An exposure-effect approach for evaluating ecosystem-wide risks from human activities

Ecosystem-based management (EBM) is promoted as the solution for sustainable use. An ecosystem-wide assessment methodology is therefore required. In this paper, we present an approach to assess the risk to ecosystem components from human activities common to marine and coastal ecosystems. We build on: (i) a linkage framework that describes how human activities can impact the ecosystem through pressures, and (ii) a qualitative expert judgement assessment of impact chains describing the exposure and sensitivity of ecological components to those activities. Using case study examples applied at European regional sea scale, we evaluate the risk of an adverse ecological impact from current human activities to a suite of ecological components and, once impacted, the time required for recovery to pre-impact conditions should those activities subside. Grouping impact chains by sectors, pressure type, or ecological components enabled impact risks and recovery times to be identified, supporting resource managers in their efforts to prioritize threats for management, identify most at-risk components, and generate time frames for ecosystem recovery

Evaluation of Polycyclic Aromatic Hydrocarbon Pollution From the HMS Royal Oak Shipwreck and Effects on Sediment Microbial Community Structure

Despite many shipwrecks containing oil there is a paucity of studies investigating their impact on surrounding environments. This study evaluates any potential effect the World War II shipwreck HMS Royal Oak is having on surrounding benthic sediments in Scapa Flow, Scotland. HMS (Her Majesty’s Ship) Royal Oak sank in 1939, subsequently leaked oil in the 1960s and 1990s, and is estimated to still hold 697 tonnes of fuel oil. In this study, sediments were analysed, over a 17.5 cm depth profile, along a 50–950 m cruciform transect away from the shipwreck. Analysis of polycyclic aromatic hydrocarbons (PAHs) revealed low concentrations (205.91 ± 50.15 μg kg‾¹ of dry sediment), which did not significantly differ with either distance from the shipwreck or sediment depth. PAH concentrations were well below the effects-range low (ERL) for the OSPAR (Oslo/Paris convention for the Protection of the Marine Environment of the North-East Atlantic) maritime area. The average Pyrogenic Index, in sediments around HMS Royal Oak, was 1.06 (±0.34), indicating PAHs were pyrogenic rather than petrogenic. Moreover, analysis of sediment microbiomes revealed no significant differences in bacterial community structure with distance from the shipwreck, with extremely low levels of obligate hydrocarbonoclastic bacteria (OHCB; 0.21% ± 0.54%). Both lines of evidence suggest that sampled sediments are not currently being impacted by petrogenic hydrocarbons and show no long-term impact by previous oil-spills from HMS Royal Oa

An environmental assessment of risk in achieving good environmental status to support regional prioritisation of management in Europe

The Marine Strategy Framework Directive (MSFD) aims to achieve Good Environmental Status (GES) in Europe's Seas. The requirement for regional sea authorities to identify and prioritise issues for management has meant that standardized methods to assess the current level of departure from GES are needed. The methodology presented here provides a means by which existing information describing the status of ecosystem components of a regional sea can be used to determine the effort required to achieve GES. A risk assessment framework was developed to score departure from GES for 10 out of the 11 GES descriptors, based on proposed definitions of 'good' status, and current knowledge of environmental status in each of the four regional seas (North-East Atlantic, Mediterranean Sea, Baltic Sea and Black Sea). This provides an approach for regional evaluation of environmental issues and national prioritisation of conservation objectives. Departure from GES definitions is described as 'high', 'moderate' or low' and the implications for management options and national policy decisions are discussed. While the criteria used in this study were developed specifically for application toward MSFD objectives, with modification the approach could be applied to evaluate other high-level social, economic or environmental objectives. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved

Search for the glueball candidates f0(1500) and fJ(1710) in gamma gamma collisions

Data taken with the ALEPH detector at LEP1 have been used to search for gamma gamma production of the glueball candidates f0(1500) and fJ(1710) via their decay to pi+pi-. No signal is observed and upper limits to the product of gamma gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have been measured to be Gamma_(gamma gamma -> f0(1500)). BR(f0(1500)->pi+pi-) < 0.31 keV and Gamma_(gamma gamma -> fJ(1710)). BR(fJ(1710)->pi+pi-) < 0.55 keV at 95% confidence level.Comment: 10 pages, 3 figure

Search for supersymmetry with a dominant R-parity violating LQDbar couplings in e+e- collisions at centre-of-mass energies of 130GeV to 172 GeV

A search for pair-production of supersymmetric particles under the assumption that R-parity is violated via a dominant LQDbar coupling has been performed using the data collected by ALEPH at centre-of-mass energies of 130-172 GeV. The observed candidate events in the data are in agreement with the Standard Model expectation. This result is translated into lower limits on the masses of charginos, neutralinos, sleptons, sneutrinos and squarks. For instance, for m_0=500 GeV/c^2 and tan(beta)=sqrt(2) charginos with masses smaller than 81 GeV/c^2 and neutralinos with masses smaller than 29 GeV/c^2 are excluded at the 95% confidence level for any generation structure of the LQDbar coupling.Comment: 32 pages, 30 figure

Measurement of the W-pair cross section in e+e−e^+ e^- collisions at 172 GeV

The e+e- --> W+W- cross section is measured in a data sample collected by ALEPH at a mean centre--of--mass energy of 172.09 GEV, corresponding to an integrated luminosity of 10.65 pb-1. Cross sections are given for the three topologies, fully leptonic, semi-leptonic and hadronic of a W-pair decay. Under the assumption that no other decay modes are present, the W-pair cross section is measured to be 11.7 +- 1.2 (stat.) +- 0.3 (syst.) pb. The existence of the triple gauge boson vertex of the Standard Model is clearly preferred by the data. The decay branching ratio of the W boson into hadrons is measured to be B(W --> hadrons) = 67.7 +- 3.1 (stat.) +- 0.7 (syst.)%, allowing a determination of the CKM matrix element |Vcs|= 0.98 +- 0.14 (stat.) +- 0.03 (syst.)

Search for R-Parity Violating Decays of Supersymmetric Particles in e+e−e^{+}e^{-} Collisions at Centre-of-Mass Energies near 183 GeV

Searches for pair-production of supersymmetric particles under the assumption that R-parity is violated via a single dominant $LL{\bar E}$, $LQ{\bar D}$ or ${\bar U} {\bar D} {\bar D}$ coupling are performed using the data collected by the \ALEPH\ collaboration at centre-of-mass energies of 181--184~\gev. The observed candidate events in the data are in agreement with the Standard Model expectations. Upper limits on the production cross-sections and lower limits on the masses of charginos, sleptons, squarks and sneutrinos are de rived

Measurement of the tau lepton lifetime with the three-dimensional impact parameter method.

A new method is presented for the measurement of the mean $\tau$ lepton lifetime using events in which $\tau$'s are pair-produced and both $\tau$'s decay to hadrons and $\nu_\tau$. Based on the correlation between the two $\tau$'s produced at a symmetric $e^+ e^-$ collider, the 3DIP method relies on the three-dimensional information from a double-sided vertex detector and on kinematic constraints for the precise measurement of the $\tau$ decay angles. Using the data collected from 1992 to 1994 with the ALEPH detector at LEP, a $\tau$ lifetime of $288.0 \pm 3.1 \pm 1.3$\fs is obtained from the sample in which both $\tau$'s decay to one charged track, and $292.8 \pm 5.6 \pm 3.0$\fs from the sample in which one $\tau$ decays to one prong and the other to three prongs. The results show small statistical correlations with those derived from other methods. When combined with the previously published ALEPH measurements, the resulting $\tau$ lifetime is $291.2 \pm 2.0 \pm 1.2$\fs

Measurement of the tau lepton lifetime with the three-dimensional impact parameter method.

A new method is presented for the measurement of the mean $\tau$ lepton lifetime using events in which $\tau$'s are pair-produced and both $\tau$'s decay to hadrons and $\nu_\tau$. Based on the correlation between the two $\tau$'s produced at a symmetric $e^+ e^-$ collider, the 3DIP method relies on the three-dimensional information from a double-sided vertex detector and on kinematic constraints for the precise measurement of the $\tau$ decay angles. Using the data collected from 1992 to 1994 with the ALEPH detector at LEP, a $\tau$ lifetime of $288.0 \pm 3.1 \pm 1.3$\fs is obtained from the sample in which both $\tau$'s decay to one charged track, and $292.8 \pm 5.6 \pm 3.0$\fs from the sample in which one $\tau$ decays to one prong and the other to three prongs. The results show small statistical correlations with those derived from other methods. When combined with the previously published ALEPH measurements, the resulting $\tau$ lifetime is $291.2 \pm 2.0 \pm 1.2$\fs

Measurement of the tau lepton lifetime with the three-dimensional impact parameter method.

A new method is presented for the measurement of the mean $\tau$ lepton lifetime using events in which $\tau$'s are pair-produced and both $\tau$'s decay to hadrons and $\nu_\tau$. Based on the correlation between the two $\tau$'s produced at a symmetric $e^+ e^-$ collider, the 3DIP method relies on the three-dimensional information from a double-sided vertex detector and on kinematic constraints for the precise measurement of the $\tau$ decay angles. Using the data collected from 1992 to 1994 with the ALEPH detector at LEP, a $\tau$ lifetime of $288.0 \pm 3.1 \pm 1.3$\fs is obtained from the sample in which both $\tau$'s decay to one charged track, and $292.8 \pm 5.6 \pm 3.0$\fs from the sample in which one $\tau$ decays to one prong and the other to three prongs. The results show small statistical correlations with those derived from other methods. When combined with the previously published ALEPH measurements, the resulting $\tau$ lifetime is $291.2 \pm 2.0 \pm 1.2$\fs