Fant 10000 publikasjoner. Viser side 293 av 400:
2018
2018
2018
A combination of local (i.e. firefighting training facilities) and remote sources (i.e., long-range transport) are assumed to be responsible for the occurrence of per- and polyfluoroalkyl substances (PFASs) in Svalbard (Norwegian Arctic). However, no systematic elucidation of local PFASs sources have been conducted yet. Therefore, a survey was performed aiming at identifying local PFASs pollution sources on the island of Spitsbergen (Svalbard, Norway). Soil, fresh water (lake, draining rivers), sea water, melt-water run-off, surface snow and coastal sediment samples were collected from Longyearbyen (Norwegian mining town), Ny-Ålesund (research facility) and the Lake Linnévatnet area (background site) during several campaigns (2014-2016) and analysed for 14 individual target PFASs. For background site (Linnévatnet area, sampling during April to June 2015), ∑PFAS levels ranged from 0.4 – 4 ng/L in surface lake water (n = 20). PFAS in melt water from the contributing glaciers showed similar concentrations (~4 ng/L, n = 2). The short chain perfluorobutanoate (PFBA) was predominant in lake water (60-80% of the ∑PFASs), meltwater (20-30 %) and run-off water (40 %). Long range transport is assumed to be the major PFAS source. In Longyearbyen, 5 water samples (i.e. 2 seawater, 3 run-off) were collected near the local firefighting training site (FFTS) in November 2014 and June 2015, respectively. The highest PFAS levels were found in FFTS melt water run-off (118 ng/L). PFOS was the most abundant compound in the FFTS meltwater run-off (53 – 58 % PFASs). At the research station Ny-Ålesund, sea water (n = 6), soil (n = 9) and fresh water (n = 10) were collected in June 2016. Low ∑PFAS concentrations were determined for sea water (5 - 6 ng/L), whereas high ∑PFAS concentrations were found in run-off water (113 – 119 ng/L) and soil (211 – 800 ng/g dry weight (dw)) collected close to the local FFTS. In addition, high ∑PFAS levels (127 ng/L) were also found in fresh water from lake Solvatnet close to former sewage treatment facility. Overall, at both FFTS affected sites (soil, water), PFOS was the most abundant compound (60 – 69% of ∑PFASs). FFTS and landfill locations were identified as major PFASs sources for Svalbard settlements.
2018
2018
2018
2018
Influence of solar wind energy flux on the interannual variability of ENSO in the subsequent year
Previous studies have tended to adopt the quasi-decadal variability of the solar cycle (e.g. sunspot number (SSN) or solar radio flux at 10.7 cm (F10.7) to investigate the effect of solar activity on El Niño–Southern Oscillation (ENSO). As one of the major terrestrial energy sources, the effect of solar wind energy flux in Earth’s magnetosphere (Ein) on the climate has not drawn much attention, due to the big challenge associated with its quantitative estimation. Based on a new Ein index estimated by three-dimensional magnetohydrodynamic simulations from a previous study, this study reveals that Ein exhibits both quasi-decadal variability (periodic 11-year) and interannual (2–4 years) variability, which has rarely before been detected by SSN and F10.7. A significant interannual relationship between the annual mean Ein and subsequent early-winter ENSO is further revealed. Following high Ein, the sea level pressure in the subsequent early winter shows significant positive anomalies from Asia southward to the Maritime Continent, and significant negative anomalies over the Southeast and Northeast Pacific, resembling the Southern Oscillation. Meanwhile, significant upper-level anomalous convergence and divergence winds appear over the western and eastern Pacific, which is configured with significant lower-level anomalous divergence and convergence, indicating a weakening of the Walker circulation. Consequently, notable surface easterly wind anomalies prevail over the eastern tropical Pacific, leading to El Niño-like sea surface temperature anomalies. It is suggested that better describing the processes in the solar wind–magnetosphere–ionosphere coupled system is essential to understand the solar influence on climate change.
2018
The safety of high quality drinking water supply relies on the quantities to be delivered, on the complexity of the water supply systems, and on the widespread phenomena of the contamination of water bodies. These parameters indicate the need for the development of an application that will allow the quick acquisition of data on strategic management. This is requires both the analysis of factors related to the hydraulic operation of the plants and the characteristics of water quality. The present paper aims to evaluate the use of models that predict data for water quality in a distribution system. The assessment is made in order to consider the use of the model as a support tool for the management system of a supply network and to optimize the quality of the provided service. The improvement of the control system related to the operations of disinfection, in particular, in the case of long pipelines, is absolutely mandatory in order to ensure the safety of public health and respect for the environment at high levels.
2018
Signals from the south; humpback whales carry messages of Antarctic sea‐ice ecosystem variability
Southern hemisphere humpback whales (Megaptera novaeangliae) rely on summer prey abundance of Antarctic krill (Euphausia superba) to fuel one of the longest‐known mammalian migrations on the planet. It is hypothesized that this species, already adapted to endure metabolic extremes, will be one of the first Antarctic consumers to show measurable physiological change in response to fluctuating prey availability in a changing climate; and as such, a powerful sentinel candidate for the Antarctic sea‐ice ecosystem. Here, we targeted the sentinel parameters of humpback whale adiposity and diet, using novel, as well as established, chemical and biochemical markers, and assembled a time trend spanning 8 years. We show the synchronous, inter‐annual oscillation of two measures of humpback whale adiposity with Southern Ocean environmental variables and climate indices. Furthermore, bulk stable isotope signatures provide clear indication of dietary compensation strategies, or a lower trophic level isotopic change, following years indicated as leaner years for the whales. The observed synchronicity of humpback whale adiposity and dietary markers, with climate patterns in the Southern Ocean, lends strength to the role of humpback whales as powerful Antarctic sea‐ice ecosystem sentinels. The work carries significant potential to reform current ecosystem surveillance in the Antarctic region.
2018
2018