珠江口珠海—深圳海底光缆路由设计与建设     

蔡锋  陈峰 《台湾海峡》1999,18(1):14-19

本文论述了珠江口珠海－深圳海底光缆路由设计,建设所涉及的主要技术问题,解决了港湾内海缆路由勘设及施工遇到的多种复杂的实际难题,为今后港湾内海缆建设提供参考。  相似文献   

Organic matter characterisation and turnover in the sediment and seawater of a tourist harbour     

Cristina Misic  Anabella Covazzi Harriague 《Marine environmental research》2009,68(5):227-235

A survey of a Ligurian tourist harbour was carried out during winter 2006 and summer 2007 in order to study the organic matter (OM) turnover through extracellular enzymatic activity. Seawater and sediments were sampled at six stations, three inside the port boundaries, one outside the port and two in an area influenced by the outflow of a minor river (Boate). The seawater showed OM turnover times similar to other oligo-mesotrophic coastal areas, and low concentrations of chlorophyll-a and inorganic nutrients. The sediments, instead, revealed high OM loads and a predominance of proteolysis. A significant reduction of the OM loads was observed in the outside station, indicating that the OM accumulation was due to the structures and activities of the harbour and to the Boate influence. The OM biotic recycling via enzymatic activity was enhanced especially during summer. Although the carbohydrates were probably highly refractory, their turnover was notably faster, due to glycolytic enzymatic activity that was enhanced more than the proteolytic in both the sediment and in the seawater. This suggested that the removal and recycling of OM were potentially efficient, and prevented the shift to eutrophication of the Rapallo harbour area.  相似文献   

Mapping Seabed Geology by Ground-Truthed Textural Image/Neural Network Classification of Acoustic Backscatter Mosaics     

R. Dietmar Müller  Sian Eagles 《Mathematical Geology》2007,39(6):575-592

We present a novel, automated method for seabed classification based on shallow water backscatter mosaics from Sydney Harbour. Our approach compares the results between two different methods of image feature extraction when combined with artificial neural networks. The association of image textures with seabed geology is used to train the artificial neural networks to recognise the variability of textural attributes for three seabed classes comprising mud, sand and gravel. After network training, we classify unknown portions of the backscatter mosaic with a success rate ranging from 77% to 92%. Our results suggest that the computationally fast grey-level co-occurrence iteration algorithm holds promise for benthic habitat mapping in space and time, leading to real-time data analysis at sea.  相似文献   

Environmental recovery in Sydney Harbour,Nova Scotia: Evidence of natural and anthropogenic sediment capping     

Tony R. Walker  Devin MacAskill  Peter Weaver 《Marine pollution bulletin》2013

Contaminants were assessed in Sydney Harbour during baseline and three years of remediation of a former coking and steel facility. Concentrations of PAHs; PCBs; and lead measured in surface sediments indicate overall spatial distribution patterns of historical contaminants remains unchanged, although at much lower concentrations than previously reported due to natural sediment recovery. Recovery rates were in broad agreement with predicted concentrations; or in some cases lower, despite remediation at the Sydney Tar Ponds (STP) site. Contaminants showed little temporal variability, except for detection of significant increases in PAH concentrations during onset of remediation compared to baseline which represented a short term interruption in the overall long term natural recovery of sediments in Sydney Harbour. Recovery (via “capping”) was enhanced following recent harbour dredging activities where less contaminated outer harbour sediments were discharged into a confined disposal facility (CDF) required for a new container in the inner harbour.  相似文献   

Building pounding damage observed in the 2011 Christchurch earthquake     

Gregory L. Cole  Rajesh P. Dhakal  Fred M. Turner 《地震工程与结构动力学》2012,41(5):893-913

Building pounding damages observed in the February 2011 Christchurch earthquake are described in this paper. The extent and severity of pounding damage is presented based on a street survey of Christchurch's central business district. Six damage severity levels and two confidence levels are defined to classify the observed damage. Generally, pounding was observed to be a secondary effect. However, over 6% of the total surveyed buildings were observed to have significant or greater pounding damage. Examples of typical and exceptional pounding damage are identified and discussed. Extensive pounding damage was observed in low‐rise unreinforced masonry buildings that were constructed with no building separation. Modern buildings were also endangered by pounding when building separations were infilled with solid architectural flashings. The damage caused by these flashings was readily preventable. The observed pounding damage is compared to that observed in the September 2010 Darfield earthquake to explore if the damage could have been predicted. It is found that pounding prone buildings can be identified with reasonable accuracy by comparing configurations to characteristics previously noted by researchers. However, detailed pounding damage patterns cannot currently be precisely predicted by these methods. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Heavy metal pollution in Wellington Harbour     

P. Stoffers  G. P. Glasby  C. J. Wilson  K. R. Davis  P. Walter 《新西兰海洋与淡水研究杂志》2013,47(3):495-512

Heavy metal analysis of the < 20 μm fraction of marine sediments from Wellington Harbour and Waiwhetu Stream have shown that the Waiwhetu Stream is easily the most polluted area in the Wellington Harbour system with Pb and Zn in the extremely polluted category and Cu, Cd, and Hg in the moderately to strongly polluted category. These elements have different distributions in the stream sediments reflecting their different sources from adjacent factories. In Wellington Harbour itself, the central basin of the harbour suffers from minimal pollution. Pb, and to a lesser extent Zn and Cu, are the main pollutants and local enrichment of these elements is noted in Lambton Harbour basin, off Pencarrow and Moa Point outfalls, in Evans Bay, and off Petone and Kaiwharawhara. The geochemical data do not enable us to identify the source of the pollutants unambiguously. A summary of the history of waste discharges into the harbour suggests that heavy metal pollution may have been higher in the past.  相似文献   

Distribution and abundance of Abarenicola affinis (Arenicolidae,Polychaeta) in tidal inlets of Otago,New Zealand     

S Goerlitz  K Berkenbusch  PK Probert 《新西兰海洋与淡水研究杂志》2013,47(4):548-560

Lugworms are important members of the macrobenthos of sheltered intertidal sediments, and this study assessed the abundance and distribution of Abarenicola affinis in Otago, southern New Zealand. Using a faecal cast:lugworm ratio (1.00:1.09) revealed a patchy distribution across inlets, with an overall mean abundance of 11.1 individuals/m² (range: 3.8 to 21.3 individuals/m²). Distribution patterns varied among inlets, with lugworms mostly confined to the high intertidal zone, but spread across all intertidal zones in one inlet. The lugworm habitat was characterised by muddy to medium sand (55–233 µm mean grain size) with low organic matter (< 2%) and chlorophyll a (1–12 µg/g dry sediment) contents. Depending on the inlet, lugworm abundance was related to sediment parameters, indicating that their distribution across Otago inlets is habitat dependent. The present findings also indicate that factors other than those measured contribute to A. affinis distribution and abundance patterns in this region.  相似文献   

Notes on New Zealand chitons (Mollusca,Amphineura)     

A. G. Beu 《新西兰海洋与淡水研究杂志》2013,47(4):475-481

A synopsis of the classification of the New Zealand Polyplacophora is presented. The name Lepidochitonidae is replaced by the earlier Callochitonidae, Plaxi‐phoridae by Mopaliidae, Aulacochitonidae by Schizochitonidae, and Cryptocon‐chidae by Acanthochitonidae.

Vaferichiton Iredale and Hull is treated as a subgenus of Aerilamma Hull. Lorica H. and A. Adams is used instead of its junior synonym Aulacochiton Shuttleworth. Lorica haurakiensis Mestayer is recorded from the Nukumaruan (Lower Pleistocene). Paricoplax profundior Dell is placed in Loricella Pilsbry. Icoplax chathamensis Dell is made the type species of a new subgenus of Anthochiton Localities in southern New Zealand for Notoplax cuneata (Suter) and Lorica haurakiensis are listed.  相似文献   

The rate of feeding of the bryozoan,Zoobotryon verticillatum     

John S. Bullivant 《新西兰海洋与淡水研究杂志》2013,47(1):111-134

The ctenostome bryozoan Zoobotryon verticillatum was found to clear suspensions of four species of algae, at rates ranging from 0.152–1.05 ml per zooid per hour, or 13.9–96.2 ml per mg dry weight per hour, when the algal suspensions were below the satiation concentrations and thus maximum clearance rates would be expected. Suspensions of Monochrysis lutheri, a small flagellate on which the bryozoan grew well and with which most experiments were made, was cleared below the satiation concentration of 7,900 cells per ml, at the mean rate of 0.368 ml per zooid per hour or 33.7 ml per mg dry weight per hour.

Satiation concentrations of the four species of algae were of the same order as the highest concentrations of nannoplankton to be expected in the bryozoan's natural habitat.

The bryozoan colony fed fairly constantly over a 48 hour period.

Assuming oxygen consumption was similar to that of other bryozoans, Zoobotryon verticillatum cleared about 11.6 litres per ml of oxygen consumed.  相似文献   

Physical oceanography of Rangaunu Harbour,Northland, New Zealand   总被引：1，自引：1，他引：0  

R. A. Heath  B. S. Shakespeare  M. J. N. Greig 《新西兰海洋与淡水研究杂志》2013,47(4):481-493

Current meter, current drogue, salinity, temperature, and tidal elevation observations from Rangaunu Harbour are presented. The flow is dominated by the tides, the ebb tide in general being stronger than the flood. The time of high tide is increasingly delayed with distance from the open ocean. High tide at the head of the harbour lags about an hour behind that at the mouth. The phase of the flow relative to that of the elevation is less than that for a frictionless system. This difference from a quarter of a tidal period results from tidal energy dissipation and probably varies through the spring‐neap tidal cycle. The outer harbour has essentially coastal water which is exchanged each tide. Residence time of the inner harbour waters and the inner harbour shallows (where evaporation is sufficient to raise the salinity) is several days.  相似文献