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Remarks on Myriophyllum sibiricum, a long-time unrecognised species of the flora of Lithuania /
No full textThis research aimed to verify the identification and distribution of Myriophyllum sibiricum in Lithuania. The study was based on a revision of available herbarium specimens and information from archival materials and literature sources. A total of 134 herbarium specimens of Myriophyllum, mainly initially identified as My-riophyllum spicatum, were examined. After revision of herbarium specimens, 101 of these were identified as Myriophyllum sibiricum. The remaining 33 herbarium specimens were tentatively determined as hybrids My-riophyllum sibiricum × Myriophyllum spicatum. None of the specimens were identified as Myriophyllum spica-tum. The distribution of Myriophyllum sibiricum is related mainly to standing waters of upland regions, while localities of putative hybrid scattered throughout the area and associated with upland lakes and river stretches. The morphological features of the leaves (number of segments pairs and its angle with the central axis, occurrence of glands at the base of young leaves and in axils of leaves segments) are helpful to distinguish typical specimens of Myriophyllum sibiricum from Myriophyllum spicatum, however useless for their separation from the hybrid. This study revealed that further research on Myriophyllum sibiricum, Myriophyllum spicatum and their putative hybrid must apply morphological and molecular methods
Establishment of biotesting system to study features of innovative multifunctional biotextile /
No full textAn established biotesting system designed to discover specific features of innovative multifunctional biotextile, encompassing integrated silica dioxide and succinite (Baltic amber) particles, is founded on reproducible, reliable, and relatively fast methods. The main idea starting this study was to create a system of test methods devoted to identification of specific features of biotextile materials designed to preserve living organisms from adverse environmental factors like enhanced electromagnetic radiation of different frequencies, without use of vivarium animals. Cultures of the freshwater macrophyte duckweed (Lemna minor) line Sta2 and fruit flies (Drosophila melanogaster) were chosen as model systems suitable for the study of the influence of electromagnetic field (EMF) radiation. The experiments showed changes of phenotypic features and growth parameters of test objects, as well as induction of point mutations of DNA (for example, insertions or deletions in chloroplast DNA and nucleotide substitutions in nuclear genes). The responses of test organisms induced by EMF were studied using microscopy, flow cytometry, and DNA sequencing methods. On the cell level, a new fast flow cytometry method for biotextile testing was developed: immature gametic (pollen) cell cultures were used as a highly sensitive model system (plant gametic cell response is comparable to human neutrophil response) to study the influence of EMF radiation. The method was based on the measurement of differences of fluorescence intensity between group of cells experimentally affected by EMF radiation and non-affected cells
The wave climate parameters change in nearshore along The Curonian Spit sea coast In 2003-2019 /
No full textOn the effectiveness of tributyltin ban part II: Temporal and spatial trends of organotin pollution in intense sediment accumulation areas and dumping sites of the Baltic Sea /
No full textBased on the knowledge gained from our previous study, our aim is to observe the current levels of butyltin (BTs) pollution, changes during different seasons, and the factors that affect these trends in the areas of highest concern. These areas include semi-enclosed bays in the Port that were previously affected by large tributyltin (TBT) inputs, as well as the dumping sites of dredged sediment in the Baltic Sea. Compared to previous studies, there has been a significant decrease in the levels of BTs in the Klaipeda Port. However, the sediment in the semi-enclosed bays still contained BTs, ranging from less than 0.5 ng Sn g−1 dw to as high as 728.5 ng Sn g−1 dw. Some BTs were also detected in the currently exploited dumping sites of the Baltic Sea. Moreover, butyltin degradation index (BDI) revealed occasional fresh TBT input or slow degradation both in the Port and in the Sea. Some trends in butyltin concentrations were indicative of the impact of climate change in Lithuania, which are consistent with global trends. We also found that variations in BTs concentrations were closely related to dredging and cleaning activities taking place in the Klaipeda Port. Correlation, principal component, and cluster analysis revealed close relationship between TBT and its degradation products, as well as between TBT and Zn, Pb, Cu. Ship cleaning/maintenance activities were identified as the main source of pollution in the study area. Despite the gradually decreasing BTs concentration in the Klaipeda Port, the problem is not yet completely solved
Nearshore sandbar switching episodes and their relationship with coastal erosion at the Curonian Spit, Baltic Sea /
No full textThe longshore realignment of nearshore sandbars is a morphodynamic phenomenon of multiple sandbar systems that has been known about for several decades. However, it is un-known how switching-related nearshore changes influence the evolution of subaerial beaches. This study aims to define the relationship between sandbar switching episodes and the dynamic state of the beach-foredune system along the Curonian Spit coast (Baltic Sea) using decadal satellite-derived and beach profiling data. To define this connection, sandbar switching lo-cations, sandbar cross-shore positions, shoreline positions, and sand volume changes in the beach-foredune system were assessed on interannual and storm-related time scales. Twenty-seven sandbar switching episodes were observed with an average duration of 14.3 months. Most of the switching episodes occurred at preferred locations, coinciding with breaking points of different shoreline orientations where oblique waves and longshore currents prevailed. Shore-line retreat at an average rate of -14.2 m was observed within most of the sandbar switching zones. During major storm events, the average rate of erosion within the sandbar switching zones was significantly higher than the rate outside them. On an interannual time scale, a moderate average rate of erosion was observed within the sandbar switching zones compared to a small accretion rate outside them. Additional case studies of coastal evolution within the switching zones indicated well-correlated rates of switching-determined outer sandbar posi-tions, shoreline positions, and sand volume on the beach and foredune during the switching episodes. The results of this study could be important for the identification of erosional hot spots and coastal prediction
