Phosphorus in marine zooplankton

In the euphotic zone, phosphorus compounds dissolved in sea water are utilized by growing plants, many of which are subsequently eaten by herbivorous zooplankton and the dietary phosphorus invested partly in growth and egg production, partly released in insoluble form as faecal pellets and partly metabolized. The fraction metabolized is excreted back into the sea water mainly as inorganic phosphate, which is again available as a nutrient for the plants.Quantitative aspects of this cyclic process are discussed with particular reference to the Calanoid copepods, animals of central importance to the marine food web in several sea areas. Topics include: (1) laboratory and field investigations of the assimilation of dietary phosphorus and the efficiency of this process; (2) the rates at which zooplankton release soluble forms of phosphorus in relation to species, body size, food availability and season; (3) the importance of zooplankton in regenerating phosphorus compounds that may be used by the plant population; (4) the daily rations of phosphorus captured by zooplankton; (5) the total amounts and chemical forms of phosphorus in the animals; (6) growth of zooplankton and the use of N:P ratios in animals, diets and excretion products in estimations of gross growth efficiency interms of phosphorus; (7) future studies.     

Thermal tolerance of the invasive oyster Crassostrea gigas: feasibility of heat treatment as an antifouling option

Pacific oysters, Crassostrea gigas are traditionally considered shellfish of great fishery and aquaculture value. For these reasons they are introduced worldwide. Recently there has been increasing reports about the prevalence of C. gigas as biofouling organism in cooling water systems. In the absence of relevant data on the susceptibility of oysters to commonly employed antifouling techniques such as heat treatment, it was presumed that oysters would be controlled by treatment programmes directed against other major fouling organisms. The present study was carried out to test the above hypothesis, and results showed that C. gigas has an upper temperature tolerance that is much higher than other major marine fouling animals including blue mussel Mytilus edulis. Apparently, temperature regimes presently used in heat treatment of cooling water systems fouled by mussels need to be increased, if C. gigas are to be controlled effectively. Our results also indicate that previous exposure of C. gigas to sublethal high temperatures could make them more resistant to subsequent thermal treatment, an aspect that should be taken into account when heat treatment is used as a fouling control option against oyster fouling.     

微波真空干燥技术在食品工业中的应用与展望

详细阐述了微波真空干燥技术的原理、特点及在食品工业中的应用,分析了微波真空干燥技术存在的问题,介绍了该技术在国内外的研究现状。微波真空干燥是综合微波干燥和真空干燥各自优点的一项新技术,非常适合食品的干燥生产,随着微波真空干燥设备的计算机监测技术和自动化水平的不断提高,微波真空干燥技术将在食品生产中获得更广泛地应用。     

镉对中间球海胆性腺脂质过氧化的影响

研究了不同浓度的镉离子对中间球海胆Strongylocentrotus intermedius性腺超氧化物歧化酶(S0D)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)的活性以及丙二醛(MDA)含量的影响。结果显示:低浓度的镉能激活海胆性腺SOD、CAT和GPx的活性,但随着镉离子浓度的增加和时间的延长,3种酶活性都受到不同程度的抑制;各试验组MDA的含量显著高于对照组。说明镉能引起海胆性腺脂质过氧化损伤。     

Ecological restoration of reclaimed wastewater lakes using submerged plants and zooplankton

High‐pollutant concentrations have led to the breakout of planktonic bloom and the breakdown of the ecosystem in many lakes in China and other countries. The removal of the organic and inorganic pollutants from industrial, agricultural and domestic wastewater and the restoration of the aquatic ecosystem of the polluted water bodies are persistent issues. Constructed wetlands are often used, and most depend on emerged plants. In this study, Daphnia magna, a type of zooplankton, and five species of submerged plants were used to remove nitrogen and phosphorus from reclaimed domestic wastewater in four scenery lakes of a garden in Peking, China. Water quality was assessed by the local environmental inspection station as the government inspection and a commercial company as the third party inspection, and the gathered data proved that ecological restoration was successful in this study.     

Heavy metals in zooplankton and decapod crustaceans from the Barents Sea

Trace metals (Cd, Cu, Pb and Zn) were analysed in zooplankton samples and decapod crustaceans collected on cruises of "RV Walther Herwig III" to the Barents Sea (Summer 1991, 1994 and 2000). We found a substantial spatial heterogeneity in the decapod crustacean Pandalus borealis, with increasing Cd concentrations from the south (North Cape Bank; 0.7 mg kg(-1) DW) to the north (north of Svalbard; 4.7 mg kg(-1)), supporting the hypothesis that the frequently reported Cd-anomaly in polar crustaceans might be extended to the Barents Sea. Regarding various crustaceans and zooplankton collectives (2000) a distinct interspecific heterogeneity of metals was obvious, with lowest Cd concentrations in euphausiids and chaetognaths and highest ones in decapods and hyperiid amphipods; lowest Cu concentrations in chaetognaths and copepods and highest ones in euphausiids and decapods; and lowest Zn concentrations in euphausiids and decapods and highest ones in some copepods. For Pb many values were below or close to the limit of detection, suggesting that Pb concentrations about 0.4 mg kg(-1) might serve as a regional background value. Results for Cd, Cu and Zn in copepods of this study are largely within the reported range, but high Cd concentrations in copepods from summer in contrast to reported lower ones during winter/spring may be related either to changing accumulation strategies of the copepod species involved or to seasonally changing Cd absorption in copepods from food.     

Effects of intensive fishing on the structure of zooplankton communities and mercury levels

Following the impoundment of hydroelectric reservoirs, a small fraction of the mercury (Hg) in the flooded soils is transformed and released into the ecosystem. This causes an increase in the mercury level in the food chain, particularly in piscivorous fish, and represents a potential risk for human health. In 1998, Hydro-Québec carried out an intensive fishing campaign to examine the feasibility of using intensive fishing as a mitigation tool. The goal of this particular part of the project was to evaluate the impact of intensive fishing on the zooplanktonic communities' structure and mercury levels. Specifically, the effects of intensive fishing on: (1) total biomass and zooplankton size structure (>500, 200-500, 100-200 and 53-100 microm); (2) species composition; and (3) total mercury and methylmercury (MeHg) concentrations in zooplankton of different size fractions were studied. Although important decreases were observed in total zooplankton biomass or its size structure, it cannot be related to the intensive fishing. The results, however, show major changes in the dominance of macrozooplanktonic species in fished lakes as opposed to reference lakes. Similarly, in contrast to the reference lakes, mercury and MeHg concentrations in the four size fractions of the zooplanktonic communities changed from 1998 to 2000 in the fished lakes. The MeHg concentration increased from approximately 20 to 200 ng/gdw from the 53 to 500 microm mesh size fraction, showing a biomagnification in the food chain. The canonical correspondence analysis showed that lakes dominated by Holopedium gibberum presented higher concentrations of Hg and MeHg than lakes dominated by Daphnia spp.     

关于"热感觉"与"热舒适"的讨论

对哈尔滨市居民的热感觉与热舒适状况的调查结果表明：热感觉投票值分布频率与热舒适投票值分布频率是有差异的。对新加坡现场调查结果的分析数据也表明：热感觉与热舒适是不同的,热感觉和热舒适既仔在于稳态热环境中又存在于动态热环境中。     

Effects of a power plant on zooplankton distribution and abundance near plant's effluent

Blount Street Power Station on Lake Monona, Wisconsin, draws cooling water at 3–4 m from two intakes 110 m offshore and discharges the water at two shoreline outfalls 200 m apart. The density of zooplankton near these outfalls was 2–7 times greater than at littoral reference stations because zooplankton density at the limnetic intakes was consistently higher than in littoral reference areas. Thus, the circulation of cooling water transported zooplankton-rich water to the littoral zone.     

The effect of dredging in a polluted estuary on the physiology of larval zooplankton

The effect of water samples from three dredging locations in Charleston Harbor and its tributaries upon the physiology of larval or juvenile zooplankton was determined, Daphnia were used for Location 1 with a salinity of 0‰, Paleomonetes for Location II with intermediate salinities and Polydora for Location III with highest salinities. Water from the disposal area of each location was most toxic. Samples from 200 yd downstream were intermediate in effect, and the dredge site sample was least toxic.     

热质墙体在我国的热适应性研究

室外大气综合温度通过热质墙体传入室内,波动大大衰减,波峰延迟,在节能降耗中具有重要意义。本文首先建立了热质墙体的一维非稳态传热模型,对应用在一栋零能耗建筑中的热质墙体传热性能进行了模拟,模拟结果与实际检测的墙体温度和热流率吻和良好。而后进一步利用该模型分析了热质墙体在我国5类典型气候区域代表城市的适应性,结果表明在昼夜温差大、室内外平均温差大的地区较适宜采用厚重围护结构,而在冬暖夏凉地区现象相对不明显。     

Trophic transfer of heavy metals from freshwater zooplankton Daphnia magna to zebrafish Danio reiro

The trophic transfer of metals along the food chain has been recognized as an important issue in the study of water quality in recent years. Feeding experiments were conducted to examine the assimilation of three metals (Cd, Cr and Zn) by the zebrafish Danio reiro feeding on the freshwater zooplankton Daphnia magna. The zooplankton were exposed to radiotracers from both the aqueous and dietary phases for different duration, and then pulse-fed to the zebrafish for measurements of metal assimilation efficiency (AE). The calculated AEs were 3-8% for Cd, 2-39% for Cr, and 17-36% for Zn in the zebrafish. For Cd and Zn, there was no statistically significant difference between the two different radiolabeling routes (aqueous and dietary exposure). For Cr, the AEs were higher when it was accumulated by D. magna from the dietary source than when it was accumulated from the aqueous phase. The gut passage time (GPT) was 6-10 h for all metals, with less variation for Zn among the different treatments. There was no obvious relationship between metal GPT and metal AE, presumably due to the narrow range of variation of metal gut passage. About 5-36%, 20-31%, and 8-30% of the total Cd, Cr and Zn was found in the soft tissue of D. magna after the radiolabeling. A much higher fraction of Cd and Zn was found in the soft tissue of D. magna when the metals were accumulated from the dietary phase. No significant relationship between the metal AE and the metal distribution in the soft tissue of D. magna was however documented in this study. Our results demonstrated that there was major difference in metal AE in freshwater fish among different metals. Metal localization in prey organisms and GPT appear to have little influence on metal assimilation by the zebrafish.     

水泥基保温材料导热系数的模型研究

通过将水泥基复合材料分为若干薄层的方法,利用概率理论,建立了热流密度通过水泥基复合材料的一维概率模型.采用所提出的模型计算了以膨胀聚苯乙烯(EPS)颗粒为保温组分的水泥基保温材料导热系数,并将其与根据传统理论模型计算的结果以及实测结果相比较.结果发现:根据所提出的一维概率模型计算的水泥基保温材料导热系数具有更高的可靠性.     

Changes in the density of zooplankton passing through the cooling system of a power-generating plant

The densities of copepods, copepod nauplii, barnacle nauplii, and bivalve larvae were determined at the inlet and outlet of the cooling system of a large power station, which is located on a lake system with a narrow opening to the sea. The variability in plankton abundance in the cooling water was examined and a sampling technique was devised to obtain data that could be reliably compared between inlet and outlet. This technique consisted of lowering and raising a net sampler through the water column. There was no significant change in numbers of copepods after passage through the cooling system. However, significant changes were recorded for copepod nauplii and bivalve larvae (decreases), and barnacle nauplii (increase). Possible causes for these changes are discussed.     

棘洪滩水库秋冬季浮游动物群落动态及多样性研究

2011-2012年秋冬季通过对棘洪滩水库浮游动物的采集,共鉴定出物种17种,其中轮虫5种,桡足类8种,枝角类4种;种类比较丰富的为桡足类,占总数的47.06％;枝角类占总物种数的23.53％;轮虫类占29.41％.秋冬季棘洪滩水库浮游动物密度范围为7.45～50.28 ind/L.对棘洪滩水库浮游动物群落多样性分析表明：Shannon-Wiener多样性指数值在2.25～2.96,且秋季＞冬季.而浮游动物与叶绿素a的相关性分析表明,浮游动物与前一季节浮游植物密度高度相关且具有一定的时滞性.     

土体热传导性能及其热导率模型研究

为研究不同土体的热传导特性变化规律,利用热探针测试了南京地区典型土体在不同含水量和干密度状态下的热阻系数,分析了含水量、干密度、饱和度以及矿物成分等因素对土体热阻系数的影响,研究了不同状态下土体热导率的预测模型,提出了适用于不同地区土体热阻系数估算的修正系数.结果表明:南京地区典型土体的热阻系数随含水量和干密度增加而减小,当含水量超过一定范围后,热阻系数趋于稳定;热阻系数与饱和度之间的关系表现出与其含水量之间相似的变化规律;土颗粒的热传导特性由其矿物成分决定,石英含量对土颗粒热传导特性有着显著影响;提出了可用于非饱和土热导率估算的修正归一化模型,该模型对于粗粒土具有较高的预测精度,细粒土则需考虑区域差别进行修正.     

夏季工况条件下热反射隔热涂料热工性能实测分析

热反射隔热涂料作为一种新型的节能材料,越来越多地应用于民用建筑中,其高反射率的特点也多被研究者所关注。通过对位于广西南宁市的3间试验房进行热工性能连续监测,并对监测数据进行比较分析,结果显示,热反射隔热涂料晴天对建筑外表面温度降温效果好,可使室内温度相应降低,起到较好的隔热效果,特别是对建筑东、西及水平向围护结构的隔热效果更为明显。另外,热反射隔热涂料墙体延迟时间较长,在房间各个朝向效果均匀。     

动态热环境下人体热舒适的实验研究

室内热环境是影响人体热舒适的关键因素,研究动态热环境下人体的热舒适温度范围,对促进建筑节能有着重要的意义。本文以深圳市某居住小区的住户为研究对象,在动态的室内环境中,测试分析了不同状况下的人体热舒适温度和自然通风的热舒适性效果,提出了有关建议:住宅建筑应尽量采用自然通风来达到舒适性要求,在自然通风无法满足要求时,可采用风扇等其他机械通风方式;空调状态下人体热舒适温度在国家标准规定的26℃基础上可适当提高1～2℃。     

外观设计对复合保温砌块热工性能的影响研究

对原始复合保温砌块的块型设计、热工性能进行探讨,采取延长传热路径和增加有机保温材料体积思路,对原始复合保温砌块进行改良,同时,研制出先进的成型流水线和生产工艺,采用QXFY型保温砌块成型设备,做到一次复合成型,且块型、规格配套齐全。分别采用节能计算软件和实体检测手段对自保温系统进行计算和检测,结果表明软件计算结果与实体检测结果符合度较好,改良复合保温砌块及其砌体的热工性能优于原始复合保温砌块及其砌体的热工性能。用改良复合保温砌块砌筑的外墙体比用原始复合保温砌块砌筑的外墙体按每平方米墙面展开面积计算大约节约35元。