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161.
Studies of reef fish herbivory have mainly focused on the impacts and behaviour of adults of tropical species. In this study,
the ontogenetic shifts in home range, aggression, feeding rate, diet and gut morphology in juveniles and adults of two temperate
territorial damselfishes, Parma microlepis and Parma unifasciata, were determined. Both P. microlepis and P. unifasciata juveniles under 80 mm TL exhibited no aggressive chases towards conspecifics or other species, while above 80 mm TL aggressive
chase frequency increased in conjunction with an increase in home range, defended as a territory. Ontogenetic diet shifts,
characterised by an increase in herbivory (P. unifasciata: juveniles: 64% plant material, adults: 95% plant material; P. microlepis: juveniles: 43% plant material, adults: 67% plant material) were observed for both species. The ratio of digestive tract
length to body length, which often accompanies a switch to herbivory, increased significantly with ontogeny for both species.
Compared to tropical confamilial grazers, these temperate damselfish species feeding rates were lower, and they had larger
territories which were not as strongly defended (fewer aggressive chases). 相似文献
162.
The inarticulated brachiopod, Lingula reevii Davidson (1880) is a filter-feeding invertebrate that burrows vertically in sandy or mixed sediments. Its only recorded occurrence
is from Kaneohe Bay, Oahu, Hawaii, southern Japan, and Ambon, Indonesia. Past surveys of Kaneohe Bay populations suggested
a distinct decrease in abundance following the diversion of sewage effluent from the bay in 1978/1979. In the summer of 2004
and 2007, visual surveys were conducted in areas of historical L. reevii abundance as well as in areas appearing to have suitable habitat. In 2004, approximately 2,950 m2 at 20 sites within the bay were surveyed using quantitative belt transecting methods. A maximum density of 4 Lingula/m2 was observed, a decrease from previous maximum estimates of 500 individuals/m2 (Worcester, Dissertation, Zoology Department, University of Hawai′i, pp 49, 1969) and 100 individuals/m2 (Emig, J Exp Mar Biol Ecol 52:47–61, 1981). When these 20 sites were revisited in 2007, many had fewer or no L. reevii; therefore, broader scale presence/absence surveys were conducted at 16 additional sites in the bay (also surveyed in 2004).
The highest density of L. reevii found in 2007 was 0.94 individuals/m2. The continued decline in abundance of L. reevii in Kaneohe Bay may be due, in addition to decreased organic enrichment from diversion of sewage discharge almost 30 years
ago, to the more recent reduction of suitable habitat by the invasion of mat-forming alien algae species. 相似文献
163.
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the global environment and are subsequently transported into aquatic sediments. As PAHs are formed by various processes, source identification using diagnostic ratios can provide insight to PAH emission sources to distinguish between pyrogenic and petrogenic PAH sources. PAH diagnostic ratios were applied as a forensic source apportionment technique to assess aggregate historical sediment data from 31 small craft harbors (SCHs) across Nova Scotia, Canada. Multiple diagnostic ratios suggest that PAHs present in Nova Scotia SCH sediments are pyrogenic (combustion) in origin, while consistently suggesting that coal‐related PAH sources are potential dominant specific sources. National Institute of Standards and Technology Standard Reference Materials (SRMs) were used as reference for coal tar, urban dust, and diesel exhaust particulates in ratio applications. The SRM for coal tar was most similar to Nova Scotia SCH sediments in multiple ratio applications. Diagnostic ratio results were corroborated by comparing the PAH profile of sediments to source profiles from the literature. Results indicate that Nova Scotia SCH sediments follow global trends by exhibiting a dominant pyrogenic PAH signature, and the specific coal‐related PAH signature of Nova Scotia SCH sediments may be influenced by contamination inputs related to historical industrial coal mining and combustion activities in the province. 相似文献
164.
Eric M. Fujita David E. Campbell William R. Stockwell Emily Saunders Rosa Fitzgerald Roberto Perea 《Journal of the Air & Waste Management Association (1995)》2016,66(2):201-214
This study examined the effects of varying future reductions in emissions of oxides of nitrogen (NOx) and volatile organic compounds (VOC) on the location and magnitude of peak ozone levels within California’s South Coast Air Basin (SoCAB or Basin). As ozone formation is currently VOC-limited in the Basin, model simulations with 2030 baseline emissions (?61% for NOx and ?32% for VOC from 2008) predict 10–20% higher peak ozone levels (i.e., NOx disbenefit) in the western and central SoCAB compared with the 2008 base simulation. With additional NOx reductions of 50% beyond the 2030 baseline emissions (?81% from 2008), the predicted ozone levels are reduced by about 15% in the eastern SoCAB but remain comparable to 2008 levels in the western and central Basin. The Basin maximum ozone site shifts westward to more populated areas of the Basin and will result potentially in greater population-weighted exposure to ozone with even a relatively small shortfall in the required NOx reductions unless accompanied by additional VOC reductions beyond 2030 baseline levels. Once committed to a NOx-focused control strategy, NOx reductions exceeding 90% from 2008 levels will be necessary to attain the ozone National Ambient Air Quality Standards (NAAQS). The findings from this study and other recent work that the current VOC emission estimates are underestimated by about 50% suggest that greater future VOC reductions will be necessary to reach the projected 2030 baseline emissions. Increasing the base year VOC emissions by a factor of 1.5 result in higher 2008 baseline ozone predictions, lower relative response factors, and about 20% lower projected design values. If correct, these findings have important implications for the total and optimum mix of VOC and NOx emission reductions that will be required to attain the ozone NAAQS in the SoCAB.Implications: Results of this study indicate that ozone levels in the western and central SoCAB would remain the same or increase with even a relatively small shortfall in the projected NOx reductions under planned NOx-focused controls. This possibility, therefore, warrants a rigorous analysis of the costs and effects of varying reductions of VOC and NOx on the formation and combined health impacts of ozone and secondary particles. Given the nonlinearity of ozone formation, such analyses should include the implications of gradually increasing global background ozone concentrations and the Basin’s topography and meteorology on the practical limits of alternative emission control strategies. 相似文献
165.
Child-Friendly Cities were conceived as a means to integrate children's rights into city decision-making and governance. Participatory research about child-friendly cities consistently finds overarching themes across ages and regions: children desire access to services, nature, and play; freedom from physical danger; and opportunities for inclusion within the city. This article explores a two-year visioning and participatory design process that engaged approximately 225 young people, aged 4–16, in the planning and design of a prominent public space in the City of Boulder. While participatory research with children has received much attention in the academic literature, much less attention has been given to what can be achieved through sustained integration of children into municipal planning processes, particularly in the USA. This paper thus moves children's participation beyond rhetoric and into the challenging reality of planning a city with children as a valued constituent. 相似文献
166.
Anticipatory governance for social-ecological resilience 总被引:1,自引:0,他引:1
Anticipation is increasingly central to urgent contemporary debates, from climate change to the global economic crisis. Anticipatory practices are coming to the forefront of political, organizational, and citizens’ society. Research into anticipation, however, has not kept pace with public demand for insights into anticipatory practices, their risks and uses. Where research exists, it is deeply fragmented. This paper seeks to identify how anticipation is defined and understood in the literature and to explore the role of anticipatory practice to address individual, social, and global challenges. We use a resilience lens to examine these questions. We illustrate how varying forms of anticipatory governance are enhanced by multi-scale regional networks and technologies and by the agency of individuals, drawing from an empirical case study on regional water governance of Mälaren, Sweden. Finally, we discuss how an anticipatory approach can inform adaptive institutions, decision making, strategy formation, and societal resilience. 相似文献
167.
目前对镍(Ni)生态风险评估和水质法规采用了基于机制的预测工具,如生物配体模型(BLMs)。然而,尽管有许多具体细致的研究,Ni对水生生物毒性的精确机制仍然难以确定。对Ni行为机制的不确定性导致了大家在一些管理设置中应用像BLM这样的工具时,有所顾虑。为了解决这一认知差距,作者使用了有害结局路径(AOP)分析,也是第一个用于金属的AOP分析,来确定Ni毒性的多种潜在机制以及它们与淡水水生生物的相互作用。在金属的分子起始事件(molecular initiating events)在分类群中可能存在的前提下,在许多不同种水生和陆生生物数据的基础上,考虑建立一种潜在的行为机制。通过分析,作者识别了Ni可能对水生生物产生毒性的5个潜在的分子起始事件:Ca2+体内平衡的破坏,Mg2+体内平衡的破坏,Fe2+/3+体内平衡的破坏,活性氧类物质引起的氧化损伤,以及呼吸上皮细胞的过敏反应。在生物组织的器官水平,这5个潜在的分子起始事件会分解成3个可能的途径:支持外骨骼、外壳和骨骼生长的Ca2+减少;呼吸受损;细胞毒性和肿瘤形成。在整个生物体的水平,器官水平的反应将可能导致生长、繁殖的降低和/或能量代谢的改变,并且在每个通路之间有几个潜在的反馈回路。总体来说,目前的AOP分析可指导Ni的毒性机制研究,并为其他金属开发AOPs提供了有效的参考。
精选自Brix, K. V., Schlekat, C. E. and Garman, E. R. (2017), The mechanisms of nickel toxicity in aquatic environments: An adverse outcome pathway analysis. Environmental Toxicology and Chemistry, 36: 1128–1137. doi: 10.1002/etc.3706
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3706/full 相似文献
168.
Alla Zelenyuk Michael J. Ezell Véronique Perraud Stanley N. Johnson Emily A. Bruns Yong Yu Dan Imre M. Liz Alexander Barbara J. Finlayson-Pitts 《Atmospheric environment (Oxford, England : 1994)》2010,44(9):1209-1218
The photooxidation of α-pinene in the presence of NO2, with and without added NaNO3 seed particles, has been studied in a large-diameter flow tube. Particles formed by homogeneous nucleation and by condensation on the pre-existing seeds were sampled at various stages of the reaction, dried using four diffusion dryers, size selected at different mobility diameters (dm) using a differential mobility analyzer (DMA), and characterized with a single particle mass spectrometer (SPLAT II). It was found that homogeneously nucleated particles are spherical, have a density (ρ) of 1.25 ± 0.02 g cm?3 (±2σ) and contain a significant amount of organic nitrates. The mass spectra of the low volatility products condensed on the NaNO3 seed particles were found to be virtually the same as in the case of homogeneous nucleation. The data show that the presence of even a submonolayer of organics on the NaNO3 particles causes water retention that leads to a decrease in particle density and that the amount of water retained increases with organic coating thickness. Thicker coatings appear to inhibit water evaporation from the particle seeds altogether. This suggests that in the atmosphere, where low volatility organics are plentiful, some hygroscopic salts will retain water and have different densities and refractive indices than expected in the absence of the organic coating. This water retention combined with the organic shell on the particles can potentially impact light scattering by these particles and activity as cloud condensation nuclei (CCN), as well as heterogeneous chemistry and photochemistry on the particles. 相似文献
169.
Chandana Damodaram Marcio H. Giacomoni C. Prakash Khedun Hillary Holmes Andrea Ryan William Saour Emily M. Zechman 《Journal of the American Water Resources Association》2010,46(5):907-918
Damodaram, Chandana, Marcio H. Giacomoni, C. Prakash Khedun, Hillary Holmes, Andrea Ryan, William Saour, and Emily M. Zechman, 2010. Simulation of Combined Best Management Practices and Low Impact Development for Sustainable Stormwater Management. Journal of the American Water Resources Association (JAWRA) 1-12. DOI: 10.1111/j.1752-1688.2010.00462.x Abstract: Urbanization causes increased stormwater runoff volumes, leading to erosion, flooding, and the degradation of instream ecosystem health. Although Best Management Practices (BMPs) are used widely as a means for controlling flood runoff events, Low Impact Development (LID) options have been proposed as an alternative approach to better mimic the natural flow regime by using decentralized designs to control stormwater runoff at the source, rather than at a centralized location in the watershed. For highly urbanized areas, LID practices such as rainwater harvesting, green roofs, and permeable pavements can be used to retrofit existing infrastructure and reduce runoff volumes and peak flows. This paper describes a modeling approach to incorporate these LID practices in an existing hydrologic model to estimate the effects of LID choices on streamflow. The modeling approach has been applied to a watershed located on the campus of Texas A&M University in College Station, Texas, to predict the stormwater reductions resulting from retrofitting existing infrastructure with LID technologies. Results demonstrate that use of these LID practices yield significant stormwater control for small events and less control for flood events. A combined BMP-LID approach is tested for runoff control for both flood and frequent rainfall events. 相似文献
170.
DeLorenzo ME Thompson B Cooper E Moore J Fulton MH 《Environmental monitoring and assessment》2012,184(1):343-359
Stormwater ponds are commonly used in residential and commercial areas to control flooding. The accumulation of urban contaminants
in stormwater ponds can lead to water-quality problems including nutrient enrichment, chemical contamination, and bacterial
contamination. This study presents 5 years of monitoring data assessing water quality of a residential subdivision pond and
adjacent tidal creek in coastal South Carolina, USA. The stormwater pond is eutrophic, as described by elevated concentrations
of chlorophyll and phosphorus, and experiences periodic cyanobacterial blooms. A maximum monthly average chlorophyll concentration
of 318.75 μg/L was measured in the stormwater pond and 227.63 μg/L in the tidal creek. Fecal coliform bacteria (FCB) levels
were measured in both the pond and the tidal creek that exceeded health and safety standards for safe recreational use. A
maximum monthly average FCB level of 1,247 CFU/100 mL was measured in the stormwater pond and 12,850 CFU/100 mL in the tidal
creek. In addition, the presence of antibiotic resistant bacteria and pathogenic bacteria were detected. Low concentrations
of herbicides (atrazine and 2,4-D), a fungicide (chlorothalonil), and insecticides (pyrethroids and imidacloprid) were measured. Seasonal trends were identified,
with the winter months having the lowest concentrations of chlorophyll and FCB. Statistical differences between the stormwater
pond and the tidal creek were also noted within seasons. The tidal creek had higher FCB levels than the stormwater pond in
the spring and summer, whereas the stormwater pond had higher chlorophyll levels than the tidal creek in the summer and fall
seasons. Chlorophyll and FCB levels in the stormwater pond were significantly correlated with monthly average temperature
and total rainfall. Pesticide concentrations were also significantly correlated with temperature and rainfall. Pesticide concentrations
in the stormwater pond were significantly correlated with pesticide concentrations in the adjacent tidal creek. Chlorophyll
and FCB levels in the tidal creek, however, were not significantly correlated with levels in the pond. While stormwater ponds
are beneficial in controlling flooding, they may pose environmental and human health risks due to biological and chemical
contamination. Management to reduce residential runoff may improve water quality in coastal stormwater ponds and their adjacent
estuarine ecosystems. 相似文献