ALBERT

Description: Between 6th August and 2nd September, 2021, a total of 66 lakes in Central and Eastern Yakutia were assessed as part of the joint Russian-German expedition (NEFU-AWI; RU-Land_2021_Yakutia). Samples and data were obtained with a large variety of different methods and for a wide range of sampling purposes. This dataset presents the results of hydrochemical laboratory analyses of ion concentration. Of those 66 hydrochemical analyses, 15 are from mountain lakes located within the Verkhoyansk mountain range, at the eastern end of the expedition route, including mostly intermontane basin or glacial lakes (average elevation: c. 1080 m a.s.l.). 13 lakes were sampled in Oymyakonsky District and two lakes in Tomponsky District. The hydrochemical dataset from the other 52 lakes that lie within the eastern extent of the Central Yakutian Lowland (average elevation: c. 190 m a.s.l.) represents thermokarst lakes. Thermokarst lakes originate from thawing of ice-rich permafrost and were found in different stages of their development, with a wide range of anthropogenic impact. These 52 thermokarst lakes include seven lakes within the Churapchinsky District, two are located in the Tattinsky District further east within a freshly burned forest. 42 lakes are located in Megino-Kangalassky District, of which 17 lakes are around Tungulu, and 24 lakes around Maya settlements.

Description: The Red Sea is a very young ocean, and is one of the most interesting areas on Earth (ocean in statu nascendi). It is the only ocean where hydrothermal activity associated with ore formation occurs in a sterile environment (anoxic, hot, saline). In addition, its geographical position means that it is predestined to record the monsoonal history of the region in detailed sedimentary sequences. The major aim of the present project is to investigate the dynamics of hydrothermal systems in selected Deeps (Atlantis-II, Discovery, Kebrit, Al Wajh), Additional palaeoceanographic and microbiological questions should also be addressed. Specific aims are: 1. To study the hydrographic changes in individual Deeps (hydrothermal region Atlantis-II) and to investigate the causes of the temperature increase in the last few years (increased heat flow - higher temperature of the brine supply - higher brine flow rates?). 2.a. To document the influence of the hydrothermal systems on the sedimentary organic matter in the Deeps. In particular, the thermogenic production and migration of hydrocarbons in the sediments will be studied. The complex formation mechanisms (bacterial, thermogenic) of short-chain hydrocarbons (trace gases) will also be examined, 2.b. in addition, the polar and macromolecular fraction in samples from the various deeps will be studied in order to elucidate the formation, structure and source of the macromolecular oil fraction. 3. To clarify the palaeoceanographic conditions, sea-level changes and the climatic history (relationship of the circulation system and nutrient supply to the monsoon) of the southern Red Sea. 4. To separate microorganisms from the brines and to characterise them in terms of their metabolic physiology and ecology, and to describe their taxonomy.

Description: This dataset presents the assessment of the lake types and settings together with the data on hydrophysical parameters measurements including Electrical Conductivity, on-site water temperature and pH, except at one lake (EN21426-2) of which electrical conductivity was measured in the Hydrochemical Laboratory of AWI). Lakes were surveyed between 6 August and 2 September 2021. A total of 66 lakes in Central and Eastern Yakutia were assessed as part of the joint Russian-German expedition (NEFU-AWI; RU-Land_2021_Yakutia). Of those 66 lakes, 15 are from mountain lakes located within the Verkhoyansk mountain range, at the eastern end of the expedition route, including mostly intermontane basin or glacial lakes (average elevation: c. 1080 m a.s.l.). 13 lakes were sampled in Oymyakonsky District and two lakes in Tomponsky District. The hydrochemical dataset from the other 52 lakes that lie within the eastern extent of the Central Yakutian Lowland (average elevation: c. 190 m a.s.l.) represents thermokarst lakes. Thermokarst lakes originate from thawing of ice-rich permafrost and were found in different stages of their development, with a wide range of anthropogenic impact. These 52 thermokarst lakes include seven lakes within the Churapchinsky District, two are located in the Tattinsky District further east within a freshly burned forest. 42 lakes are located in Megino-Kangalassky District, of which 17 lakes are around Tungulu, and 24 lakes around Maya settlements.

Description: Between 6th August and 2nd September, 2021, a total of 66 lakes in Central and Eastern Yakutia were assessed as part of the joint Russian-German expedition (NEFU-AWI; RU-Land_2021_Yakutia). Samples and data were obtained with a large variety of different methods and for a wide range of sampling purposes. This dataset presents the results of hydrochemical laboratory analyses of ion concentration. Of those 66 hydrochemical analyses, 15 are from mountain lakes located within the Verkhoyansk mountain range, at the eastern end of the expedition route, including mostly intermontane basin or glacial lakes (average elevation: c. 1080 m a.s.l.). 13 lakes were sampled in Oymyakonsky District and two lakes in Tomponsky District. The hydrochemical dataset from the other 52 lakes that lie within the eastern extent of the Central Yakutian Lowland (average elevation: c. 190 m a.s.l.) represents thermokarst lakes. Thermokarst lakes originate from thawing of ice-rich permafrost and were found in different stages of their development, with a wide range of anthropogenic impact. These 52 thermokarst lakes include seven lakes within the Churapchinsky District, two are located in the Tattinsky District further east within a freshly burned forest. 42 lakes are located in Megino-Kangalassky District, of which 17 lakes are around Tungulu, and 24 lakes around Maya settlements.

Description: The dataset compiles water isotope measurements of 66 lakes, sampled in Central and Eastern Yakutia during a summer field campaign in August and September 2021 (RU-Land_2021_Yakutia). Additionally, there are isotope data of a single rain event, received during the campaign. The investigated lakes are located in four different study areas in the Sakha Republic, Russia: in the mountainous region of the Verkhoyansk Range within the Oymyakonsky and Tomponsky District (EN21401 - EN21415), and in three lowland regions of Central Yakutia within the Churapchinsky, Tattinsky and the Megino-Kangalassky District (Event EN21416 - EN21467). One lake (EN21160) is centrally located in the city of Yakutsk, the capital of the Sakha Republic. Baisheva et al. (2022) gives an overview of the lakes studied and the corresponding hydrochemistry. Surface water samples (0 – 0.5 m) for measurement of stable water isotopes (δ18O, δD) have been taken for all lakes. If the lakes were deeper than five meters (≥ 5 m), water samples of the middle and bottom water (MW, BW) of the lake were taken, too. Where it was available and reachable, there are also water isotope data from in- or outflow (IF, OF). For two greater lakes, there are one or even more depth profiles composed of several isotope samples from different depths (EN21112, EN21116, EN21124¸ EN21160; numbers at the end indicate different sampling depths). There were two different methods of sampling: Either water for isotope measurements was directly sampled from the lake into 30 ml narrow-mouth PE bottles, filled to the top and closed tightly. Otherwise water samples were taken with an UWITEC water sampler (2 L), filled into a larger sample container (2 L Whirl-Pak®) and subsampled in 30 ml narrow-mouth PE bottles as soon as possible afterwards. The single rain event was sampled on the 22nd of August 2021 at one of the field camp sites, close to the lake EN21427. A dry, clean plastic container was placed outside for receiving the rain. The subsampling was done immediately after the event by rinsing it into 30 ml narrow-mouth PE bottles, filled to the top and closed tightly. All samples were stored cool and dark as soon as possible until analysis. All data were collected and processed by scientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), Germany, the University of Potsdam, Germany, and the North-Eastern Federal University of Yakutsk (NEFU), Russia. Oxygen and hydrogen isotope analyses were carried out at the ISOLAB Facility at Alfred Wegener Institute in Potsdam (hdl:10013/sensor.ddc92f54-4c63-492d-81c7-696260694001) with mass spectrometers (DELTA-S Finnigan MAT, USA): hdl:10013/sensor.af148dea-fe65-4c87-9744-50dc4c81f7c9 and hdl:10013/sensor.62e86761-9fae-4f12-9c10-9b245028ea4c employing the equilibration method (details in Meyer et al., 2000). δ18O and δD values are given in per mill (‰) vs. Vienna Standard Mean Ocean Water (VSMOW) as the standard. N indicates the number of measurements per sample. If N 〉 1, the mean isotope value of the sample was calculated from the individual measurement results. The standard deviation includes all measurements of the individual sample, which is generally better than the external (or machine) error. The external errors of long-term standard measurements for hydrogen and oxygen are better than 0.8‰ and 0.10‰, respectively (Meyer et al., 2000). The second order parameter d excess was computed according to: d excess = δD – 8 * δ18O (Dansgaard, 1964). For the calculation of d excess, the respective mean values were used.