Recent Changes in Soil Total Phosphorus in the Everglades: Water Conservation Area 3

We assessed recent changes in the distribution of soil total phosphorus (TP) in Water Conservation Area 3 (WCA-3) of the Everglades. Soil cores were collected in 1992 and 2003 at 176 sites. To reflect hydrologic boundaries within the system, WCA-3 was divided into three zones (3AN, 3AS, and 3B). Total P was mapped on both a mass (TPm) and a volumetric basis (TPv) to determine if spatial distributions varied depending on the choice of units. Interpolated maps for both years showed that the highest levels of TPm were located in 3AN and in boundary areas of all zones that received surface water inputs of P from canals. Increases in TPm were greatest in central 3AN in an area adjacent to the Miami Canal that received inputs from a water control structure. Interpolated maps for TPv illustrated that a hotspot present in 1992 had disappeared by 2003. The highest levels of TPv in 2003 were located in northwestern 3AN, a region of WCA-3 that has been chronically overdrained and burned in 1999. From 1992 to 2003, increases in TPm were observed for 53% of the area of WCA-3, while only 16% of WCA-3 exhibited increases in TPv. In 1992, approximately 21% of WCA-3 had TPm concentrations in the 0–10 cm layer >500 mg kg⁻¹, indicating P enrichment beyond historic levels. Eleven years later, 30% of the area of WCA-3 had TPm >500 mg kg⁻¹. This indicated that during this period, the area of WCA-3 with enriched TPm concentrations increased about one % year⁻¹.     

Controls on Mercury and Methylmercury Deposition for Two Watersheds in Acadia National Park, Maine

Throughfall and bulk precipitation samples were collected for two watersheds at Acadia National Park, Maine, from 3 May to 16 November 2000, to determine which landscape factors affected mercury (Hg) deposition. One of these watersheds, Cadillac Brook, burned in 1947, providing a natural experimental design to study the effects of forest type on deposition to forested watersheds. Sites that face southwest received the highest Hg deposition, which may be due to the interception of cross-continental movement of contaminated air masses. Sites covered with softwood vegetation also received higher Hg deposition than other vegetation types because of the higher scavenging efficiency of the canopy structure. Methyl mercury (MeHg) deposition was not affected by these factors. Hg deposition, as bulk precipitation and throughfall was lower in Cadillac Brook watershed (burned) than in Hadlock Brook watershed (unburned) because of vegetation type and watershed aspect. Hg and MeHg inputs were weighted by season and vegetation type because these two factors had the most influence on deposition. Hg volatilization was not determined. The total Hg deposition via throughfall and bulk precipitation was 9.4 μg/m²/year in Cadillac Brook watershed and 10.2 μg/m²/year in Hadlock Brook watershed. The total MeHg deposition via throughfall and bulk precipitation was 0.05 μg/m²/year in Cadillac Brook watershed and 0.10 μg/m²/year in Hadlock Brook watershed.     

Landscape Controls on Mercury in Streamwater at Acadia National Park, USA

Fall and spring streamwater samples were analyzed for total mercury (Hg) and major ions from 47 locations on Mount Desert Island in Maine. Samples were collected in zones that were burned in a major wildfire in 1947 and in zones that were not burned. We hypothesized that Hg concentrations in streamwater would be higher from unburned sites than burned watersheds, because fire would volatilize stored Hg. The Hg concentrations, based on burn history, were not statistically distinct. However, significant statistical associations were noted between Hg and the amount of wetlands in the drainage systems and with streamwater dissolved organic carbon (DOC). An unexpected result was that wetlands mobilized more Hg by generating more DOC in total, but upland DOC was more efficient at transporting Hg because it transports more Hg per unit DOC. Mercury concentrations were higher in samples collected at lower elevations. Mercury was positively correlated with relative discharge, although this effect was not distinguished from the DOC association. In this research, sample site elevation and the presence of upstream wetlands and their associated DOC affected Hg concentrations more strongly than burn history.     

Mass Balances of Mercury and Nitrogen in Burned and Unburned Forested Watersheds at Acadia National Park, Maine, USA

Precipitation and streamwater samples were collected from 16 November 1999 to 17 November 2000 in two watersheds at Acadia National Park, Maine, and analyzed for mercury (Hg) and dissolved inorganic nitrogen (DIN, nitrate plus ammonium). Cadillac Brook watershed burned in a 1947 fire that destroyed vegetation and soil organic matter. We hypothesized that Hg deposition would be higher at Hadlock Brook (the reference watershed, 10.2 μg/m²/year) than Cadillac (9.4 μg/m²/year) because of the greater scavenging efficiency of the softwood vegetation in Hadlock. We also hypothesized the Hg and DIN export from Cadillac Brook would be lower than Hadlock Brook because of elemental volatilization during the fire, along with subsequently lower rates of atmospheric deposition in a watershed with abundant bare soil and bedrock, and regenerating vegetation. Consistent with these hypotheses, Hg export was lower from Cadillac Brook watershed (0.4 μg/m²/year) than from Hadlock Brook watershed (1.3 μg/m²/year). DIN export from Cadillac Brook (11.5 eq/ha/year) was lower than Hadlock Brook (92.5 eq/ha/year). These data show that ∼50 years following a wildfire there was lower atmospheric deposition due to changes in forest species composition, lower soil pools, and greater ecosystem retention for both Hg and DIN.     

滇池湖滨带生态湿地建设中的土地利用问题探析

随着城市建设不断地向湖滨区扩展,滇池原有的湖滨带被大量用于建设各类建筑物,原有的湖滨带几乎失之殆尽,为保护及修复滇池湖滨完整的生态系统,实施湖滨生态湿地建设工程显得尤为重要,而征地工作难度很大,甚至成为制约湖滨生态带建设工程顺利实施的关键因素之一。本文指出征地工作难度大的主要原因是缺乏征地拆迁补偿标准、拆迁安置费用较高,引起的社会问题复杂等,并提出应采取编制规划控制土地的无序开发、调整农业产业结构、建立新型的征地补偿制度以及妥善安置失地农民等对策措施及建议。     

TROPHIC STATE EVALUATION FOR SELECTED LAKES IN GRAND TETON NATIONAL PARK1

ABSTRACT: Increased visitation at Grand Teton National Park (GTNP) has raised concerns about impacts on surface water in the park. The purposes of this study are to perform a benchmark trophic state survey for comparison to future evaluations and to identify possible areas of concern. Four watershed regions based on geographic and geologic features were delineated for study. Six Alpine lakes, six Moraine lakes, three Valley lakes, and two Colter Bay lakes are evaluated. Lakes were sampled for total phosphorus (TP), chlorophyll‐a, and transparency. The water quality, as defined by trophic state, in the park is generally good. Oligotrophic to mesotrophic conditions were found in the Alpine and Moraine lakes and mesotrophic to eutrophic conditions were found in the Colter Bay and Valley lakes. High inflow TP concentrations in the park's northeast side may be due to the presence of natural geologic phosphate from the Phosphoria Formation.     

扎龙河滨湿地对地表径流氮磷污染物的净化作用

通过对扎龙河滨湿地内龙安桥及水库桥河段水体空间采样分析,研究了2个典型河滨湿地对地表径流中TN、TP及PO₄^3-的净化作用规律.应用空间净化方程分析表明,2个河段河滨湿地在春、夏、秋3季对水体TP及PO₄^3-有持续净化能力,TP净化系数范围为0.00186～0.01175mg·(L·km)^-1 ,PO₄^2-净化系数范围为2.5E 4～0.00704mg·(L·km)^-1.而河滨湿地对TN的净化作用仅出现在春、夏2季,且夏季净化作用最明显,净化系数达0.07354～0.16036mg·(L·km)^-1;在秋季则出现TN沿径流向下累积输出的特征,输出能力最高达0.48175mg·(L·km)^-1.2河段的径流量及氮磷污染物输入浓度特征分析表明了河滨湿地对水体TN、TP及PO₄^2-的净化作用受到这2种因素的综合影响而表现出季节性规律特征.     

典型化工园区民众对生态恢复的参与研究

通过问卷探讨泰兴化工园区民众对生态恢复的认知度和参与度,分析民众参与生态恢复的影响因素.研究发现:园区民众生态恢复意识处于政府依赖型,忽视科研部门的指导作用;性别、年龄、文化程度和职业是影响民众生态恢复认知、诉求意愿与途径的主要因素,此外,民众对生态恢复的参与深度虽受年龄、文化程度、职业和当地居住时间的影响,但与性别和...     

重金属钼的迁移特性及人工湿地处理研究

针对重金属钼污染的面源性及重金属传统处理工艺的一些弊端,综合国内外人工湿地治理重金属污染研究现状,提出了用人工湿地治理重金属钼污染的构思。环境中重金属钼主要来源于钼尾矿中辉钼矿的氧化而淋滤释放的MoO42-。由于土壤和水体中酸碱和氧化还原环境的差异,钼的存在形态具有易变特征,并影响着钼的迁移过程。基于钼迁移特征的研究成果,本文从植物、基质、微生物三方面对人工湿地处理钼污染进行了系统的分析。结论表明,人工湿地处理重金属钼具有一定的应用价值,为我国人工湿地治理重金属钼污染的研究开展以及实际工程应用提供理论支持。     

黄河三角洲湿地研究进展

从湿地研究内容和研究方法两方面,回顾了近10年来黄河三角洲湿地研究的成果。在这10年间,黄河三角洲湿地研究的内容和范围明显拓宽,主要研究内容包括湿地修复、湿地评价、湿地管理等。研究方法日趋先进成熟,模型模拟、遥感动态监测及3S等新技术和方法得到广泛应用。文章在分析黄河三角洲湿地的研究现状和特点的基础上,对未来研究趋势和热点进行了展望,认为未来黄河三角洲湿地的研究重点应在湿地演化机制与恢复、湿地对环境变化的响应与反馈、湿地动态监测、湿地保护技术等方面。