11 research outputs found

    Effects of dredging-related pressures on critical ecological processes for organisms other than fish or coral. Report of Theme 9 - Project 9.1 prepared for the Dredging Science Node

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    In November 2013 a workshop was held at CSIRO Floreat, which brought together national and international marine scientists. The workshop addressed two primary objectives: • identify the timing of critical ecological processes in tropical and temperate ecosystems with a focus on non-coral and non-fish biota (seagrass, seaweed, sponges, ascidians, bryozoans, molluscs, echinoderms, crustaceans and non-coral cnidarians); and • identify environmental windows for critical ecological processes identified in Objective 1. This will be achieved by compiling information on the timing of reproduction, release of propagules and recruitment for these organisms, as well as the temporal and spatial scales of reproduction and recruitment events. During Workshop 1 a conceptual diagram was developed to illustrate and guide the decision process behind the selection of environmental windows (EWs) (see Figure 1). The life histories of the biota investigated were then identified and listed in detailed tables with specific reference to potential effects of dredging at each life history stage..

    Review and analysis of fire and explosion accidents in maritime transportation

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    The globally expanding shipping industry has several hazards such as collision, capsizing, foundering, grounding, stranding, fire, and explosion. Accidents are often caused by more than one contributing factor through complex interaction. It is crucial to identify root causes and their interactions to prevent and understand such accidents. This study presents a detailed review and analysis of fire and explosion accidents that occurred in the maritimetransportation industry during 1990–2015. The underlying causes of fire and explosion accidents are identified and analysed. This study also reviewed potential preventative measures to prevent such accidents. Additionally, this study compares properties of alternative fuels and analyses their effectiveness in mitigating fire and explosionhazards. It is observed that Cryogenic Natural Gas (CrNG), Liquefied Natural Gas (LNG) and methanol have properties more suitable than traditional fuels in mitigating fire risk and appropriate management of their hazards could make them a safer option to traditional fuels. However, for commercial use at this stage, there exist several uncertainties due to inadequate studies, and technological immaturity. This study provides an insight into fire and explosion accident causation and prevention, including the prospect of using alternative fuels for mitigating fire and explosion risks in maritime transportation

    Observations of the chemistry and concentrations of reactive Hg at locations with different ambient air chemistry

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    The Hg research community needs methods to more accurately measure atmospheric Hg concentrations and chemistry. The Reactive Mercury Active System (RMAS) uses cation exchange, nylon, and PTFE membranes to determine reactive mercury (RM), gaseous oxidized mercury, and particulate-bound mercury (PBM) concentrations and chemistry, respectively. New data for Atlanta, Georgia (NRGT) demonstrated that particulate-bound Hg was dominant and the chemistry was primarily N and S HgII compounds. At Great Salt Lake, Utah (GSL), RM was predominately PBM, with NS > organics > halogen > O HgII compounds. At Guadalupe Mountains National Park, Texas (GUMO), halogenated compound concentrations were lowest when air interacting with the site was primarily derived from the Midwest, and highest when the air was sourced from Mexico. At Amsterdam Island, Southern Indian Ocean, compounds were primarily halogenated with some N, S, and organic HgII compounds potentially associated with biological activity. The GEOS-Chem model was applied to see if it predicted measurements at five field sites. Model values were higher than observations at GSL, slightly lower at NRGT, and observations were an order of magnitude higher than modeled values for GUMO and Reno, Nevada. In general, data collected from 13 locations indicated that N, S, and organic RM compounds were associated with city and forest locations, halogenated compounds were sourced from the marine boundary layer, and O compounds were associated with long-range transport. Data being developed currently, and in the past, suggest there are multiple forms of RM that modelers must consider, and PBM is an important component of RM

    Effects of dredging on critical ecological processes for marine invertebrates, seagrasses and macroalgae, and the potential for management with environmental windows using Western Australia as a case study

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    Dredging can have significant impacts on benthic marine organisms through mechanisms such as sedimentation and reduction in light availability as a result of increased suspension of sediments. Phototrophic marine organisms and those with limited mobility are particularly at risk from the effects of dredging. The potential impacts of dredging on benthic species depend on biological processes including feeding mechanism, mobility, life history characteristics (LHCs), stage of development and environmental conditions. Environmental windows (EWs) are a management technique in which dredging activities are permitted during specific periods throughout the year; avoiding periods of increased vulnerability for particular organisms in specific locations. In this review we identify these critical ecological processes for temperate and tropical marine benthic organisms; and examine if EWs could be used to mitigate dredging impacts using Western Australia (WA) as a case study. We examined LHCs for a range of marine taxa and identified, where possible, their vulnerability to dredging. Large gaps in knowledge exist for the timing of LHCs for major species of marine invertebrates, seagrasses and macroalgae, increasing uncertainty around their vulnerability to an increase in suspended sediments or light attenuation. We conclude that there is currently insufficient scientific basis to justify the adoption of generic EWs for dredging operations in WA for any group of organisms other than corals and possibly for temperate seagrasses. This is due to; 1) the temporal and spatial variation in the timing of known critical life history stages of different species; and 2) our current level of knowledge and understanding of the critical life history stages and characteristics for most taxa and for most areas being largely inadequate to justify any meaningful EW selection. As such, we suggest that EWs are only considered on a case-by-case basis to protect ecologically or economically important species for which sufficient location-specific information is available, with consideration of probable exposures associated with a given mode of dredging

    Does Social Media Influence Conflict? Evidence from the 2012 Gaza Conflict

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    Putting Integrity into Finance: A Purely Positive Approach

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