Oxygen consumption rates of fecal pellets produced by three coastal copepod species fed with a diatom Thalassiosira pseudonana

Fecal pellet production rate and oxygen consumption rate of copepod fecal pellets egested by Paracalanus sp., Acartia spinicauda and Centropages orsinii feeding on a diatom Thalassiosira pseudonana were measured. Fecal pellet production rates varied between 3.6 and 80.6 pellets ind⁻¹ d⁻¹ among three species, with fecal pellet production of Paracalanus sp. significantly higher than the other two copepod species. Average pellet size varied between 2.82 × 10⁵ μm³ for Paracalanus sp. and 5.36 × 10⁵ μm³ for A. spinicauda. Average volumetric oxygen consumption rates were 27.32, 5.84 and 45 fmol O₂ μm⁻³ d⁻¹ for fecal pellets produced by Paracalanus sp., A. spinicauda and C. orsinii, respectively. The potential oxygen consumption of fecal pellets egested from Paracalanus sp. was the highest due to its high fecal pellet production rate and high population abundance throughout the year. Overall, the approximate in situ oxygen consumption due to copepod fecal pellet degradation was significant in estuarine and coastal waters of Hong Kong. Results of this study give insight of the role of zooplankton in potential occurrence of hypoxia in coastal waters during summer.     

青岛近岸海区海底地貌类型及声学特征

在对海岸带地貌发育主要影响因素进行讨论的基础上,根据实测数字声纳资料,对青岛海岸带近岸海区海底冲刷槽、潮流脊、侵蚀洼地、水下岸坡、潮滩、岛礁等地貌类型及次级微地貌声学特征进行了较详细的论述,通过对声图资料的精细解释,取得了对上述地貌特征的系统认识。     

九孔鲍肠道及其养殖水体中弧菌抗药性的研究

为更好地防治鲍鱼病害的发生和流行,我们对分离自广东汕尾粤顺鲍鱼养殖场九孔鲍肠道及其养殖水体的弧菌菌株的耐药性进行了研究。对所分离鉴定的菌株进行了16种抗生素药物敏感性试验。结果表明,对绝大多数分离的菌株,四环素、青霉素G、卡那霉素、丁胺卡那霉素和新生霉素都不敏感或无作用,氟哌酸、红霉素、氯霉素以及环丙沙星等则均比较敏感：复方新诺明、链霉素和多粘霉素B对所有所实验的菌株均有作用。     

多元逐步回归分析应用于固化土强度与微结构参数相关性评价

用石灰固化不同含盐量的滨海盐渍土,固化后土微结构参数发生了变化,力学强度大幅度提高。多元逐步回归分析计算结果表明二者之间存在着良好的相关关系,颗粒粒度分维、颗粒定向分维、等效直径、扁圆度和面积比是对固化土力学强度影响较为显著的5个微结构参数。借助土微结构参数与强度间的相关性计算分析,从另外一个角度验证石灰对滨海盐渍土的固土作用。     

Chlorohydrocarbon pesticides in the Australian marine environment after banning in the period from the 1970s to 1980s

The chlorohydrocarbon pesticides (CHPs) (principally DDT, dieldrin, hexachlorocyclohexane (HCH) including lindane, chlordane, heptachlor and heptachlorepoxide, aldrin and hexachlorobenzene (HCB)) were used extensively in Australia during the 1960s and 1970s. These were progressively banned from the 1970s with DDT being totally banned in 1987. The levels in marine waters are believed to have progressively declined as indicated by water in the Brisbane River, which consistently fell from maximum concentrations of about 1.7 μg/l in 1972–1973 to not detectable in 1986–1987. In some urban areas sediment concentrations, up to 1700 μg/kg dry weight, were recorded in the early 1990s which may reflect the reworking and exposure of older more contaminated material. Fish exhibited consistent occurrence of DDT, HCH, dieldrin and HCB through the 1970s to the 1990s. Maximum concentrations of DDT and dieldrin occurred generally in the 1970s at 40.3 and 8.8 μg/g wet weight, and minimums in the 1990s at 2.4 and 0.041 μg/g wet weight respectively. Inputs of dialdrin from sewage and DDT from the broad environment, reflected by the calculated daily human uptake in the diet, were shown to decline with half-lives of 1.1–1.5 and about 3 years respectively. This evidence suggests that banning of the CHPs has greatly reduced the inputs into the marine environment with consequent reductions in concentrations in biota but there is the occasional occurrence of relatively high concentrations.     

The potential role of freshwater luminescence measurements in exploring runoff pathways in upland catchments

The forested Coalburn catchment (1·5 km²) in northern England experiences episodic stream acidification. To plan for sustainable management of the plantation forest cycle, an understanding is required of the flow pathways and hydrochemical routing signatures of the organic and mineral soils that make up the source areas for runoff. A tentative mixing model, based on simple water chemistry exists for the major (terrestrial) sources and buffers of acidification; it is being expanded and consolidated by a detailed approach to the organic components of runoff, via sampling and analysis of the luminescence of surface waters at the catchment outlet and in two distinctive feeder streams. Luminescence measurements are presented that permit a simple apportionment of source areas. However, the technique also appears to have potential for identifying differential flow sourcing between the acrotelm and catotelm of intact peat deposits and for clarifying the influence of forest root systems in altering the organic chemistry of infiltrating waters. Applications may include the monitoring and prediction of coloured water events for the water supply industry. Copyright © 2001 John Wiley & Sons, Ltd.     

Hydrogeological and geochemical assessments of the Gediz Graben geothermal areas, western Anatolia, Turkey

Gediz Graben is an important area for geothermal activity in Turkey. Menderes Massif rocks consisting of gneisses, schists, marbles and granodiorite, comprise the aquifers of the geothermal systems. Neogene terrestrial sediments made up mainly of sandy and clayey conglomerates cap the systems. Gediz Graben geothermal areas are physically divided into seven main groups: Turgutlu-Urganl, Sart-Çamur, Caferbeyli, Üfürük, Kurunlu, Kavakldere-Sazdere and Alaehir geothermal areas. The third highest aquifer in Turkey temperature (182 ^°C) after Kzldere (242 ^°C) and Germencik (232 ^°C) was discovered in the Kavakldere-Sazdere area. The thermomineral waters of the Gediz Graben geothermal areas have outlet temperatures of 25^–95 ^°C and an electrical conductivity of 874–6020 S/cm. Mineralization is mostly dominated by Na⁺ (188–2027 ppm) and HCO₃^– (544–2950 ppm). Kavakldere-Sazdere area shows the highest boron content among the entire geothermal aquifers of Turkey. Major geochemical processes for thermomineral waters are carbonate and silicate dissolution and mixing.     

Survey of stable isotope values in Irish surface waters

We present a study of the spatial distribution of δ¹⁸O and δD values of lake and river waters from 144 locations in Ireland. Before we can gain a better understanding of paleoclimate records derived from lacustrine carbonate minerals we must understand mechanisms that produce variation in isotope values of modern surface waters. The focus of this study is to provide insight into the behavior of lakes and rivers in Ireland, including source, recycling and loss through evapotranspiration. The short duration of sampling in this project provides a snapshot of modern isotope variability to be applied towards long-term climate change in Ireland and provides a basis of comparison for other proxy records.Electronic supplementary material to this article is available at and accessible for authorized users.     

Advantages of longer–term tracing -- three case studies from Slovenia

A variety of human activities can negatively impact on sensitive karst environments, especially on karst water. To protect such water adequately it is necessary to obtain as much information as possible on the extent of the recharge zones and characteristics of the groundwater flow. The authors experience has shown tracer tests to be a very useful tool in acquiring such information. Three examples from Slovenia are presented in this paper. In the first, an estimate was made of the danger of water contamination resulting from a petrochemical storage depot. In the second, the possible impacts of an area used for military training were studied. In the third, the effects of the construction of a railway line on regionally important water resources were assessed. Besides basic information about the direction and velocity of groundwater flow, some methodological principles were also identified by the studies. In all three test areas sampling was carried out for a lengthy period and continued after the detection of the peak concentrations. The results show that only the use of such lengthy tracer tests enable the definition of those flow paths, which are activated in extreme hydrological conditions.