共查询到18条相似文献，搜索用时 328 毫秒
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在文献资料分析研究的基础上,针对武汉东湖生态质量下降、水污染严重等问题,详细论述了国内对东湖湖泊水资源环境进行的水质污染成因调查、富营养化状况分析、沉积物重金属分布特性、湿地生物多样性现状以及治理方略与措施等应用研究状况。基于前人及现有的研究成果,提出了东湖水资源环境质量的改善在于整个东湖区域生态环境优化的治理对策。 相似文献
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《绿色科技》2020,(10)
采用主成分分析法(PCA)对百花湖上游河流2019年的水质情况进行了分析。得到了以下结果:湖泊上游水质污染的原因是浮游藻类和有机污染物的结合;湖泊富营养化的控制因子为COD、高锰酸盐指数、温度、水体透明度和叶绿素a;水质变化有明显的时间性:2019年上半年水质好,而下半年水质不如上半年,水质最差的是第三季度;污染物来源主要是农业面源氮磷污染物和生活废水有机污染。为了更好地对百花湖治理成效期的水质状况进行全面了解,对2019年全年百花湖水质状况的时空分布特征进行了全面研究,深入分析了影响百花湖水体富营养状态的主控因子,限制因子及驱动因子,探索了富营养状态变化规律,为百花湖水质及富营养化、过程进一步污染防控和生态调控提供科学依据。 相似文献
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淮南矿区塌陷水域沉积物营养物质和重金属现状调查与评价 总被引：1，自引：0，他引：1
对淮南矿区潘集杨庄塌陷水域沉积物中的营养盐及重金属元素进行了分析,揭示了其环境现状和受污染程度。结果表明:潘集杨庄塌陷水域沉积物OI和ON属于尚清洁级别。沉积物的重金属污染主要以Cd元素为主,并依据潜在生态风险指数,表明该区域重金属总潜在风险达到强生态危害程度。 相似文献
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为了鉴定武汉市汤逊湖桥梁建成后汤逊湖水体水质状况,2010年12月至2011年3月于汤逊湖沿线11个点多次采水样,以水体总氮、总磷、叶绿素a、COD及透明度等为参数,对水体理化因子、水质状态特征、富营养化程度等进行分析,探讨各影响因子对汤逊湖富营养化的影响程度.结果表明,汤逊湖目前处于轻度富营养化状态,工业废水、生活污水及水产养殖是汤逊湖的主要污染源.可通过加强对湖区工业污染源、城市生活污水、农业生产等污染的外源控制以及对湖区内的水产养殖污染的内源控制和科学管理,加强湖泊生态修复工程治理力度等方式进行调控.提出了汤逊湖水质富营养化治理的基本对策. 相似文献
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土壤重金属赋存形态研究进展 总被引：1，自引：0，他引：1
《绿色科技》2018,(22)
指出了土壤中重金属赋存形态决定其生物有效性及毒性,对土壤重金属污染治理与修复研究具有重要意义。对土壤重金属赋存形态的分类及其提取方法进行了讨论,分析了影响土壤重金属形态分布与迁移转化的因素,表明土壤pH值、有机质、外源重金属量和人为活动干扰影响最显著,并展望了土壤重金属形态研究趋势。 相似文献
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Soil and sediment phosphorus fractions in a forested watershed at Acadia National Park,ME, USA 总被引：1，自引：0，他引：1
Phosphorus (P) is often the critical limiting nutrient controlling the productivity of natural waters. Understanding the linkages between terrestrial and aquatic P dynamics is essential to defining the mechanisms governing P availability in the ecosystem. We used P fractionation techniques to investigate landscape patterns of P distribution in soils, and associated stream and lake sediments, in a forested watershed at Acadia National Park, ME, USA. Specifically, we investigated the chemical and spatial distribution of P in primary and secondary mineral phases along a topographic and bathymetric transect based on distance from the stream for soils and lake sediments. The dominant P fraction was associated with aluminum (Al) hydroxides, a fraction that also included some iron (Fe) hydroxides and organic P. The Al–P fraction accounted for 62% and 66% of total P in all soil and lake samples, respectively. These results suggest that secondary Al, and to a lesser extent Fe, dominate P dynamics in these soils and lakes. Stream sediments appear to originate from deeper, less weathered portions of the soil with lower accumulations of secondary Al and Fe. As a result, stream sediments have little capacity for adsorbing P, relative to soil or lake sediments. Phosphorus fractionation results also suggested that both exposed and occluded primary apatite-P still persists in these soils, stream sediments, and lake sediments. Extractable apatite-P concentrations increased progressively with decreasing distance from the stream in the watershed and with increasing distance from the stream and depth in the lake. These trends were attributed to spatial patterns in the intensity of pedogenesis in the watershed and the influence of winnowing and sedimentation on lake sediment composition. 相似文献
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Root respiration uses a significant proportion of photosynthetically fixed carbon (C) and is a globally important source of C liberated from soils. Mangroves, which are an important and productive forest resource in many tropical and subtropical countries, sustain a high ratio of root to shoot biomass which may indicate that root respiration is a particularly important component in mangrove forest carbon budgets. Mangroves are often exposed to nutrient pollution from coastal waters. Here we assessed the magnitude of fine root respiration in mangrove forests in Belize and investigated how root respiration is influenced by nutrient additions. Respiration rates of excised fine roots of the mangrove, Rhizophora mangle L., were low (4.01 +/- 0.16 nmol CO(2) g(-1) s(-1)) compared to those measured in temperate tree species at similar temperatures. In an experiment where trees where fertilized with nitrogen (N) or phosphorus (P) in low productivity dwarf forests (1-2 m height) and more productive, taller (4- 7 m height) seaward fringing forests, respiration of fine roots did not vary consistently with fertilization treatments or with forest stature. Fine roots of taller fringe trees had higher concentrations of both N and P compared to dwarf trees. Fertilization with P enhanced fine root P concentrations in both dwarf and fringe trees, but reduced root N concentrations compared to controls. Fertilization with N had no effect on root N or P concentrations. Unlike photosynthetic C gain and growth, which is strongly limited by P availability in dwarf forests at this site, fine root respiration (expressed on a mass basis) was variable, but showed no significant enhancements with nutrient additions. Variation in fine root production and standing biomass are, therefore, likely to be more important factors determining C efflux from mangrove sediments than variations in fine root respiration per unit mass. 相似文献
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Jorge Durán Alexandra Rodríguez Felisa Covelo José María Fernández-Palacios Antonio Gallardo 《European Journal of Forest Research》2012,131(5):1327-1335
Two types of measures have traditionally been used to monitor changes after disturbances in the nutrient availability of forest ecosystems: (1) soil nutrient pools and transformation rates and (2) foliar nutrient content. We used a wildfire chronosequence in natural and unmanaged Pinus canariensis forests to determine which kind of measure is more effective in discriminating between disturbed and undisturbed plots and to determine whether the different availability indices provide comparable and consistent results within the chronosequence and between different sampling dates. The results showed that (1) foliar N and P concentrations were the variables that best discriminated between the plots of the chronosequence, (2) the various soil N availability indices neither showed steady relationships nor predicted the plant nutrient availability, and (3) P availability indices showed steady relationships and predicted plant nutrient availability. Due to the changing nature of the soil N pools, repeated sampling over a long period of time could yield results different from those presented here. However, the large sampling effort required would favor the use of foliar nutrient concentrations as the most desirable first approach to the community’s nutritional status, especially when time or budget constraints are relevant. 相似文献
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[目的]研究外源性氮和磷对马占相思凋落叶的分解速率、分解过程中N、P、K含量和土壤生化特性的影响,以便为森林土壤养分管理提供参考。[方法]以广东省云勇林场马占相思林下凋落叶为试验材料,采用尼龙网袋分解法,设置对照(CK)、施N(10 g·m~(-2))、施P(5 g·m~(-2))、施N+P(N 10 g·m~(-2)+P 5 g·m~(-2))4种处理,每隔3个月取样1次,并测定凋落叶残留量和N、P、K含量。[结果]表明:施N、P和N+P处理对马占相思凋落叶的分解均为促进作用。各处理马占相思凋落叶的N含量在分解过程中大致保持稳定,施P和N+P处理的凋落叶P含量在分解过程中总体呈波动性上升,而各处理的凋落叶K含量变化规律不明显。施N、P和N+P处理提高了马占相思林土壤的有机质和全N含量,促进脲酶、磷酸酶及过氧化氢酶的活性。[结论]施N、P和N+P处理促进了马占相思凋落叶的分解,有利于马占相思林的养分循环。 相似文献
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Andean-Patagonian forests are especially interesting for the study of N and P limitation because they receive minimal atmospheric pollution, have little influence of vascular N-fixing species, and grow on volcanic soils that retain P. In a previous study of 10 woody species (four broad-leaved deciduous species, three broad-leaved evergreens and three conifers) conducted during an exceptionally dry year in NW Patagonia, and on the basis of nutrient resorption efficiency and proficiency, we suggested that N was the most limiting nutrient except for the broad-leaved evergreen Lomatia hirsuta. In the present work, we compared patterns of nutrient limitation during a dry and a wet year, quantified the percentage of mycorrhizal infection, and related mycorrhizal behavior and nutrient limitation to soil fertility. We used N and P concentrations in green leaves as indicators of nutrient requirements, and N and P concentrations in senescent leaves (resorption proficiency) and the N/P ratio in green leaves as indicators of nutrient limitation. We also determined leaf mass area (LMA) and lignin concentration as indicators of structural and chemical defences. From previous works, the following soil fertility indicators were included: pH, organic C, total N, exchangeable cations, Olsen-P, potential N mineralization (pNmin) and N retained in microbial biomass (N-MB). Nitrogen, P and lignin concentrations in green and senescent leaves did not differ significantly between the dry and the wet year either by species or by functional groups. Most species behaved as N-proficient and P-non-proficient; this together with values of foliar N/P ratios lower than 14–16 confirmed N limitation in these forests. The only species limited by P but not by N was L. hirsuta (1.0–1.1% N in senescent leaves, N/P ratio = 21–23), a non-mycorrhizal species with cluster roots. The lack of P limitation in the other species was probably related to the high percentages of infection with arbuscular mycorrhizae (80–90% in Maytenus boaria and the conifers Araucaria araucana, Austrocedrus chilensis and Fitzroya cupressoides), and ectomycorrhizae (73–79% in five Nothofagus species). Nitrogen and P requirements were positively correlated among themselves and negatively with lignin and LMA. Soil fertility was positively correlated with nutrient requirements and negatively with lignin and LMA. Conifers had lower N and P requirements, higher LMA, lower foliar N/P ratio and grew on soils of lower soil N dynamics (lower pNmin and N-MB) than ectomycorrhizae-associated species. 相似文献
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Shudong Wei Xiaowei Liu Lihua Zhang Hui Chen Hui Zhang Haichao Zhou 《Southern Forests》2015,77(3):237-242
Avicennia marina is a typical mangrove species of subtropical coastlines of China. However, little is known about the retention of nutrients by this species in oligotrophic, coastal environments. In this study, seasonal changes in nitrogen (N) and phosphorus (P) concentrations, N:P ratio and total phenolic concentration in A. marina leaves during senescence were studied. Avicennia marina leaves had high N and P concentrations but the seasonal pattern of N concentration was different from that of P concentration. The A. marina forest was N-limited as the N:P ratio of mature leaves was less than 14. Nitrogen resorption efficiency was higher than P resorption efficiency, and the concentrations of N and P in senescent leaves indicated that N resorption was mostly complete whereas P resorption was incomplete. Avicennia marina leaves contained low tannin concentrations, particularly condensed tannins, as the leaf extracts did not react with acid butanol. Total phenolic concentrations were not correlated with N concentrations in mature and senescent leaves of A. marina. These findings suggest that the high N resorption efficiency and low nutrient losses play an important role in nutrient conservation strategies for A. marina forests, whereas low tannin concentations have limited effects on nutrient cycling. 相似文献