Cost-Effective Control of Interdependent Water Pollutants

Excess nutrient loads to coastal waters lead to increased production of algae, which when decaying cause oxygen depletion in bottom sediments, which in turn leads to major changes in marine ecosystems. A cost-minimization model was investigated in which nitrogen and phosphorus were assumed to interact with respect to algae production. It was investigated under what conditions only a single nutrient should be decreased and when it is cost-effective to decrease both nutrients. The model was applied to the Baltic Proper, which is the largest of the seven major basins in the Baltic Sea. Results showed that the stringency of the environmental target, as well as assumptions regarding substitutability between nutrients, are important factors to determine the nutrient on which to focus. Uniform decrease rates for emissions are often used in international agreements, and the results of this model showed that the costs of making such proportional decreases could be substantial.     

Limited acid deposition inferred from diatoms during the 20th century — A case study from lakes in the Tatra Mountains

Mountain lakes are usually sensitive to the effects of global and regional environmental changes. Since the second half of the 20th century, surface-water acidification has become a significant ecological problem, and many lakes in Europe and North America have anthropogenically acidified. Additionally, following reduction in emissions of sulfur (S) and nitrogen (N) compounds, recovery from acidification has been observed in many lakes. In this study, we used changes in diatom communities to reconstruct the pH histories based on changes recorded in nine Tatra lakes (Western Carpathians, Poland) since approximately 1850 AD. Overall, results indicate that acidic precipitation had little influence on lake-water pH in the Tatra Mountain lakes. Changes in diatom-inferred pH (DI-pH) generally were small and showed little evidence of acidification during the time of the highest air pollution (since the 1960s), and have shown little change since the reduction of acidic deposition since the 1990s. Lakes that showed some evidence of acidification included dystrophic lakes with low acid neutralizing capacity. However, as illustrated by the PCA trajectories of the diatom assemblages, the majority of the lakes currently contain diatom assemblages that are unlike the diatom floras that existed ca. 1850.     

三峡库区大宁河回水段水华暴发时空分布特征分析

对三峡库区一级支流大宁河巫山段2004年到2008年常规监测、水华期间加密监测以及单个测点水华垂线24小时监测数据进行了统计、分析及评价。结果发现,该河段水华暴发具有明显的时空分布特征,时间上,全年各月份均有出现,但主要集中在3～6月,占观测频次的79%;24小时内叶绿素a含量在下午16:00～18:00时间段内达到最大值;空间上,总体呈现出离入长江口越近暴发的频次越高,回水河湾较平直河道,宽阔河段较狭窄河段更重的趋势,主要集中在大宁河的开阔河段(小三峡三个峡谷之间及其上、下游开阔河段);24小时内水华垂线分布明显,0.5～5m的叶绿素a含量上层高于下层,水面下30m及以下区域叶绿素a含量变化不显著。     

Structural and functional variations of phytoplankton communities in the face of multiple disturbances

The global decline of freshwater biodiversity caused by climate change and human activities are supposed to disrupt ecosystem services related to water quality and alter the structure and function of aquatic communities across space and time, yet the effects of the combination of these factors on plankton community ecosystem has received relatively little attention. This study aimed to explore the impacts of disturbances (e.g. human activity, temperature, precipitation, and water level) on phytoplankton community structure (i.e. community evenness and community composition) and function (i.e. resource use efficiency) in four subtropical reservoirs over 7 years from 2010 to 2016. Our results showed that community turnover (measured as community dissimilarity) was positively related to disturbance frequency, but no significant correlation was found between phytoplankton biodiversity (i.e. evenness) and disturbance frequency. Phytoplankton resource use efficiency (RUE = phytoplankton biomass/ total phosphorus) was increased with a higher frequency of disturbance with an exception of cyanobacteria. The RUE of Cyanobacteria and diatoms showed significantly negative correlations with their community evenness, while the RUE of Chlorophyta exhibited a positive correlation with their community turnover. We suggest that multiple environmental disturbances may play crucial roles in shaping the structure and functioning of plankton communities in subtropical reservoirs, and mechanism of this process can provide key information for freshwater uses, management and conservation.     

Pollutant toxicology with respect to microalgae and cyanobacteria

Microalgae and cyanobacteria are fundamental components of aquatic ecosystems. Pollution in aquatic environment is a worldwide problem. Toxicological research on microalgae and cyanobacteria can help to establish a solid foundation for aquatic ecotoxicological assessments. Algae and cyanobacteria occupy a large proportion of the biomass in aquatic environments; thus, their toxicological responses have been investigated extensively. However, the depth of toxic mechanisms and breadth of toxicological investigations need to be improved. While existing pollutants are being discharged into the environment daily, new ones are also being produced continuously. As a result, the phenomenon of water pollution has become unprecedentedly complex. In this review, we summarize the latest findings on five kinds of aquatic pollutants, namely, metals, nanomaterials, pesticides, pharmaceutical and personal care products (PPCPs), and persistent organic pollutants (POPs). Further, we present information on emerging pollutants such as graphene, microplastics, and ionic liquids. Efforts in studying the toxicological effects of pollutants on microalgae and cyanobacteria must be increased in order to better predict the potential risks posed by these materials to aquatic ecosystems as well as human health.     

Facilitating access to the algal economy: Mapping waste resources to identify suitable locations for algal farms in Queensland

Algae offer a multiple-benefit opportunity as the products that can result from algal cultivation are numerous and diverse. However, commercial production of algal-derived materials is scarce and in Queensland Australia is virtually non-existent, partly due to challenges around readily available resources. In this work, the potential to regionally recycle waste nitrogen (N), phosphorus (P) and CO₂ to support algal production is considered. A feature of the work is mapping the availability of the three resources for algal cultivation (N, P and CO₂) together with climatic and land use considerations. Mapping resolution is defined by the boundaries of Queensland's (Australia) regional authorities. Layering the maps enables identification of regional hotspots for growing algae. Waste resources are shown to be most abundant in Mackay, Burdekin, Toowoomba, Cassowary and Bundaberg; regions which also have favourable eco-climatic conditions. Waste nitrogen is the limiting waste stream, in these and most other regions however additional requirements can be fixed atmospherically, whereas waste CO₂ is shown to be abundant relative to waste nutrients. It is found that, based on the availability of waste phosphorus, the top 5 most suitable regions have sufficient resources to produce around 1.1 million t/y of algal biomass. This could potentially produce 309 ML of biodiesel which is 5% of Queensland's 2011 diesel oil sales. The outcomes of this work highlight new opportunities for industrial ecology in non-urban regions.     

汉江“水华”成因分析及防治

汉江是长江的最大支流,是陕西、湖北两省沿岸居民生活用水和工业用水的重要水源。随着沿岸人口的增加,工业的发展,排污量不断增加,使汉江水质逐年下降,于近几年多次出现水华。本文在调查的基础上,对汉江水华成因进行了分析并提出了防治措施,供有关部门参考。     

藻类抗毒性效应研究现状

污染物的毒性大小决定其在环境中的安全浓度，大力开展各类污染物对藻类毒性的研究，了解各种污染物在生态系统的迁移、转化及整体生态效应以及其生态风险评价无疑具有重要的理论意义和应用价值。本文综述了近年来我国在有机污染物对单种藻类和藻类群落的毒性效应的研究成果。     

藻类在污水净化中的应用及机理简介

利用藻类的吸收，富积和降解作用，可有效地去除污水中的重金属和营养盐，还能降解多种有机毒物，与传统的污水处理方法相比，它具有原料低廉，吸附容量大，无二次污染，良好的选择性等优点，近年来，国内外对这项经济有效的净化污水的生物技术进行了广泛的研究。本文介绍了藻类净化污水的机理及其国内外研究概况。     

柴油对3种海藻光合和呼吸作用的影响

通过实验室试验，以不同浓度的柴油海水乳浊液对３种海藻了培养，并在２，４，６ｄ等时间段观察了３种海藻的光合作用和呼吸作用的变化。结果表明，海带对柴油的抗性最强，其闪是裙采和甘柴菜。较低的柴油浓度可促进３种海藻的光合和呼吸作用，而较高的柴油浓度则抑制它们的光合呼吸作用。