Three-dimensional distributions of sewage markers in Tokyo Bay water--fluorescent whitening agents (FWAs)

Three-dimensional distributions of fluorescent whitening agents (FWAs: more specifically, DSBP and DAS1), which are sewage-derived water-soluble markers, were observed in Tokyo Bay water through multi-layer sampling of water at 20 locations. In summer, FWAs predominated in the surface layers, with trace but significant concentration of FWAs in bottom water due to stratification of seawater. In winter, on the other hand, FWAs were extensively mixed into the bottom layers because of the vertical mixing of seawater. In the surface layer, FWA concentrations and the DSBP/DAS1 ratio (the concentration ratio of DSBP to DAS1) were lower in summer than in winter, suggesting more efficient photodegradation of FWAs in euphotic zones during the summer due to stronger solar radiation. Horizontally, FWAs were widely distributed over the surface layer of Tokyo Bay. Surface water with DSBP concentrations above 50ng/L, corresponding to <200 times dilution of sewage effluent, was found to have spread up to 10km from the coastline. In addition, an offshore decline in FWA concentrations was observed, showing a half-distance of 10-20km. The decrease was caused by dilution by seawater of fresh water containing FWAs. The eastern part of the bay was different with respect to surface layers, with higher concentrations seen in northeastern parts. Furthermore, dispersion of combined sewer overflow (CSO)-derived water mass was observed in Tokyo Bay after heavy rain.     

Spatial rainfall model using a pattern classifier for estimating missing daily rainfall data

Missing data in daily rainfall records are very common in water engineering practice. However, they must be replaced by proper estimates to be reliably used in hydrologic models. Presented herein is an effort to develop a new spatial daily rainfall model that is specifically intended to fill in gaps in a daily rainfall dataset. The proposed model is different from a convectional daily rainfall generation scheme in that it takes advantage of concurrent measurements at the nearby sites to increase the accuracy of estimation. The model is based on a two-step approach to handle the occurrence and the amount of daily rainfalls separately. This study tested four neural network classifiers for a rainfall occurrence processor, and two regression techniques for a rainfall amount processor. The test results revealed that a probabilistic neural network approach is preferred for determining the occurrence of daily rainfalls, and a stepwise regression with a log-transformation is recommended for estimating daily rainfall amounts.     

TBT toxicity on the marine microalga Nannochloropsis oculata

Commercial antifouling formulations containing TBT are the major source of organotin contamination in coastal waters. In view of the persisting TBT residues (13 ng Sn l⁻¹) in the coastal waters of South Korea, an attempt has been made to evaluate the growth response and biochemical composition of laboratory-cultured Nannochloropsis oculata to TBT toxicity. It is evident that the persisting concentration level of TBT is high enough to cause adverse effect on the microalgal species. The EC₅₀ (24 h) was found to be at 0.89 nM level of TBT for this marine eustigmatophyte N. oculata. Photosynthetic pigment content was significantly affected. At elevated TBT concentrations of 1.0 nM, especially pronounced changes in biochemical composition was found. TBT tolerance of N. oculata and its growth as well as biochemical responses are discussed.     

格列菲列岛的地质地球物理研究

本文是中、韩国际合作项目“黄海地质地球物理场特征研究”的一部分 .具体研究了格列菲列岛的基础地质问题及地球物理场特征 .格列菲列岛是由三个小岛组成的位于黄海中部的一组群岛 ,位于朝鲜半岛布格重力异常正值区 ,莫霍面埋深在 2 9km左右 .三个岛屿主要由安山集块岩构成 .安山集块岩是由大小不同的火成岩碎块和熔岩混合而成 .火成岩的碎块成分主要为石英岩、片岩、片麻岩、玄武岩、安山岩和流纹岩 .主要节理方向为NE10°～NE2 0°,倾角近乎垂直 ;另一组节理为NW70°～NW80° ,倾角也近垂直 .本研究为我们了解这个地区的基础地质情况 ,岩石物性和随后进行的黄海海域典型剖面的地球物理物性反演工作以及地质模型的建立 ,打下重要基础 .     

Land acquisition: a means to mitigate water scarcity and reduce conflict?

ABSTRACT

In recent years there has been a surge in land investments, primarily in the African continent, but also in Asia and Latin America. This increase in land investment was driven by the food pricing crisis of 2007–2008. Land investors can be identified from a variety of sectors, with actors ranging from hedge funds to national companies. Many water-scarce countries in the Middle East and North Africa (MENA) are among these financiers, and primarily invest in Africa. Recognizing the potential for “outsourcing” their food security (and thereby also partly their water security), Middle Eastern countries such as Jordan, Qatar and the United Arab Emirates have invested in land for food production in Africa. The extent to which this is happening is still unclear, as many contracts are not yet official and the extent of the leases is vague. This paper investigates the land investments and acquisitions by Middle Eastern countries. It also seeks to analyse what effect, if any, these investments can have on the potential for conflict reduction and subsequent peacebuilding in the Middle East region as the activity removes pressure from transboundary water resources.

EDITOR D. Koutsoyiannis ASSOCIATE EDITOR K. Aggestam     

Development and application of a GIS-based tool for earthquake-induced hazard prediction

An integrated GIS-based tool (GTIS) was constructed to estimate site effects related to the earthquake hazards in the Gyeongju area of Korea. To build the GTIS for the study area, intensive site investigations and geotechnical data collections were performed and a walk-over site survey was additionally carried out to acquire surface geo-knowledge data in accordance with the procedure developed to build the GTIS. For practical applications of the GTIS used to estimate the site effects associated with the amplification of ground motion, seismic microzoning maps of the characteristic site period and the mean shear wave velocity to a depth of 30 m were created and presented as a regional synthetic strategy addressing earthquake-induced hazards. Additionally, based on one-dimensional site response analyses, various seismic microzoning maps for short- and mid-period amplification potentials were created for the study area. Case studies of seismic microzonations in the Gyeongju area verified the usefulness of the GTIS for predicting seismic hazards in the region.     

High-Speed x-ray Jets Associated with the 18 June 1999 Limb Flares

Peculiar high-speed X-ray jets associated with the 18 June 1999 limb flares have directly been observed with the soft X-ray Telescope (SXT) aboard Yohkoh. The jets have a much shorter lifetime (within 200 s) and a much larger velocity (∼ 1700 km s⁻¹) than the previously reported jets. Judged from their large velocity, the kinetic energy of the jets is approximately one order of magnitude larger than the thermal energy content, which is far different from the jets previously reported by other researchers. Here we present the preliminary results and discuss the particular features of the jets. Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1023/A:1013324126229     

Small-scale marine fisheries policy in Vietnam

Vietnam's marine fisheries are considered to be small scale and are concentrated in coastal near-shore waters. This has resulted in heavy pressure on near-shore fisheries resources. Near-shore fisheries are considered by fishers and the government to be over-exploited, causing hardship for many coastal communities. This paper reviews and analyzes changes in policy towards small-scale fisheries in Vietnam over the last two decades. The primary issues facing the small-scale fisheries in Vietnam are to restructure the near-shore fisheries and to address over-capacity. Recommended actions include improved fisheries statistics, resources for provincial fisheries staff, and a coordinated and integrated approach involving a mixed strategy of resource management; resource restoration; economic and community development; and new governance arrangements.