Water hygiene of two swimming pools: microbial indicators

The microbiological quality of the water of two swimming pools was evaluated to determine which organisms might be the best indicators of pollution. Membrane filtration gave low numbers of the common indicators of faecal pollution but high counts of the indigenous skin bacteria. As illnesses normally contracted in a swimming pool are mostly those of the skin rather than intestinal, it is suggested that the best indicators of the hygienic condition of water in a swimming pool are staphylococci because of their resistance to disinfection, high numbers in the environment, and ease of recovery.     

Water hygiene of two swimming pools: microbial indicators

The microbiological quality of the water of two swimming pools was evaluated to determine which organisms might be the best indicators of pollution. Membrane filtration gave low numbers of the common indicators of faecal pollution but high counts of the indigenous skin bacteria. As illnesses normally contracted in a swimming pool are mostly those of the skin rather than intestinal, it is suggested that the best indicators of the hygienic condition of water in a swimming pool are staphylococci because of their resistance to disinfection, high numbers in the environment, and ease of recovery.     

Using Amplicon Sequencing To Characterize and Monitor Bacterial Diversity in Drinking Water Distribution Systems

Drinking water assessments use a variety of microbial, physical, and chemical indicators to evaluate water treatment efficiency and product water quality. However, these indicators do not allow the complex biological communities, which can adversely impact the performance of drinking water distribution systems (DWDSs), to be characterized. Entire bacterial communities can be studied quickly and inexpensively using targeted metagenomic amplicon sequencing. Here, amplicon sequencing of the 16S rRNA gene region was performed alongside traditional water quality measures to assess the health, quality, and efficiency of two distinct, full-scale DWDSs: (i) a linear DWDS supplied with unfiltered water subjected to basic disinfection before distribution and (ii) a complex, branching DWDS treated by a four-stage water treatment plant (WTP) prior to disinfection and distribution. In both DWDSs bacterial communities differed significantly after disinfection, demonstrating the effectiveness of both treatment regimes. However, bacterial repopulation occurred further along in the DWDSs, and some end-user samples were more similar to the source water than to the postdisinfection water. Three sample locations appeared to be nitrified, displaying elevated nitrate levels and decreased ammonia levels, and nitrifying bacterial species, such as Nitrospira, were detected. Burkholderiales were abundant in samples containing large amounts of monochloramine, indicating resistance to disinfection. Genera known to contain pathogenic and fecal-associated species were also identified in several locations. From this study, we conclude that metagenomic amplicon sequencing is an informative method to support current compliance-based methods and can be used to reveal bacterial community interactions with the chemical and physical properties of DWDSs.     

Intestinal barrier function of Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis> L.) post smolts is reduced by common sea cage environments and suggested as a possible physiological welfare indicator

Background  

Fish farmed under high intensity aquaculture conditions are subjected to unnatural environments that may cause stress. Therefore awareness of how to maintain good health and welfare of farmed fish is important. For Atlantic salmon held in sea cages, water flow, dissolved oxygen (DO) levels and temperature will fluctuate over time and the fish can at times be exposed to detrimentally low DO levels and high temperatures. This experimental study investigates primary and secondary stress responses of Atlantic salmon post smolts to long-term exposure to reduced and fluctuating DO levels and high water temperatures, mimicking situations in the sea cages. Plasma cortisol levels and cortisol release to the water were assessed as indicators of the primary stress response and intestinal barrier integrity and physiological functions as indicators of secondary responses to changes in environmental conditions.     

The Pseudomonas group as an indicator of potential regrowth in water distribution systems

The regrowth of micro-organisms in the water distribution system is assisted by the presence of biodegradable organic matter (BDOC). The low concentration of available organic carbon in this type of water favours the growth of bacteria belonging to the Pseudomonadaceae family, as this group can grow better at low concentrations of substrate than other bacteria also present in the distribution system. Although the genus Aeromonas has already been adopted as an indicator of this potential regrowth, members of the Pseudomonadaceae have not yet been proposed as indicators of potential bacterial regrowth in the water distribution system. The results are presented of a year-long study of the Barcelona distribution system in which the presence of Pseudomonas and Aeromonas was analysed and the validity of these micro-organisms as indicators of potential regrowth in the distribution system was assessed. It seems that, at least in the drinking waters of the Barcelona area, Pseudomonas is a better indicator of potential bacterial regrowth than Aeromonas.     

安康水库表层浮游藻类群落结构及其与环境因子的关系

为了解安康水库表层水质与浮游藻类群落现状以及浮游藻类群落结构与环境因子之间的关系,于2012年1—12月对水库表层水进行每月一次的采样,分别对浮游藻类分布状况和理化因子进行分析.利用Shannon指数(H)和Pielou均匀度指数(J)分析浮游藻类群落特征,根据理化指标和综合营养状态指数(TSI)评价水体营养状态.共检测到浮游藻类7门110属,丰度为0.11×10⁴～2.08×10⁴ cells·L^-1.藻类组成、污染指示种分布情况、多样性分析和TSI显示安康水库表层属于中污染水质,处于中营养状态.此外,高密度投饵水产养殖及生活污水直接排放入库对水质产生负面影响,支流岚河的水质状况也较差.典范对应分析(CCA)结果显示,测定的8个环境因子中,不同季节影响浮游藻类群落组成及分布的环境因子不同,且氮是影响浮游藻类组成的主要营养盐因子.理化指标分析显示,安康水库表层水大体满足Ⅱ类水标准,水质良好.但部分采样点的总氮出现差于Ⅱ类水标准的现象,表明安康水库水质有变差的趋势.     

A preliminary study of the Odonata of S’Albufera Natural Park, Mallorca: status, conservation priorities and bio-indicator potential

This study obtained baseline information for adult Odonata and assessed their conservation priorities and suitability as biological indicators in S’Albufera Natural Park in Mallorca, Spain. At this site, human activities in and around the wetland have raised concerns about their impact on the ecosystem. Investigations on adult diversity produced records of 14 species (four Zygoptera and 10 Anisoptera) and included the first record of Erythromma viridulum for the park. Detrended Correspondence Analysis (DCA) ordination categorised study sites according to their geographical locations in the park and showed clustering of the sites around particular species based on these locations. This pattern might reflect the differences in brackishness in water supplied by different water sources. Canonical Correspondence Analysis (CCA) indicated that some environmental factors were related to particular species. Water flow, vegetation, and depth and size of a water body could discriminate stenotopic species from eurytopic species. Only a few species appeared to be tolerant to the sites with high salinity and low oxygen concentration. The ordination results can be useful for establishing conservation priorities with information of species diversity, abundance, distribution and flight period. Although, with the current limited basic information, the use of Odonata species as biological indicators seems to be difficult, some clear relationships between environmental factors and particular species indicate the great potential of using adult Odonata as biological indicators in the park.     

乌梁素海冰封期浮游植物分布特征及其与水质指标的关系北大核心CSCD

为揭示寒旱区冰封期富营养化湖泊水体中浮游植物群落结构及其与水质指标的响应关系,该研究以乌梁素海为对象,于2019年1月在湖区设立12个采样点采集水样及浮游植物,通过对浮游植物定性定量检测和水体理化性质测定分析,以明确冰封期乌梁素海浮游植物群落结构空间变化特征及主要水质指标的分布规律;结合RDA分析和Pearson相关性分析揭示了浮游植物与水质指标的响应关系,为水体富营养化程度评估及防控提供理论依据。结果显示:(1)冰封期乌梁素海12个样点的水质指标特征差异明显,各水质指标从北到南具有不同的变化趋势。(2)冰封期乌梁素海共检出浮游植物61种,其中隐藻门的丰度最高(4.76×10^(6)个·L^(-1)),甲藻门的生物量最高(18.09 mg·L^(-1)),但湖区不同位置的优势浮游植物类群有所差异,北湖区蓝隐藻和伪鱼腥藻丰度明显高于南湖区。(3)不同种类的浮游植物在空间分布上存在明显的差异,且在P3样点的多样性最低,P8样点的多样性最高,并发现中、下湖区物种类型多且组成较为均匀。(4)浮游植物的丰度与TP呈显著正相关关系,生物量与TP呈极显著正相关关系,多样性指数与TP呈正相关关系。研究表明,冰封期乌梁素海水体处于中等营养水平,水体中总磷(TP)含量是影响浮游植物物种丰度和生物量的主要影响因子;寒旱区冰封期富营养化湖泊浮游植物分布特征为北湖区隐藻门、蓝藻门和甲藻门占优势;南湖区中绿藻门丰度最高。     

The use of diatoms to assess past and present water quality

Abstract Diatoms possess a number of attributes which contribute to their suitability as biological indicators. They are highly sensitive to water chemistry changes, abundant in aquatic environments, largely cosmopolitan in distribution, less habitat dependent than macroinverte-brates and have a well-studied taxonomy and ecology. Furthermore, the preservation of diatom valves in lake sediments means that they can provide otherwise unavailable baseline data which can be used to assess and contextualize human impacts on aquatic ecosystems. The value of diatoms as bioindicators in contemporary and palaeolimnological studies has been well established overseas. Despite this, they have been under-utilized in Australia. This paper outlines some of the applications and potential for the use of diatoms as biological indicators in Australia.     

华南植物园的豆娘及其栖境选择

对广州华南植物园的豆娘的生物学特征及特有的栖境选择进行了初步的调查研究,同时在实验室的条件下对豆娘幼虫进行培育.通过对各类豆娘种类的水体状况、栖境水生植被、不同季节的分布情况研究,发现某些豆娘由于其对生境条件的敏感,因而对于湿地水生生物群落的结构变化及水质的污染状况可以起到生态指示的作用.本研究对于水质污染的生物监测、豆娘栖息地的保护、城市中对于湿地的兴建和改造有十分重要的意义.     

Helminth communities in avocets: importance of the compound community

This paper reports patterns of similarity and overlap in species presence and patterns of linear distribution of intestinal helminths in 22 avocets from 4 populations. Avocets collected from ephemeral bodies of water in Alberta and Manitoba had communities composed largely of species that are avocet specialists plus some that are host generalists. The composition of helminth communities in these hosts was similar to that reported in earlier surveys of avocet helminths. There was little evidence for competition between helminth species in these communities. In contrast, avocets collected from permanent bodies of water in Alberta had communities composed largely of species that are specialists in various duck species, particularly lesser scaup. These helminths were superimposed on the normal community, fitting into linear gaps along the intestine but also overlapping the distributions of avocet specialists. These lesser scaup specialists exhibit interactive patterns amongst themselves and, to some extent, with avocet specialists. Helminth communities in avocets from ephemeral bodies of water have vacant niches and are largely isolationist in nature. Those in avocets from permanent bodies of water are saturated and are more interactive in nature.     

Effects of hexavalent chromium at non-lethal concentrations on the enzymology of the intestine of Salmo gairdneri and Dicentrarchus labrax (Pisces)

Effects of non lethal concentrations of hexavalent chromium on intestinal enzymology of Salmo gairdneri and Dicentrarchus labrax (Pisces). The effects of an exposure to potassium dichromate on intestinal enzyme activities (Alkaline phosphatase, maltase, leucine amino peptidase and ATPases) have been studied on a fresh water fish (Salmo gairdneri) and a salt water fish (Dicentrarchus labrax). Fish were exposed at seasonal temperatures (13 or 21 degrees C) to toxic concentrations equal to 1/10 of the 24 h-LC 50 (i.e. 18 mg/l Cr for trout and 5 mg/l Cr for bass) during respectively 13 and 21 days. Intoxicated trout stopped feeding and showed a decrease in their intestinal weight at the end of the experiments. A decrease of brush border membrane activities (Alkaline phosphatase, maltase and leucine amino peptidase) were also observed. These alterations have been interpreted as the consequence of the chromium induces fasting. Intoxicated bass showed no alterations of their feeding habits. Two specific effects of chromium on enzyme activities have been found: a severe decrease of the alkaline phosphatase activity and an increase of the Na/K ATPase activity. These enzyme activities could be useful indicators of chromium intoxication in marine fish.     

Distribution of living polycystine radiolarians in the Gulf of Mexico and Caribbean Sea,and comparison with the sedimentary record

Plankton tows and bottom samples from the Gulf of Mexico and Caribbean Sea were examined to study the distribution, ecology, and preservation of modern radiolarians. Abundances of radiolarians from this region, an area of low primary productivity, are low. Diversities are variable in the surface waters; diversity indices decrease with increasing water depth, indicating that fewer niches are occupied by radiolarians in deep water. Living radiolarians are confined to specific water masses, some species ranging between two masses, and can be used as indicators of these water masses in ecologic or paleo-oceanographic studies.The record of radiolarian tests present in the sediment is dissimilar to the record of living radiolarians in the water column, but is similar to the record of empty tests falling through the water column. This indicates that a considerable length of time is involved in the settling of radiolarian tests. It also confirms the validity of ecologic interpretations based on a study of sediments only.     

东海浮游糠虾类生态类型划分及其对水团的指示作用

根据1997-2000年东海23°30′-33°N、118°30′-128°E海域4个季节海洋调查资料,对浮游糠虾类丰度和同步的表层温、盐度数据进行曲线拟合,构造数学模型,计算糠虾类分布的最适温度和盐度,分析其地理分布和季节分布特征,确定物种的生态类型.结果表明:宽尾刺糠虾(Acanthomysis latiscauda)、漂浮囊糠虾(Gastrosaccus pelagicus)、中华节糠虾(Siriel-la sinensis)和美丽拟节糠虾(Hemisiriella pulchra)是亚热带近海种,同时具有暖温种的特征;极小假近糠虾(Pseudanchialina pusilla)、东方原糠虾(Promysis orientalis)、小红糠虾(Erythropsminuta)和双眼准异糠虾(Anisomysis bipartoculata)虽是亚热带外海种,但具有热带大洋种特征.东海浮游糠虾类大多数物种的最适温、盐度偏低,冬春季在东海近海有更多的分布,因而具有暖温近海类型的生物学特征,这是该类浮游动物区别于其它浮游动物类群的重要特征.宽尾刺糠虾、中华节糠虾和美丽拟节糠虾的较高丰度区,也正是长江冲淡水与暖流水团交汇、沿岸水团与外海高盐水团交汇的位置.小红糠虾和双眼准异糠虾可作为暖流指示种.四刺端糠虾(Doxomysis quadrispinosa)和东方原糠虾是台湾暖流指示种.其它种均不是良好的水团指示种.     

Existence of serotonin and neuropeptides-immunoreactive endocrine cells in the small and large intestines of the mole-rats (Spalax leucodon)

The present study was conducted to clarify the regional distribution and relative frequency of endocrine cells secreting serotonin, substance P (SP), cholecystokinin-8 (CCK-8), vasoactive intestinal polypeptide (VIP) and neurotensin in the small and large intestine of the mole-rats (Spalax leucodon), by specific immunohistochemical methods. In the small and large intestine of mole-rats (Spalax leucodon), serotonin, SP and VIP were identified with various frequencies, but CCK-8 and neurotensin were not observed. Most of the IR cells in the small and large intestine were located in the intestinal crypt and epithelium however, they were more frequency in the intestinal crypt. Serotonin-IR cells were detected throughout the whole intestinal tract, predominantly in the duodenum and colon. SP-IR cells were demonstrated throughout the whole intestinal tract except for the ileum and rectum with highest frequencies in the cecum. VIP-IR cells were found in all parts of the small intestine except for the large intestine.In conclusion, the general distribution patterns and relative frequency of intestinal endocrine cells of the mole-rats (Spalax leucodon) was similar to those of some rodent species. However, some species-dependent unique distributions and frequencies characteristics of endocrine cells were also observed in the present study.     

Evidence for Coexistence of Distinct Escherichia coli Populations in Various Aquatic Environments and Their Survival in Estuary Water

Escherichia coli, a commensal bacterium from the intestinal tracts of humans and vertebrate animals, has been used as one of two bacterial indicators of fecal contamination, along with intestinal enterococci, to monitor the microbiological quality of water. However, water environments are now recognized as a secondary habitat where some strains can survive. We investigated the survival of E. coli isolates collected from bodies of water in France exhibiting distinct profiles of contamination, defined according to the following criteria: vicinity of the point sources of contamination, land use, hydrology, and physicochemical characteristics of the receiving water. We selected 88 E. coli strains among a collection of 352 strains to carry out a microcosm experiment in filtered estuarine water for 14 days at 10°C. The relationship between the survival of E. coli strains and genotypic and phenotypic characteristics was analyzed. This work showed that distinct E. coli survival types, able to survive from between 7 and 14 days to less than 2 days, coexisted in the water. E. coli isolates that rapidly lost their culturability were more frequently isolated in water recently contaminated by fecal bacteria of human origin, and most were multiresistant to antibiotics and harbored several virulence factors. In contrast, persistent strains able to survive from 4 to 14 days were more often found in water with low levels of fecal bacteria, belonged mainly to the B1 phylogroup, often harbored only one virulence factor, kspE or ompT, and were able to grow at 7°C.     

Potential usefulness of bacteriophages that infect Bacteroides fragilis as model organisms for monitoring virus removal in drinking water treatment plants.

The presence of bacteriophages at different stages in three drinking water treatment plants was evaluated to study the usefulness of phages as model organisms for assessing the efficiency of the processes. The bacteriophages tested were somatic coliphages, F-specific coliphages, and phages infecting Bacteroides fragilis. The presence of enteroviruses and currently used bacterial indicators was also determined. Most bacteriophages were removed during the prechlorination-flocculation-sedimentation step. In these particular treatment plants, which include prechlorination, phages were, in general, more resistant to the treatment processes than present bacterial indicators, with the exception, in some cases, of clostridia. Bacteriophages infecting B. fragilis were found to be more resistant to water treatment than either somatic or F-specific coliphages or even clostridia. Enteric viruses were found only in untreated water in low numbers, and consequently, the efficiency of the plants in the removal of viruses could not be evaluated with precision. The numbers and frequencies of detection of the various microorganisms in water samples taken in the distribution network served by the three plants confirm the results found in the finished water at the plants.     

额济纳天然绿洲景观演化驱动因子分析

额济纳天然绿洲位于我国西北干旱内陆河流域黑河流域下游 ,近年来 ,随着黑河中、上游地区下泄地表径流量的减少 ,额济纳天然绿洲景观退化严重。基于研究区近十几年来的景观演化总体特征 ,分别从气候因素、水文因素、人类干扰因素等几个主要的景观变化驱动因子入手 ,探讨其演化机制、揭示其演化规律。研究结果表明 :黑河流域中、上游下泄地表径流量的锐减而导致研究区地下水水位下降、地下水矿化度升高以及水质恶化是额济纳天然绿洲景观发生退化的根本原因 ,绿洲人类活动强度的增加、绿洲关键区域的超载和过牧以及蒸发度指数的升高、湿润系数的下降均加剧了研究区景观退化的程度。     

Diversity, persistence, and virulence of Aeromonas strains isolated from drinking water distribution systems in Sweden

The Aeromonas populations in 13 Swedish drinking water distribution systems, representing different treatments, were investigated. From each system, water samples were collected four times during the period from May to September 1994 from raw water and water after treatment and at two to five sites within the distribution system. In total, 220 water samples were collected. From samples containing presumptive Aeromonas, up to 32 colonies were analyzed by the PhenePlate Aeromonas (PhP-AE) system, which is a highly discriminating biochemical fingerprinting method. Selected isolates from different phenotypes (PhP types) were further identified by the API 20 NE system and by gas-liquid chromatography analysis of fatty acid methyl esters (FAMEs). Selected isolates were also assayed for their potential to produce hemolysin and cytotoxin and for their ability to adhere to human intestinal cells. In total, 117 water samples (53%) contained presumptive Aeromonas which numbered up to 10(6) CFU/100 ml in raw water and up to 750 CFU/100 ml in tap water. Among the 2,117 isolates that were subjected to typing by the PhP-AE system, more than 300 distinct PhP types were found, of which the majority occurred only sporadically. Raw (surface) water samples usually contained many different PhP types, showing high diversity indices (Di) (median Di = 0.95). The Aeromonas populations in samples collected from within the distribution systems were less diverse (median Di = 0.58) and were often dominated by one major PhP type that was found on several sampling occasions. Seventeen such major PhP types could be found and were represented in 1,037 isolates (49%). Identification by API 20 NE and FAME analysis revealed that most of the major PhP types were Aeromonas hydrophila or belonged to unidentified Aeromonas species. Hemolysin and cytotoxin production was observed in most major PhP types (representing 87 and 54% of the assayed isolates, respectively), and adherence was found in 89% of the isolates that produced cytotoxin. Thus, the data presented here show that although raw water may contain very diverse Aeromonas populations, the populations seemed to be remarkably stable within the studied water distribution systems, and that some potentially pathogenic Aeromonas strains could persist for several months in drinking water.     

Water and NaCl absorption by the intestine of the tilapiaSarotherodon mossambicus adapted to fresh water or seawater and the possible role of prolactin and cortisol

Summary Rates of intestinal water, sodium and chloride absorption in tilapia, adapted to fresh water (FW) and seawater (SW), were measured in vitro, using noneverted sacs made from the anterior, middle and posterior intestinal regions. The anterior intestine from SW fish showed considerably less water, sodium and chloride absorption compared with that seen in FW fish. The middle intestine showed either minimal absorption or some secretion in both FW and SW. In the posterior intestine, water absorption was only limitedly affected by SW-adaptation, but sodium and chloride absorption rates were significantly lower in SW fish. Reductions in water absorption were already evident in the anterior intestine 24 h after transfer to 1/3 SW but reached lower levels 3 to 5 days following transfer to 100% SW. Thus, the anterior intestine of tilapia responds to increased environmental salinity by decreasing uptake of ions, whereas the posterior intestine maintains similar water absorption in both FW and SW, although ion absorption is lower in SW.Prolactin administration to SW fish augmented sodium and water absorption in the anterior intestine but had no effect on chloride absorption. In contrast, cortisol administration to FW fish decreased absorption of sodium, chloride and water to levels usually seen in SW fish. The observed effects of these hormones in tilapia intestinal absorption may be confined to the specialized anterior intestinal region in this species; hormonal effects on the rest of the intestine were not examined.