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Carbon sequestration and noise attenuation provided by hedges in Rome: the contribution of hedge traits in decreasing pollution levels
2013
Gratani, Loretta | Varone, Laura
Hedges are ubiquitous green elements in many European cities. The selection of hedge types characterized by different traits can be suggested for urban greening projects to decrease pollution levels. At this end, carbon dioxide (CO2) sequestration and noise attenuation capability were analyzed in the following hedge types: Laurus nobilis, Nerium oleander, Pittosporum tobira and Pyracantha coccinea, largely used as green infrastructure in Rome (Italy). Representative hedges for each species were selected from high level traffic streets in the city centre (P sites). Traffic density (TD) was monitored simultaneously with CO2 concentration and noise level (N) in each of the considered P sites. The monthly CO2 sequestration capability (MSC) was calculated multiplying the total photosynthesis per hedge by the total photosynthetic activity time (in hours) per month. The multiple regression analysis predicted noise attenuation (ΔN) by a linear combination of total leaf area (TLA), total leaf density (TLD) and leaf mass area (LMA) of the considered hedge types. All the considered species, being evergreens, were active all year long, including winter, when CO2 emissions from road transport peaked. Nevertheless, among the considered hedge types, P. tobira and L. nobilis were the most efficient species in both MSC (31.6±2.8 and 25.4±2.4 kg CO2 month–1, respectively) and ΔN (15±1%, mean value). The results give insight on the use of hedges to mitigate pollution effects. Moreover, this method can be used to monitor hedge contribution to air quality, in relation to various elements in the city (i.e. traffic density, new cars produced, application of management projects, local laws). These results might be available for projects based on the use of vegetation in order to improve environmental quality in urban areas.
اظهر المزيد [+] اقل [-]Seemingly unrelated intervention time series models for effectiveness evaluation of large scale environmental remediation
2013
Ip, Ryan H.L. | Li, W.K. | Leung, Kenneth M.Y.
Large scale environmental remediation projects applied to sea water always involve large amount of capital investments. Rigorous effectiveness evaluations of such projects are, therefore, necessary and essential for policy review and future planning. This study aims at investigating effectiveness of environmental remediation using three different Seemingly Unrelated Regression (SUR) time series models with intervention effects, including Model (1) assuming no correlation within and across variables, Model (2) assuming no correlation across variable but allowing correlations within variable across different sites, and Model (3) allowing all possible correlations among variables (i.e., an unrestricted model). The results suggested that the unrestricted SUR model is the most reliable one, consistently having smallest variations of the estimated model parameters. We discussed our results with reference to marine water quality management in Hong Kong while bringing managerial issues into consideration.
اظهر المزيد [+] اقل [-]Towards environmental management of water turbidity within open coastal waters of the Great Barrier Reef
2013
Macdonald, Rachael K. | Ridd, Peter V. | Whinney, James C. | Larcombe, Piers | Neil, David T.
Water turbidity and suspended sediment concentration (SSC) are commonly used as part of marine monitoring and water quality plans. Current management plans utilise threshold SSC values derived from mean-annual turbidity concentrations. Little published work documents typical ranges of turbidity for reefs within open coastal waters. Here, time-series turbidity measurements from 61 sites in the Great Barrier Reef (GBR) and Moreton Bay, Australia, are presented as turbidity exceedance curves and derivatives. This contributes to the understanding of turbidity and SSC in the context of environmental management in open-coastal reef environments. Exceedance results indicate strong spatial and temporal variability in water turbidity across inter/intraregional scales. The highest turbidity across 61 sites, at 50% exceedance (T50) is 15.3 NTU and at 90% exceedance (T90) 4.1 NTU. Mean/median turbidity comparisons show strong differences between the two, consistent with a strongly skewed turbidity regime. Results may contribute towards promoting refinement of water quality management protocols.
اظهر المزيد [+] اقل [-]Sample preparation methods for quantitative detection of DNA by molecular assays and marine biosensors
2013
Cox, Annie M. | Goodwin, Kelly D.
The need for quantitative molecular methods is growing in environmental, food, and medical fields but is hindered by low and variable DNA extraction and by co-extraction of PCR inhibitors. DNA extracts from Enterococcus faecium, seawater, and seawater spiked with E. faecium and Vibrio parahaemolyticus were tested by qPCR for target recovery and inhibition. Conventional and novel methods were tested, including Synchronous Coefficient of Drag Alteration (SCODA) and lysis and purification systems used on an automated genetic sensor (the Environmental Sample Processor, ESP). Variable qPCR target recovery and inhibition were measured, significantly affecting target quantification. An aggressive lysis method that utilized chemical, enzymatic, and mechanical disruption enhanced target recovery compared to commercial kit protocols. SCODA purification did not show marked improvement over commercial spin columns. Overall, data suggested a general need to improve sample preparation and to accurately assess and account for DNA recovery and inhibition in qPCR applications.
اظهر المزيد [+] اقل [-]Optimizing early detection of non-indigenous species: Estimating the scale of dispersal of a nascent population of the invasive tunicate Ciona intestinalis (L.)
2013
Collin, Samuel B. | Edwards, Paul K. | Leung, Brian | Johnson, Ladd E.
Knowledge of dispersal and establishment during the early stages of invasion is essential for allocating monitoring effort, detecting nascent populations and predicting spread. The scarcity of these data, however, provides little guidance for monitoring programs. Here we present data on the adult distribution and the subsequent pattern of larval recruitment from a nascent population of the invasive tunicate Ciona intestinalis in Prince Edward Island, Canada. Existing niche models indicate the entire study site is suitable for recruitment, suggesting an equal probability of detection throughout the site. In contrast, we found a heterogeneous pattern of larval recruitment, including areas of zero recruitment. By fitting a dispersal kernel, we show Ciona is not capable of naturally dispersing between bays, restricting further spread, and provide guidance for future monitoring. Our results also highlight how large-scale models, although important, lack the small-scale patterns essential for monitoring and early detection of invasive species.
اظهر المزيد [+] اقل [-]Chemical dispersion of oil with mineral fines in a low temperature environment
2013
Wang, Weizhi | Zheng, Ying | Lee, Kenneth
The increasing risks of potential oil spills in the arctic regions, which are characterized by low temperatures, are a big challenge. The traditional dispersant method has shown limited effectiveness in oil cleanup. This work studied the role of mineral fines in the formation of oil–mineral aggregates (OMAs) at low temperature (0–4°C) environment. The loading amount of minerals and dispersant with different dispersant and oil types were investigated under a full factorial design. The shapes and sizes of OMAs were analyzed. Results showed that the behavior of OMA formation differs when dispersant and mineral fines are used individually or together. Both the experimental and microscopic results also showed the existence of optimal dispersant to oil ratios and mineral to oil ratios. In general, poor oil removal performance was observed for more viscous oil. Corexit 9500 performed better than Corexit 9527 with various oils, in terms of oil dispersion and OMA formation.
اظهر المزيد [+] اقل [-]Influence of an intensive agricultural drainage basin on the seasonal distribution of organic pollutants in seawater from a Mediterranean coastal lagoon (Mar Menor, SE Spain)
2013
Moreno-González, R. | Campillo, J.A. | León, V.M.
The seasonal distribution of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine pesticides, organophosphorus pesticides, triazines and other organic pollutants in surface seawater from the Mar Menor lagoon (SE Spain) was characterized from spring 2009 to winter 2010 by stir bar sorptive extraction and thermal desorption followed by capillary gas chromatography coupled to mass spectrometry (SBSE–GC–MS). The most ubiquitous pollutants were chlorpyrifos, chlortal-dimethyl, terbuthylazine, naphthalene and propyzamide throughout the year. Insecticides and herbicides were predominant in summer and spring, and fungicides were more abundant in autumn and winter. Chlorpyrifos was predominant in autumn and spring; herbicides (propyzamide, terbuthylazine and terbuthylazine-desethyl) in autumn and fungicides (flutolanil, boscalid, cyprodinil) in autumn and winter. The highest concentrations for the majority of pollutants were detected in autumn as consequence of air and surface/ground water inputs, and above all of desorption from terrigenous materials deposited in sediments by two intense flash flood events (September 2009).
اظهر المزيد [+] اقل [-]High coral cover and subsequent high fish richness on mature breakwaters in Taiwan
2013
Wen, Colin Kuo-Chang | Chen, Kao-Song | Hsieh, Hernyi Justin | Hsu, Chia-Min | Chen, Chaolun Allen
Breakwaters are widely used in coastal development. Breakwaters can alter habitats by undermining shallow coastal ecosystems, especially coral reefs. However, recent studies indicate that mature breakwaters can have well-developed corals and coral-associated fishes. Breakwaters with colonized corals may act as surrogates of natural coral reefs against the global coral crisis. Here, we examined the composition of corals, fishes, and benthic biota/abiota between natural reefs and mature breakwaters to evaluate the possibility of breakwaters supplementing natural reefs. We found equal or higher coral cover, fish abundance, and species richness on breakwaters. Conversely, differential coral growth forms and fish assemblages on mature breakwaters suggested the irreplaceability of natural reefs. Corals and coral reef fishes on mature man-made structures, however, may improve the resistance and resilience of coral reefs. Conclusively, despite high coral cover on mature man-made structures appropriate management (e.g., marine reserves) is still necessary to sustain the coral reefs.
اظهر المزيد [+] اقل [-]Impacts of marine debris on wild animals in the coastal area of Korea
2013
Hong, Sunwook | Lee, Jongmyoung | Jang, Yong Chang | Kim, Yŏng-jun | Kim, Hee Jong | Han, Donguk | Hong, Sang Hee | Kang, Daeseok | Shim, Won Joon
Over the last decade, marine debris has become a major factor affecting the coastal ecosystem of Korea. This study compiled information regarding how marine debris impacts wildlife in Korea. Cases of marine debris impacting wildlife were collected from experts of various fields and from local participants through an open access website from February 2010 to March 2012. A total of 21 species were affected by marine debris: 18 species of birds, 2 species of mammals, and 1 species of crustacean. Five threatened or protected species were identified: black-faced spoonbill, finless porpoise, water deer, whooper swan, and greater painted snipe. Recreational fishing gears were the types of debris that most frequently impacted wildlife, especially birds. Black tailed gulls were the most vulnerable species to recreational fishing hooks and lines. Although it was preliminary, this study revealed that recreational fishing activities should be prioritized when managing marine debris in Korea.
اظهر المزيد [+] اقل [-]An integrative method for the evaluation, monitoring, and comparison of seagrass habitat structure
2013
Irving, Andrew D. | Tanner, Jason E. | Gaylard, Sam G.
Assessing environmental condition is essential for the management of coasts and their resources, but better management decisions occur when large databases are simplified into more manageable units of information. Here we present the habitat structure index (HSI), which enables rapid assessment and direct comparison of seagrass habitat structure using scores of 0 (poor) to 100 (excellent) based on integrating five habitat variables: area, continuity, proximity, percentage cover, and species identity. Acquiring data to calculate the HSI can be done in situ or from video recordings, and requires relatively simple methodology of belt transects, estimating percentage cover, and basic taxonomy. Spatiotemporal comparisons can usefully identify locations and periods of seagrass habitat change, potentially providing an early warning indicator of habitat damage and decline in environmental quality. Overall, the integrative approach of the HSI represents a step toward simplifying the exchange of environmental information among researchers, coastal managers, and governing bodies.
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