainly responsible for radiocesium inventory in lake sediments, which reaches maximum in the upper part of the water column above the ~5.4-m depth. The maximum values of radiocesium inventories in lake sediments are consistent with the respective densities of its deposits in the nearest forest soils. The main process of sediment activation is the direct sorption of radiocesium onto the sediment surface. Sedimentation rates in the lake vary mainly in the range of 3.5–5 mm·a–1. Lake bottom feeding sources located mainly on the southern terrace as well as their related near-bottom flows reduce respective sedimentation and radiocesium inventories in the sediments. Santrauka Straipsnyje nagrinėjama radiocezio elgsena Tapelių ežere, naudojant ne tik radiocezio savitojo ir tūrinio aktyvumų duomenis, bet ir standartinius vertikaliuosius parametrus, tokius kaip temperatūra, elektros laidumai ir oksiduoto sluoksnio storis. Radiocezio aktyvumas ežero vandenyje priklauso nuo spalvoto pelkinio vandens, kuriame yra radiocezio, patekimo į ežerą. Radiocezio apkrova dugno nuosėdose yra didžiausia viršutinėje ežero dalyje, t. y. iki 5,4 m gylio. Sedimentacijos greitis svyruoja 3,5–5 mm·m–1. Ežero priedugniniai vandens šaltiniai daugiausia išsidėstę pietinėje ežero terasoje, jų srovės sumažina sedimentaciją ir radiocezio apkrovą dugno nuosėdose.

Improvements in Quantifying the Phosphorus Concentration in Lake Water

1982 ◽  
Vol 39 (6) ◽  
pp. 822-829 ◽  
Author(s):  
E. E. Prepas ◽  
F. H. Rigler
Keyword(s):  
Particulate Matter ◽  
Water Column ◽  
Total Phosphorus ◽  
Lake Water ◽  
Separate Experiment ◽  
Phosphorus Concentration ◽  
Water Bottle ◽  
Acid Digestion ◽  
Average Variance ◽  
The Mean

Vertical and horizontal patterns in limnetic phosphorus concentrations ([P]) were detected in an oligotrophic lake by dividing the total phosphorus pool into two fractions: dissolved and particulate matter smaller than 250 μm (smaller fraction) and particulate matter larger than 250 μm (larger fraction). The smaller fraction was estimated from samples collected with a water bottle, and the larger fraction was estimated with tow net samples taken at several stations and to various depths. Our samples were digested with potassium persulfate which gave less variable results than other acid digestion techniques. The average variance associated with the mean [P] (n = 3) for samples collected and analyzed according to our procedure was less than 0.05 mg P/m3. During summer stratification there was a consistent metalimnetic maximum in the smaller fraction, and there were small but significant differences in the concentrations found at two stations less than 1 km apart. During the same period the larger fraction was a significant portion (14–28%) of the phosphorus pool in the epilimnion which varied from 3 to 5 m in depth. It was a relatively constant portion of the phosphorus in the trophogenic zone (0–10 m) and in the 0- to 20-m portion of the water column i.e. 10–14% and 7.3–8.8%, respectively. In a separate experiment it was shown that by removing the larger fraction, the average variance associated with the mean [P] was reduced from 1.0, to 2.4 × 10−2 mg/m3. This reduction occurred because the larger fraction contained zooplankters with relatively high but variable amounts of phosphorus, and which occur in densities too low to be adequately sampled with the smaller fraction.Key words: phorphorus, lakes, phosphorus in zooplankton

Bioassay of the seasonal ability of water from a eutrophic Alberta lake to promote selective growth of strains of Anabaena flos-aquae and other blue-green algae

1979 ◽  
Vol 57 (21) ◽  
pp. 2443-2451 ◽  
Author(s):  
Ferdinand Schanz ◽  
E. Dale Allen ◽  
Paul R. Gorham
Keyword(s):  
Water Column ◽  
Lake Water ◽  
Photosynthetically Active Radiation ◽  
Dominant Species ◽  
Nutrient Deficiencies ◽  
Filament Length ◽  
Active Radiation ◽  
Blue Green Algae ◽  
Nutrient Variability ◽  
L 13

Significant differences were observed in the capacity of samples of filtered, unautoclaved water from Hastings Lake, Alta., to support growth of two strains of Anabaena flos-aquae (A-l 13-9q2, NRC-445-i), a strain of Aphanizomenon flos-aquae (NRC-568), and a culture of Anabaena sub-cylindrica isolated from Hastings Lake when tested by a 2-week, 1-L standard bioassay in aerated hydrometer cylinders at 20 °C with photosynthetically active radiation (400–700 nm) of 60 μE m−2 s−1. Growth was measured by two independent methods, optical density at 750 nm and mean filament length × mean filament number, and analyzed by fitting logistic curves to the data for comparisons of yields, lag phases, and growth rates. Anabaena A-113-9q2 grew best in spring and fall, poorest in summer, and the growth was always much lower than the controls in ASM-1-TR minus nitrogen (NO3) medium. The results support the hypothesis that nutrient variability in the water column contributes to the selection and growth of dominant species and strains and is one of the factors (along with buoyancy and other concentrating mechanisms) which cause observed successional changes and localized differences in composition of bloom-forming populations and scums. Inhibitors along with nutrient deficiencies may have caused the low biomass densities supported by the lake water. Buoyancy can best account for the 10-fold higher biomass densities observed for heavy bloom-forming populations collected from the top 0.25 m of the water column of Hastings Lake.

scholarly journals Authigenic formation of Ca-Mg carbonates in the shallow alkaline Lake Neusiedl, Austria

2019 ◽  
Author(s):  
Dario Fussmann ◽  
Avril Jean Elisabeth von Hoyningen-Huene ◽  
Andreas Reimer ◽  
Dominik Schneider ◽  
Hana Babková ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Water Column ◽  
Pore Water ◽  
Lake Water ◽  
Bacterial Community Composition ◽  
Anoxic Sediment ◽  
Magnesium Calcite ◽  
Core Depth ◽  
High Magnesium Calcite ◽  
Dolomite Formation

Abstract. Despite advances regarding the microbial and organic-molecular impact on nucleation, the formation of dolomite in sedimentary environments is still incompletely understood. Since 1960, apparent dolomite formation has been reported from mud sediments of the shallow, oligohaline and alkaline Lake Neusiedl, Austria. To trace potential dolomite formation or diagenetic alteration processes in its deposits, lake water samples and sediment cores were analyzed with respect to sediment composition, hydrochemistry and bacterial community composition. Sediments comprise 20 cm of homogenous mud with 60 wt % carbonate, which overlie dark-laminated consolidated mud containing 50 wt % carbonate and plant debris. Hydrochemical measurements reveal a shift from oxic lake water with pH 9.0 to anoxic sediment pore water with pH 7.5. A decrease in SO42− with a concomitant increase of ΣH2S and NH4+ from 0–15 cm core depth, indicates anaerobic heterotrophic decomposition, including sulfate reduction. The bacterial community composition reflects the zonation indicated by the pore water chemistry, with a distinct increase of fermentative taxa below 15 cm core depth. The water column is highly supersaturated with respect to (disordered) dolomite and calcite, whereas saturation indices of both minerals rapidly approach zero in the sediment. Notably, the relative proportions of different authigenic carbonate phases and their stoichiometric compositions remain constant with increasing core depth. Hence, evidence for Ca-Mg carbonate formation or ripening to dolomite is lacking within the sediment of Lake Neusiedl. As a consequence, precipitation of high-magnesium-calcite (HMC) and very-high-magnesium-calcite (VHMC) does not occur in association with anoxic sediment and sulfate reducing conditions. Instead, analytical data for Lake Neusiedl suggest that authigenic HMC and VHMC precipitate from the supersaturated, well-mixed aerobic water column. This observation supports an alternative concept to dolomite formation in anoxic sediments, comprising Ca-Mg carbonate precipitation in the water column under aerobic and alkaline conditions.

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