Gyttja Layers Research Articles

Monitoring Erosion of a Submerged Stone Age Site and Its Implications for Managing Underwater Cultural Heritage. A Case Study at Tybrind Vig, Denmark

Abstract Known locations with submerged and well-preserved Stone Age sites in Denmark are, in most cases, under constant threat of erosion. The results presented here have been gathered at Tybrind Vig by surveying a 165 m-long transect at 5-metre intervals from the shore, by measurements taken with a total station. To supplement this, the surrounding area was surveyed with an echo sounder/sonar unit that yielded 3D coordinates post-processed in GIS to investigate volumetric changes in the seabed over time. The transect data was used to calibrate the elevation data from the echo sounder, following the correction of sea level change with data gathered from the Danish Coastal Authority. It was established that sediment transport – both erosion and accumulation – has occurred, but from the methods used, it cannot be determined how much of the archaeologically rich gyttja layers have been eroded at Tybrind Vig.

Lake sediments of the Kindo Peninsula and its surroundings (Karelian Coast of the White Sea) Holocene stratigraphy and dynamics of organic accumulation

Abstract. Sediment stratigraphy and dynamics of organic accumulation of eight small isolation basins at the Kindo Peninsula and its surroundings (Karelian Coast of the White Sea) were studied. The sediments structure and organic matter dynamics were found to depend on the age of the isolation that, in turn, depends on the lake s elevation. The thickest gyttja layer (up to 3 m) with loss-on-ignition values ca 60% formed in the lakes at the highest elevations. The thickness of marine-lacustrine transitional units varies from few cm to tens cm. The earlier isolation from the sea took place the thinner the transitional unit. In the lakes where isolation has not finished yet, the transitional sediments with LOI values ca 20-30% still form.

Preliminary data on formation and depositional environments of lake Chaika in the central part of the Curonian Spit (Kaliningrad region, Russia, South-Eastern Baltic)

Lake Chaika is the only major water body present in the sand barriers of the entire territory of South-Eastern Baltic shoreline. The article provides new insights into the formation of Lake Chaika, based on data acquired through a lithological investigation of the lake sediment core combined with an organic matter content analysis, a macrofossil analysis, a radiocarbon AMS-dating and a bathymetric survey. The study revealed that Lake Chaika was formed around 500 years ago. The kettle of the lake appears to have not been submerged during the Littorina transgressions. During the mid-late Holocene, the kettle of the lake was occupied by the peat-forming ecosystems of alder carrs and sedge fens with scattered alder. The accumulation of ligneous and sedge peat occurred. The sand horizon, separating the gyttja layer from peat deposits, is considered to be a time marker for the so-called “sand disaster”, which began in the study site 200-250 years earlier than in the main territory of the Curonian Spit. There are three main formation phases of the lake’s ecosystem: the period of carrs (5390–510 cal. yr BP), the “sand disaster” period (≈550–500 cal. yr BP) and the proper lake period (500 cal. yr BP – present time).

The uptake of Ni<sup>2+</sup> and Ag<sup>+</sup> by bacterial strains isolated from a boreal nutrient-poor bog

We studied the uptake of Ni2+ and Ag+ by bacterial strains of Paenibacillus, Pseudomonas, Burkholderia and Rhodococcus isolated from an acidic nutrient-poor boreal bog. The tests were run in two different growth media at two temperatures; +4 °C and +20 °C. All bacterial strains removed Ni2+ and Ag+ from the solution with highest efficiencies shown by one of the Pseudomonas sp. and one of the Paenibacillus sp. strains. Highest Ni2+ uptake was found in 1% Tryptone solution, whereas the highest removal of Ag+ was obtained using 1% Yeast extract. Temperature affected the uptake of Ni2+ and Ag+, but statistically significant difference was found only for Ni2+. Based on tests carried out for the bacteria in nutrient broths and for fresh samples taken from varying depth up to seven meters from the ombrotrophic bog, from which the bacteria were isolated, we estimated that in in situ conditions of the bog the uptake of Ni2+ by bacteria accounts for approximately 0.02% of the total sorption in the uppermost moss layer, 0.01% in the peat layer, 0.02% in the gyttja layer and 0.1% in the bottom clay layer of the bog. For Ag+ the corresponding values were 2.3% in the moss layer, 0.04% in the peat layer, 0.2% in the gyttja and 0.03% in the clay layer.

Sorption of radioiodide in an acidic, nutrient-poor boreal bog: insights into the microbial impact

Batch sorption experiments were conducted to evaluate the sorption behaviour of iodide and the microbial impact on iodide sorption in the surface moss, subsurface peat, gyttja, and clay layers of a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of iodide decreased as a function of sampling depth. The highest Kd values, 4800 L/Kg dry weight (DW) (geometric mean), were observed in the fresh surface moss and the lowest in the bottom clay (geometric mean 90 mL/g DW). In the surface moss, peat and gyttja layers, which have a high organic matter content (on average 97%), maximum sorption was observed at a pH between ∼4 and 5 and in the clay layer at pH 2. The Kd values were significantly lower in sterilized samples, being 20-fold lower than the values found for the unsterilized samples. In addition, the recolonization of sterilized samples with a microbial population from the fresh samples restored the sorption capacity of surface moss, peat and gyttja samples, indicating that the decrease in the sorption was due to the destruction of microbes and supporting the hypothesis that microbes are necessary for the incorporation of iodide into the organic matter. Anoxic conditions reduced the sorption of iodide in fresh, untreated samples, similarly to the effect of sterilization, which supports the hypothesis that iodide is oxidized into I2/HIO before incorporation into the organic matter. Furthermore, the Kd values positively correlated with peroxidase activity in surface moss, subsurface peat and gyttja layers at +20 °C, and with the bacterial cell counts obtained from plate count agar at +4 °C. Our results demonstrate the importance of viable microbes for the sorption of iodide in the bog environment, having a high organic matter content and a low pH.

Recent and Ancient Death-assemblages of Molluscs in Lakes Eğirdir and Beyşehir (SW Anatolia, Turkey)

In the summer of 2000 samples of beach deposits on the shore of Lake Eğirdir were collected. Subsequently, in August 2002, further samples were taken from a sequence exposed near Lake Beyşehir that was composed of carbonatic and gyttja layers containing abundant aquatic molluscs; these were dated to the end of the Middle Pleistocene. Species identification was made difficult by the fact that anatomical studies could not be made, and also because the taxonomy of Turkish molluscs still suffers from the effects of the once widespread habit of identifying Anatolian species as similar European species. The latter difficulty is well on the way to be resolved.<br />For much of the Middle-Upper Pleistocene and Holocene, Lake Eğirdir had characteristics similar to those of the large Beyşehir-Suğla Basin: a piedmont location enclosed by mountain ranges, large size and north-south orientation, maximum depth of about 15 m, variable water level and nutrient concentration (occasionally becoming a large pond), and probable increases in salinity. The qualitative and quantitative study of both malacofaunas, together with taphonomic observations on the shells,gave deeper insight into the formation processes of natural lacustrine shell accumulations and certain aspects of zooarchaeological interest, improving our understanding of such phenomena.

Does vivianite control phosphate solubility in anoxic meadow soils?

Vivianite (Fe3(PO4)2·8H2O) may precipitate in anoxic wetland soils where it may control orthophosphate (Pi) equilibrium solution concentrations at micromolar levels, and thus be of key importance in reducing excessive P from agricultural sources and eutrophication. However, vivianite equilibria and kinetics under in situ conditions are not fully understood and the occurrence of vivianite in wetland soils is rarely documented. In the present investigation we have monitored the temporal (November to June) variation in the pore water chemistry of a wet meadow soil (Sapric Medihemist) including a vivianite-containing gyttja layer. Pore water concentrations of Ca, FeII, HCO3, and NH4 in the gyttja layer were higher than in adjacent horizons. In contrast, dissolved Pi concentrations were the lowest observed in the profile and showed only minor fluctuations (between 0.1 and 6μM). Pore water composition in the gyttja layer was close to equilibrium with vivianite (saturation index, SIviv, 2.01±0.53) at constant pH (~6.8). Dissolution and precipitation experiments in the laboratory with soil suspensions from the gyttja layer demonstrated that vivianite solubility equilibria were only slowly restored. Even after 120days following perturbation the supersaturation was still high (SIviv~6). It seems that vivianite does contribute to Pi immobilization in anoxic soil horizons, but due to slow precipitation kinetics such soils cannot maintain Pi concentrations at levels below critical thresholds for eutrophication (~1μM), except if pore water geochemistry is kept stable.

Gyttja production by charophytes and its roles in the interaction with other submerged species in an oligotorphic lake

Charophyte ecology in Lake Myall, an oligotrophic lake in Australia, was investigated particularly focusing on the interaction with Najas marina and Myriophyllum salsugineum. Chraophytes intensively produces Gyttja, accumulating on the bottom. The Gyttja layer with its soft characteristics and low Redox potential inhibits colonization of submerged species except for Charophytes and Najas, thereby extremely decreasing biodiversity of flora of the lake. In Lake Myall, under high current, where Gyttja is washed away, M. salsugineum can grow on rocky bottom worsens the light climates for Charophytes, while in stagnant water, N. marina, although low in biomass most of the year, vigorously grows in May, suppressing Charophyte communities, although they are tolerant in low light regime. These process was confirmed by measuring light intensity inside the plant canopy, compared with depthwise and biomass distribution in the lake.

Tsunamis and tectonic deformation at the northern Cascadia margin: a 3000-year record from Deserted Lake, Vancouver Island, British Columbia, Canada

Three layers of sand occur within a sequence of muddy gyttja in a 3 m core recovered from Deserted Lake, which lies at the head of a fjord on the central west coast of Vancouver Island, British Columbia, Canada. The sedimentology and microfossil assemblages of these layers are consistent with deposition by tsunamis. Radiocarbon ages suggest that the tsunamis were generated by plate-boundary earthquakes at the Cascadia subduction zone about 2600, 1600 and 300 years ago. Diatom and protozoan contents of the gyttja layers indicate that relative sea level fell in the periods between tsunamis. The sea-level changes are probably a product of interseismic uplift of the North America plate margin. Post-tsunami diatom and protozoan assemblages are generally more marine than their pre-tsunami counterparts, suggesting that the study site subsided during earth quakes. Estimates of interseismic and coseismic deformation during one earthquake cycle indicate that less than half of the interseismic uplift was recovered during the earthquake, leading to cumulative, or permanent, uplift of the area.

Pleistocene stratigraphy in the Lappajarvi meteorite crater in Ostrobothnia, Finland

Seventy‐four meters of a 95‐m‐long drill core recovered from the Lappäjarvi crater, a meteoritic impact site in western Finland, consisted of Pleistocene sediments. These sediments refer to two events of glacial deposition (Saalian and Weichselian) interrupted by non‐glacigenic freshwater sedimentation. The sediments contain abundant redeposited Holsteinian and Tertiary microfossils, and possibly represent a pre‐Weichselian interstadial not described from elsewhere in Finland. The pollen flora indicates a mixed primary arctic to subarctic succession that followed deglaciation, i.e. the beginning of an interglacial or interstadial event. The secondary pollen component derives from an eroded interglacial deposit that can be interpreted as Holsteinian, or possibly Eemian, in age. The vegetation succession interpreted from the primary pollen flora reflects a transition from arctic conditions to subarctic birch forests. The diatom flora indicates a primary succession that can be observed clearly in the uppermost gyttja layer in which the rich alkaliphilous diatom flora refers to more or less eutrophic conditions. The diatom flora of sediments below the gyttja layer is composed of a primary component and a secondary, redeposited or relict component. The diatoms encountered are interglacial or Tertiary in origin. The results show that meteorite craters can provide long, representative stratigraphic sequences in glacially eroded Precambrian shield areas such as Finland.

A STUDY ON POLLEN DISPERSAL AND SEDIMENTATION IN THE WESTERN PART OF THE NETHERLANDS

SUMMARY The interpretation of palynological data into a history of the plant communities in a region requires (1) the estimation of the pollen density in the samples, (2) the knowledge of the relative representation rates of the vegetation elements in the pollen spectra and (3) a careful distinction between air-borne and water-borne pollen because of their different recording values. In the present article, a method is described for pollen density determination which is convenient when cores have to be analysed consisting of peat, gyttja and clastic sediments. This method involves the addition of a foreign pollen. Examples are given of the variation which may occur in the pollen density of sediments in a horizontal series of samples. In three cores the pollen densities were determined and the use of this additional information for the interpretation of the analysis data is demonstrated. In a number of nature reserves a comparison was made between the composition of the local stand of vegetation and the pollen sedimentation. To this purpose moss samples were analysed. The representation of the plant communities was generally found to be fair. The dispersal of water-borne pollen was studied by a comparison of the regional vegetation types with the pollen precipitated on river banks and tidal flats; there was also made a series of analyses of the pollen content of the water, which shows that the seasonal variations are so small that the pollen which is precipitated from the water in the regions investigated is not representative for the regional vegetation type. The pollen which is deposited in such conditions may originate from three different sources: (1) the local or regional stand of vegetation, (2) forests or other plant communities in remote upstream areas and (3) peat or gyttja layers or other pollen containing deposits which are eroded by the water currents. A number of examples of these dispersal mechanisms is described in this article. In a few cases it is demonstrated how the determination of pollen density may contribute to the solution of the problem, in which proportion these three dispersal mechanisms have been responsable for the presence of the pollen in the sediment under investigation.