浅析西京古道沿线客家村落的风水林塘体系

风水林和风水塘是粤北客家古村落重点经营的典型风水要素,不仅能反映粤北地区的乡土自然资源,还与区域内人们的民俗风情、文化信仰息息相关。以西京古道(乳源段)客家村落为研究对象,通过实地调研,分析人工式和自然式风水塘,以及风水林中村口林和龙座林的特征和功能,最终揭示风水林塘体系对区域小气候调节的作用,反映客家村落与自然间的和合关系和人与自然和谐相处的生态智慧,以此说明风水林塘文化复兴在西京古道活化利用中颇具意义。     

版纳甜龙竹笋早发多发技术措施试验

对云南省勐海县竹类科技园的版纳甜龙竹笋用林进行4因素3水平正交试验L9(34),即施肥、晒塘、覆盖、断顶4种处理,每种处理3个水平。结果表明,施肥可明显提高竹笋总产量,达到极显著差异;晒塘、覆盖和断顶都能明显提高提前发笋产量,达到显著或极显著差异;施肥、晒塘和覆盖都能提高经济效益,而断顶对提高经济效益没有达到显著差异。版纳甜龙竹笋早发多发技术措施最优组合为在春节后对竹篼晒塘30天,原表土恢复后,再用砻糠覆盖20cm厚,在10中旬施底肥(农家肥),3月中旬施第一次追肥(尿素+复合肥),6月中旬施第二次追肥(尿素+复合肥),能明显提高其发笋总产量、提前发笋产量和经济效益。     

Effects of Rice-Fish Co-culture on Oxygen Consumption in Intensive Aquaculture Pond

Rice-fish co-culture has gained increasing attention to remediate the negative environmental impacts induced by intensive aquaculture. However, the effect of rice-fish co-culture on oxygen depletion has rarely been investigated. We constructed a rice-fish co-culture system in yellow catfish (Pelteobagrus fulvidraco) and freshwater shrimp (Macrobrachium nipponense) ponds using a new high-stalk rice variety, and conducted a field experiment to investigate the effect of rice-fish co-culture on water parameters and oxygen consumption. The results showed that rice-fish co-culture reduced the nutrients (total nitrogen, ammonia-N, total phosphorous and potassium) and the dissolved oxygen content in fish and shrimp ponds. However, they showed similar seasonal change of dissolved oxygen in the water of fish and shrimp ponds. Rice-fish co-culture reduced the total amount of oxygen consumption and optimized the oxygen consumption structure in pond. The respiration rates in water and sediment were significantly reduced by 66.1% and 31.7% in the catfish pond, and 64.4% and 38.7% in the shrimp pond, respectively, by additional rice cultivation. Rice-fish co-culture decreased the proportions of respiration in sediment and water, and increased the proportion of fish respiration. These results suggest that rice-fish co-culture is an efficient way to reduce hypoxia in intensive culture pond.     

基于Gamma-χ~2分布的混油拖尾现象预测

混油拖尾现象与批次跟踪的准确性、调度计划的可靠性、切割方案的经济性密切相关,准确描述混油拖尾现象对控制混油量、预测油品质量指标十分重要。分析了混油拖尾曲线的变化规律,建立了混油界面非对称分布的模拟模型。基于混油界面检测数据得到混油等效密度分布特点及其梯度变化规律,分别利用Gamma、Gamma-χ~2分布函数逼近混油等效密度梯度变化曲线。通过编程模拟分布函数,近而反演出分布函数中的关键参数后,得到混油等效密度的分布曲线。基于此,分析不同边界条件和运行工况下管道系统各参数与等效密度分布函数参数的关系,得到拟合公式,进一步利用部分数据预测完整混油等效密度分布曲线,以实现等效密度曲线的实时在线预测,为顺序输送混油量预测和油品切割提供有效指导。     

Zn and Pb release of sphalerite (ZnS)-bearing mine waste tailings

Background, aim, and scope  Contaminated mine drainage water has become a major hydrogeological and geochemical problem. Release of soluble metal contaminants and acidity from mining sites can pose serious chemical risks to surface and groundwater in the surrounding environment, and it is an important socio-economic factor addressed by working groups like SUITMA Morel and Heinrich (J Soils Sediments 8:206–207, 2008). The release of Zn and Pb from sulfide-bearing flotation residues of a small scale mine in Western Germany is investigated with focus on metal transfer to soil solution. Total contents of the soil material as well as soil water sampled with suction cups were analyzed. The influence of pH on leaching behavior was investigated with pH_stat tests. Isotopic analyses helped assessing seepage water velocity. The aim of this study was the assessment of the environmental behavior of zinc and lead caused by the weathering of sulfide-bearing mine tailings. Especially, we address in this paper the dissolution of sphalerite (ZnS) in contrast to the well-known dissolution processes of pyrite (FeS₂). Materials and methods  Total metal contents of the soil samples were analyzed by energy-dispersive X-ray fluorescence spectroscopy, total C concentration was measured using a CHNS elemental analyzer. X-ray diffraction (XRD) spectra were recorded from powdered soil samples. Soil water was sampled in nylon suction cups. Electrical conductivity (EC), pH, and temperature of the soil water samples were measured in the field immediately after sampling. Major anions (F, Cl, NO₂, NO₃, SO₄) were analyzed by ion chromatography, major cations (Ca, Na, K, Li) were analyzed by flame photometry, heavy metals (Zn, Pb, Fe, Mn, and Mg) by flame atomic absorption spectrometry. Tritium was analyzed by liquid scintillation counting (LSC), ¹⁸O and ²H were analyzed by isotope ratio mass spectrometry (IRMS). pH_stat tests were performed at four different pH values between 2 and 5. Results  Total Zn contents of the soil samples averaged 10 g kg⁻¹, Pb contents averaged 2.5 g kg⁻¹, Fe 22 g kg⁻¹, S 8.0 g kg⁻¹, and total carbon 4.0 g kg⁻¹. Below 2-m depth, soil samples had neutral pH values. Toward the surface, pH decreased down to pH 5.4 in P1 and P3, and to pH 5.9 in core P2, respectively. Dissolved contents of major ions (Mg, Ca, K, SO₄, and HCO₃) in the soil solution increased with depth. Metal concentrations (Fe, Mn, Zn) decreased with depth. The solution pH was neutral to slightly alkaline in samples below 2 m and slightly acidic (pH 6) at 1 m depth. Tritium values are around 7 TU and correspond to modern rain, i.e., after 1975. Stable isotope values plot on the global meteoric water line. The pH_stat tests provide two kinds of information, the acid neutralization capacity after 24 h (ANC24) and the release of metals depending on pH. The ANC24 increases linearly with decreasing pH from about 60 mmol(eq) kg⁻¹ at pH 5 to about 460 mmol(eq) kg⁻¹ at pH 2. Zn and Fe release show a strong increase with decreasing pH to 126 and 142 mmol(eq) kg⁻¹, respectively. Pb release increases at pH <4 and Mn release at pH <5, both to about 10 mmol(eq) kg⁻¹. Discussion  With an average of 10 g kg⁻¹, this field site is highly enriched in Zn. In the oxidized topsoil, Zn concentrations are significantly lower than in the anoxic subsoil. The distribution pattern of total Zn contents and soil pH values indicate that the topsoil, which is prone to oxidation and acidification, is already depleted in Zn. Only in soil core P2, Zn (and Fe) contents in the topsoil were higher than in the subsoil. Oxidation of the sulfidic material leads to redistribution into mobilizable species. High soil water concentrations (10 to 15 mg L⁻¹) can be found at acidic pH. The dominant Zn species in the soil solution is Zn²⁺. At neutral pH, Zn concentrations are below 0.001 mg L⁻¹. During the soil passage, the contaminated seepage water enters the anoxic subsoil with pH buffering carbonates. Results indicate that Zn is immobilized there. However, when the acid neutralization capacity is exhausted, a breakthrough of dissolved Zn to the groundwater has to be expected. Lead averages 2.5 g kg⁻¹ inside the flotation dump. In contrast to Zn, the first centimeters of the oxidized topsoil with high TOC contents show higher Pb contents than the anoxic subsoil. About 80% of the cation exchange capacity in the topsoil is occupied by Pb. In contrast to Zn, Pb is not abundant as aqueous species at slightly acidic pH. Values lower than pH 4 are necessary to mobilize Pb in higher amounts, as pH_stat experiments confirm. Hence, Pb is not expected to be leached out until the buffer capacity of the soil is exhausted. Conclusions  The environmental fate and behavior of Zn and Pb in the flotation dump is strongly depending on pH and redox conditions. Oxidation of sphalerite leads to a transfer of Zn from immobile to easily mobilizable species. Sulfide oxidation leads to an acidification of the topsoil where the buffer capacity is already exhausted due to the leaching of carbonates. At acidic pH, Zn is transferred to the aqueous phase and leached to the subsoil where soil pH is neutral. Electron supply and the buffer capacity of the material are found to be the main factors controlling the mobility of Zn. In contrast, the transfer of comparable amounts of Pb to the aqueous phase requires pH values <4. Since Pb is enriched in the topsoil, not leaching to the groundwater, but direct uptake (e.g., children, animals) and uptake by plants is the highest environmental risk. If the acidification of the soil proceeds with the same rate as in the last 40 years, it will reach the bottom of the tailing in about 200 years and a breakthrough of metals to the groundwater has to be expected. Recommendations and perspectives  The behavior of the different metals and their environmental impact depends on the different metal properties as well as on external conditions, e.g. pH, redox conditions, buffer capacity, and groundwater recharge. To assess the future release of metals from a flotation dump it is crucial to determine the main processes leading to acidification, the buffer capacity, and heavy metal binding forms. The release of heavy metals to the groundwater could be prevented by liming or other buffering techniques de Andrade et al. (J Soils Sediments 8:123–129, 2008). Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Chemical and organic immobilization treatments for reducing phytoavailability of heavy metals in copper‐mine tailings

This study was conducted to evaluate the efficiency of diammonium phosphate (DAP), agricultural limestone (lime), and green‐waste compost mixed with 30% treated sewage sludge (GCS) applied alone or in combination as chemical immobilization treatment using tomato as a test crop. Mine waste was collected from an abandoned copper‐mine tailing site at Mynydd Parys, Anglesey (UK). Lime was applied at the rate of CaCO₃ equivalent (CCE, pH = 7), DAP at the rate of 23 g P per kg substrate, and 10% by weight, GCS as sole application. Half rate of each amendment was also tested as a combined treatment and an untreated substrate (control). Plant‐available metals (Cd, Cu, Fe, Pb, and Zn) were measured in substrate with conventional diethylenetriaminepentaacetic acid (DTPA) and sequential Ca(NO₃)₂ extraction. Plant–dry biomass yield was significantly (p < 0.001) increased by the combined application of all the three amendments while sole application of DAP reduced yield by 4‐fold compared to unamended soil probably due to P toxicity. Addition of lime reduced the DTPA‐extractable Cu, Fe, and Zn by 75%, 81%, and 85%, respectively, while Pb availability was reduced by 88% in combined DAP + lime + GCS treatment compared to control. The extraction capacity of DTPA was higher than that of Ca(NO₃)₂ by 3‐fold for Cu and Fe, 8‐fold for Pb, and 2‐fold for Zn. The leaf‐tissue concentrations of Cu and Fe were reduced by 77% and 83% in the lime + GCS amendment, respectively, while both Pb and Zn were reduced by 89% and 33%, respectively, in substrate treated with the combined application of all three amendments. These results suggest that alkaline amendments (both lime and GCS) were effective in reducing the phytoavailability of Cu, Fe, and Zn while DAP mixed with either GCS or lime was effective in reducing Pb availability.     

古菌群落视角评估某退役铀尾矿库的治理效果

为了尝试从微生态－古菌群落视角,评估中国西北某铀尾矿库退役治理效果,本研究在前期尾矿库表层覆土0~5 cm和5~15 cm两个垂向剖面放射性核素、重金属/类金属分布特征研究的基础上,通过16S rRNA基因扩增子测序技术对土壤古菌群落进行测序分析,采用生物信息学方法研究铀尾矿库及毗邻区域土壤古菌群落特征及其对环境因子的响应。结果表明：在尾矿库与毗邻区域,尽管土壤中4个优势菌门和3个优势属呈现不均匀分布,但尾矿库内外土壤古菌优势群落结构基本已无显著差异;土壤古菌群落的α多样性（Chao1、ACE和Shannon指数）和β多样性（PCoA）分析显示群落间已不存在差异,群落组成已具有相似性;冗余分析结果表明,土壤pH、TN（总氮）、TOC（总有机碳）、²³²Th、EC（电导率）是影响优势菌群的主要环境因子,但并未造成库区内外土壤菌群结构的显著改变。尾矿库与毗邻区域的土壤古菌群落已无明显差异,说明尾矿库内外土壤古菌群落并未受到放射性核素、重金属/类金属的显著影响,反映出尾矿库退役治理效果良好。     

基于Ecopath模型的海水池塘主要养殖模式比较分析

为了揭示温台地区海水池塘不同养殖模式间的物质流动规律,以贝类单养和虾贝综合养殖两种模式的海水池塘为研究对象,基于 EWE 6.5软件分别构建了14和15个功能组的Ecopath模型。分析结果显示,综合养殖模式第I、Ⅱ营养级之间物质传输效率（52.1%）高于贝类单养模式（26.5%）,同时其碎屑组的物质流通量占比（20.81%）也高于贝类单养模式（4.65%）。与贝类单养模式相比,综合养殖模式关键种从大型浮游动物转为南美白对虾,混合营养效益分析显示虾功能组主要对浮游生物和碎屑产生影响,导致浮游动物生态营养学效率（EE值）升高,浮游植物EE值降低,而两种模式中贝类功能组混合营养效益未发生明显改变。贝类单养和虾贝综合养殖模式的Finn’s循环指数分别为2.75%、13.21%,系统连接指数分别为0.256、0.25,杂食指数分别为0.049、0.065,这表明由于综合养殖模式具有更完善的食物网,整体结构要优于单养模式,但两种模式整体成熟度和稳定性均较低,存在较大提升空间,可引入新功能组,以进一步提高系统稳定性、饵料利用率以及养殖效益。     

池塘养殖条件下当年口虾蛄生长特性的研究

为了了解口虾蛄在池塘养殖条件下的生长规律,并为其规模化生产提供科学依据。在水温15℃~31℃条件下,通过测量体重、体长等指标,对当年口虾蛄的生长特性进行了研究。结果表明:（1）30日龄口虾蛄经100天培育后,体长从(8.20 ± 0.45)cm增至(11.79 ± 0.67)cm,日均增长0.036 cm,体重从(7.14 ± 1.17)g增至(20.54 ± 3.44)g,日均增重0.134 g。（2）当年口虾蛄的体重与体长的拟合方程为W=0.016L^2.879(R²=0.978),其b值接近于3;体长、体重与养殖日龄的最佳方程均为指数函数。（3）当年口虾蛄的肥满度在30日龄时最高,90日龄最低,肥满度与养殖水温没有明显相关关系;在水温23℃以上时,口虾蛄的瞬时增长率、瞬时增重率指标逐渐升高并在90日龄达到最大值。综上所述,口虾蛄在池塘养殖条件下生长效果良好,其体长与体重的生长基本同步,适宜进行规模化人工养殖。     

城市池塘水质时间变化特性--以扬州大学江阳路南校区池塘为例

城市中的池塘是城市水体的重要组成部分,为揭示城市化背景下池塘水体水质的时间变化特性,选取扬州大学江阳路南校区池塘为研究区,对该池塘2018年7月至2019年6月的水质参数蓝绿藻浓度(Phyco)、水温(WT)、溶解氧(DO)、pH与电导率(EC)进行观测,采用变异系数法、单因子水质标识指数法以及多元线性回归法对各参数的变化特性进行评价。结果显示:池塘WT呈季节性变化;观测期间pH变化范围为7.74~9.98,水体呈碱性;DO变化的随机性较强,未表现出明显变化规律;各水质参数变异性及权重从大到小依次为WT>DO>EC>pH;以DO为指标的单因子水质标识指数结果表明:池塘DO达到Ⅲ类水要求的时段占总观测时段的84%;多元线性回归分析结果表明:DO与WT、pH呈正相关,与Phyco呈负相关,Phyco及pH的变化对DO浓度的影响相对于WT大。