淀山湖浮游植物营养限制因子的研究

通过藻类增长的生物学评价(Nutrient Enrichment Bioassay)研究淀山湖浮游植物生长限制性因子，并采用析因方差分析和事后比较方法分析营养盐（PO^3-₄P、NH₃N、NO^-₃N）对浮游植物生长速度、平均最大现存量和平均最大特定增长率的影响。研究表明：磷对浮游植物生长有明显的促进作用，能提高浮游植物的生长速度和现存量，且促进作用随磷浓度（0.13～0.53 mg/L）的增加而加强，磷是淀山湖浮游植物增长的第一限制性因子；低浓度硝氮（2.91～5.91 mg/L）对浮游植物生长有微小的促进作用，但高浓度（5.91～8.91 mg/L）的硝氮表现出抑制作用；氨氮对浮游植物生长有抑制作用，并随浓度（1.25～7.25 mg/L）的增加而增大；添加磷+硝氮能明显促进浮游植物生长，磷与硝氮之间存在一定的交互作用.     

有机农药对土壤的污染及生物修复技术研究

农药的大量使用污染了大气、水体及生态系统。有机农药以直接施用、拌种、喷撒、随降水落入等方式进入土壤。农药在土壤中会以吸附、扩散稀释和降解等几种方式发生转化，并改变土壤结构、对土壤中生物的生存及酶的活性产生影响。生物修复技术可以通过动植物、微生物及根际环境对农药污染的降解来治理土壤中的农药，是治理农药污染的一种推荐方法。     

Biomass and nutrient concentration of sweet corn roots and shoots under organic amendments application

Two field experiments were conducted at the Waimanalo research station on the island of O'ahu, Hawaii to study the effect of chicken (CM) and dairy (DM) manures on biomass and nutrient concentration in sweet corn roots and shoots. Sweet corn (super sweet 10, Zea Mays L. subsp. mays) was grown for two consecutive growing seasons under four rates of application (0, 168, 337, and 672 kg ha^{? 1} total N equivalent) and one time (OTA) or two time (TTA) applications of organic manure types and rates. There were significant effects of types, rates, and number of manure applications on dry biomass and macro- and micro-nutrient concentration in roots and shoots tissues. Results of root tissue indicated a significant accumulation of N and C under CM and DM treatments compared with the control treatment. Manure application rates significantly increased the accumulation of N and C in root tissue. Dry weight of roots and shoots and both macro- and micro-nutrient contents in the plant tissues significantly increased under TTA treatment compared with OTA treatment. There was a significant correlation (r² = 0.46 to 0.81) between root biomass, macro-, and micro-nutrient contents during both growing seasons. The results of the study indicates that amending soils with CM at the highest application rate provided the best crop performance in terms of root and shoot biomass, crop N, C, and other macro- and micro-nutrients.     

安徽省旅游业转型升级对策研究

随着我国经济增长结构和产业增长方式调整转变，旅游业转型升级成为提高旅游业经济效益，实现旅游业可持续发展的必然要求。在全面分析安徽省旅游业转型升级背景的基础上，结合安徽省旅游业转型升级的优势条件与制约因素，提出安徽省旅游业在旅游产业结构、旅游产品、旅游企业、旅游市场、旅游人才等方面转型升级的路径与对策。     

不同营养水平下悬浮细菌数量对生物粘泥性质的影响

循环水系统中的微生物有悬浮态和附着态,悬浮细菌的存在对附着态生物粘泥的生长及特性有明显影响。通过向模拟循环冷却水系统中投加不同数量初始悬浮细菌,考察在营养水平不同的情况下,悬浮细菌数量对生物粘泥化学组成和脱氢酶活性的影响。结果表明,营养水平不同,初始悬浮细菌数量对生物粘泥的化学组成和脱氢酶活性的影响程度不同;在不同营养水平下,应分别控制初始悬浮细菌数量。贫营养下,初始悬浮细菌数量应控制在6×105个/mL左右;中营养下,初始悬浮细菌数量应控制在1×105～2.6×105个/mL之间;富营养下,初始悬浮细菌数量应控制在0.11×105～2.6×105个/mL之间最不利于生物粘泥的生长。     

CHEMISTRY RESPONSE OF TWO FORESTED WATERSHEDS TO ACID ATMOSPHERIC DEPOSITION1

ABSTRACT: The deposition and chemistry of precipitation were estimated for one year in two forest ecosystems in the South-Central United States. Precipitation, throughfall, litter leachate, and soil leachate were analyzed for a small catchment of pine-hardwoods in southeastern Oklahoma and for a catchment of loblolly pines (Pinus taeda L.) in northern Mississippi. In the pine-hardwood forest, 98 percent of the acid deposition was neutralized, 50 percent in the forest canopy, and 48 percent in the forest floor. In the pine forest, 75 percent of the acid deposition was neutralized, all in the forest floor. The pine-hardwood ecosystem accumulated sulfate, nitrate, and ammonia ions, and lost base cations. During seasons of deficient precipitation, dry deposition appeared to enrich the concentrations of hydrogen, nitrate, sulfate, and ammonia ions in throughfall samples at both locations.     

THE RHIZOSPHERE ECOLOGY OF SUBMERSED MACROPHYTES1

ABSTRACT: This article, based on a review of the literature, examines several aspects of the rhizosphere ecology of submersed macrophytes. These include the role of the rhizosphere microflora in affecting plant growth through influences on nutrient availability and production of plant growth regulating compounds. Interactions between components of the sediment microflora and plant roots are considered in relation to plant nitrition and growth. Possible applications of this information to the management of submersed macrophytes are considered.     

EFFECTS OF FOREST FERTILIZATION ON STREAM WATER CHEMISTRY IN THE APPALACHIANS1

ABSTRACT: Stream water chemistry was monitored on two watersheds on the Fernow Experimental Forest in north-central West Virginia to determine the effects of forest fertilization on annual nutrient exports. Ammonium nitrate and triple superphosphate were applied simultaneously at rates of 336 kg ha^?1 N and 224 kg ha^?1 P₂O₅, respectively, which are similar to rates used in commercial forest operations. The treatment significantly increased outputs of several ions. Annual outputs of nitrate N increased as much as 18 times over pretreatment levels, and calcium and magnesium increased as much as three times over pretreatment levels the first year after fertilization. Outputs for these nutrients were elevated for all three post-treatment years. Although nitrate N increased significantly, only about 20 percent of the applied fertilizer was accounted for in stream water exports. Outputs of phosphate P declined following fertilization, probably because the watersheds are phosphorus deficient, but by the third year, they slightly exceeded predicted values. Estimated nutrient losses to deep seepage were substantial, especially on the leakier south-facing catchmeat, on which some nutrient losses were equal to or greater than those in stream water. When the nutrient exports associated with both stream discharge and ground water recharge were combined, the percentages of applied N that were lost were similar on the two watersheds, averaging 27.5 percent. Less than 1 percent of the applied P was lost from either watershed in the combination of streamflow and deep seepage.     

ON THE USE OF SEEPAGE METERS TO ESTIMATE GROUNDWATER NUTRIENT LOADING TO LAKES1

Data from a study on East Lake Tohopekaliga, Florida, indicate that the seepage meter measurement method may often overestimate nutrient contributions to lakes. Nutrient loading data from this method and a method employing lakeside piezometer nutrient data and seepage meter flows were not comparable. Seepage nutrient loading from the meter and piezometer methods comprised 39 and 18 percent of the nitrogen budget and 38 and 9 percent of the phosphorus budget, respectively, for East Lake Tohopekaliga. In terms of water, groundwater seepage accounted for only 14 percent of the total input to the lake. It is felt that some of the past studies using the seepage meter method to estimate nutrient loading may be in error due to reasons related to the enclosure of lake sediments by the meter and the accompanying anaerobic conditions which quickly result.     

Integrated economic-ecological analysis and evaluation of management strategies on nutrient abatement in the Rhine basin

Management of river basins involves the making of informed choices about the desired levels of economic activities and ecosystem functioning in the catchment. Information on the economic and ecological effects of measures as well as their spatial distribution is therefore needed. This paper proposes the following instruments to support decision-making in river basins: (1) the linking of models and indicators to describe the economic and ecological effects of management actions and their spatial distribution and (2) an extended evaluation framework that aims to evaluate management actions on three objectives for sustainable river management. These are cost-effectiveness, spatial equity, and environmental quality. This paper illustrates the potential of these instruments for river basin management by a case-study on nutrient management in the Rhine basin. In this case-study four nutrient abatement strategies are formulated, based on policies of the International Commission for the Protection of the Rhine and the North Sea Commission. These strategies are analysed and evaluated on their contribution to the three management objectives. Results show that none of these strategies score highest on cost-effectiveness, spatial equity and environmental quality simultaneously. It appears that cost-effectiveness is in conflict with environmental quality, whereas spatial equity and cost-effectiveness show quite close correspondence. This means that a trade-off has to be made between costs and spatial equity on the one hand, and environmental standards on the other hand. This paper offers a framework to make these trade-offs more explicit and provides quantitative information on cause-effect relationships, economic and environmental effects and the spatial distribution of these effects for various management strategies. This information can be particularly useful in the development of compromises required to establish international agreement and co-operation.