Ventilation or nest defense—parental care trade-offs in a fish with male care

Brood guarding animals face many critical trade-offs. Sand goby males (Pomatoschistus minutus) build nests with larger openings during low oxygen conditions, presumably to enhance ventilation. However, this may make the nest easier for egg predators to detect and harder for guarding males to defend. Manipulating oxygen level and predator presence (a small crab) for small and large males, we found support for a parental trade-off between fanning and nest defense. An increased fanning activity resulted in less time for guarding. Small males and males in low oxygen showed a higher fanning expenditure than large males and males in high oxygen, but surprisingly, filial cannibalism did not differ between these groups. Males built larger nest openings in low than high oxygen. However, males in both high and low oxygen treatments reduced their nest opening size in the presence of a predator, again indicating an important trade-off between ventilation and nest defense.     

Degradation of the herbicide imazapyr by Fenton reactions

The degradation of the herbicide imazapyr has been carried out by three advanced oxidation processes involving iron ions as catalysts: Fentons reagent, photo-Fenton and electro-Fenton. We show that all processes are rapid and efficient. The kinetic rate constant was found to be k=5.4×10⁹ M^–1 s^–1. The mineralization of imazapyr is almost complete using the photo-Fenton and electro-Fenton processes.     

微电解杀藻研究

研究表明，用杀藻器进行微电解杀灭湖泊中藻类的效果显著，当进水流量１ｍ＾３／ｈ，电流密度为８．９－１１．８ｍＡ／ｃｍ６２以及当进水流量０．５ｍ＾３／ｈ，电流密度在５．９－８．９ｍＡ＝ｃｍ＾２时，杀藻效果均极好，明显破坏藻类细胞中叶绿体的结构，使藻类的光合使用明显减弱。     

上海新港河道耗氧特性研究及其综合整治措施

通过实验室试验测定，得出了上海市新港河道水体和底泥的耗氧特性曲线，分析了水体和底泥耗氧的阶段历时、阶段耗氧特性及动力学过程。在缺乏河道水质模型的情况下，利用耗氧特性曲线可以估算各个阶段的耗氧量和河道的总耗氧量，为河道充氧设备的选择提供一定的理论指导。通过计算，上海新港河道的总耗氧量约为75．7kg／d。上海宏成实业发展有限公司采用充氧曝气、投加微生物、种植水生植物等措施对河道进行了治理，实践表明，这些措施可以使新港河道的水质有明显的改善。     

An improved product-process for cleaner chrome tanning in leather processing

Severe restrictions imposed by the pollution control authorities on the disposal of chromium, total dissolved solids and chlorides in tannery effluents have forced the tanners to look for low-waste, high exhaust chrome tanning salts. An improved chrome syntan with more than 90% uptake of chrome has been developed. The new product serves both as tanning and retanning agent and can be applied directly to delimed pelts thus eliminating the conventional pickling stage in the leather processing. This modified process helps to reduce the chemical oxygen demand (COD), total dissolved solids (TDS) and chlorides in the spent tan liquor by 51, 81 and 99%, respectively. The product offers full, soft leathers having shrinkage temperature comparable to conventional chrome tanned skins. Since the developed product is highly reactive, it saves time and reduces the water requirement when compared to the conventional chrome tanning method. Thus the novel product/process developed not only has advantages in reducing pollution loads but also seems to be techno-economically viable.     

CODcr 5分钟快速测定法与国家标准方法对比试验

国家标准方法中重铬酸钾法测定化学需氧量,准确度高,但操作时间长,试剂使用量大,耗电耗水.采用5分钟快速测定法后能大大缩短测定时间,同时能耗低.通过对比试验表明,5分钟快速测定法具有较好的抗氯性,精密度及准确度均能达到要求,且具有成本低特点,证明了方法的可行性,特别适于污水处理厂等需频繁监测点的快速测试.     

氨基磺酸修正碘量法测定亚硝酸盐存在情况下水中的溶解氧

为了测定较高浓度亚硝酸盐存在时水中的溶解氧 ,提出了氨基磺酸修正碘量法 ,实验结果表明 ,对于清洁水和废水 ,与标准碘量法相比 ,氨基碘酸修正碘量法在亚硝酸盐浓度约为 10mg L、4 0mg L、70mg L情况下测定结果的相对标准偏差均小于 1% ,相对误差均小于 2 % ,表明方法的准确度和精密度可以满足实验室测定DO的要求。本方法测定DO时对亚硝酸盐氮适用的上限为 70mg L。     

浅谈生物化学需氧量质控考核

简要概述了在环境监测质量控制考核中,如何保证生物化学需氧量测定的可靠性和准确性.     

TL-1(A)型污水COD速测仪在萝北企业污水排放监测中的应用

萝北县环境监测站采用TL-1(A)型污水COD速测仪测定企业排放污水中的化学需氧量,此法在强酸性介质中,复合催化剂存在下,恒温消解水样只需10分钟,操作简单,工作效率高,克服了重铬酸钾法耗时长,每次只能同时测定几个样品的缺点.通过与国家规定的标准方法进行对比实验,结果表明,仪器测定的结果与标准法测定的结果具有良好的可比性,COD速测仪在企业污水排放监测中具有实际意义.     

锶同位素在沉积学中的应用新进展

随着分析测试技术的不断提高 ,锶同位素研究取得了重大进展。近年来 ,显生宙以来海水锶同位素的变化曲线不断得以补充和修正 ,已建立起具有全球一致性、可对比的海水锶同位素变化曲线背景值 ,为锶同位素的应用奠定了基础。现在 ,锶同位素不仅在示踪岩浆及成矿热液的来源和演化、计算晚期成岩改造作用的规模和程度及流体 /岩石比等方面已趋于成熟 ,并且越来越广泛运用于海平面变化、板块活动、海底扩张、成岩演化等方面的研究。此外 ,在一些热点研究上 ,如全球变化、生态环境等方面 ,也逐渐显现出重要性