Ion-exchange properties and swelling capacity of leaf cell wall of Arctic plants

Ion-exchange (number of functional group) properties and swelling capacity of leaf cell walls of plant species Betula nana, Salix polaris, Dryas octopetala and Cassiope tetragona from Western Spitsbergen Island were investigated. It was found out that cell wall of Arctic plants is cation exchanger which has similar functional groups (amine groups, carboxyl groups and phenolic OH-groups) with cell wall of boreal plants. In all investigated species, the highest percentage in the structure of the cell wall was recorded for the carboxyl groups of hydroxycinnamic acids and phenolic OH-groups, which are part of phenolic compounds. In comparison with species from other climatic zones leaf cell wall of arctic plants has in 2–3 times higher amount of ion exchange groups of all types as well as the higher values of swelling coefficients. It was proposed that the high values of the ion-exchange capacity and swelling coefficient of the cell wall of all studied species contribute to greater water flow system by the apoplast and enhance the metabolic processes in the cell wall of plants at high latitudes.

The Origin of Heavy Metals and Radionuclides Accumulated in the Soil and Biota Samples Collected in Svalbard, Near Longyearbyen

Heavy metals and radioactive compounds are potentially hazardous substances for plants, animals and humans in the Arctic. A good knowledge of the spatial variation of these substances in soil and primary producers, and their sources, is therefore essential. In the samples of lichen Thamnolia vermicularis, Salix polaris and Cassiope tetragona, and the soil samples collected in 2014 in Svalbard near Longyearbyen, the concentrations of the following heavy metals were determined: Mn, Ni, Cu, Zn, Cd, Pb and Hg, as well as the activity concentrations of the following: K-40, Cs-137, Pb-210, Pb-212, Bi-212, Bi-214, Pb-214, Ac-228, Th-231 and U-235 in the soil samples. The differences in the concentrations of the analytes accumulated in the different plant species and soil were studied using statistical methods. Sea aerosol was indicated as the source of Pb, Hg, Cs-137, Pb-210 and Th-231 in the studied area. A relatively high concentration of nickel was determined in the biota samples collected near Longyearbyen, compared to other areas of Svalbard. It was supposed that nickel may be released into the atmosphere as a consequence of the local coal mining around Longyearbyen.

Deglaciation chronology, sea-level changes and environmental changes from Holocene lake sediments of Germania Havn Sø, Sabine Ø, northeast Greenland

Germania Havn Sø is located at the outermost coast of northeastern Greenland. According to radiocarbon dating, the lake basin was deglaciated in the early Holocene, around 11,000 cal yr BP. At that time the lake was a marine bay, but the lake was isolated soon after deglaciation at ~ 10,600 cal yr BP. The marine fauna was species-poor, indicating harsh conditions with a high sedimentation rate and lowered salinity due to glacial meltwater supply. The pioneer vegetation around the lake was dominated by mosses and herbs. Deposition of relatively coarse sediments during the early Holocene indicates erosion of the newly deglaciated terrain. Remains of the first woody plant (Salix herbacea) appear at 7600 cal yr BP and remains of other woody plants (Salix arctica, Dryas octopetala, Cassiope tetragona and Empetrum nigrum) appear around one millennium later. Declining concentrations of D. octopetala and the caddis fly Apatania zonella in the late Holocene probably imply falling summer temperatures. Only moderate changes in the granulometric and geochemical record during the Holocene indicate relatively stable environmental settings in the lake, which can probably be explained by its location at the outer coast and the buffering effect of the neighboring ocean.