Caco<inf>3</inf> precipitation in multilayered cyanobacterial mats: Clues to explain the alternation of micrite and sparite layers in calcareous stromatolites

© 2015 by the authors; licensee MDPI, Basel, Switzerland. Marine cyanobacterial mats were cultured on coastal sediments (Nivå Bay, Øresund, Denmark) for over three years in a closed system. Carbonate particles formed in two different modes in the mat: (i) through precipitation of submicrometer-sized grains of Mg calcite within the mucilage near the base of living cyanobacterial layers, and (ii) through precipitation of a variety of mixed Mg calcite/aragonite morphs in layers of degraded cyanobacteria dominated by purple sulfur bacteria. The 13C values were about 2‰ heavier in carbonates from the living cyanobacterial zones as compared to those generated in the purple bacterial zones. Saturation indices calculated with respect to calcite, aragonite, and dolomite inside the mats showed extremely high values across the mat profile. Such high values were caused by high pH and high carbonate alkalinity generated within the mats in conjunction with increased concentrations of calcium and magnesium that were presumably stored in sheaths and extracellular polymer substances (EPS) of the living cyanobacteria and liberated during their post-mortem degradation. The generated CaCO3 morphs were highly similar to morphs reported from heterotrophic bacterial cultures, and from bacterially decomposed cyanobacterial biomass emplaced in Ca-rich media. They are also similar to CaCO3 morphs precipitated from purely inorganic solutions. No metabolically (enzymatically) controlled formation of particular CaCO3 morphs by heterotrophic bacteria was observed in the studied mats. The apparent alternation of in vivo and post-mortem generated calcareous layers in the studied cyanobacterial mats may explain the alternation of fine-grained (micritic) and coarse-grained (sparitic) laminae observed in modern and fossil calcareous cyanobacterial microbialites as the result of a probably similar multilayered mat organization

Group 2i Isochrysidales produce characteristic alkenones reflecting sea ice distribution

AbstractAlkenones are biomarkers produced solely by algae in the order Isochrysidales that have been used to reconstruct sea surface temperature (SST) since the 1980s. However, alkenone-based SST reconstructions in the northern high latitude oceans show significant bias towards warmer temperatures in core-tops, diverge from other SST proxies in down core records, and are often accompanied by anomalously high relative abundance of the C37 tetra-unsaturated methyl alkenone (%C37:4). Elevated %C37:4 is widely interpreted as an indicator of low sea surface salinity from polar water masses, but its biological source has thus far remained elusive. Here we identify a lineage of Isochrysidales that is responsible for elevated C37:4 methyl alkenone in the northern high latitude oceans through next-generation sequencing and lab-culture experiments. This Isochrysidales lineage co-occurs widely with sea ice in marine environments and is distinct from other known marine alkenone-producers, namely Emiliania huxleyi and Gephyrocapsa oceanica. More importantly, the %C37:4 in seawater filtered particulate organic matter and surface sediments is significantly correlated with annual mean sea ice concentrations. In sediment cores from the Svalbard region, the %C37:4 concentration aligns with the Greenland temperature record and other qualitative regional sea ice records spanning the past 14 kyrs, reflecting sea ice concentrations quantitatively. Our findings imply that %C37:4 is a powerful proxy for reconstructing sea ice conditions in the high latitude oceans on thousand- and, potentially, on million-year timescales.</jats:p

Wpływ deficytu kierowców zawodowych na rozwój przedsiębiorstw transportowych z obszarów wiejskich województwa zachodniopomorskiego

The aim of the article is to present and evaluate the effects of the deficit of professional drivers and changes in remuneration on the activities and development opportunities of road freight transport enterprises from rural areas of Western Pomerania. To achieve this objective, literature analysis, comparative analysis and elements of descriptive statistics were used. The research material was constituted by data for 58 transport enterprises registered in rural areas of the West Pomeranian Province. Financial and employment data was obtained from financial statements and InfoVeriti and Bisnode Polska databases. In the complimentary research, qualitative data was obtained through the use of CAWI and CAPI survey methods. Changes in the employment volume of the surveyed entities and the amount of remuneration paid by them in 2008-2017 were examined and evaluated. The results obtained indicate that both employment and remuneration as well as other benefits paid to drivers increased in the period under consideration. Enterprises from urban and rural areas pointed out serious problems in recruiting employees. On the basis of the study, the effects of the driver deficit on enterprises were also determined. Among them were: difficulties in finding employees, rising labour costs, employment turnover, incomplete use of transport means and difficulties in the timely performance of contracts. In the opinion of the surveyed enterprises, personnel problems were caused by factors such as a decrease in the number of people with appropriate qualifications on the labour market, emigration for financial purposes and high competition among employers.Celem artykułu jest przedstawienie i ocena skutków deficytu kierowców zawodowych oraz zmian wynagrodzeń dla działalności i możliwości rozwojowych przedsiębiorstw transportu drogowego ładunków z terenów wiejskich Pomorza Zachodniego. Zastosowano analizę literatury, analizę porównawczą i elementy statystyki opisowej. Materiał badawczy stanowiły dane dla 58 przedsiębiorstw transportowych zarejestrowanych na obszarach wiejskich województwa zachodniopomorskiego. Dane finansowe oraz dotyczące zatrudnienia pozyskano ze sprawozdań finansowych i baz danych – InfoVeriti i Bisnode Polska. Dla określenia danych jakościowych zastosowano metody ankietowe – CAWI i CAPI. Oceniono zmiany w wielkości zatrudnienia badanych podmiotów oraz wysokości wypłacanych w nich wynagrodzeń w latach 2008-2017. Uzyskane wyniki wskazują, że w badanym okresie zwiększyło się zarówno zatrudnienie, jak i wynagrodzenia oraz pozostałe świadczenia wypłacane dla kierowców. Przedsiębiorstwa z obszarów miejskich i wiejskich wskazywały na poważne problemy z pozyskaniem pracowników. Określono również skutki deficytu kierowców dla przedsiębiorstw, były to: trudności w znalezieniu pracowników, rosnące koszty pracy, rotacja zatrudnienia, niepełne wykorzystanie taboru i trudności z terminowym realizowaniem kontraktów. W opinii badanych przedsiębiorstw na problemy kadrowe przekładały się takie czynniki, jak spadek liczby osób posiadających odpowiednie uprawnienia na rynku pracy, emigracja zarobkowa oraz duża konkurencja wśród pracodawców

Geochemical composition of Vistulian loess and micromorphology of interstadial palaeosols at the Kolodiiv site (East Carpathian Foreland, Ukraine

This paper summarizes geochemical and palaeopedological investigations of the Upper Pleistocene loess-palaeosol sequences at the Kolodiiv site. The Kolodiiv 2, 3 and 5 profiles were selected for this study. The Kolodiiv 2 profile contains loesses, interglacial (Eemian) and interstadial (Vistulian) palaeosols. A set of Early Vistulian soils over lying Eemian gyttja and peat is exposed in the Kolodiiv 3 and 5 profiles. The mineral composition of the 50-2 mm silt fraction was analysed using non-oriented powder samples by means of X-ray dif - fraction. The total concentrations of nine major (Si, Ti, Al, Fe, Mn, Mg, Ca, K and Na) and nine trace elements (Zn, Pb, Ni, Rb, Cr, Sr, Ba, Co, V) as well as the humus content and loss on ignition were measured. The major elements concentrations in mineral deposits from the Kolodiiv 2 loess-palaeosol sequence indicate that the loess particles were derived from poorly weathered source rocks that have under - gone at least one sedimentary cycle. Climatic conditions have strongly in fluenced the mobilization and accumulation of elements in the palaeosol horizons due to the changes in the intensity of weathering and pedogenic processes. For the micromorphological study, ten samples from the Kolodiiv 3 and 5 profiles were used. Thin sections representing the Kolodiiv and Dubno set of palaeosols from Early Vistulian and Middle Pleniglacial show, be sides palaeopedologic characteristics, significant evidence of redeposition of sediments and soils

Geology, stratigraphy and palaeoenvironmental evolution of the Stephanorhinus kirchbergensis

The sedimentary succession exposed in the Gorzów Wielkopolski area includes Eemian Interglacial (MIS 5e) or Early Weichselian (MIS 5d–e) deposits. The sedimentary sequence has been the object of intense interdisciplinary study, which has resulted in the identification of at least two palaeolake horizons. Both yielded fossil remains of large mammals, alongside pollen and plant macrofossils. All these proxies have been used to reconstruct the environmental conditions prevailing at the time of deposition, as well as to define the geological context and the biochronological position of the fauna. Optically stimulated luminescence dating of the glaciofluvial layers of the GS3 succession to 123.6 ± 10.1 (below the lower palaeolake) and 72.0 ± 5.2 ka (above the upper palaeolake) indicate that the site formed during the Middle–Late Pleistocene (MIS 6 – MIS 5). Radiocarbon-dating of the lacustrine organic matter revealed a tight cluster of Middle Pleniglacial Period (MIS 3) ages in the range of ~41–32 ka cal bp (Hengelo – Denekamp Interstadials). Holocene organic layers have also been found, with C ages within a range of 4330–4280 cal bp (Neolithic). Pollen and plant macrofossil records, together with sedimentological and geochemical data, confirm the dating to the Eemian Interglacial.This research was supported by grant 0201/2048/18 ‘Life and death of extinctrhino (Stephanorhinus sp.) from Western Poland: a multiproxy palaeoenvironmental approach’ financed by the National Science Centre, Poland. LiDAR DTM data presented in this study were used under academic licences DIO.DFT.DSI.7211.1619.2015_PL_N and DIO.DFT.7211.9874. 2015_PL_N awarded to the Faculty of Earth Sciences and the Environmental Management University of Wrocław, in accordance with the Polish legal regulations of the administration of the Head Office of Land Surveying and Cartography