Long-term trends in the chemistry of precipitation and lake water in the Adirondack Region of New York,USA

Long-term changes in the chemistry of precipitation (1978–94) and 16 lakes (1982–94) were investigated in the Adirondack region of New York, USA. Time-series analysis showed that concentrations of SO₄ ^2–, NO₃ ^–, NH₄ ⁺ and basic cations have decreased in precipitation, resulting in increases in pH. A relatively uniform rate of decline in SO₄ ^2– concentrations in lakes across the region (1.81±0.35 eq L^–1 yr^–1) suggests that this change was due to decreases in atmospheric deposition. The decrease in lake SO₄ ^2– was considerably less than the rate of decline anticipated from atmospheric deposition. This discrepancy may be due to release of previously deposited SO₄ ^2– from soil, thereby delaying the recovery of lake water acidity. Despite the marked declines in concentrations of SO₄ ^2– in Adirondack lakes, there has been no systematic increase in pH and ANC. The decline in SO₄ ^2– has corresponded with a near stoichiometric decrease in concentrations of basic cations in low ANC lakes. A pattern of increasing NO₃ ^– concentrations that was evident in lakes across the region during the 1980's has been followed by a period of lower concentrations. Currently there are no significant trends in NO₃ ^– concentrations in Adirondack lakes.     

Determinants of Summer Nitrate Concentration in a Set of Adirondack Lakes,New York

Following reductions in the emission and deposition of sulfur compounds in the past decade, atmospheric deposition of nitrogen has become a focus of concern. Identification of watershed characteristics that mediate the effect of atmospheric nitrogen deposition can help evaluate the sensitivity of lakes to chronic and episodic nitrogen addition. Twenty four lakes in the southwestern portion of the Adirondack Park, New York, U.S.A., were classified into three N classes by cluster analysis of lakewater NO3- N concentration [N] during the summers of 1994–1996. The lake-N classes were best characterized as having (1) low [N] throughout the summer, (2) high [N] in early- but low [N] in late-summer, and (3) high [N] throughout the summer. The three lake-N classes were reconstructed perfectly by canonical discriminant analysis based mainly on lake average depth (AD), and lakewater concentrations of chlorophyll a [Chla] and SO4-S [S] in mid-summer. Increases in AD and [S], but decrease in [Chla] corresponded with a transition from low- to high-N classes.     

Relationship Between Landscape Characteristics,History, and Lakewater Acidification in the Adirondack Mountains,New York

Interactions between acidic deposition and watershed characteristics were evaluated for a group of lakes in the Adirondack Mountains, New York. Landscape characteristics were compiled and examined relative to paleolimnological inferences of historical acidification. Results of estimates of acidification using the Model of Acidification of Groundwater in Catchments (MAGIC) and paleolimnological analysis were compared to physical, biological, and landscape change data, including such factors as watershed disturbance, logging, fire, and windthrow, to evaluate if inclusion of additional processes could improve model estimates. Results of bivariate and multivariate analysis confirmed that lakes that have experienced historical acidification tend to be those that receive relatively high amounts of precipitation and have short hydraulic residence times. These variables explained 58% of the diatom-inferred acidification. A combined model of long-term precipitation amount, hydraulic residence time, and recent blowdown accounted for 71% of the historic acidification in the Adirondacks. Lakes that have increased in pH since pre-industrial times tend to be those subject to substantial human disturbance and those that burned during major fires recorded after 1900. The magnitude of the discrepancy between MAGIC model and diatom-inferred hindcasts of acidification was not significantly correlated with any of the landscape change variables, suggesting that additional modifications to the MAGIC model to take into account landscape change are not likely to appreciably improve model performance.     

A Spatially and Temporally Disaggregated Anthropogenic Emission Inventory in the Southern Balkan Region

ICP Forest Monitoring data collected for more than 10 years made it possible to analyse key factors responsible for changes in forest conditions on a regional European scale. Observation routines may vary between different countries, which makes it difficult to gain more insight into stress-effect relationships. The effects on defoliation of Scots pine (Pinus sylvestris L.) of air concentrations and wet deposition of acidifying compounds, as well as effects of meteorological, site, stand and tree variables were investigated in Lithuania to test the hypothesis that spatial and temporal changes in pine defoliation were closely associated with atmospheric inputs of acidity. Over the period 1994–2004 crown defoliation of more than 8,000 pine trees was monitored in totally 45 stands distributed among three National Parks, where Integrated Monitoring Stations were situated. Air concentrations of SO2, and $ {\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}} $ and $ {\text{NH}}^{{\text{ + }}}_{{\text{4}}} $ deposition, as well as spring and summer precipitation and mean winter temperature were shown to be the key factors affecting defoliation. The acidifying compounds accounted for nearly 58% of the variance in pine defoliation. Meteorological factors increased the degree of explanation to 65%, and stand and site variables to 79%.     

Chemistry differences in two streams entering an acidic lake in the Adirondack Mountains,New York (U.S.A.)

Solution chemistry was measured in two major inlets, lake water column, lake outlet, and soils of the South Lake watershed in the Adirondack Mountains, New York. The east inlet had greater concentrations of H⁺, sulfate-S, and Al and smaller concentrations of base cations and silica than the west inlet (70, 116, 25, 90, 64 and 4, 99, 8, 228, 148 μeq L^?1 of H⁺ and sulfate-S, μmol L^?1 Al, μeq L^?1 total base cations and μmol L^?1 silica in east and west inlets, respectively). Concentrations of base cations in C horizon soil solutions (157 μeq L^?1 total base cations) were smaller and greater than west and east inlets, respectively. This suggests that water flowing into the west inlet contacted deeper mineral layers, whereas water reaching the east inlet did not. Lake and lake outlet concentrations were also intermediate between the two inlets, and the lake was acidic (pH 4.9 to 5.1) with relatively high total monomeric Al concentrations (8 to 9 μmol Al L^?1). The east inlet also had greater DOC concentrations than the west (0.38 and 0.24 μmol C L^?1, respectively), again indicating that soil solutions entering the east inlet passed through the forest floor but had more limited contact with deeper mineral layers in comparison with the west inlet. Differences between the streams are hypothesized to be related to contact of percolating solutions with mineral soil horizons and underlying glacial till, which provides neutralization of acidic solutions and releases base cations. This work indicates that processes controlling surface water acidification can be spatially quite variable over a small watershed.     

An evaluation of New York state lake liming data and the application of models from Scandinavian lakes to Adirondack lakes

Limestone dissolution efficiencies and reacidification rates observed in ten small Adirondack Mountain lakes, treated in 1983 to 1984 as part of the Extensive Liming Study (ELS), were compared with Scandinavian model predictions of dissolution (Sverdrup and Bjerle, 1983), and reacidification (Wright, 1985). The standard deviation of predicted initial dissolution was 15.4% of the observed fraction of limestone dissolved. Model predictions of dissolution for the Scandinavian lakes were similarly within 8 to 14% of observed values. Further analysis of the ELS data indicated that of the dissolution model parameters, dose rate alone was the best predictor of initial dissolution efficiency. Dissolution rates declined exponentially with time to undetectable levels within 2 to 3 yr following treatment. Total limestone dissolution efficiencies were in the range of 17 to 59% for the ELS lakes, which are comparable to levels observed in Scandinavian treatments with similar limestone materials (26 to 64%). Analysis of data from other Adirondack lakes limed by private groups and the New York State Department of Environmental Conservation for fisheries management programs, yielded similar estimates of dissolution efficiency for calcite based materials (average 36%). However, some of these lakes which were treated with slaked lime [Ca(OH)₂], exhibited initial dissolution efficiencies approaching 100%. The simple two box dilution model of reacidification, satisfactorily predicted Ca loss rates in the ELS lakes, indicating the importance of hydrology (water retention time) as a factor controlling reacidification rates in these small, limed lakes. For the ELS lakes, the ratio of watershed area/lake volume satisfactorily predicted Ca loss rates (R² = 0.96) and this simplified empirical model was applied to other Adirondack lakes where inadequate water chemistry and hydrologic data were available to utilize the dilution model. Limed Adirondack lakes with mean water retention times less than 4 mo reacidified within 1 yr after treatment. Given the preponderance of acidified lakes in the Adirondack region with retention times less than this threshold value of 4 mo (approximately 80% of lakes <10 ha surface area), simple whole lake liming practices would not be adequate for maintaining water quality suitable for the support of viable fish populations in these lakes.     

宁南山区土地利用规划模式及效益监测

通过对宁夏南部山区固原县上黄村土地利用中存在问题的调查分析，拟定了该村土地资源合理利用的总体构思，农林牧优化配置方案及实施技术，经过１３年的实践和监测，获得了极高的可信度与显的生态经济效益，同时，对黄土丘陵西部半干旱地区土地资源的合理利用与高效持续农业的发展提出了见解。     

黄淮海平原缺水盐渍区农业持续与生态系统研究

针对试验区的自然经济条件经研究农业持续途径，历经12年，建设了农林果草多元生态经济结构，形成了一套水土资源管理、机械化的农林作物栽培、农区畜牧业发展的技术，提高了农业生态系统抗灾能力，改变了中低产面貌，农民生活走向富裕。     

Transformation of Nitrogen Compounds in Soils of Mountain Tundra Ecosystems in the Khibiny

Eurasian Soil Science - The content of nitrogen compounds and processes of nitrogen mineralization and nitrification were studied in the soils of four tundra ecosystems in the Khibiny Mountains....     

A Comparison of Cadmium in Ecosystems on Metalliferous Mine Tailings in Wales and Ireland

A comparative study of the concentrations of cadmium in ecosystems developed on tailings from lead/zinc mines was undertaken. Mine soils, vegetation, ground-dwelling invertebrates and Apodemus sylvaticus from nine historic and abandoned mines in Wales and a modern Irish mine site were sampled in order to evaluate and compare exposure risks to wildlife. There were three high soil cadmium sites (155–300 mg kg^-1) all from north-east Wales sites, one intermediate site (21 mg kg^-1) the Irish mine tailings, with the other sites having low (background) cadmium levels. The cadmium levels reflected differencesin ore minerology and in particular the presence of the zinc ore, sphalerite. The highest plant and invertebrate cadmium levels generally occurred in the three high soil cadmium sites. However, occasional high levels were found in plant and invertebrate samples from one or more of the low cadmium sites. Of particular significance was, despite the relatively high soil cadmium, the very low cadmium concentrations in the plants and invertebrates from the Irish tailings. Evidence of food-chain transfer and even biomagnification in invertebrates did not lead to high cadmium levels in kidneys of A. sylvaticus. Onlyat one high site were the kidney cadmium residues significantly higher than the reference site.     

Long-Term Acid Load and its Consequences in Forest Ecosystems of Saxony (Germany)

Between 1993 and 1995 a system of six intensive monitoring stations in representative stands of Norway spruce (Picea abies), sessile oak (Quercus robur) and Scots pine (Pinus sylvestris) were installed in forests of Saxony (Germany), they are integrated in the European Level II - Programme. As a complementary system, and in addition to the annual nation-wide forest decline survey, 280 sites within the forest soil condition survey (European Level I - Programme) have been examined since 1992. The results of deposition monitoring show that until 1997 the acidity in precipitation and troughfall still was very high, despite of strong reductions in industrial emissions between 1989 and 1992. The annual fluxes (hydrological year 1996) of sulphur in throughfall ranged between 16 and 77 kg-ha^-1, whereas the fluxes of total inorganic N varied between 17 and 46 kg-ha^-1. The forest soils show high degrees of acidification with only low base saturation. In most cases the nutrient status of the soils has to be improved in the course of a regeneration programme in order to rebuild more natural forest ecosystems.     

红壤丘岗区林草生态系统土壤水分状况

在红壤丘岗区自然次生马尾松-草灌植被基础上,组建4种林草生态系统,长期观测结果表明,各生态系统地表径流量逐年减少,而入渗量和渗漏量逐年增加,径流量呈现阔叶林和混交林<马尾松林<自然草被,渗漏量则相反。阔叶林和混交林与马尾松林和自然草被比较,前者径流量年内分布在雨季更加集中,这正是不同林草生态系统涵养水源能力不同的体现。干旱季节4种林草系统土壤剖面水分分布有差别,阔叶林和混交林上下层土壤水吸力差别较小,而马尾松林和自然草被上下层土壤水吸力差别较大,前者土壤导水能力好而后者导水能力差是原因之一;阔叶林和混交林下层土壤水分含量比马尾松林和自然草被低。     

浅谈贵州峰丛山地地区土地石漠化及其治理

贵州是我国石漠化分布中心地区之一 ,其喀斯特地貌的代表是峰丛山地 ,分布面积约占 2 0 %。该地区特殊的地形地貌、土壤、植被、降雨、气象和水文条件易形成石漠化 ,使水土流失加剧、自然灾害频繁、人类生存环境恶化。贵州峰丛山地地区石漠化防治要遵循自然规律、改善资源开发条件 ,综合治理、发展山区经济 ,搞好配套措施、开发山区资源 ,加快群众的脱贫致富步伐     

新疆天山地区管道工程水工保护径流调控新模式

近几年水土流失造成管道工程的水毁灾害频发,建设管道工程水毁灾害防控体系,对维护和保障管道工程安全具有十分重要的意义。以新疆天山地区为例,针对山地亚区和平原亚区两个典型地貌单元的三种管道敷设类型,分析了管道工程水土流失的成因,提出了山地坡面管道横坡敷设时采取的上截下拦模式、纵坡敷设时采取的侧排中挡模式、戈壁冲积扇采取的以挡为主,以导为辅模式、河沟道采取防冲护岸模式4种相应的水工保护径流调控模式,以期为该地区管道工程的安全建设和运营提供水土保持技术保障。     

三江源地区林草生态系统水源涵养服务评估

[目的]分析青海省三江源地区生态工程实施前后生态系统水源涵养服务的变化情况,客观评估生态工程的效果。[方法]采用降水贮存量法估算三江源地区林草生态系统的水源涵养量。[结果]1997—2012年三江源地区林草生态系统水源涵养服务在波动中有所提升,平均水源涵养量为1.54×1010m~3/a,单位面积水源涵养量为430.67m~3/hm~2。三江源生态保护与建设工程实施后(2005—2012年)林草生态系统年平均水源涵养量比前期(1997—2004年)增加了15.60%。从空间格局而言,三江源地区林草生态系统涵养水源能力自东南向西北逐渐递减。单位面积水源涵养量澜沧江流域最高,其次为黄河流域,长江流域最低。真实气候条件和平均气候状况下,生态工程实施后的区域林草生态系统水源涵养量均比前期高。前期主要受到区域气候变化的影响,后期则叠加了生态工程的驱动作用。两种情况下,生态工程实施后三江源地区林草生态系统水源涵养量的线性变化趋势分别为1.94×10~9和4.64×10~8 m~3/10a。[结论]生态工程对三江源地区水源涵养服务提升的贡献率约为23.98%。     

Assessment of the Extent to Which Intensively-studied Lakes are Representative of the Adirondack Region and Response to Future Changes in Acidic Deposition

Many lakes in the Adirondack Mountains, New York, have acidified over the past century due to acidic atmospheric deposition. More recently, most monitored lakes have shown signs of chemical recovery (increase in acid neutralizing capacity) as sulfur deposition levels have declined in response to the Clean Air Act and other emissions control legislation. We used measured and modeled trends in past lakewater acidification and projections of future recovery from acidification to extrapolate results from judgment samples of intensively studied lakes to the population of acid-sensitive Adirondack lakes. Simulations were developed for 70 watersheds using the Model of Acidification of Groundwater in Catchments (MAGIC) to classify lakes according to their sensitivity to change in atmospheric S and N deposition. MAGIC simulations suggested that the modeled Adirondack Long-Term Monitoring Project (ALTM) and Adirondack Effects Assessment Project (AEAP) lakes were largely among the lakes in the population that had acidified most between 1850 and 1990. Most of the modeled ALTM/AEAP lakes were within the top 36% of acid sensitivity, based on model projections of past acidification and future chemical recovery, compared with the 1,829 Adirondack lakes in EPA’s Environmental Monitoring and Assessment Program (EMAP) statistical frame. Results of this research will allow fuller utilization of data from on-going chemical and biological monitoring and process-level studies by providing a basis for regionalization of findings and developing/refining relationships among watershed characteristics, chemical change, and biological responses to changing levels of acidic deposition.     

Comparison of Long-Term Precipitation Chemistry Measurements at the Hubbard Brook Experimental Forest,New Hampshire

From 1978 through 1989, a wet-onlyprecipitation collector operated for the NationalAtmospheric Deposition Program, an independantwet-only collector, and a bulk precipitation collectorwere co-located at the Hubbard Brook ExperimentalForest (HBEF) in central New Hampshire. A secondbulk precipitation collector was maintained at anotherlocation within the HBEF. There were statisticallysignificant differences between the chemistry fromco-located wet-only collections for Ca²⁺,K⁺, NH₄ ⁺, pH, and NO₃ ^-. Thedifferences for K⁺ and pH though statisticallysignificant were very small but consistant. Thedifferences for Ca²⁺ were related to earlycontamination problems, and differences inNH₄ ⁺ and NO₃ ^- were related toepisotic events. Bulk precipitation was significantlyricher in K⁺ than wet-only precipitation. Therewere no differences for any ions between the bulkcollections at the two locations. While there wereminor differences, after 1981 when the contaminationproblems had been resolved, data from all collectorsat all locations adequately characterized theprecipitation chemistry of the site.     

东北寒温带永久冻土区森林沼泽湿地生态系统碳储量

摘 要 湿地在全球碳循环中具有重要作用,但目前湿地碳储量估算仍存在诸多不确定性。利用相对生长方程与碳/氮分析仪测定法,同步测定寒温带大兴安岭永久冻土区沿过渡带环境梯度依次分布的7种典型天然沼泽类型(草丛沼泽-C、灌丛沼泽-G、毛赤杨沼泽-M、白桦沼泽-B和落叶松苔草沼泽-LT、落叶松藓类沼泽-LX、落叶松泥炭藓沼泽-LN)的生态系统碳储量(植被和土壤)、植被净初级生产力与年净固碳量,定量评价各沼泽类型的生态系统碳库及植被固碳能力,并揭示两者沿过渡带环境梯度的空间分布规律性。结果表明：①其植被碳储量(3.60~62.18 t·hm-2)沿过渡带环境梯度呈先上升后降低的偏态型分布趋势;②土壤碳储量(179.47~320.81 t·hm-2)呈森林沼泽(M除外)与灌丛沼泽显著高于C (56.4%~78.8%,P<0.05)和M (32.0%~50.9%,P<0.05)的变化规律性;③生态系统碳储量(183.07~347.14 t·hm-2)也呈现森林沼泽(M除外)与灌丛沼泽显著高于C (64.0%~89.6%,P<0.05)和M (28.1%~48.1%,P<0.05)的变化规律性,但森林沼泽土壤碳储量占比(82.1%~96.4%)要低于C和G (98.0%~98.3%);④植被净初级生产力(6.76~11.22 t·hm-2·a-1)和年净固碳量(2.97~5.37 t·hm-2·a-1)均呈现森林沼泽(LN除外)显著高于C和G (26.9%~61.4%和30.5%~66.0%;38.6%~77.2%和41.4%~80.8%,P<0.05)的变化规律性。因此,寒温带永久冻土区各类型沼泽湿地的生态系统碳储量均相对较低(仅相当于北方泥炭地碳储量(390~1 395 t·hm-2)下限值的46.9%~89.0%),且沿过渡带环境梯度总体上呈递增趋势;森林沼泽(LN除外)的植被固碳能力强于灌丛沼泽与草丛沼泽,且前者略高于全球陆地植被年均净固碳量估计值(4.1 t·hm-2·a-1),而后两者仅相当于其3/4。