Analyzing Spatio-temporal Land Cover Dynamics in an Atlantic Forest Portion Using Unsupervised Change Detection Techniques

Environmental Modeling & Assessment - Over the past decades, the Southeast Atlantic Forest in Paraíba do Sul River Valley has suffered intense deforestation and human disturbances. Due to...     

抚仙湖、星云湖与杞麓湖营养状态演变及突变分析

为科学评价抚仙湖、星云湖和杞麓湖(简称三湖)营养状态及其变化趋势,基于三湖1991—2015年水质数据,采用综合营养状态指数法评价其富营养化水平,通过Mann-Kendall(Sneyers)方法判识三湖富营养化趋势及突变时间。结果表明:三湖都存在水质恶化现象,其综合营养状态指数及各分项指数均呈变差趋势,表征其营养物质在增加。三湖的营养化水平和演变时间存在显著差异,抚仙湖处于贫营养,星云湖由中营养转变为富营养,杞麓湖表现为中度-重度富营养化;抚仙湖和杞麓湖分别在2004、2011年出现突变点,星云湖自2000年后综合营养状态指数显著增加。基于三湖营养状态演变及趋势,结合变化特征及相关情况的讨论,提出对抚仙湖的管理应减少农业化肥和农药排放,对星云湖和杞麓湖的管理应削减高污染工矿企业排放等。     

Scaling the trophic index (TRIX) in oligotrophic marine environments

The TRIX index used for the assessment of trophic status of coastal waters has been applied in many European seas (Adriatic, Tyrrhenian, Baltic, Black Sea, and North Sea). However, all these waters are characterized by high nutrient levels and phytoplankton biomass; index calibration based on systems that are principally eutrophic may introduce bias to the index scaling. In the present work the TRIX trophic index is evaluated using three standard sets of data characterizing oligotrophy, mesotrophy, and eutrophication in the Aegean (Eastern Mediterranean) marine environment. A natural eutrophication scale based on the TRIX index that is suitable to characterize trophic conditions in oligotrophic Mediterranean water bodies is proposed. This scale was developed into a five-grade water quality classification scheme describing different levels of eutrophication. It is questionable whether this index can form a universal index of eutrophication or the scaling of TRIX should be region specific.     

钦州湾枯水期富营养化评价及其近5年变化趋势

利用近5年枯水期现场调查的结果,采用富营养化指数法对该海湾富营养化程度进行评价并探求其变化趋势。结果表明近5年钦州湾枯水期富营养化指数的变化为0.08~10.2,其空间分布表现为沿着盐度梯度从茅岭江或钦江河口往外富营养化逐渐减轻。从2006年到2010年钦州湾富营养化从贫营养化往中度和重富营养化程度发展,富营养化显逐渐加重的趋势,在近两年河口区达到了重富营养化程度。陆源径流污染源的输入是富营养化空间分布的主要决定因素,而近5年富营养化逐渐加重的趋势主要是由不断增加的磷酸盐导致。海湾富营养化程度的增加并没有引起浮游植物生物量的急剧增加,但却增加了赤潮等生态灾害的风险。     

Trophic state index of a lake system using IRS (P6-LISS III) satellite imagery

Water pollution has now become a major threat to the existence of living beings and water quality monitoring is an effective step towards the restoration of water quality. Lakes are versatile ecosystems and their eutrophication is a serious problem. Carlson Trophic State Index (CTSI) provides an insight into the trophic condition of a lake. CTSI has been modified for the study area and is used in this study. Satellite imagery analysis now plays a prominent role in the quick assessment of water quality in a vast area. This study is an attempt to assess the trophic state index based on secchi disk depth and chlorophyll a of a lake system (Akkulam?CVeli lake, Kerala, India) using Indian Remote Sensing (IRS) P6 LISS III imagery. Field data were collected on the date of the overpass of the satellite. Multiple regression equation is found to yield superior results than the simple regression equations using spectral ratios and radiance from the individual bands, for the prediction of trophic state index from satellite imagery. The trophic state index based on secchi disk depth, derived from the satellite imagery, provides an accurate prediction of the trophic status of the lake. IRS P6-LISS III imagery can be effectively used for the assessment of the trophic condition of a lake system.     

Monitoring water quality in reservoirs for human supply through multi-biomarker evaluation in tropical fish

Paraíba do Sul River is located at a very densely inhabited region of Brazil crossing the three most industrialized states of the country (S?o Paulo, Minas Gerais and Rio de Janeiro states). As a result, industrial and farming residues as well as urban sewage are frequently disposed without appropriate treatment. The current study aimed at investigating the water quality in three reservoirs along the Paraíba do Sul River (Ilha dos Pombos, Santa Cecília and Santa Branca), through physiological, morphological, biochemical, and genetic biomarkers. The bioindicator chosen was the catfish Pimelodus maculatus, sampled during the dry (June 2008) and rainy (February 2009) seasons. Also, some water physicochemical parameters were analyzed from the sampling sites, but displayed no alterations according to the Brazilian Agency for Water Quality Legislation. Branchial carbonic anhydrase activity was inhibited in the dry season, while renal carbonic anhydrase activity was inhibited in the rainy season in the Santa Branca reservoir, indicating disturbance of osmoregulatory and acid-base regulation processes. Histopathological alterations were observed in the gills (neoplasic and tissue hyperplasia processes) and liver (necrosis), indicating serious damage to the functional integrity of these organs. A high incidence of melanomacrophage centers was observed in the liver, suggesting an intense immune response in all reservoirs. Acetylcholinesterase and catalase activity showed also differences corroborating some morphological results. Likewise, the induction of the micronucleus and DNA damage indicate genotoxicity, but mainly in the Santa Branca reservoir. Thus, the health status of P. maculatus warrants caution in the use of the water from the 3 reservoirs for direct human consumption, particularly after the accidental spill of endosulfan in November 2008, three months before the rainy season sampling.     

淀山湖富营养化驱动力初探

通过2015—2019年在淀山湖布设5个采样点,监测总氮、总磷等12项水质指标,运用综合营养状态指数法和潜在性富营养化评价法对该水域富营养化水平进行分析,采用主成分分析法初步确定影响该水域富营养化水平的主要驱动因子。结果表明：监测期间淀山湖水质因子时空分布差异显著。综合营养状态指数法评价结果表明,淀山湖富营养化在轻—中度富营养化水平,并且季节变化规律明显;潜在性富营养化法评价结果表明,监测期间淀山湖以磷限制潜在性富营养为主。驱动因子分析表明硝酸盐氮是该水域富营养化最主要的驱动因子。     

Plankton diversity and water quality assessment of three freshwater lakes of Mandi (Himachal Pradesh, India) with special reference to planktonic indicators

The present study deals with the limnobiotic status of three selected lakes of Himachal Pradesh using physicochemical and biological parameters (especially phytoplankton and zooplankton) over a period of 2 years. One hundred forty-eight species belonging to nine groups of phytoplankton and 79 species belonging to five groups of zooplankton were identified from the lakes. Trophic level and the pollution status of the lakes were assessed upon the basis of Shannon diversity index (H′), species richness index (S), and physicochemical parameters. Plankton population size was correlated with biotic and abiotic parameters (pH, alkalinity, temperature, dissolved oxygen, transparency, phosphate, chloride, and nitrate). The present investigation revealed that the distribution of plankton species depended upon the physicochemical parameters of the environment. Based on water quality standards given by the Central Pollution Control Board, the water quality was between “A–B” at Prashar wetland, “C–D” at Kuntbhyog Lake, and “D–E” at Rewalsar Lake. The results from the present study indicated that the potential of planktons as bioindicators of trophic status is very high.     

Assessing the water quality index of water treatment plant and bore wells, in Delhi, India

Water quality monitoring exercise was carried out with water quality index (WQI) method by using water characteristics data for bore wells and a water treatment plant in Delhi city from December 2006 to August 2007. The water treatment plant received surface water as raw water, and product water is supplied after treatment. The WQI is used to classify water quality as excellent, good, medium, bad, and very bad. The National Sanitation Foundation WQI procedure was used to calculate the WQI. The index ranges from 0 to 100, where 100 represents an excellent water quality condition. Water samples were collected monthly from a bore well in Nehru Camp (site 1), a bore well in Sanjay Gandhi pumping station (site 2), and water treatment plant in Haiderpur (site 3). Five parameters were analyzed, namely, nitrate, pH, total dissolved solids, turbidity, and temperature. We found that the WQI was around 73–80 in site 3, which corresponds to “good,” and it decreased to 54.32–60.19 and 59.93–70.63 in site 1 and site 2, respectively, indicating that these bore wells were classified as “medium” quality.     

Research on aquatic ecoregions for lakes and reservoirs in China

Aquatic ecoregion, as one type of ecoregions, is a unit of land of relative homogeneity in aquatic ecosystems or in relationships between organisms and their environments. It is the base of establishing the trophic state standard for the lakes and reservoirs, and that of controlling the eutrophication. In this paper, we put forward the principles and assessment index of trophic state divisions for the lakes and reservoirs in China. Based on the assessment index and with the help of spatial analysis of geographic information system, expert judgment and qualitative analysis, we suggest that all the lakes and reservoirs in China be divided into three Level I and six Level II ecoregion divisions. Moreover, the trophic state characteristics of each ecoregion division are summarized.     

湖泊富营养化评价的Euclid贴近度评价法──兼与《湖泊营养状态的Hamming贴近度评价法》作者商榷

针对湖泊富营养状态Ｈａｍｍｉｎｇ贴近度评价模型存在的“阈值漂移”问题,重新构造了评价参数隶属函数,提出了一种湖泊营养状态Ｅｕｃｌｉｄ贴近度评价模型,经过对全国２３个湖泊富营养状态的实例分析,证明这种评价模型结构合理,评价过程简单,模型通用性好。     

Dissolved inorganic nutrients and chlorophyll a in an estuary receiving sewage treatment plant effluents: Cachoeira River estuary (NE Brazil)

Sampling was conducted monthly during a transition period between the dry and rainy seasons in order to evaluate the effectiveness of a municipal sewage treatment plant (STP) in eutrophication control. STP effluent and fluvial input data were also estimated. In the dry period, high concentrations of nutrients, chlorophyll a (up to 360 μg?L^?1), and anoxia in bottom waters were observed in the upper portion of the estuary. Nitrate was scarce during the dry months, although high concentrations were observed at the river sources and the upper estuary. The N:P and Si:P molar ratios were usually below 16:1, and the Si:N ratio was higher than 1:1. The fluvial inputs were a greater source of nutrients to the estuary than the STP, but nutrient loading by these effluents were also important in contributing to the eutrophication of the upper estuarine zone, especially in the dry season when symptoms were more intense.     

Copper availability assessment of Cu-contaminated vineyard soils using black oat cultivation and chemical extractants

Grapevines grown on acid soils with low fertility in southern Brazil are treated with intense foliar applications of copper (Cu) fungicides, resulting in an increased level of Cu in the soil and increased toxicity. The present study evaluated the accumulation and bioavailability of Cu, and soils with varying levels of Cu from the main producing regions of southern Brazil were collected. The forms of Cu present in the soil were assessed using chemical extractants; additionally, oat cultivation was performed, reflecting the use of the plant as an indicator of Cu bioavailability. Cu accumulated in the topsoil, mainly in bioavailable forms, and there was also an increase of Cu up to a depth of 0.4 m. Cu was primarily found in the mineral fraction, with apparent saturation of the soil organic matter functional groups. Inceptisol and Alfisol soils with a long history of cupric fungicide application were found to have levels of Cu toxic to oat plants. Furthermore, accumulated copper in Alfisol soil from the Campanha Gaúcha region of the state of Rio Grande do Sul had higher bioavailability compared to Cu accumulated in Inceptisol soil from the Serra Gaúcha region. In addition, the copper concentration in roots was found to serve as an indicator of Cu bioavailability in soil, but not of copper phytotoxicity in plants.     

Changes of the phytoplankton community as symptoms of deterioration of water quality in a shallow lake

Covering more than 60% of the lake surface, macrophytes determined the taxonomic composition of phytoplankton. We have found numerous indications of ecological deterioration and an increased trophic level year to year: an increased total number of taxa; a significantly increased number of species of Chlorophyta, Bacillariophyceae and Cyanoprokaryota; a decreased number of Chrysophyceae; increased Nygaard index, and high diversity and variability of phytoplankton functional groups. Within 2 years (2002 and 2003) algal biomass doubled: from 3.616 to 7.968 mg l^?1. An increased contribution of Chlorococcales and Cyanoprokaryota indicates progressive eutrophication of the lake. The average size of planktonic algae increased, particularly Cyanoprokaryota, where small-celled decreased dramatically and were replaced by large colonies. Cyanoprokaryota remained the dominant group of phytoplankton after 10 years, and the ecosystem of the lake remained in the turbid state. This group of algae had the average biomass 9.734 mg l^?1, which constituted almost 92% of the total biomass.     

抚河河口富营养化现状评价

2009年4-5月对抚河下游分流处及河口进行浮游生物及水质状况的调研,基于优势种评价法和污水生物系统法并结合化学评价对其富营养化状况进行评价.共检出11大类,230种浮游生物.生物优势种评价法与化学营养状况指标法分析均表明,抚河下游分流处、东支河口和西支河口水体均呈富营养型.污水生物系统评价结果表明,抚河下游分流处水体介于多污染带与β中污带之间;东支河口水体介于多污染带与β中污带中间;西支河口水体处于多污染带.与分流处相比,河口浮游生物密度激增,还增加了金藻、黄藻、甲藻等浮游植物种类,说明河口富营养化程度比分流处严重,其中金溪湖处河口营养化程度最严重.     

基于灰色聚类方法的湖泊营养状态综合评价

将湖泊水体的营养状态看作一个灰色系统,建立用于识别湖泊营养状态属性的灰色聚类综合评价模型,将水质级别作为一个灰类,水质状态作为灰色变量,根据灰色白化权函数聚类方法来确定水体营养状况归类。以太湖为例,基于分布全湖的20个监测点数据,运用灰色聚类法对其进行富营养状态综合评价,结果表明,监测时段太湖大部分水体基本处于中营养水平,局部湖面达到中度富营养状态,客观地反映了太湖湖区水体营养状况。     

Trophic state assessment of Bhindawas Lake,Haryana, India

Trophic state allows for identification of problems and pressures that an ecosystem faces as well as demarcation of remedial measures. This study focuses on spatial and temporal variations in the trophic state and detection of possible causes of its divergence in Bhindawas Lake, India. The trophic state of the lake undulated between eutrophic and hyper-eutrophic state throughout the study period. Higher phosphorus concentration within the lake ecosystem is the dominant causal factor for its eutrophic state. The influence of other water quality parameters has also been analyzed using Spearman’s coefficient of correlation. Deviations between trophic state index (TSI)-chlorophyll-a (Chl-a), TSI-total phosphorus (TP), and TSI-Secchi depth (SD) pointed out that the lake is principally phosphorus limited, and its trophic status is influenced by non-algal turbidity to a large extent. Spatial analysis of trophic levels in geographic information system (GIS) helped in identification of pollution sources and chemical attributes affecting the trophic state of the lake. This study provides a rationale for further investigation of nutrient and sediment loading into the lake system and development of sustainable management and conservation strategy identifying suitable measures ascertaining the ecosystem integrity.     

Impact of artificial lagoons on seawater quality: evidence from 7 years of physicochemical seawater monitoring

Seven years (2010–2016) of data on the basic physicochemical properties of seawater, temperature, salinity, dissolved oxygen (DO), nutrients, chlorophyll a (Chl a), and hydrocarbons from two lagoons were used to evaluate the impact of the anthropogenic activities inside the lagoon on the water quality and to explore the relationship of any impact from the lagoons’ design. Statistical analysis shows the modification in water quality inside the lagoon compared to the ambient seawater is particularly evident for nitrate, silicate, and Chl a. The modification is attributed to the extensive boat activities in the lagoons and the limited water exchange between the lagoons and ambient seawater. However, the impact to both lagoons is generally limited to inside the lagoons. The oligotrophic state of the two lagoons was evaluated and it was found that the most marked code violations were found in DIN inside both lagoons. In order to explore the design importance, the water exchange and overall water quality was compared between the two lagoons. This study highlights the importance of an environmental design study before the construction of any lagoon project. Proper design would maintain acceptable water quality inside the lagoons, critical for environmental health and supporting continued recreational activities.     

海门市长江水厂饮用水源地富营养化调查及污染防治对策研究

采用综合营养状态指数法对2008年至2011年海门市长江水厂饮用水源地水质状况进行评价,结果表明,该水源地已呈现出富营养化的发展趋势。结合饮用水源地现状,必须采取控制外源和内源的排放、恢复生态系统等措施,遏止水体富营养化,确保人民群众的饮用水源安全。     

Inputs of heavy metals due to agrochemical use in tobacco fields in Brazil’s Southern Region

Only a few studies have assessed the joint incorporation of heavy metals into agricultural systems based on the range of agrochemicals used on a specific agricultural crop. This study was conducted to assess the heavy metals input through application of the main agrochemicals used in Brazilian tobacco fields. A total of 56 samples of different batches of 5 fertilizers, 3 substrates, 8 insecticides, 3 fungicides, 2 herbicides, and 1 growth regulator commonly used in the cultivation of tobacco in Brazil’s Southern Region were collected from 3 warehouses located in the States of Rio Grande do Sul, Santa Catarina, and Paraná. The total As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, and Zn content of the samples was then determined and compared with the regulations of different countries and information found in the available literature. The fertilizers were identified as the primary source of heavy metals among the agrochemicals used. Application of pesticides directly to the shoots of tobacco plants contributed very little to the supply of heavy metals. The agrochemicals used in Brazilian tobacco fields provide lower inputs of the main heavy metals that are nonessential for plants than those registered in the international literature for the majority of crop fields in different regions of the world.