Holocene climate and environmental change in north-eastern Kamchatka (Russian Far East), inferred from a multi-proxy study of lake sediments

The study was supported by the Swedish Research Council through grants 621-2004-5224 and 621-2005-4444 to K.D. Bennett. A. Self and N. Solovieva acknowledge S. Brooks and V. Jones and were supported by NERC grant NE/H008160/1.A sediment record from a small lake in the north-eastern part of the Kamchatka Peninsula has been investigated in a multi-proxy study to gain knowledge of Holocene climatic and environmental change. Pollen, diatoms, chironomids and selected geochemical parameters were analysed and the sediment record was dated with radiocarbon. The study shows Holocene changes in the terrestrial vegetation as well as responses of the lake ecosystem to catchment maturity and multiple stressors, such as climate change and volcanic eruptions. Climate change is the major driving force resulting in the recorded environmental changes in the lake, although recurrent tephra deposition events also contributed. The sediment record has an age at the base of about 10,000 cal yrs BP, and during the first 400 years the climate was cold and the lake exhibited extensive ice-cover during winter and relatively low primary production. Soils in the catchment were poor with shrub alder and birches dominating the vegetation surrounding the lake. At about 9600–8900 cal yrs BP the climate was cold and moist, and strong seasonal wind stress resulted in reduced ice-cover and increased primary production. After ca. 8900 cal yrs BP the forest density increased around the lake, runoff decreased in a generally drier climate resulting in decreased primary production in the lake until ca. 7000 cal yrs BP. This generally dry climate was interrupted by a brief climatic perturbation, possibly attributed to the 8.2 ka event, indicating increasingly windy conditions with thick snow cover, reduced ice-cover and slightly elevated primary production in the lake. The diatom record shows maximum thermal stratification at ca. 6300–5800 cal yrs BP and indicates together with the geochemical proxies a dry and slightly warmer climate resulting in a high productive lake. The most remarkably change in the catchment vegetation occurred at ca. 4200 cal yrs BP in the form of a conspicuous increase in Siberian dwarf pine (Pinus pumila), indicating a shift to a cooler climate with a thicker and more long-lasting snow cover. This vegetational change was accompanied by marked shifts in the diatom and chironomid stratigraphies, which are also indicative of colder climate and more extensive ice-cover.Publisher PDFPeer reviewe

Diatom responses to 20th century climate warming in lakes from the northern Urals, Russia.

Changes in diatom assemblages and spheroidal carbonaceous particle (SCP) profiles during the last 200 years in 210Pb-dated sediment cores from five remote arctic and sub-arctic lakes in the northern Urals were analysed. The study area covers a large territory from arctic tundra in the north to boreal forest on the western slopes of the Ural mountains in the south. pH was reconstructed using a diatom-based model. The degrees of compositional turn-over and rates-of-change were estimated numerically. The 20th century diatom floristic shifts, the rise in diatom accumulation rates and the rates of diatom compositional change in the northern Ural lakes correlate well with June temperature in the region and with the overall circum-arctic temperature increase from the 1970s. The main driving force behind diatom compositional shifts in the study lakes are the changes in the duration of ice-free season, timing of water turn-over and stratification periods and habitat availability. Changes in spheroidal carbonaceous particles show no pronounced effect on diatom assemblages. Pollution is restricted to regional sources originating mainly from the Vorkuta coal industry. Changes in diatom plankton are more pronounced than changes in diatom benthos. There is no clear north–south gradient in degree of compositional changes, with greatest changes occurring in Lake Vankavad situated in northern boreal forest. The degree of the 20th century diatom changes in Lake Vankavad is greater than in most circum-arctic and sub-arctic lakes from northern Europe and Canada

Coordinates and main environmental parameters of the lakes from the River Pechora basin, East European Russian Arctic

We investigated surface sediments from the lakes and a short sediment core (lake Bolshoy Kharbey) from the River Pechora basin, East European Russian Arctic. The twenty three investigated lakes have thermokarst, glacial or floodplain origin and are characterised by low mineralization, mostly hydrocarbonat-calcium type of water and low concentration of biogenic elements. The lakes have close to neutral pH, but in 14 lakes pH is less than or equal to 7 and in 2 lakes less than or equal to 6. These two lakes are classified as acidothrophic

Data_Sheet_1_Developing effective student learning environment: Case study from Sharjah, United Arab Emirates.PDF

The impact of COVID-19 on college education has been profound. At the same time, it has also provided an opportunity to test the effectiveness of new teaching approaches in challenging circumstances when the new delivery modes were introduced. In this case study, we have taken the project-based learning approach a little further by directly involving students as co-researchers in the ongoing research project in a higher education institution in Sharjah. This campus-based research project aimed at finding effective solutions to reduce plastic waste at the Sharjah campus. We enabled several groups of students to participate in the primary data collection for our project by aligning their course work projects with the aims of our own research. Hence, the students were directly involved in the ongoing community project, which raised their awareness about important sustainability issues. In addition, the students acquired essential research skills and were able to apply their knowledge to practical issue. This approach was effective: the difference between the final grades of students in the project and non-project groups was statistically significant in 2020 and in 2021. In 2020, the students in the project group scored 5.16% higher than the students in the non-project group. (95% confidence interval is [−0.9044, 11.2244], p = 0.047). In 2021, this difference was 6.5% (95% confidence interval is [2.1176, 10.9026], p = 0.002).</p

Late Holocene expansion of Siberian dwarf pine (Pinus pumila) in Kamchatka in response to increased snow cover as inferred from lacustrine oxygen-isotope records

Holocene records of cellulose-inferred lake-water delta O-8 were produced from two lake-sediment sequences obtained in central and northern Kamchatka, Russian Far East. The sediment records share similar fluctuations in delta O-8 during the interval of ca. 5000-800 cal yr BP that correspond (inversely) with changes in K+ content of the GISP2 ice-core record from Greenland, a proxy for the relative strength of the Siberian High, suggesting control by climate-related variability in delta O-8 of regional precipitation. The dramatic expansion of Siberian dwarf pine (Pinus pumila) in northern and central Kamchatka between ca. 5000 and 4000 cal yr BP, as inferred from pollen records from the same and neighbouring sites, appears to have occurred at a time of progressively declining delta O-8 of precipitation. This development is interpreted as reflecting a regional cooling trend accompanied by increasing winter snowfall related to gradual intensification of the Siberian High from ca. 5000 to ca. 3000 cal yr BP. A thicker and more long-lasting snow cover can be assumed to have favoured P. pumila by providing a competitive advantage over other boreal and subalpine tree and shrub species in the region during the later part of the Holocene. These results, which are the first of their kind from Kamchatka, provide novel insight into the Holocene vegetational and climatic development in eastemmost Asia, as well as long-term atmospheric circulation dynamics in Beringia. (C) 2015 Elsevier B.V. All rights reserved

Measurement of the Ωc0\Omega_c^0 lifetime at Belle II

We report on a measurement of the $\Omega_c^0$ lifetime using $\Omega_c^0 \to \Omega^-\pi^+$ decays reconstructed in $e^+e^-\to c\bar{c}$ data collected by the Belle II experiment and corresponding to $207~{\rm fb^{-1}}$ of integrated luminosity. The result, $\rm\tau(\Omega_c^0)=243\pm48( stat)\pm11(syst)~fs$, agrees with recent measurements indicating that the $\Omega_c^0$ is not the shortest-lived weakly decaying charmed baryon