Synthetic shorelines in New Zealand? Quantification and characterisation of microplastic pollution on Canterbury's coastlines     

PJ Clunies-Ross  GPS Smith  KC Gordon 《新西兰海洋与淡水研究杂志》2016,50(2):317-325

Microplastics are persistent environmental contaminants found in marine environments worldwide. Microplastic particles isolated from coastlines in the Canterbury region of New Zealand were quantified and characterised. Sediment samples were collected from 10 locations representing exposed-beach, estuarine and harbour environments in both urban and non-urban settings. Particles were isolated from sediments using an NaCl density-separation procedure and quantified and characterised with a combination of optical/fluorescence imaging and micro-Raman spectroscopy. Microplastics were detected at eight out of 10 locations, at concentrations ranging from 0–45.4 particles kg^?1 of dry sediment. The majority of microplastics were identified as polystyrene (55%), polyethylene (21%) and polypropylene (11%). Microplastic concentrations in exposed-beach environments were significantly greater than in harbour and estuarine environments.  相似文献   

Hydrological footprints of urban developments in the Lake Simcoe watershed,Canada: a combined paired‐catchment and change detection modelling approach          下载免费PDF全文

Stephen K. Oni  Martyn N. Futter  James Buttle  Peter J. Dillon 《水文研究》2015,29(7):1829-1843

Urban sprawl and regional climate variability are major stresses on surface water resources in many places. The Lake Simcoe watershed (LSW) Ontario, Canada, is no exception. The LSW is predominantly agricultural but is experiencing rapid population growth because of its proximity to the Greater Toronto area. This has led to extensive land use changes that have impacted its water resources and altered run‐off patterns in some rivers draining to the lake. Here, we use a paired‐catchment approach, hydrological change detection modelling and remote sensing analysis of satellite images to evaluate the impacts of land use change on the hydrology of the LSW (1994 to 2008). Results show that urbanization increased up to 16% in Lovers Creek, the most urban‐impacted catchment. Annual run‐off from Lovers Creek increased from 239 to 442 mm/year in contrast to the reference catchment (Black River at Washago) where run‐off was relatively stable with an annual mean of 474 mm/year. Increased annual run‐off from Lovers Creek was not accompanied by an increase in annual precipitation. Discriminant function analysis suggests that early (1992–1997; pre‐major development) and late (2004–2009; fully urbanized) periods for Lovers Creek separated mainly based on model parameter sets related to run‐off flashiness and evapotranspiration. As a result, parameterization in either period cannot be used interchangeably to produce credible run‐off simulations in Lovers Creek because of greater scatter between the parameters in canonical space. Separation of early and late‐period parameter sets for the reference catchment was based on climate and snowmelt‐related processes. This suggests that regional climatic variability could be influencing hydrologic change in the reference catchment, whereas urbanization amplified the regional natural hydrologic changes in urbanizing catchments of the LSW. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Principles to coordinate managed aquifer recharge with natural resource management policies in Australia     

John Ward  Peter Dillon 《Hydrogeology Journal》2012,20(5):943-956

Managed aquifer recharge (MAR) is a tool available to water-resources managers that assists agencies to secure water supplies and protect aquifers and groundwater-dependent ecosystems in the face of climate change and growing water demand. Yet few natural-resources managers have access to a coordinated set of policies that enable the potential benefits of MAR to be fully realised in urban and rural areas. This paper reviews contemporary Australian water-resource policies and systematically applies a refined set of ‘robust separation of rights’ principles based on secure entitlements, annual allocations and end-use obligations to guide the coordination of policies specific to each of the four operational processes central to MAR schemes: source water harvesting, aquifer recharge, recovery of stored water and end use. Particular attention is given to the formulation of policies relating to the recovery of water, including the feasibility for market exchange of permanent and temporary rights to recover recharged water, as these have the potential to greatly expand the role of MAR. Aquifer characteristics, existing groundwater extractions and potential third party effects need to be taken into account in determining both recovery entitlements and annual allocations. A transitional pathway to implement novel MAR policies is suggested.  相似文献   

A comparison of the geochemical response to different managed aquifer recharge operations for injection of urban stormwater in a carbonate aquifer     

J.L. Vanderzalm  D.W. PageK.E. Barry  P.J. Dillon 《Applied Geochemistry》2010

Managed aquifer recharge (MAR) is increasingly being considered as a means of reusing urban stormwater and wastewater to supplement the available water resources. Subsurface storage is advantageous as it does not impact on the area available for urban development, while the aquifer also provides natural treatment. However, subsurface storage can also have deleterious effects on the recovered water quality through water–rock interactions which can also impact on the integrity of the aquifer matrix. A recent investigation into the potential for stormwater recycling via Aquifer Storage Transfer and Recovery (ASTR) in a carbonate aquifer is used to determine the important hydrogeochemical processes that impact on the recovered water quality. An extensive period of aquifer flushing allows observation of water quality changes under two operating scenarios: (1) separate wells for injection and recovery, representing ASTR; and (2) a single well for injection and recovery, representing Aquifer Storage and Recovery (ASR).  相似文献   

运用LANDSAT ETM+和ASTER数据进行岩性分类   总被引：5，自引：0，他引：5  

余海阔  李培军 《岩石学报》2010,26(1):345-351

本文评价了运用ASTER和LANDSAT ETM+数据进行岩性制图的性能。分别利用ASTER数据不同波段区图像及其组合,以及ETM+数据进行岩性分类,并探讨了将ASTER和ETM+数据叠加在一起进行了岩性分类; 利用现有地质图对所有分类结果进行了定量评价。结果表明,ASTER数据不同波段的岩性识别能力不同,并且较ETM+数据能更准确地识别岩性。更重要的是,把ASTER与ETM+数据结合在一起进行岩性分类,可获得比用任一数据单独分类更高的分类精度,表明二者的光谱特征具有一定的互补性。  相似文献   

塔里木盆地库鲁克塔格地区二叠纪末-中三叠世基性岩床的发现及其地质意义   总被引：2，自引：1，他引：1  

边伟华  王璞珺  孙晓猛  唐华风 《岩石学报》2010,26(1):274-282

新疆塔里木盆地东北缘库鲁克塔格地区的中寒武统莫合尔山组沉积地层中发现三条形成于二叠纪末到中三叠世的基性岩床。三条岩床沿沉积岩层面顺层侵入,按照从下到上的顺序,分别为辉绿岩床(厚3m)、辉长岩床(厚20m)和粗玄岩床(厚2.5m)。三条岩床的地球化学特征相似,稀土含量高(∑REE=210×10^-6~297×10^-6),轻稀土元素富集((La/Yb)_N =13.54~17.96),Eu负异常不明显(δEu=0.97~1.21),Ce稍具正异常(δCe=1.11~1.25)。大离子亲石元素(Rb、Ba、Th、Sr)富集,Sr具明显正异常; Ta、Nb和Hf具负异常。低氧化度(0.13~0.40)。三条岩床为同源岩浆活动的产物,岩浆源于上地幔或下地壳,但有下陆壳成分混染。三个样品的MgO含量在4%~6%之间,Mg^#值在37.6~55.6之间,固结指数SI值位于18.7~29.3之间,反映原始的岩浆经历了比较明显的分异作用。粗玄岩床K-Ar年龄为255.2±7.3Ma,辉绿岩床K-Ar年龄为242.8±5.7Ma,辉长岩床Ar-Ar年龄为229.7±3.7Ma。本次岩浆侵入事件发生在南天山洋闭合之后,构造背景为造山后碰撞伸展环境。  相似文献   

Differences in zooplankton feeding rates and isotopic signatures from three temperate lakes     

Anurani D. Persaud  Peter J. Dillon 《Aquatic Sciences - Research Across Boundaries》2011,73(2):261-273

Bacteria and phytoplankton are integral in the mobilization and transfer of organic matter to higher trophic levels. Hence, we examined their role in zooplankton diets and assessed trends in their nitrogen isotopic variability. We performed feeding experiments with natural particulate organic matter (POM) and four zooplankton groups (Daphnia, Holopedium, large calanoids and small calanoids) to (1) examine whether there are differences in consumption (presented as clearance and ingestion rates) of phytoplankton and bacteria, and (2) determine whether differences in zooplankton clearance and ingestion rates are correlated with their δ¹⁵N isotopic signatures. In general, phytoplankton and bacteria clearance rates and biomass ingested per animal varied significantly among different zooplankton groups within lakes and between lakes for a given zooplankton group. Within a given lake, Daphnia and Holopedium had the highest phytoplankton and bacteria clearance and ingestion rates, followed by large calanoids, and then small calanoids. For a given zooplankton group, bacteria and phytoplankton clearance rates varied among lakes. In contrast, phytoplankton ingestion rates were consistently highest in Dickie Lake for all taxa, whereas bacteria ingestion rates were more variable among lakes for the different zooplankton taxa. The percentage contribution of different phytoplankton taxa to the biomass of phytoplankton ingested also varied significantly among lakes for a given taxa, but there were few differences within a given lake among zooplankton. Zooplankton δ¹⁵N_DOMC values were correlated with their size adjusted phytoplankton and bacteria clearance and ingestion rates. The correlations were stronger with (1) phytoplankton compared to bacteria, and (2) clearance rates compared to ingestion rates of biomass. Together our results suggest that zooplankton taxa with low phytoplankton and bacteria clearance and ingestion rates and higher δ¹⁵N_DOMC are likely exploiting food sources from higher trophic levels.  相似文献   

Photochemical production and decomposition of particulate organic carbon in a freshwater stream     

Petr Porcal  Peter J. Dillon  Lewis A. Molot 《Aquatic Sciences - Research Across Boundaries》2013,75(4):469-482

Irradiation of dissolved organic carbon (DOC) of terrestrial origin that is freshly released to surface waters can produce particulate organic carbon (POC). Laboratory experiments with stream water were conducted to determine POC and particulate metals formation during exposure to artificial solar radiation comparable to surface intensity. The results showed that decreases in DOC concentration were accompanied initially by increasing and later by decreasing POC concentrations. Data were fit to first order kinetics models to compare rates of POC formation and loss with DOC and absorbance loss, and to better understand how metals might be involved in photochemical POC formation. This abiotic mechanism may be important for the transfer of allochthonous DOC and metals to sediments in temperate aquatic systems.  相似文献   

Recovery of Injected Freshwater from a Brackish Aquifer with a Multiwell System   总被引：2，自引：0，他引：2  

Konrad Miotliński  Peter J. Dillon  Paul Pavelic  Karen Barry  Sarah Kremer 《Ground water》2014,52(4):495-502

Herein we propose a multiple injection and recovery well system strategically operated for freshwater storage in a brackish aquifer. With the system we call aquifer storage transfer and recovery (ASTR) by using four injection and two production wells, we are capable of achieving both high recovery efficiency of injected freshwater and attenuation of contaminants through adequately long residence times and travel distances within the aquifer. The usual aquifer storage and recovery (ASR) scheme, in which a single well is used for injection and recovery, does not warrant consistent treatment of injected water due to the shorter minimum residence times and travel distances. We tested the design and operation of the system over 3 years in a layered heterogeneous limestone aquifer in Salisbury, South Australia. We demonstrate how a combination of detailed aquifer characterization and solute transport modeling can be used to maintain acceptable salinity of recovered water for its intended use along with natural treatment of recharge water. ASTR can be used to reduce treatment costs and take advantage of aquifers with impaired water quality that might locally not be otherwise beneficially used.  相似文献   

The effect of low-level kelp supplementation on digestive enzyme activity levels in cultured abalone Haliotis midae fed formulated feeds     

A Nel  BI Pletschke  PJ Britz 《African Journal of Marine Science》2017,39(2):175-182

Previous studies have found that macroalgal inclusion in formulated diets for cultured abalone improves feed utilisation, and it was suggested that seaweed-associated bacteria supply enzymes that aid in the animal's digestion. In the present study, we hypothesised that kelp supplementation in formulated feed affects the profile of digestive enzymes in farmed Haliotis midae. Commercially reared sub-adult abalone fed a kelp-supplemented (Ecklonia maxima; 0.88% dry weight) or kelp-free control feed were collected for analysis of the amylase, alginate lyase, laminarinase, fucoidanase and protease activities in the gut. Levels of polysaccharidase and protease activity did not significantly differ between the diet treatments. However, enzyme-activity levels were more variable in abalone fed the kelp-free diet as compared with those fed the kelp-supplemented diet (coefficients of variation: 73%, 48.3–60.2% and 31.9% [control diet] versus 42.7%, 13.6–33.8% and 14.6% [KS diet] for amylase, macroalgal polysaccharidases and acid protease activity, respectively). We suggest that the presence of dietary kelp modulates the abalone's gut bacteria and their nutrient exchange. Proteomic identification of proteins in abalone gut sections showed that exogenous enzymes associated with the gut microbiome aid in bacterial utilisation of digested molecules, whereas abalone endogenous enzymes degrade the macronutrients in formulated feeds.  相似文献