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161.
Tolo Harbour has received massive discharges of municipal sewage, agricultural wastes and cottage industrial effluents, via three river systems, in the past two decades before the mid Eighties. The Harbour is almost land locked and poorly flushed. The soft sediment acted as a sink for nutrients and organic pollutants. After a decade of efforts in establishing and enforcing water pollution control legislations and upgrading wastewater treatment facilities, the sediments have turned into sources of nutrients and exert a measurable oxygen demand upon the overlying waters. In vitro measurements showed that the sediments oxygen demand (SOD) was between 17.6 and 54.3 mgo2 · m-2 · h-1. The maximum rates of release of ortho-phosphate phosphorus and ammonia nitrogen were 15.0 and 206.0 mg · m-2 · h-1, respectively. 相似文献
162.
将传统定位浮标加以改进,可以形成一种能有效吸收和传递波浪能的锚泊系统。此系统的最上端是漂浮着的海面浮标,海面浮标下端连着锚泊钢缆,锚泊钢缆下端到海底之间又依次连有张紧锤、储链和重物锚块。锚泊系统中的海面浮标随波浪同步上下起伏,从而带动与其连在一起的由张紧锤绷直的锚泊钢缆上下振动,于是海面浮标吸收波浪能并由引导缆向下传递。20 m长的储链可以保证整个装置在涨潮、退潮的极限水深情况下,仍旧可以有效地传递海表面波浪能;合适的重物锚块可以起到为整个系统定位的功能。最后给出了一个实际应用波浪能的例子。设计制作的锚泊系统可以有效吸收和传递波浪能,为波浪能的利用提供了一种行之有效的方法。 相似文献
163.
给出了村镇滑移隔震建筑瞬时摩擦耗能的概念,并以此概念为响应指标。通过极差大小的对比,分析了该响应指标对刚度比、第二阶段刚度系数、隔震层屈服位移、隔震层摩擦系数、系统质量比和上部结构自振周期六个参数变化的敏感程度,阐述了上述系统参数对瞬时摩擦耗能这一响应指标的影响规律。研究表明:场地条件和地震动幅值大小对瞬时摩擦耗能均有显著影响;在所考虑的参数范围内,上部结构自振周期总是对瞬时摩擦耗能有较为显著的影响,摩擦系数对瞬时摩擦耗能的影响跟场地条件有关,Ⅰ类场地条件中摩擦系数对瞬时摩擦耗能影响不显著,而Ⅱ、Ⅲ和Ⅳ类场地条件中,摩擦系数对瞬时摩擦耗能的影响则非常显著;隔震层屈服位移、刚度比和第二阶段刚度系数总得来讲对瞬时摩擦耗能影响不显著,质量比对瞬时摩擦耗能影响居中。 相似文献
164.
C. Fernandez 《Marine Ecology》1998,19(1):1-11
Abstract. Monthly soluble and insoluble protein, carbohydrate, lipid and ash levels and energetic content were measured in tissues of Paracentrotus lividus adults living in a lagoonal environment over a 1-year period to increase our understanding of resource allocation to the different tissues. The biochemical composition of P. lividus individuals in this environment is similar to that observed in other environments. The gonad and gut contained a high level of proteins soluble or insoluble, a lesser amount of lipids and, finally, a low level of carbohydrates. The main component of the test was ash, followed by protein levels. The lipid and carbohydrate levels in the test were very low. Seasonal variability in the biochemical composition of the different body parts was observed. In the gonad, an increase in the level of lipids was recorded concomitant to an increase in gonad weight. The lipids and carbohydrates, after an initial increase, decreased with the maturation of the gonad. The biochemical variations observed in the gut seem to be linked to both the reproductive cycle and the sea urchin's trophic activity. Variability in the test was low and irregular for all of the observed biochemical components. As P. lividus is an important member of the benthic community in the Urbinu lagoon, this echinoid represents an important store of materials and energy within this lagoonal environment. 相似文献
165.
The co-location of offshore windfarms and decapod fisheries in the UK: Constraints and opportunities
《Marine Policy》2014
The offshore wind sector in the UK is expanding rapidly and is set to occupy significant areas of the coastal zone, making it necessary to explore the potential for co-location with other economic activities. The presence of turbine foundations introduces hard substrates into areas previously dominated by soft sediments, implying that artificial reef effects may occur, with potential benefits for fisheries. This review focuses on the possibilities for locating fisheries for two commercially important decapods, the brown crab Cancer pagurus and the European lobster Homarus gammarus, within offshore wind farms.Existing understanding of habitat use by C. pagurus and H. gammarus suggests that turbine foundations have the potential to act as artificial reefs, although the responses of these species to noise and electromagnetic fields are poorly understood. Offshore wind farm monitoring programmes provide very limited information, but do suggest that adult C. pagurus associate with turbine foundations, which may also serve as nursery areas. There was insufficient deployment and monitoring of rock armouring to draw conclusions about the association of H. gammarus with offshore wind farm foundations. The limited information currently available demonstrates the need for further research into the ecological and socio-economic issues surrounding fishery co-location potential. 相似文献
166.
Guiomar Rotllant Carles G. Simeó Guillermo Guerao Marta Sastre Daniel F. R. Cleary Ricardo Calado Alicia Estévez 《Marine Ecology》2014,35(3):298-307
The spider crab Maja brachydactyla is an important commercial species in Europe and supports intensive fisheries in the NE Atlantic. A field survey was performed to assess long‐term and consecutive interannual (2005–2010) variation of the biochemical composition of newly hatched larvae of M. brachydactyla. Larval biochemical profiles differed significantly among years, with pronounced differences being recorded in 2010. Differences among batches of newly hatched larvae were mainly explained by the contribution of triacylglycerols and, to a lesser degree, by protein and lipid content. The use of different nutrition indices is discussed. The biochemical composition of newly hatched larvae from M. brachydactyla was highly variable, even though surveyed broodstock was obtained from the same local population and was always sampled during the same season. The unpredictable biochemical profiles of newly hatched larvae may condition their survival and recruitment. This largely overlooked aspect of larval variability should be considered in future fisheries management strategies and captive production of marine organisms that still rely on wild seeds. 相似文献
167.
The improvement on the calculation of anti-Stokes energy transfer rate is studied in the present work. The additional proportion coefficient between Stokes and anti-Stokes light intensities of quantum Raman scattering theory as compared with the classical Raman theory is introduced to successfully describe the anti-Stokes energy transfer. The theoretical formula for the improvement on the calculation of anti-Stokes energy transfer rate is derived for the first time in this study. The correctness of introducing coefficient exp{ΔE / kT} from well-known Raman scatter theory is demonstrated also. Moreover, the experimental lifetime measurement in Er0.01YbxY1 - 0.01 - xVO4 crystal is performed to justify the validity of our important improvement in the original phonon-assisted energy transfer theory for the first time. 相似文献
168.
INTRODUCTIONBiologicalfoulingonthehullsofshipsandothersubmergedmarinestructurescausesgreatha~s.Inadditiontodecreasingship'sspeed,andincreasingitsfuelconsumption,biologicalfoulingalsoincreasestheweightofnavigationalbuoys,interfereswithoperatingequipmentandsounddevices,clogsseawaterpipingsystems,adverselyaffectsheat-exchangerperformance,andpromotescorrosionofmetalsurface(HuangandCat,1984).UPtothepresent,antifoulingpaintshaveachievedtheireffectivenessbyreleasingattheirsurfacebiocides,allcom… 相似文献
169.
Marine renewable energy and public rights 总被引:1,自引:0,他引:1
Paul Todd 《Marine Policy》2012,36(3):667-672
Marine renewable energy is likely to be an important part of UK energy policy over the next decades. A start has already been made, but to generate power on a significant scale requires the use of vast areas of ocean, on which there are competing claims. Legislation, and in particular the Energy Act 2004, goes a long way towards giving developers the legal infrastructure they need, to invest with confidence. But it is far from perfect, in dealing with important competing rights. This article has a narrow (but important) focus. It assumes that there are no problems over jurisdiction or international law. It is concerned principally with the rights of UK citizens. The issue is about reconciling the generation of large-scale marine renewable energy with other legitimate uses of the sea, and in particular fishing and navigation rights. 相似文献
170.