Temporal and spatial changes in marine benthic habitats in relation to the EU Water Framework Directive: The use of sediment profile imagery

In 2002 to 2006, sediment profile imagery (SPI) was used to study the environmental impact of eutrophication-induced irregular and seasonal hypoxia on marine benthic habitats in six regions in the Skagerrak and Kattegat (West Sweden). The benthic habitat quality (BHQ) was assessed by parameterisation of biogenic structures observed by the SPI technique, and benthic quality status was related to the EU Water Framework Directive (EU-WFD). The temporal changes were analysed by a 5-factor nested ANOVA and significant temporal differences were recorded within three of the regions. Two of these were affected by hypoxia in the deeper parts and one was probably affected by hypoxia below the halocline. The environmental quality status according to the EU-WFD was bad to high in two regions, moderate to good in three regions, and good to high, i.e., acceptable according to the EU-WFD, in only one region. As BHQ is highly correlated to benthic faunal data, measures have to be taken to improve the coastal water quality in five of the six studied areas.     

Management information system of lakes and reservoirs

Information technologies provide a significant support in the management of lakes and reservoirs. Existing information systems mostly did not comprise all the necessary data and enabled collecting only a limited set of reports. More complex data analyses such as statistical analyses and data research were conducted in separate environments and recquired additional preparation of the data. Information system of lakes and reservoirs in Serbia (SeLaR) was produced in order to provide all the neccessary information for lake and reservoir management. The information system integrates a large data set and provide users with necessary information in the form of reports and charts. The users of the system are scientists and experts who study these issues, as well as students with the objective of continuous education. Furthermore, an interface was produced to enable linking with data research software. In this way a unique working environment was created to provide users with an efficient model of acquiring all the information necessary for the management and to find out new facts in data interaction, and also to make a forecast. This study presents an overview of the information system, its production model, the information available and the possibilities of data research.     

Transient electromagnetic modelling of an isolated wire loop over a conductive medium

A large closed wire loop is generally used in field experiments for testing airborne electrical exploration equipment. Thus, methods are required for the precise calculation of an electromagnetic response in the presence of a closed wire loop. We develop a fast and precise scheme for calculating the transient response for such a closed loop laid out at the surface of a horizontally layered conductive ground. Our scheme is based on the relationship between the magnetic flux flowing through a closed loop and the current induced in it. The developed scheme is compared with 2D and 3D finite‐element modelling for several positions of an airborne electromagnetic system flying over a closed loop. We also study the coupling effect between the current flowing in the closed loop and the current flowing in the horizontally layered conductive medium. The result shows that for the central position of the transmitter, the difference between axisymmetrical finite‐element modelling and our scheme is less than 1%. Moreover, for the non‐coaxial transmitter–receiver–loop system, the solution obtained by our scheme is in good agreement with full 3D finite‐element modelling, and our total simulation time is substantially lower: 1 minute versus 120 hours.     

Landfill Base Liners: Assessment of Material Equivalency and Impact to Groundwater

This paper gathered available flow and transport solutions and used them for two composite liners, consisting of geomembrane (GM) overlying either a compacted clay liner (CCL) or a geosynthetic clay liner (GCL). Its aim is to provide a guiding framework for the possible choices of (a) approaches to bottom liner design, (b) respective analytical solutions to flow and transport equations, as well as (c) parameters required for each type of solution. On the basis of the obtained results, the following recommendations are made. When the goal of analysis is to determine material equivalency, leachate flow rate is an adequate key parameter for GM-CCL composite liners. For GM-GCL composite liners, it is necessary to compute contaminant concentration or mass flux, considering (a) transport through defects for inorganic contaminants and (b) diffusion and the contribution of any available attenuation layer for organic contaminants. When the goal of analysis is to assess impact to groundwater, it is advised to calculate both discharge rate and contaminant mass flux regardless of liner type. The critical parameter for the transport calculations is the retardation factor of the contaminant, for the case of CCLs, while the results for GCLs are much less sensitive to this parameter.     

Woolly rhino discovery in the lower Kolyma River

A nearly complete frozen mummy of a woolly rhinoceros (Coelodonta antiquitatis Blum., 1799) was discovered in a gold mine on the lower reaches of the Kolyma River, north–eastern Siberia. This is the first find of the whole body of woolly rhino in permafrost. A large part of the mummified body was preserved, including the left part of the body, covered by skin, including skin of the head and ear, fore and hind legs. The skull with 2 horns and the lower jaw were also preserved. Most of the internal organs were lost, except the intestines, stomach, and their contents. A rib fragment from this individual was dated by AMS-radiocarbon method to 39,140 ± 390 years BP (OxA-18755). Spore and pollen analyses of the stomach contents indicate that grasses and sagebrushes formed the main part of the diet of C. antiquitatis in this region of Arctic Siberia.     

Climate change effects on snow melt and discharge of a partly glacierized watershed in Central Switzerland (SoilTrec Critical Zone Observatory)

A comprehensive hydrological modeling study in the drainage area of a hydropower reservoir in central Switzerland is presented. Two models were tested to reproduce the measured discharge dynamics: (1) a detailed energy-balance model (ALPINE3D) primarily designed for snow simulations; (2) a conceptual runoff model system (PREVAH), including a distributed temperature-index snow and ice melt model. Considerable effort was put into distributing available meteorological station data to the model grids as forcing data. The recent EU regional climate modeling initiative ENSEMBLES provided up-to-date climate predictions for two 30-a periods in mid and late 21st century. These were used to estimate evolutions in the water supply of the hydropower reservoir in response to expected climate changes. The simulations suggest a shift of spring peak-flow by almost two months for the end of the century. Warmer winter temperatures will cause higher winter base-flow. Due to glacier retreat, late-summer flow will decrease at the end of the century.     

Multi-proxy climate and environmental records from a Holocene eutrophic mire,southern taiga subzone,West Siberia

Palaeoenvironmental reconstructions from peat are strongly focused on ombrotrophic mires, but this study demonstrates that eutrophic mires can also be used. A multi-proxy approach was applied to a eutrophic mire on a floodplain terrace in the southern taiga of West Siberia. The results of the reconstruction were considered in the wide geographic context of the surrounding regions, including Siberia and Central Asia. Different palaeoecological proxies (analysis of plant macrofossils, testate amoebae, oribatid mites, molluscs, peat humification, ash content and spectral characteristics of humic acids) were used in this study. The results of different proxies showed a high level of consistency among themselves, which allowed for a robust interpretation of Holocene mire development. Throughout the ~7800 years history of the mire, there was a high level of surface wetness. The presence of mineral matter in the peat between 7800 and 5100 cal. a BP indicates regular flooding caused by the intensive fluvial activity, apparently resulting from increased precipitation. This was followed by a trend towards a gradual decrease in surface wetness from conditions of high surface moisture (stagnant water) between 5100 and 3000 cal. a BP to present day conditions of moderate surface moisture with a water table slightly below the mire surface. This pattern is consistent with the well-documented long-term trend from palaeoecological records throughout the taiga and arctic zones in West Siberia and central arid Asia. Our data further support the idea that the westerlies were the dominant driver of climate for the southern taiga of West Siberia during the Middle to Late Holocene.     

The sources and seasonal fluxes of particulate organic carbon in the Yellow River

The Yellow River transports a large amount of sediment and particulate organic carbon (POC), which is thought to mainly derive from erosion of the Chinese Loess Plateau (CLP). However, the compositions, sources and erosional fluxes of POC in the Yellow River remain poorly constrained. Here we combined measurements of mineralogy, total organic carbon content (OC_total), stable organic carbon isotopes (δ¹³C_org), radiocarbon (¹⁴C) activity of organic matter in bulk suspended sediments collected seasonally from the upper and middle Yellow River, to quantify the compositions and fluxes of the POC and to assess its sources (biospheric and petrogenic POC, i.e. POC_bio and POC_petro, respectively). The results showed that the POC loading of sediments was controlled by mineralogy, grain size and specific surface area of loess particles. The F_mod of POC (0.71 to 0.31) can be explained by mixing of POC_petro with modern and aged POC_bio. A binary mixing model based on the hyperbolic relationship of the F_mod and OC_total revealed a wide range of ages of POC_bio from 1300 to 11100 ¹⁴C years. Relative to the upstream station, the annual POC_bio and POC_petro fluxes in the Yellow River are more than doubled after it flows crossing the CLP within 35% drainage area gain, resulting in POC_bio and POC_petro yields of the CLP at 3.50 ± 0.59 and 0.48 ± 0.49 tC/km²/yr, respectively. POC flux seasonal variation revealed that monsoon rainfall exerts a first-order control on the export of both POC_bio and POC_petro from the CLP to the Yellow River, resulting in more than 90% of the annual POC exported during the monsoon season. Around one third of annual POC erosional flux was transported during a storm event period, highlighting the important role of extreme events in POC export in this large river. © 2020 John Wiley & Sons, Ltd.