高硫酸盐有机废水厌氧处理技术的进展

本文通过硫酸盐还原菌和产甲烷菌的竞争、硫化物对产甲烷菌的毒害二方面,论述了在高硫酸盐有机废水厌氧处理过程中,硫酸盐还原作用对产甲烷菌活性的抑制机理,同时,介绍了当前高硫酸盐有机废水的厌氧处理工艺     

Reduction of ferric chelate caused by various wood-rot fungi

The reduction of ferric chelate caused by various wood-rot fungi was analyzed. Ferric chelate reductive activity was detected in cell-free extracts of seven wood-rot fungi:Phanerochaete chrysosporium, P. sordida YK-624,Ganoderma sp. YK-505,Coriolus versicolor, Bjerkandera adusta, Tyromyces palustris, andGloeophyllum trabeum. These fungi produced NADPH- or NADH-dependent ferric chelate reductive enzymes (or both) of different molecular weight. In the liquid culture ofP. sordida YK-624 andC. versicolor, a positive correlation was observed between extracellular MnP activity and intracellular NADPH-dependent ferric chelate reductive activity.     

我国关税下调的政治效应分析

由于其深刻的国际、国内背景的影响．我国关税自1986以来,先后进行了5次下调,这对促使人们更新观点、加速我国现代外贸体制的建立及提高我国在国际政治、经济舞台上的影响等产生了重大的政治效应。     

The use of GUS-reporter gene to study the effect of Azospirillum-Rhizobium coinoculation on nodulation of white clover

 The gusA-marked Azospirillum lipoferum T1371, constructed by inserting transposon mTn5SSgusA20 from Escherichia coli S17-1 λ-pir into the genome of Azospirillum lipoferum 137, was used to evaluate its effect on nodulation of white clover with and without Rhizobium inoculation. When inoculated alone, Azospirillum colonized the tap roots, secondary roots and root hairs. The combined inoculation of white clover with Rhizobium leguminosarum bv trifolii and A. lipoferum enhanced the number of nodules by 2–3 times from 5 to 20 days after inoculation (DAI). The combined inoculation also enhanced acetylene reduction activity by 2.3–2.7 times at 20 DAI. Moreover, Azospirillum was observed colonizing the tap root, root hairs and sites near or on the nodules. These results suggest that the formation of additional infection sites by A. lipoferum, with a combined inoculation, may be the mechanism that will enhance nodulation and nitrogen fixation of white clover. Received: 23 July 1997     

Ethylene production and decomposition in soils

Six soils differing in texture and use were investigated for their ability to produce and decompose ethylene. In addition, changes in methane and CO₂ concentrations were monitored. The effects of organic amendments and different water tensions were studied, and a method using low concentrations of acetylene as an inhibitor of ethylene degradation was tested. Possible reduction of acetylene to ethylene was identified by the use of CO or NH₄ ⁺-N, of which the latter turned out to be the more reliable method. This reduction only occurred in a grassland soil. Under aerobic soil conditions, gross ethylene production rates of up to 4.7pmol g^–1 h^–1 could be measured. Highest ethylene production and lowest ethylene decomposition was detected in a spruce forest soil. Fine textured soils produced more ethylene than coarse textured soils. Amended soils produced more ethylene at –100kPa and –5kPa than at 0kPa water tension. Ethylene decomposition was most effective in soils from deciduous woodlands and reached rates of up to 137pmol g^–1 h^–1. Parallels between ethylene and methane decomposition were observed. The addition of 5mgg^–1 glucose and 1mgg^–1 methionine not only promoted ethylene production but also inhibited ethylene decomposition. Received: 4 April 1997     

中国某些水稻土中硝态氮向铵态氮的还原研究

Three paddy soils were examined for their capacities of dissimilatory reduction of nitrate to ammonium (DRNA). 15N-labelled KNO3 was added at the rate of 100 mg N/kg. Either glucose or rice straw powder was incorporated at the rate of 1.0 or 2.0 mg C/kg respectively. Three treatments were designed to keep the soil saturated with water: (1) a 2-cm water layer on soil surface (with beaker mouth open); (2) a 2-cm water layer and a 1-cm liquid paraffin layer (with beaker mouth open); and (3) water saturated under an O2-free Ar atmosphere. The soils were incubated at 28℃ for 5 days. There was almost no 15N-labelled NH4+-N detected in Treatment 1. However, there was 1.4 to 3.4 mg N/kg 15N-labelled NH4+-N in Treatment 2, and 2.1 to 13.8 mg N/kg in Treatment 3. Glucose was more effective than straw powder in ammonium production. Because there was sufficient amount of non-labelled NH4+-N in the original soils, 15N-labelled NH4+-N produced as such should be the result of dissimilatory reduction. Studies on microbial population showed that there were plenty of bacteria responsible for DRNA process (DRNA bacteria) in the soils examined, indicating that number of DRNA bacteria was not a limiting factor for ammonium production. However, DRNA bacteria were inferior in number to denitrifiers. The DRNA process in soil suspension started after 5 days of incubation. Glycerol and sodium succinate, though both are readily available carbon sources to organisms, did not facilitate DRNA process. DRNA occurred only when glucose was available and at a C:NO3--N ratio >12. Both availability and quality of the carbon sources affected DRNA.     

对虾养殖实验围隔中的固氮作用及其氮输入

１９９７年６～１０月,以乙炔还原法进行了不同放养模式下对虾养殖实验中生物固氮作用的测定。结果表明,各围隔中,对虾单养（Ｙ－４）和对虾＋海湾扇贝（Ｙ－５）的固氮作用较高,均值分别为２．６２μｇＮ／（Ｌ·ｈｒ）和２．６５μｇＮ／（Ｌ·ｈｒ）;对虾＋罗非鱼＋缢蛏（Ｔ－５）的最低,为１．５３μｇＮ／（Ｌ·ｈｒ）,对虾＋缢蛏（Ｙ－６）和对虾＋罗非鱼（Ｙ－７）的分别为２．３０μｇＮ／（Ｌ·ｈｒ）和１．８９μｇＮ／（Ｌ·ｈｒ）。各围隔中固氮速率较高与水体有效氮含量较低及有效氮磷比值不高有关。水层固氮蓝藻主要为蓝球藻（Ｃｈｒｏｃｏｃｕｓ）和念珠藻（Ｎｏｓｔｏｃ）。估算各围隔实验期间固氮作用输入分别为Ｙ－４∶１７．７２ｇ;Ｙ－５∶１９．６３ｇ;Ｙ－６∶９．０５ｇ;Ｙ－７∶１０．５９ｇ;Ｔ－５∶７．９９ｇ。     

冰温下包装方式对大黄鱼的保鲜效果研究

在冰温(-1.0±0.3) ℃贮藏条件下,研究了真空包装对大黄鱼的保鲜效果.通过对贮藏过程中感官、理化和微生物指标的测定,评价了不同包装方式对大黄鱼品质的影响.试验结果表明,冰温真空包装法能够抑制贮藏过程中细菌总数、TBA值和盐基氮的增加,与空气包装相比,保鲜时间延长6~7 d.应用冰温真空包装法延长了大黄鱼的保鲜时间,且保持较好的品质.     

Global reduction fisheries and their products in the context of sustainable limits

Globally, one‐sixth of landings from marine capture fisheries are destined for the production of fishmeal and fish oil (FMFO), which are currently overwhelming utilized by fed aquaculture. Many different species are used globally for the production of FMFO, but little concern has been given to the divergent environmental and ecological impacts of FMFO products based on species, ecosystem and fishing gear used in their capture. We evaluated the variable environmental performance of FMFO products from a wide range of fisheries whose products are either primarily intended for reduction or whose by‐products are redirected to reduction. Assessed fisheries accounted for 44% of global reduction fishery landings in 2014. Analysis was conducted on the basis of two measures: the carbon footprint (i.e., greenhouse gas [GHG] emissions) and the marine footprint (i.e., primary production required [PPR]). We found large differences between the impacts of FMFO products across the 18 reduction fisheries examined. Cumulatively, we estimate that reduction fisheries emitted 4.6 million tonnes of CO₂‐e GHGs in 2014, and appropriated over 4% of primary production in some ecosystems, demonstrating a non‐trivial impact. As demand for aquafeeds grow, the sustainable sourcing of raw material inputs will be of great importance. Results here suggest that the source of FMFO inputs can have dramatic effects on the environmental performance of fish feeds and fed aquaculture. We recommend further research on the environmental and ecological impacts of food production systems, and specifically to understand these results in relation to global production and sustainable boundaries.     

Primary fisheries management: a minimum requirement for provision of sustainable human benefits in small‐scale fisheries

The social and economic importance of small‐scale fisheries is frequently under‐valued, and they are rarely effectively managed. There is now growing consensus on how these fisheries could be managed for sustainability and to minimize the risks of crossing undesirable thresholds. Using a concept developed in health care, these approaches have been referred to as primary fisheries management. By encouraging the use of best‐available information in a precautionary way, the approaches will facilitate sustainable use and should therefore be encouraged, but they accept high scientific and implementation uncertainties as unavoidable because of limited management and enforcement resources and capacity. It is important to recognize that this limitation will result in social costs, because application of a precautionary approach in the face of high uncertainties will require forgoing potential sustainable benefits. Acceptance of primary fisheries management as a final and sufficient goal could therefore add a further constraint on the possibility of fishing communities escaping the poverty trap. Primary fisheries management should be seen as a first and minimum target for fisheries where there is currently no or inadequate management, but the longer‐term goal should still be well informed and adaptive management that strives for optimal benefits, referred to here as tertiary management.