The different conceptions of wetlands and their classifications as well as their definitions in Lithuania are represented in this paper. According to existing databases, Lithuanian wetlands are represented by: suo wetlands, peatlands, lentic, lotic, and marine/coastal wetlands. The harmonisation of the Ramsar classification system with the traditional classifications of Lithuanian wetlands is emphasised. The distribution of the distinguishable wetland types is identified. The following Ramsar inland and man-made wetland types are found in Lithuania: non-forested and forested peatlands (9.9% area of Lithuania), seasonal pools on mineral soils and tree-dominated wetlands (>13.92% area of Lithuania), permanent freshwater lakes (1.27% area of Lithuania), permanent freshwater marshes/pools (0.08% area of Lithuania), aquaculture ponds (0.18% area of Lithuania), ponds (0.16% area of Lithuania), water storage areas (0.3% area of Lithuania), excavations (0.04% area of Lithuania), permanent rivers/streams/creeks, seasonal streams/creeks (~0.69% area of Lithuania), canals and drainage ditches (0.11% area of Lithuania), and permanent inland deltas (0.01% area of Lithuania). The authors identified the following types of Ramsar marine/coastal wetlands in Lithuania: permanent shallow marine waters (0.09% area of Lithuania), sand, shingle or pebble shores (94 km marine and 77.89 km lagoon shores), coastal freshwater lagoons (0.52% area of Lithuania).

Depth measurements of Lake Tapeliai (located in Vilnius, Lithuania) were taken in February 2019. At the same time, the shoreline of the lake was revised. Measurements were made from ice in 767 spots. Depth measurement accuracy up to 0,05 m, accuracy of spot coordinates and water surface elevation measurement using GNSS device Topcon Hiper SR up to 1–2 cm. Later, a detailed (1 x 1 m) digital lake bottom model (DEM) was developed, a bathymetric plan of the lake was created, the main morphometric features were calculated, the boundaries and area of the lake catchment were adjusted, and the physi cal-geographical characteristics of the lake and its catchment were examined based on various data. Morphometric features of Lake Tapeliai measured and calculated in 2019 are as follows: coordinates of mean center 54.774378, 25.4468 (WGS), water surface elevation 136.48 m (in Height System LAS07 of Lithuania), surface area 13.14 ha, shoreline length 1689 m, maximum length 687 m, maximum width 295 m, mean width 191 m, shoreline development 1.31, maximum depth 9.45, mean depth 4.36, volume 573.8 thousands m3, mean width of littoral zone 17,4 m, catchment area (including the lake itself) 2,93 km2. Lake Tapeliai catchment is located in the moraine and limnoglacial plains of Vilija, it is characterized by a rather diverse relief, which consists of a section of Tapeliai glacial tunnel valley, limnoglacial and fliuvioglacial plains, aeolian landforms and moraine hills. Average annual precipitation is ~686 mm. Significant portion (45 %) of the annual precipitation replenishes the lake, mostly through groundwater discharge. Water residence time in the Lake Tapeliai is 0.63 years. Lake Tapeliai covers 4.5 % of the catchment area. Forests cover as much as 79.4 % of the catchment area, pine forests predominate (82.3 %). Built-up areas occupy 11.3 % of the catchment area. The predominantly sandy soils in the catchment area result in abundant groundwater inseeping, which is reflected in the springs found at the bottom of the lake. Abundant groundwater inseeping also reduces lake water level fluctuations, whose estimated amplitude from June 2018 to May 2020 reached just 21 cm. Keywords: Tapeliai Landscape Reserve, Tapeliai, Lake, Vilnius, Lithuania, bathymetric chart, morphometry.

Nagrinėjamas kartografinių kūrinių vertimo skaitmeniniais skenuojant, gautų rastrinių žemėlapių kokybės vertinimo ir gerinimo bei įvairių defektų šalinimo, taikant Adobe PhotoShop programą, procesas, pateikiamas rastrinio žemėlapio rengimo numatytai paskirčiai algoritmas.

Bathymetric surveys of Gelionys and Žaliasis Lakes (located in the Baltic Uplands, Aukštadvaris Regional Park, Lithuania) were carried out on April 21, 2020, from a boat with attached Lowrance HDI SKIMMER XDCR transducer (200 kHz), Simrad GO5 chartplotter and Lowrance Point-1 GPS/Glonass receiver. At the same time, the shorelines of the lakes were revised. Average distance between profiles was ~10 m and depth measurement accuracy up to 2–5 cm. Accuracy of water surface elevation measurement using GNSS receiver Topcon Hiper SR up to 1–2 cm. Later, detailed (0.5 × 0.5 m) digital lake bottom models (DEM) were developed, bathymetric plans of the lakes were created, the main morphometric features were calculated, the boundaries and area of the lake catchments were defined, and the physical-geographical characteristics of the lakes were described based on field observations and various data. Gelionys and Žaliasis are small lakes of glaciokarst origin. Gelionys Lake is oval-shaped while shape of Žaliasis Lake is closer to the circle. Despite small surface area the lakes are quite deep. According to survey data, the surface area of Gelionys Lake is 4.79 ha, water surface elevation 216.1 m a.s.l., maximum depth 19.8 m, mean depth 6.0 m, volume 288.3 thousands m3, catchment area 71 ha. The surface area of Žaliasis Lake is 2.14 ha, water surface elevation 120.9 m a.s.l., maximum depth 15.84 m, mean depth 5.7 m, volume 122.2 thousands m3, catchment area 60 ha. During the observation period (from May of 2018 to September of 2020), the annual amplitude of water level fluctuations in Gelionys Lake reached up to 0.47 m, and in Žaliasis Lake up to 0.33 m. Keywords: Gelionys, Žaliasis, glaciokarst, lake, bathymetric chart, morphometry, Lithuania, Aukštadvaris Regional Park.

Straipsnyje nagrinėjama Akmenių erozinio klonio sapropelio geocheminė sudėtis ir užterštumas minerogeniniais ir sunkiaisiais metalais. Tyrimai atlikti rentgeno fluorescenciniu spektrometru Niton XL2. Analizuojami kokybiniai Šamuko, Antakmenių ir Drabužaičio ežerų parametrai: minerogeninių elementų (Rb, Zr, Sr) ir sunkiųjų metalų (As, Cr, Cu, Zn, Pb) koncentracijų pasiskirstymas paviršiniuose (0,0–0,6 m) ir giluminiuose (0,6–2,0 m) sluoksniuose. Pateikiami ir aptariami tyrimų duomenys, kurie lyginami su aplinkosauginiais normatyvais (foninėmis ir didžiausiomis leistinomis koncentracijomis (DLK)) bei rodikliais: suminiu užterštumu (Zd) ir praturtinimo faktoriumi (EF). Tyrimų rezultatai ir jų analizė leidžia nustatyti ežerų būklę, juose vykstančius procesus ir pokyčius per kelių šimtų metų laikotarpį.