Ecosystem Health Assessment of Honghu Lake Wetland of China Using Artificial Neural Network Approach

Honghu Lake,located in the southeast of Hubei Province,China,has suffered a severe disturbance during the past few decades.To restore the ecosystem,the Honghu Lake Wetland Protection and Restoration Demonstration Project(HLWPRDP) has been implemented since 2004.A back propagation(BP) artificial neural network(ANN) approach was applied to evaluatinig the ecosystem health of the Honghu Lake wetland.And the effectiveness of the HLWPRDP was also assessed by comparing the ecosystem health before and after the project.Particularly,12 ecosystem health indices were used as evaluation parameters to establish a set of three-layer BP ANNs.The output is one layer of ecosystem health index.After training and testing the BP ANNs,an optimal model of BP ANNs was selected to assess the ecosystem health of the Honghu Lake wetland.The result indicates that four stages can be identified based on the change of the ecosystem health from 1990 to 2008 and the ecosystem health index ranges from morbidity before the implementation of HLWPRDP(in 2002) to middle health after the implementation of the HLWPRDP(in 2005).It demonstrates that the HLWPRDP is effective and the BP ANN could be used as a tool for the assessment of ecosystem health.

Human impact recorded in the sediment of Honghu Lake, Hubei, China

Vertical profiles of the total organic carbon （TOC）, total nitrogen （TN）, phosphorus, susceptibilities, elements and partical size were analyzed in a short ^137Cs-dated sediment core collected from Honghu Lake, China. The average sedimentation rate was 1.55 mm/a. The results indicated that trophic status of Honghu Lake in the historical period had experienced three stages. Before 1840 the lake was characterized with lower productivity, TOC was less than 9.92 g/kg; TN was 0.902 to 1.24 g/kg. During about 1840-1950, population increased quickly, there was an obvious change in TOC with an average of 13.0 g/kg. Since 1950, human impacts have accelerated the lake eutrophication and nutrients enriched in the sediment with TOC of 21.7 to 93.1 g/kg, TN of 1.77 to 8.78 g/kg. The heavy metal concentration profiles presented similar distribution trends except Pb .and Mn. The results from elements analyses indicated that Honghu Lake had not been polluted by heavy metals except lead.

Valuation of Air Regulation Service Value in the Honghu Lake Wetland

To assess the value of air regulation in the Honghu Lake Wetland,a quantitative study was conducted based on existing literatures. Results showed that the total service value of air regulation in the Honghu Lake Wetland was 254. 52 million yuan/a,which was 11. 6 times of that by previous studies. The net value of fixed greenhouse gases via wetland plants( including carbon emission value from methane emission conversion into carbon dioxide greenhouse gas effect) was 58. 50 million yuan/a,the data indicated that this lake wetland was a strong carbon sink. The value of oxygen released by the wetland ecosystem was 176. 51 million yuan/a,and the value of regulating air humidity and temperature was 19. 51 million yuan/a. The net value of greenhouse gases fixed by the Honghu Lake Wetland vegetation,the value of released oxygen,and the value of lifting air humidity and temperature regulation accounted for 22. 98%,69. 35%,and 7. 70% of the total value of the air regulation services,respectively.

Trace elements spatial distribution characteristics,risk assessment and potential source identification in surface water from Honghu Lake,China

Five trace elements including Zn, Cu, Cd, Cr and As were investigated in surface water from ten typical sampling sites in Honghu Lake. The consequence indicated that all of the detected trace element levels were within the allowed standard of China’s safe water guideline. The hazard quotients （HQ） and the hazard index （HI） value levels of all the five heavy metals in all sampling sites did not exceed the acceptable risk limits of non-carcinogenic value through the selected assessment method. Pearson’s correlation analysis and principal component analysis （PCA） indicated that Zn and Cu mainly originated from the natural alluviation and non-point agricultural sources, whereas Cr and As were mainly derived from industrial effluents. Moreover, Cd mainly originated from both non-point agricultural and industrial pollution sources. In addition, cluster analysis （CA） implied that cluster 1 （including S3, S5, S6 and S10） was considered the set of high pollution sites and cluster 2 （including S4 and S9） was identified as the set of moderate pollution sites.

Organochlorine pesticides in sediments from Honghu Lake, China

The levels of 13 organochlorine pesticides （OCPs） in sediments of Honghu Lake were investigated in order to evaluate their potential pollution and risk. A total of 30 sediment samples from 15 sampling locations were collected in the lake during July, 2005. The total concentrations in top-sediment samples and sub-sediment samples ranged from 3.52 ng/g to 69.71 ng/g and 0.49 ng/g to 97.37 ng/g, respectively. The HCH isomers, DDT congeners, aldrin, trans-chlordane, cis-chlordane, heptachlor and endrin-ketone were significant in these samples. The concentrations of OCPs in the lakeshore sediments were higher than those sampled across the lake. Distribution of HCHs, DDTs and other OCPs were different, indicating their various contamination sources. Composition analysis in sediments indicated recent usage or discharge of lindane, dicofol into the lake.

洪湖周边三种典型养殖类型池塘浮游植物群落特征及其与环境因子的关系

不同养殖水体浮游植物群落结构和丰度的变化,可反映水质和水产品状态,认识其变化特征和驱动力,对养殖管理和尾水处理有重要的指导意义。本研究于2019-2020年在洪湖养殖区域选择了三种典型养殖类型池塘(克氏原螯虾、中华绒螯蟹、大宗淡水鱼,以下分别简称为龙虾塘、河蟹塘和鱼塘),解析了各类型池塘浮游植物的物种组成、细胞密度、生物量和多样性的季节变化趋势。结果显示:(1)共检测到浮游植物132种,隶属于7门96属。浮游植物细胞密度和生物量总体趋势为鱼塘>河蟹塘>龙虾塘,年平均细胞密度分别为1.06×10^(8)、6.04×10^(7)和2.35×10^(7)cell/L,年平均生物量(叶绿素a表示)分别为94.82、65.95和31.15μg/L。(2)三种养殖模式池塘中浮游植物群落结构具有显著性差异,并具有明显的季节演替。春夏两季中龙虾塘与河蟹塘的浮游植物群落结构组成更为相似,而秋冬两季中河蟹塘与鱼塘更为相似。龙虾塘和河蟹塘浮游植物多样性指数和均匀度指数均在收获季节(龙虾为夏季,河蟹为秋季)最低。(3)冗余分析结果表明温度(Temp)、溶氧(DO)、pH和溶解性总磷(DTP)是影响养殖池塘中浮游植物群落组成的主要环境因子。多元线性回归模型显示,不同季节中解释浮游植物生物量变化的主要因素不同,春季和秋季为总氮(TN)和养殖动物类型,冬季为TP、DTP、NH_(4)^(+)-N。鉴于各养殖类型在排水季节的浮游植物优势类群变动,建议加强养殖尾水监控,以预判尾水种源迁移对邻近水域的潜在影响。

洪湖流域冬季浮游植物多样性调查与评价

为了解洪湖水体中浮游植物的群落结构特征,于2021年10月在洪湖布设10个采样点进行调查,并采用多样性指数对浮游植物群落进行评价。研究结果表明,洪湖水体中共鉴定出浮游植物6门、49属、66种,其中蓝藻门浮游植物种类最多,其次为硅藻门。洪湖冬季浮游植物生物量变化范围为7.85~42.45 mg/L,平均生物量为22.35 mg/L。根据马格勒夫多样性指数(M)、香农维纳多样性指数(H)、辛普森多样性指数(D)、物种均匀度指数(J)和物种优势度(Y)对水体营养状态进行综合评价,结果表明,洪湖水体为中污染—重污染水平。建议从3个方面改善洪湖水质:①加大洪湖水体保护力度,严格控制下游和周边地区各类水污染物入湖量,对湖区内农村水污染开展及时、高效防治,合理组织水生浮游植物平衡收割;②加强水环境治理,逐渐恢复水体自净能力;③加强宣传力度,定期开展水污染防治教育进农村、进社区、进校园。

Temporal variation of major nutrients and probabilistic eutrophication evaluation based on stochastic-fuzzy method in Honghu Lake, Middle China

Honghu Lake, which is listed in the Ramsar Convention, was found to be contaminated with elevated nutrients to a certain extent.This study investigated the seasonal variation of major nutrients and probabilistic eutrophic state in surface water from Honghu Lake. Average concentrations of total nitrogen(TN), total phosphorus(TP), chlorophyll-a(Chl-a), chemical oxygen demand(COD_(Mn)) and transparency(SD) in summer and winter generally exceeded Grade III of the Chinese environmental quality standards for surface water(GB 3838-2002), with the exception of COD_(Mn)in winter. Mean concentrations of Chl-a and COD_(Mn) in summer were higher than that in winter, while mean concentrations of TN, TP and SD were slightly higher in winter. The improved probabilistic comprehensive trophic level index(PTLI) method based on stochastic-fuzzy theory was established to evaluate the eutrophic state in Honghu Lake. Compared with the Monte-Carlo sampling method, the Latin Hypercube sampling(LH-TFN) method was selected for the evaluation simulation due to its efficiency and stability. Evaluation results indicated that mean PTLI in summer(69.70) and winter(61.96) were both subordinated to Grade IV(Medium eutrophication). The corresponding reliability of eutrophication level subordinating to Grade IV in summer was of relatively low reliability(51.27%),which might mislead decision makers to some extent and suggest recheck. The probabilistic eutrophication level in summer developed with a trend from medium to severe eutrophication. Sensitivity analysis illustrated that COD_(Mn)and Chl-a were the priority pollutants in summer, with the contributions to PTLI of 43.3% and 22.5% respectively. Chl-a was the priority pollutant in winter, with the contribution to PTLI up to 51.3%.

洪湖沉积物营养盐分布特征及释放潜力评价

介绍了洪湖及主要入湖河流沉积物中营养盐分布特征和释放潜力,分别测定不同区域不同深度沉积物中总氮(TN)、氨氮(NH_(4)^(+)-N)、总磷(TP)、易释放态磷(Labile-P)的含量。结果表明:沉积物中TN和TP浓度均处于严重污染水平,河流沉积物中的TN含量低于湖泊,而TP则相反;TN污染在湖泊南部、东北部区以及河流中上游最为严重,而TP仅在湖泊中呈中部低、南北高的特征;洪湖沉积物NH_(4)^(+)-N静态释放量约为192.4 t/a,动态释放量为51.18~259.69 t/次;Labile-P静态释放量约为3.37 t/a,动态释放量为18.80~46.58 t/次;TN动态释放量为162.44~1243.34 t/次,TP动态释放量为40.89~64.54 t/次。

Numerical simulations of nutrient transport changes in Honghu Lake Basin, Jianghan Plain

Nutrients transported from catchments are one of the most important sources for lake eutrophication. In this study, the Honghu Lake Basin, located at the middle reaches of the Yangtze River, was chosen as the study area, and the watershed hydrological distribution model SWAT (Soil Water Assessment Tool) was applied to evaluate the trajectory of watershed nutrient transportation over time. Based on the analysis of driving factors, three experiments corresponding to natural, traditional and modern agriculture processes respectively were designed to evaluate the changes of nutrient inputs from catchments under the three environments. The simulation results showed that there were variations in nutrient production and changes in the range and rate. For three periods of the experiments, TN concentrations have changed as 0.12→0.31→1.15 mg/L, and production as 420→1650→6522 T/a; while TP concentrations changed as 0.018→0.057→0.117 mg/L, and production as 78→303→665 T/a. The nutrient transportation experienced slowly long-term increases during 1840―1950, then showed a relatively rapid increase during the period of 1950―1980s and the period from 1980 to early 1990s, with increasing rate of 1.4% and 2.4% respectively. And from the later 1990s to now, an obviously increasing trend with 15% increasing rate occurred. The effect from human activities on the watershed nutrient transportation increased rapidly, and had become a dominant factor in changes of the nutrient transportation.

洪湖水质问题核心及水质综合提升途径思考

作为长江中游重要的生态敏感区域和节点区,洪湖多年来一直承接江汉平原的调蓄与灌溉功能,剧烈的人类活动导致洪湖水体污染和生态系统退化加剧,洪湖水质的提升现已成为实施长江保护修复攻坚战行动的重点。通过系统剖析发现洪湖水质提升的关键问题在于入湖水质不达标、内源污染较重以及水生态受损严重3个方面。要解决洪湖的水污染问题,应坚持系统思维和流域视角,做好洪湖外源控污截污、底泥清淤、湖区和湖滨带生态修复以及水资源科学调度利用等工作,并推行包括洪湖及其支流流域河湖长制联防联控联治机制、生态补偿机制等在内的综合水质提升管理措施。

洪湖莲藕病虫草害和无人机施药情况调查及分析

洪湖莲藕(Nelumbo nucifera Gaertn.)营养丰富,具有保健和药用等功能,一直以来深受大众喜爱。随着莲藕产业的不断发展,莲藕病虫草害发生频率逐渐升高,粗放式施药既不科学也达不到防治病虫草害的效果,反而影响莲藕的质量,对洪湖莲藕产业的可持续发展造成了严重的威胁。通过实地考察、问卷调查、统计分析等方式,对湖北省洪湖市6个乡镇103位种植户莲藕病虫草害发生情况、农药使用情况和无人机施药情况进行调研,分析了洪湖地区莲藕农药使用和无人机施药所存在的问题,并提出前景展望,研究为莲藕产业绿色现代化种植提供一些新思路。

基于开放性围栏研究洪湖退垸还湖区沉水植物生长限制因子

为探讨不同退垸还湖区的环境因子对沉水植物恢复的影响,本研究在两种不同类型的退垸还湖区(阳柴湖和八卦洲)内分别建立开放性围栏,选取3种不同生长型(共9种)沉水植物为实验对象,基于不同围栏、围栏内外及不同生长时间(7、30 d)的生长指标差异来评估限制不同沉水植物生长的环境因子并排序。结果显示,保留部分功能的单退垸区域风浪干扰较小,比完全去除圩垸的双退垸区域更适合沉水植物的生长。密刺苦草(Vallisneria denseserrulata Makino)是适合洪湖退垸还湖区沉水植物群落恢复的先锋物种。部分植物如黑藻(Hydrilla verticillata Royle)在围栏内外生长指标的显著差异也表明草(杂)食性鱼类的潜在影响。研究结果表明,退垸还湖工程应在去养殖功能化后保留现有围堤,这样更有利于沉水植被的恢复,此外,构建保护性围栏有助于沉水植物的迅速建群。

洪湖湿地生态系统演变及稳态转换关键驱动因子阈值研究

利用19902020年洪湖水环境监测数据和20112020年洪湖沉水植物调查数据,探讨洪湖湿地生态环境演化规律,识别稳态转换关键驱动因子并确定其阈值。研究结果表明:19902020年以来洪湖水质变化主要总结为5个阶段和3个时期,整体上呈现出不断恶化的趋势;20112020年以来洪湖沉水植物Margalef物种丰富度指数、Shannon-Wiener多样性指数、Simpson和Pielou均匀度指数分别降低32%、59%、60%和46%,特别是2016年洪涝灾害后沉水植物出现严重衰退;洪湖生态系统发生稳态转换的关键时期是2002和2011年,总磷是洪湖湿地生态系统稳态转换的关键驱动因子;清水态向浊水态转换的总磷阈值为0.092 mg/L,浊水态向清水态转化的阈值为0.051 mg/L。本研究可为洪湖入湖污染负荷削减量估算提供参考,为洪湖湿地生态修复的营养盐优先控制策略提供指导。

湖北省洪湖区域旅游资源空间分布特征研究

运用空间聚类分析、核密度分析、最邻近指数、地理集中指数和不平衡指数等方法,对洪湖区域84处旅游资源进行空间分析.结果显示,洪湖区域旅游资源空间分布不均衡,聚类特征明显,总体呈现“一核二带多点”的集聚型分布格局,河流、湖泊、路网和镇区1 km缓冲区是集聚热点区,并在“新堤-滨湖”区域形成分布高密度区.

洪湖市土壤酸碱度趋势分析及影响因素

洪湖市土地质量地球化学评价工作获得了大量地球化学数据,对近4年所取得的数据进行整体研究,系统分析了所属各乡镇农用地土壤酸碱度。结果表明:该市土壤酸碱度总体特征表现为南部、北部乡镇的土壤酸碱度大于中部乡镇;土壤pH值从西向东逐渐升高,从北向南变化不明显;不同类型土壤对土壤酸碱度的影响由大到小依次为:沙土型潮土>沙土型灰潮土>浅色草甸土=壤土型灰潮土>灰潮土田>黏土型灰潮土>浅灰潮土田>灰青泥田>壤土型潮土>烂泥田>青泥田>黏土型潮土>浅潮土田>黄棕壤;不同成土母质的pH值由大到小依次为:河流冲积物>湖泊沉积物>第四系黏土沉积物>河流沉积物>红砂岩风化物。洪湖市土壤平均pH值在1982—2007年降低了0.87个单位,在2007—2014年升高了0.35个单位,在2014—2019年又升高了0.47个单位。该研究成果可为地方政府开展耕地质量保护、耕地酸化治理、农业产业结构调整等提供决策参考。

洪湖底泥特性及生产有机肥的分析研究

为研究洪湖底泥生产有机肥的可行性,对洪湖底泥的有机质、营养物质和重金属含量进行检测分析。研究表明:洪湖底泥有机质平均含量为10.5%,为中度污染;全氮含量为4026 mg/kg,为重度污染;全磷含量为1632 mg/kg,为中度污染。此外,洪湖底泥中重金属汞(Hg)、铅(Pb)、镉(Cd)、铬(Cr)的含量平均值均低于有机肥限量标准,但砷(As)的含量略高于限量标准。全湖范围内Hg、Pb、Cd、Cr、As单因子污染指数Pi均≤1,为无污染状态。南、北部湖区重金属的内梅罗综合污染指数P值分别为0.81、0.80,处于尚清洁状态。以上结果表明洪湖底泥是作为有机肥料的良好资源。

长江禁捕政策背景下上岸渔民城市适应性研究--以湖北省洪湖市为例

随着长江大保护及长江禁捕政策的出台,为加快上岸渔民家庭的城市融入过程,需要构建有针对性的相应公共政策,进而促进新型城镇化进程和区域协调发展。该文以湖北省洪湖市为例,通过访谈、问卷调查等形式,收集当地上岸渔民上岸前后的生活状况及渔民全面融入城市过程中的问题与困难,借助科学分析方法,从城市适应的角度聚焦渔民适应过程,得出影响渔民适应性的相关因子,并提出相应的策略,以提升渔民的生活品质,促进上岸渔民更快更好地融入城市社会。

洪湖市“稻-再-油”三熟制模式创建

通过试验示范,洪湖市建立了“稻-再-油”三熟制周年轮作模式,该模式创新利用再生稻冬季的茬口期播种油菜,由“一田两收”模式变成“一田三收”模式。通过合理的种植方式和技术手段,使再生稻与油菜在时间上形成高效衔接,从而提高土地利用率与经济效益。同时,也能减少化肥和农药的使用量,降低环境污染,为中国农业生产提供新的发展思路。