Wyniki wyszukiwania - Biblioteka Nauki

1

The application of photoinduced luminescence in research on humic substances of various origins

100%

Mielnik L.

|

2009

|

tom Vol. 38, No.3

61-67

EN

This paper discusses preliminary research on using photoinduced luminescence phenomena in determining the structural properties of humic acids extracted from the bottom sediments of two lakes. The lakes examined differ in the hydrochemical parameters of the water body, as well as in the drainage basins surrounding the lakes. Photoinduced luminescence of humic acids was induced with a halogen light of 1500 ěmol m-2 s-1 photon flux density. The differences observed are evidence of both the variable qualitative and quantitative contribution of photoluminophors to the structure of the examined humic acids, and of their different photochemical activity. Furthermore, photoinduced luminescence intensity depends on the degree of transformation of the humic acids.

2

Paleolimnology in uruguay - a personal perspective

100%

Garcia-Rodriguez F.

|

2004

|

tom Vol. 21

167-169

EN

Paleolimnological research only started in Uruguay in 1999 in the frame of the German-Uruguayan Academic Cooperation Program (DAAD-UDELAR). Research focused in costal lagoons and special attention was paid to the relationship between trophic development and sea level changes. Paleolimnology was also used as tool to assess human impact on aquatic water bodies and to provide a basis for the development of a management plan. Concomitantly, diatom taxonomy was also developed as diatoms are very well established indicators of paleoenvironmental change. In this sense, about 70 diatom species have been described as new for science.

3

Algal and invertebrate microfossil assemblages from lake sediments in the reconstruction of past community dynamics - preliminary information

88%

Antipushina Z. , Szeroczyńska K. , Zawisza E.

|

tom Vol. 29

53--58

EN

This paper focuses on the usefulness of a palaeolimnological method called the joint algological and zoological analysis. The joint algo-zoological analysis involves counting all identifiable remains of the main algae groups (Bacillario- phyta, Cyanophyta, Desmidiales, other Chlorophyta, Trachelomonas sp.) and invertebrate groups (Cladocera, Ostra- coda, Chironomidae, Chaoborus sp., and other insects, Turbellaria, Bryozoa, Spongia and Testacida) in volumetric samples. We present results from recent sediments of Lake Glubokoe (Moscow region, Russia) as an example of the application of this method. We reconstruct the structure of phytoplankton, zooplankton and zoobenthos communities and their dynamics over the last 25 years. Our results support the validity of this method in the reconstruction of the structure of phyto- and zooplankton communities and their dynamics, information that may be lost when carrying out separate analyses for individual groups. Simplicity is another advantage of this methodology.

4

Chemical composition of soil and lake sediments - an indicator of geological processes in Lithuania

88%

Gregorauskienė V. , Kadūnas V.

|

tom Vol. 44, Nr 4

347-354

EN

Long-term multipurpose geochemical studies in Lithuania show that the chemical composition of surface sediment can be used as an indicator of geological process: duration of weathering, soil formation and thickness of sediment. The chemical composition of upper and lower soil layers and of lake sediments gives information on past sedimentation: the type and age of Quaternary deposits and the location and depth of Pleistocene glaciolacustrine basins. We therefore have a baseline to predict changes in surface chemistry provoked by current anthropogenic pressures.

5

Comparing Varve Counting And 14C-Ams Chronologies In The Sediments Of Lake Żabińskie, Northeastern Poland: Implications For Accurate 14C Dating Of Lake Sediments

88%

Bonk A. , Tylmann W. , Goslar T. , Wacnik A. , Grosjean M.

|

tom Vol. 42, no.1

159--171

EN

Varved lake sediments from Lake Żabińskie (northeastern Poland) provide a highresolution calendar-year chronology which allows validation of 14C dating results. Microscopic analysis of the varve microfacies revealed that laminations found in Lake Żabińskie were biogenic (calcite) varves. Three independent counts indicated a good preservation quality of laminae in the 348 cm long sediment profile which contained 1000+12/-24 varves. The varve chronology was validated with the 137Cs activity peaks, the tephra horizon from the Askja eruption at AD 1875 and with the timing of major land-use changes of known age inferred from pollen analysis. 32 AMS 14C dates of terrestrial macrofossils distributed along the profile were compared with the varve chronology. After identification of outliers, the free-shape model performed with 21 14C dates provided the best possible fit with the varve chronology. We observed almost ideal consistency between both chronologies from the present until AD 1250 while in the lower part (AD 1000–1250) the difference increases to ca. 25 years. We demonstrate that this offset can be explained by too old radiocarbon ages of plant remains transported to the lake by the inflowing creek. Results of this study highlight that careful interpretation of radiocarbon age-depth models is necessary, especially in lakes where no annual laminations are observed and no independent method are used for cross-validation.

6

Subfossil shell margins and tail spines of Daphnia in Finnish lake sediments - is Daphnia underrepresented in cladocera analysis?

88%

Sarmaja-Korjonen K.

|

2007

|

tom Vol. 24

61-64

EN

One of the shortcomings of the analysis of subfossil Cladocera (water flee) remains is that preservation of remains is selective. Of Daphnia spp. which are very common in zooplankton assemblages of lakes, usually only postabdominal claws and ephippia are found. In the present paper I describe Daphnia shell margins and some tail spines from the Holocene sediments of a lake in southern Finland where the margins were much more abundant than the postabdominal claws, indicating that postabdominal claws may be underrepresented. Daphnia claws, shell margins and tail spines were found also in surface samples of 17 Finnish lakes and thus the abundance of tail spines could be compared with that of postabdominal claws. The results showed that in most cases the tail spines are more abundant than postabdominal claws and may give a closer estimate of the true abundance of Daphnia. However, in some lakes claws were clearly more frequent than tail spines. Apparently, there are differences in preservation of different types of Daphnia remains between lakes, possibly connected with water chemistry. Overall, the results indicate that probably Daphnia remains are always underrepresented in lake sediments.

7

First isotope studies on the late weichselian/holocene part of the limnic type sequence from the former lake aschersleben (saxony-anhalt, Germany)

88%

Boettger T. , Hiller A. , Stottmeister L. , Junge F. W.

|

2004

|

tom Vol. 21

207-211

EN

Isotopic-geochemical pilot investigations were carried out on a limnic sediment sequence from the former Lake Aschersleben in central Germany. Radiocarbon data based on peat and lake marl material cover a time span between approximately 2,560 BP and 17,030 years BP for the drilling cores investigated. The variations in isotope levels characterize the specific lake development such as changes in the temperature regime and the water balance from stable cold climatic conditions in the Upper Glacial period to warmer Late Glacial conditions partly influenced by the influx of glacial water and the rising water level in the Early Holocene.

8

Distribution of phosphorus and heavy metals in the sediments of lake arendsee (Altmark, Germany)

88%

Zachmann D. W. , van der Veen A. , Muller S.

|

2004

|

tom Vol. 21

179-185

EN

Lake Arendsee is a dimictic lake with a surface area of about 5 km2 and a maximum depth of about 50 m. Due to the input of untreated sewage rich in P the lake turned to eutrophic state in the 1950s. Sediment cores were taken by different methods: short cores (0-50 cm) with a gravity corer, long cores (0-160 cm) with a piston corer. The sediments were sliced into subsamples under argon atmosphere in a glove box. The samples were analysed by ICP-OES and ICP-MS on main and trace elements after digestion in either aqua regia or HF-HNO3-HClO4. Analogous cores were dated by varve counting and radiometric methods. The enforced build-up of industry and agriculture since the 1950s is displayed in the sediment composition. The P concentrations increase from a background of about 600 ppm (oligotrophic state of the lake) to more than 4,000 ppm in a depth of 14 cm, which corresponds to the 1970s. In 1976, a hypolimnetic withdrawal and a sewage plant were built. Above the corresponding depth the concentrations of P and heavy elements decrease in the sediments but are still by far higher than the background values. The bonding form analyses dokument mineral equilibration by diagenetic processes. Stable sulfidic bonding forms become predominant with increasing depth.

9

Isotope analyses of the lake sediments in the Plitvice Lakes, Croatia

75%

Horvatinčić N. , Sironić A. , Barešić J. , Bronić I. , Nikolov J. , Todorović N. , Hansman J. , Krmar M.

|

tom 12

|

nr 10

707-713

EN

The analyses of radioactive isotopes 14C, 137Cs and 210Pb, and stable isotope 13C were performed in the sediment cores, top 40 cm, taken in 2011 from karst lakes Prošće and Kozjak in the Plitvice Lakes National Park, central Croatia. Frozen sediment cores were cut into 1 cm thick layers and dried. 14C activity in both carbonate and organic fractions was measured using accelerator mass spectrometry technique with graphite synthesis. 137Cs, 210Pb, 214Pb and 214Bi were measured by low level gamma spectrometry method on ORTECHPGe detector with the efficiency of 32%. Distribution of 14C activity from both lakes showed increase of the 14C activity in the top 10–12 cm in both carbonate and organic fractions as a response to thermonuclear bomb-produced 14C in the atmosphere in the sixties of the 20th century. Anthropogenically produced 137Cs was also observed in sediment profiles. Sedimentation rates for both lake sediments were estimated based on the unsupported 210Pb activity. Different 14C activity of the carbonate fraction (63–80 pMC, percent of modern carbon) and organic fraction (82–93 pMC) is the result of geochemical and biological processes of the sediment precipitation in the lake waters. This is also confirmed by the δ 13 C values of both fractions. Carbon isotope composition, a 14 C and δ 13 C, was compared with the lake sediments from the same lakes collected in 1989 and 2003.

10

Geochemiczna zmienność pierwiastków ziem rzadkich i metali ciężkich w osadach profundalu i litoralu wybranych jezior Polski

75%

Małecka K.

|

tom nr 450

63--74

PL

Z 30 jezior położonych na pojezierzach Pomorskim, Wielkopolsko-Kujawskim i Warmińsko-Mazurskim pobrano po 2 próbki osadów (ze strefy litoralnej i profundalnej). Do badań wytypowano jeziora położone na podłożu o jednorodnej budowie geologicznej. Połowa z nich leży na podłożu o małej przepuszczalności (gliny, iły) i połowa na obszarach o dużej przepuszczalności (piaski, żwiry). Po roztworzeniu w wodzie królewskiej w próbkach osadów jeziornych oznaczono zawartość REE (La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) metodą ICP-MS oraz As, Cd, Co, Cu, Hg, Mo, Ni, Pb, Sn, V, W, Zn metodą ICP-OES. Osady jezior położonych na glinach i iłach charakteryzowały się większą zawartością pierwiastków REE, metali ciężkich i arsenu w stosunku do osadów jezior położonych na piaskach i żwirach. Większe zawartości REE występują w strefie litoralnej w porównaniu ze strefą profundalną, co wskazuje, że na ich zawartość wpływa głównie skład chemiczny podłoża zlewni, czynnik antropogeniczny odgrywa mniejszą rolę. Dystrybucja metali ciężkich i arsenu zależy od rodzaju podłoża, na którym powstała misa jeziorna i głębokości sedymentacji – gromadzą się one głównie w strefie profundalnej.

EN

Sixty sediment samples were collected from 30 glacial lakes of Pomerania, Wielkopolska-Kujawy and Warmia-Masuria Lakelands. The influence of the lake basin lithology and sedimentation zone on the contents of the elements in sediment was investigated. The samples were digested in Aqua Regia and analysed by ICP-MS methods and ICP-OES techniques for REE contents (La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). As, Cd, Co, Cu, Hg, Mo, Ni, Pb, Sn, V, W, Zn contents were determined by ICP-OES method. The sediments show higher contents of REE in the littoral zone than in the profundal zone. The sediments from the lakes located on low-permeable glacial sediments are more abundant in heavy metals and REE in relation to the sediments from the lakes located on highly permeable glacial sediments. Distribution of the trace elements in lake sediments is strongly dependent on the type of geological formations on which the lake is developed and on the sedimentation zone of the lake. REE are preferentially accumulated in the littoral zone contrary to the heavy metals that are accumulated in the deepest zone of the lake. Factor analysis proves that the presence of REE and heavy metals in the lake sediment is associated with the type of geological formation.

11

Isotopic investigations of uppermost sediments from Lake Wigry (NE Poland) and its environment

75%

Pawlyta J. , Pazdur A. , Piotrowska N. , Poręba G. , Sikorski J. , Szczepanek M. , Król K. , Rutkowski J. , Hałas S.

|

tom Vol. 23

71-78

EN

This paper presents the results of the first isotopic investigations of sediments recovered from Lake Wigry (NE-Poland). In the spring/summer 2002 few sediment cores, plant samples and water profiles were collected specially for isotopic investigations. We obtained 210Pb activity profiles, 137Cs activity profiles and 14C activity/age profiles. Apparent ages of carbonate fraction for all sediment cores were determined. Sedimentation rates for collected cores were estimated using 14C dating method. In addition oxygen isotopic ratios of the water profiles, carbon stable isotopes ratio of collected sediment cores were determined.

12

Subfossil shell margins and tail spines of Daphnia in Finnish lake sediments - is Daphnia underrepresented in cladocera analysis?

75%

Sarmaja- Korjonen K. , Sarmaja- Korjonen K.

|

tom 24

13

Zapis izotopów tlenu i węgla w kopalnych osadach jeziornych stanowisk Sucha Wieś (Pojezierze Ełckie) i Czarnucha (Równina Augustowska), północno-wschodnia Polska

63%

Nitychoruk J.

|

tom nr 435

75--84

PL

Badania stosunków izotopów tlenu i węgla w kopalnych osadach zbiornikowych kompleksu augustowskiego, w stanowiskach Sucha Wieś i Czarnucha w północno-wschodniej Polsce, pokazują złożony obraz zmian klimatu, w którym występują przynajmniej dwa ocieplenia. Detrytyczny kalcyt występujący w obrębie kopalnych osadów jeziornych utrudnia interpretację stosunków izotopowych. Zaznaczający się w osadach wzrost zawartości kalcytu pochodzenia morskiego, ze starszych formacji, jest charakterystyczny dla zimnych okresów interglacjału augustowskiego, w którym następowało rozrzedzenie pokrywy roślinnej ułatwiające spłukiwanie osadów, co jest wyrażone w postaci wysokich wartości δ. Tam, gdzie przeważa kalcyt autochtoniczny powstały w zbiorniku czwartorzędowym, wartości δ maleją. Stwierdzenie obecności okrzemek słonawowodnych we wszystkich profilach osadów może wskazywać na okresowe przesuszenia jezior. W takich warunkach dochodziło do koncentracji izotopów cięższych, co objawia się wysokimi wartościami δ.

EN

Investigations of the O/C ratio in ancient deposits of the Augustovian complex of the Sucha Wieś and Czarnucha sites, northern Poland, indicate a complicated image of climate changes with at least two warmings. Detrital calcite, found in the ancient lacustrine deposits, makes it difficult to interpret the isotope ratio. An increase in content of marine calcite derived from older formations is characteristic of cool periods of the Augustovian when the vegetation was sparse, favouring washout of the particles, as evidenced by high δ values. If there is apredominance of autochthonous calcite deposited in the Quaternary basin, then the δ values are lower. The presence of saline-water diatoms in all the sections can indicate a periodic drying up of the lakes when heavier isotopes were being concentrated resulting in high δ values.

14

Trace elements in the tanneries environment

63%

Zinkute R. , Taraškevičius R. , Radzevičius A.

|

tom Vol. 17

94-99

EN

Two tanneries "Elnias' and 'Stumbras" have been functioning in Šiauliai (Lithuania) since XIX century. They have created heavy metal anomalies in their environment: topsoil, Talša lake, and even KulpĹ river. The aim of the research was to recognise the extent of tanning influence on the surrounding environment and its changes since 1989. The repeated sampling of the topsoil was carried out in 2003 at the same 55 investigation sites as before (on the territories of the tanneries and in their nearest surroundings). Talša sediments were sampled in 1989, 1991, and 2002. All samples were analysed for total contents of a large group of elements, including Ag, B, Ba, Co, Cr, Cu, Mo, Mn, Ni, Pb, Sn, V, and Zn. Accumulated associations in topsoil of tanneries included at different time Cr>>Zn, Cu, Pb, Mo, Ni, and Sn. Associations accumulated in various time in Talša sediments were also similar, but except for the above mentioned elements they contained also Ag, Ba, Co, and V. Median additive contamination has increased in topsoil of "Stumbras" territory and in the nearest surroundings of 'Elnias'. It has increased also in Talša but mainly due to essential growth of Zn and Pb pollution.

PL

Dwie garbarnie "Elnias" i "Stumbras", które funkcjonowały w Šiauliai (Litwa) od dziewiętnastego wieku, spowodowały anomalię metali ciężkich w środowisku: w powierzchniowym poziomie gleb, w jeziorze Talëa i w rzece KulpĹ. Celem badań było określenie zakresu wpływu garbarni na otaczające środowisko i zaobserwowanie zachodzących zmian w porównaniu do roku 1989. Powtórne opróbowanie gleb zostało wykonane w 2003 r. w tych samych 55 punktach obserwacyjnych (na obszarze garbarni oraz w ich najbliższym sąsiedztwie). Osady jeziora Talša zostały opróbowane w latach 1989, 1991 i w 2002. We wszystkich próbkach oznaczono zawartość Ag, B, Ba, Co, Cr, Cu, Mo, Mn, Ni, Pb, Sn, V i Zn. Akumulacja metali ciężkich w górnej warstwie glebowej na terenie garbarni w obu okresach badawczych obejmowała Cr>>Zn, Cu, Pb, Mo, Ni i Sn. Akumulacja w osadach jeziora Talša była podobna, jednakże oprócz wymienionych poprzednio pierwiastków obejmowała także Ag, Ba, Co i V. Zaobserwowano, że średni poziom zanieczyszczeń w glebach wzrósł w tym czasie na terenie garbarni "Stumbras" i w sąsiedztwie garbarni "Elnias". Odnotowano także wzrost zanieczyszczenia w osadach jeziora Talša; był on spowodowany głównie wzrostem zawartości Zn i Pb.

15

Carbon dynamics in hardwater lake: effect of charophyte biomass on carbonates deposition

51%

Pukacz A. , Pełechaty M. , Frankowski M.

|

tom Vol. 62, nr 4

695--705

EN

The photosynthetic activity of phytoplankton (in pelagial) and macrophytes (in littoral) is considered to be one of the main factors affecting the carbon cycle in lakes. This concerns in particular hardwater ecosystems, where most of the carbon is available in the form of Ca- or Mg-bicarbonates. In such ecosystems charophytes (macroscopic green algae, forming dense meadows) are regarded as the most effective carbonate producer due to the HCO3 — utilization and the formation of thick CaCO3/sub> encrustations. Calcium carbonate and biomass production of charophytes were studied in a small and shallow charophyte-dominated Lake Jasne (Western Poland). Fresh and dry weight of plants, percentage contribution of calcium carbonate and production of CaCO3 per 1 m2 were studied at three depths (1, 3 and 5 m) in three sample sites (each sampled area − 0.04 m2). Additionally, physical-chemical parameters of water samples were studied. It was found that the dry weight of charophytes and the values of calcium carbonate were similar for all sites but varied for depth of sampling. The dry weight exceeded 2000 g m-2 (average 1165 g m-2) at the most shallow sample sites. CaCO3 encrustations constituted from 39.5% at the depth of 5m, to over 82% of the charophyte dry weight at the depth of 1m. The maximum and average values of carbonates precipitated by charophytes were 1696 g m-2 and 891 g m-2, respectively, and exceeded results reported so far. The results of physical-chemical analyses revealed no statistically significant differences between all the sample sites. Nevertheless, distinct correlations were found between dry weight of charophytes, carbonates precipitated by charophytes and some physical-chemical properties of water from the sample sites. The results highlight the habitat engineering role of charophytes, evidenced in particular by great amounts of biomass influencing sedimentary processes and biogeochemical cycle within littoral zone.