Chemical pollution impinges on the quality of water systems and the ecosystem services (ESs) they provide. Expression of ESs in monetary units has become an essential tool for sustainable ecosystem ...management. However, the impact of chemical pollution on ESs is rarely quantified, and ES valuation often focuses on individual services without considering the total services provided by the ecosystem. The purpose of the study was to develop a stepwise approach to quantify the impact of sediment pollution on the total ES value provided by water systems. Thereby, we calculated the total ES value loss as a function of the multi-substance potentially affected fraction of species at the HC50 level (msPAF(HC50)). The function is a combination of relationships between, subsequently: the msPAF(HC50), diversity, productivity and total ES value. Regardless of the inherent differences between terrestrial and aquatic ecosystems, an increase of diversity generally corresponded to an increase in productivity with curvilinear or linear effects. A positive correlation between productivity and total values of ESs of biomes was observed. The combined relationships showed that 1% msPAF(HC50) corresponded to on average 0.5% (0.05–1.40%) of total ES value loss. The ES loss due to polluted sediments in the Waal-Meuse river estuary (the Netherlands) and Flemish waterways (Belgium) was estimated to be 0.3–5 and 0.6–10 thousand 2007$/ha/yr, respectively. Our study presents a novel methodology to assess the impact of chemical exposure on diversity, productivity, and total value that ecosystems provide. With sufficient monitoring data, our generic methodology can be applied for any chemical and region of interest and help water managers make informed decisions on cost-effective measures to remedy pollution. Acknowledging that the ES loss estimates as a function of PAF(HC50) are crude, we explicitly discuss the uncertainties in each step for further development and application of the methodology.
•A stepwise approach to assess impacts of chemical mixture on ecosystem service (ES).•Total ES value loss as a function of potentially affected fraction of species (PAF).•1% PAF corresponds to 0.5% (0.05–1.40%) of total ES value loss.•The methodology is applied to sullied sediments in the Netherlands and Flanders.•The PAF-ES methodology improves chemical risk assessment and management decisions.
As filter-feeders, freshwater mussels provide the ecosystem service (ES) of biofiltration. Chemical pollution may impinge on the provisioning of mussels' filtration services. However, few attempts ...have been made to estimate the impacts of chemical mixtures on mussels' filtration capacities in the field, nor to assess the economic benefits of mussel-provided filtration services for humans. The aim of the study was to derive and to apply a methodology for quantifying the economic benefits of mussel filtration services in relation to chemical mixture exposure. To this end, we first applied the bootstrapping approach to quantify the filtration capacity of dreissenid mussels when exposed to metal mixtures in the Rhine and Meuse Rivers in the Netherlands. Subsequently, we applied the value transfer method to quantify the economic benefits of mussel filtration services to surface water-dependent drinking water companies. The average mixture filtration inhibition (filtration rate reduction due to exposure to metal mixtures) to dreissenids was estimated to be <1% in the Rhine and Meuse Rivers based on the measured metal concentrations from 1999 to 2017. On average, dreissenids on groynes were estimated to filter the highest percentage of river discharge in the Nederrijn-Lek River (9.1%) and the lowest in the Waal River (0.1%). We estimated that dreissenid filtration services would save 110–12,000 euros/million m3 for drinking water production when abstracting raw water at the end of respective rivers. Economic benefits increased over time due to metal emission reduction. This study presents a novel methodology for quantifying the economic benefits of mussel filtration services associated with chemical pollution, which is understandable to policymakers. The derived approach could potentially serve as a blueprint for developing methods in examining the economic value of other filter-feeders exposed to other chemicals and environmental stressors. We explicitly discuss the uncertainties for further development and application of the method.
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•We derive the economic value of mussel filtration services under chemical exposure.•Dreissenids on groynes on average filter 0.1–9.1% of Dutch river discharge.•Dreissenid filtration may save 110–12,000 €/million m3 in producing drinking water.•The method can be applied in valuing other filter-feeders exposed to stressors.
Insufficient oxygen delivery to tissues is hypothesised to limit thermal tolerance, but evidence in ectotherms is mixed. We assessed heat tolerance under hypoxia, normoxia and hyperoxia to test ...whether the extent in which oxygen can lower or increase heat tolerance differed with mode of respiration, comparing gill-breathing caenogastropods and lung-breathing pulmonates with or without an accessory gill. Hypoxia lowered heat tolerance in three of the four pulmonates (Physa fontinalis, Physa acuta and Planorbis carinatus) by 1.2–2.1°C. Hyperoxia, however, did not increase the heat tolerance in any of the pulmonate species. Thus, heat tolerance limits of these pulmonates does not appear to be oxygen limited under normoxia, possibly because of their high capacity to regulate oxygen consumption associated with aerial gas exchange. Instead, other processes may become limiting at thermal extremes such as loss of protein function, loss of membrane stability or neuronal dysfunction. The caenogastropod species tested (Potamopyrgus antipodarum, Bithynia tentaculata) closed their operculum during the warming experiments. This behavioural response prevented us from obtaining clear results. Nevertheless, our results suggested hyperoxia may increase heat tolerance in B. tentaculata. This could be related to its lower capacity to regulate oxygen, owing to its fully aquatic gas exchange mechanism.
Summary
Laboratory data on desiccation tolerance of native and non‐native mollusc species were used to derive species sensitivity distributions (SSDs), to predict effects of desiccation on mollusc ...assemblages in rivers during low discharge events and to prioritise various environmental stressors (i.e. desiccation, temperature and salinity).
The predicted absence and observed absence of mollusc species by desiccation at a specific site were expressed as potentially not occurring fraction (PNOF) and not occurring fraction (NOF) of their regional species pool in the River Rhine.
Calculations of PNOFs for desiccation explained 57% (LT99) and 65% (LT50) of the NOFs of the mollusc species. Sensitivity to desiccation did not differ between native and non‐native mollusc species pools.
Due to differences in frequency of low river discharge events and water level fluctuations, mollusc species in an impounded reach of the River Meuse were less affected by desiccation than in a free‐flowing distributary of the River Rhine.
Earlier calculations of the PNOFs for combined effects of temperature and salinity in the River Rhine explained 22 and 3% of the NOFs of native and non‐native species, respectively, for the period 1988–2003. Accounting for the effects of desiccation, 62 and 80% of the NOFs of the native and non‐native species pool, respectively, were explained, indicating that desiccation during low discharge events was an important stressor in comparison with water temperature or salinity.
Since a relatively high percentage of the NOFs of native species in the River Rhine still remain unexplained, an effort to assess potential effects of other stressors is recommended (e.g. toxic substances or water turbulence caused by commercial shipping).
Within impounded sections of the rivers Rhine and Meuse, epibenthic macroinvertebrate communities are impoverished and dominated by non-native invasive species such as the zebra mussel (Dreissena ...polymorpha) and quagga mussel (Dreissena rostriformis bugensis). In the winter of 2012 management of the water-level resulted in a low-water event in the River Nederrijn, but not in the River Meuse. Low-water levels persisted for five days with average daily air temperatures ranging from -3.6 to -7.2degreesC. We assessed the effects of this low-water event on settled dreissenid mussel populations using a before-after-control-impact (BACI) design. Desiccation had a negative effect on the overall density of dreissenids. Six months after the water level recovered, mussel density had increased slightly. After 18 months, mussel density had recovered to pre-event level. Mussels collected after the event were smaller than specimens collected before the event, indicating recolonization originating from upstream river sections. At the control site, the dreissenid populations showed no significant change in density or shell size distribution. In total, 99.4% of empty shells washed up and sampled directly after the low-water event consisted of invasive bivalves, including zebra mussel, quagga mussel and Asian clams (Corbicula fluminea and Corbicula fluminalis). The high number of empty dreissenid shells stranded on the river banks directly after the event coincided with a mass mortality of mussels in the littoral zone. Imposing a sudden water-level drawdown during severe winter conditions could be a tool for the temporary reduction of invasive mollusc density in impounded river sections. Full recovery of the population structure likely may require a period of two to three years. Therefore, we recommend that the long-term effects of recurrent water-level drawdowns on the diversity of invasive and native species be assessed.
The use of residual biomass for the production of bioenergy and biomaterials is often suggested as a strategy to avoid negative effects associated with dedicated biomass production. One potential ...source is biomass from landscape management. The goal of this study was to find the lowest net greenhouse gas (GHG) emissions of various applications of residual biomass from landscape management. GHG balances of thirteen residual biomass applications were calculated and compared to their respective conventional counterfactuals. As a case study, the potential contribution to climate change mitigation through the use of residual biomass available from vegetation management in floodplains of the Dutch Rhine delta were quantified. The greatest GHG benefits are achieved when using woody biomass to produce heat (−132 kg CO2-eq./tonne wet biomass) and grassy biomass to produce growth media (−229 kg CO2-eq./tonne wet biomass). In contrast, composting grassy biomass for fertiliser replacement on agricultural fields results in the largest GHG burdens of 62 kg CO2-eq./tonne wet biomass. The findings imply that residual biomass from landscape management can contribute to both GHG benefits and burdens, depending on the application. Higher benefits were found for bioenergy than for biomaterial applications. Biomass applications should be chosen with care and consideration of their counterfactuals.
•A life cycle GHG analysis of residual biomass applications was performed.•Counterfactuals were defined to evaluate various application options.•Generally higher benefits were found for bioenergy than for biomaterial applications.•Composting grassy biomass for growth media achieves the highest GHG benefits.•Using woody biomass for the production of heat also provides net GHG benefits.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) The production cross-section of J/ψ pairs is measured using a data sample of pp collisions collected by the LHCb experiment ...at a centre-of-mass energy of ... TeV, corresponding to an integrated luminosity of 279 ±11 pb−1. The measurement is performed for J/ψ mesons with a transverse momentum of less than 10 GeV/c in the rapidity range 2.0 < y < 4.5. The production cross-section is measured to be 15.2 ± 1.0 ± 0.9 nb. The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the J/ψ pair are measured and compared to theoretical predictions. Figure not available: see fulltext.
Study of the D^sup 0^p amplitude decays Adeva, B; Ajaltouni, Z; Amhis, Y ...
The journal of high energy physics,
05/2017, Letnik:
2017, Številka:
5
Journal Article
Recenzirano
Odprti dostop
An amplitude analysis of the decay Lambda ^sub b ^ ^sup 0^ right arrowD ^sup 0^ ppi ^sup -^ is performed in the part of the phase space containing resonances in the D ^sup 0^ p channel. The study is ...based on a data sample corresponding to an integrated luminosity of 3.0 fb^sup -1^ of pp collisions recorded by the LHCb experiment. The spectrum of excited Lambda ^sub c ^ ^sup +^ states that decay into D ^sup 0^ p is studied. The masses, widths and quantum numbers of the Lambda^sub c^(2880)^sup +^ and Lambda^sub c^(2940)^sup +^ resonances are measured. The constraints on the spin and parity for the Lambda^sub c^(2940)^sup +^ state are obtained for the first time. A near-threshold enhancement in the D ^sup 0^ p amplitude is investigated and found to be consistent with a new resonance, denoted the Lambda^sub c^(2860)^sup +^, of spin 3/2 and positive parity. Figure not available: see fulltext.
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