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Factors affecting the distribution patterns of aquatic macrophytes

response to physical and chemical environment of the lakes along an altitudinal gradient in the Himalayas, Nepal [Ph.D. Thesis], Dalhousie University, Halifax. Lacoul P., Freedman B., 2006, Environmental influences on aquatic plants in freshwater ecosystems, Environ. Rev. 14: 89-136. Lambert S.J, 2007, The environmental range and tolerance limits of British stoneworts Charophytes [PhD Thesis], University of East Anglia, Norwich. Lodge D.M., 1991, Herbivory on freshwater macrophytes, Aquat. Bot. 41: 195

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Variations of microcystins in freshwater ecosystems

Abstract

Koreivienė J., Belous O., Kasperovičienė J., 2012: Variations of microcystins in freshwater ecosystems [Mikrocystinai gėlavandenėse ekosistemose]. - Bot. Lith., 19(2): 139-148 Increased frequency, severity of harmful algae blooms and their extent worldwide have become a global challenge due to the production of toxins that are released to the water. Cyanotoxins are detected in 25-75% of blooms. Hazardous hepatotoxin-microcystin potential producers, spatial and temporal variations of toxins as well as their variations depending on environmental variables are discussed in this overview. The most common species among microcystin producers belong to the genera Dolichospermum and Microcystis. Variations of the amount of microcystins detected through the bloom are associated with the dominant cyanobacteria species or its genotype. The abundance of toxic cyanobacteria genotype and cyanotoxin values increase with the rise of water temperature and nutrient concentrations in the freshwaters. On the seasonal basis, cell-bound microcystin concentrations increase with bloom development, whereas extracellular cyanotoxin values rise with the senescing of bloom after cyanobacterial cell lysis.

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Rare Macroscopic Algae Species In The Pechora And Vychegda River Basins (North-Eastern Part Of European Russia)

Abstract

Ten rare species of macroscopic algae were found in freshwater ecosystems of the Pechora and Vychegda River basins, belonging to four divisions: Cyanoprokaryota - 1 species, Rhodophyta - 3, Chrysophyta - 1, Charophy-ta - 5. Some of these were included in the regional Red Data Books of Nenets Autonomous District and Komi Republic, others were recommended to be included. Areas of distribution were marked; algae development conditions and limiting factors were described.

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Accumulation of Cd and Pb in water, sediment and two littoral plants (Phragmites australis, Typha angustifolia) of freshwater ecosystem

Abstract

Cd and Pb concentrations were measured in water, sediment and plant organs collected from selective sites located along the Bogdanka river (Poznań, Poland) in the 2012 growing season. The aim of the investigations was to monitor changes in heavy metal (HM) concentrations in different media over the periods, as well as to evaluate potential of two littoral plants, Phragmites australis and Typha angustifolia, for phytoremediation under natural conditions. Investigations revealed differences in HM concentrations in water and sediments. Higher values were observed in sediments than in water. The decrease in concentrations of both HMs in sediments was noted in two of the three selected water reservoirs during growing seasons, which suggests the possibility of their adsorption and accumulation by aquatic plants. Both investigated plant species accumulated ample amount of Cd and Pb in underground and aboveground plant tissues, however T. angustifolia revealed higher Cd translocation potential than P. australis. The latter revealed higher Pb accumulation in two lakes. Moreover, the translocation ratio was usually higher in spring, especially for Pb, in both plant species. Increasing level of pollution load index in sediment along the Bogdanka watercourse indicates accumulation of measured HMs.

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EU Project of Life Programme “Algae Service for Life” Creates Tools for Ecological Service to Mitigate Cyanobacteria and Macroalgae Blooms in Freshwater Ecosystems

Abstract

EU international project of LIFE programme “Algae Service for LIFE” seeks to promote best practices in ecological service and development of circular economy. The goal of the project is to demonstrate integrated efficient management of nutrients and nuisance algal blooms at the catchment scale by harvesting cyanobacteria scums and macroalgae mats in various types of water bodies (rivers, lakes and estuarine lagoon). Also, it seeks to raise awareness of the national and local authorities, business community and society on the environmental, water quality and health hazard issues. The paper provides the idea of applying ecological measures to control algal blooms. Thus, issues related to the causes and mechanisms of eutrophication in inland freshwaters as well as to consequences such as algal blooms are highlighted. The measures proposed in the project are briefly discussed in the light of European Union directives.

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Contemporary threats of bacterial infections in freshwater fish

many studies conducted around the world. The great interest aroused by these topics indicates their important role in fish pathology. However, the development of disease is a complicated process, dependent not only on bacteria being capable of causing health disorders, but also on the immune status of fish, environmental conditions, and virulence of the disease agent. Therefore, changes occurring in freshwater ecosystems seem to be fundamental in the development of any disease, including emerging ones ( 18 ). The development of a particular fish disease depends

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The pathogenic Asian fish tapeworm, Bothriocephalus acheilognathi Yamaguti, 1934 (Cestoda) in the Red discus (Symphysodon discus)

Abstract

The Asian fish tapeworm, Bothriocephalus acheilognathi Yamaguti, 1934, was detected for the first time in breeding of discus fish Symphysodon discus (Perciformes, Cichlidae), a popular South American cichlid. In examined samples, the adult and juvenile cestodes of B. acheilognathi with mean intensity of infection 30 (range 19 - 47) individuals per fish were found. The infected fish displayed acute behavioral symptoms. Mortality was significant; it reached almost 80 % in youngest age categories. As treatment, praziquantel immersions in dose 2 mg per liter were well tolerated and efficacious. The risk of spreading pathogens via imported fish is actual menace for ornamental breeding fish, therefore, thorough quarantine and prophylactic measures needs to be done by all fish imports and introductions. Import and subsequent release of infected ornamental fish into freshwater ecosystems may represent serious risk for spread and establishment of the parasite in native fish species. This case study illustrates that ornamental fish play also a key role in national and international movements of parasites in freshwater habitats.

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Determining the change point for the error in the Macrophyte Index for Rivers

Summary

The consequences of the growing demand for water include a significant deterioration in its quality and a drastic decline in biodiversity, which is a serious threat to the hydrological and biocenotic balance of freshwater ecosystems. A good indicator of aquatic environment quality is macrophytes. Studies on macrophytes are one of the primary elements in the ecological status assessment of surface waters, in accordance with the guidelines of the Water Framework Directive. In Poland, research on the ecological status of rivers with regard to macrophytes has been carried out since 2008, using the Macrophyte Index for Rivers (MIR), which takes into account the number and coverage of macrophyte taxa. An analysis of numbers of species that need to be indicated at a site for valid assessment of the ecosystem was conducted on the basis of studies on macrophytes from 2008–2013, at 60 sites in small lowland rivers with a sandy substrate, of which 20 sites were selected on the most diverse watercourses: the least clean (quality class V), moderate (quality class III), and the cleanest (quality class I). The results of the botanical studies served to assess the completeness of the samples (the number of species recorded at a site) used to evaluate the ecological status of a river. The proposed analyses enabled estimation of the approximate number of species required to determine the MIR for rivers in each quality class.

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Roosting Colony of Cormorants (Phalacrocorax Carbo Sinensis L.) as a Source of Nutrients for the Lake

Abstract

Since 2005, great cormorants have been observed on the Lake Góreckie (Wielkopolski National Park) shoreline. The population of these birds occurring within the lake has gradually increased. In autumn 2008, more than 100 individuals were observed. In the period 2009-2012 the number of birds occupying the island periodically exceeded 250 individuals. So far, there is no breeding colony of great cormorants, but the birds have established a roosting colony on the island. In the period 2009-2012 we conducted research on the impact of the colony of great cormorants on the accumulation of nitrogen, phosphorus and other elements in soils beneath the colony and transfer of chemical elements from the colony to a nearby freshwater ecosystem. Our results show that a relatively small and recent colony of great cormorants can significantly affect the chemistry of soil. Compared to a control, the soil beneath the colony was characterized by statistically higher concentrations of nitrogen and phosphorus. A significant accumulation of nutrients was observed in the topsoil zone (to a depth of about 20 cm). Enrichment of soil in chemical elements has resulted in their further transport to a nearby lake. Compared to the control, the groundwater and surface runoff from the colony area revealed several-fold higher concentrations of nitrogen and phosphorus. The maximum abundance of cormorants in the roosting colony was reflected in the elevated concentrations of nitrogen and phosphorus in the littoral water near the colony. Our study demonstrates that the roosting colony of great cormorants can play a significant role in accelerating the eutrophication of surface waters.

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Life table estimates of the invasive snail Physa acuta Draparnaud, 1805, occurring in India

Abstract

The life table characteristics of the invasive snail Physa acuta were assessed in the laboratory using the individuals occurring in a newly colonised area in Burdwan, West Bengal, India. Using the changes in the shell length and the body weight of the snails as surrogate, the population growth of the snails was estimated along with longevity and the fecundity schedule. The cohort of P. acuta lived for a maximum of 22 weeks with a life expectancy (ex) of 7.27 weeks and the age-specific survivorship being 0.825. Increment of the shell length of the snails complied with the von Bertalanffy growth equation, lt = 11.75(1 − exp−0.17(t−0.06)), and the observed and the expected data of the length at time t (lt) did not vary significantly (z score = 0.230; P = 0.818; n=20 pairs). Following attainment of sexual maturity between 28 and 42 days, oviposition continued till 20 weeks time, with 0.1-10 eggs laid by each individual. The eggs present per capsule remained between 01 and 11, whilst the net reproductive rate (R0), intrinsic rate of increase (rm) and the finite rate of increase (λ) were 116.07, 0.1 and 1.11, respectively. The observations are similar to those made earlier on the same species but from African and South American continents. The results of the present observation are pioneer in providing the initial studies about the life history of the invasive snail P. acuta in Indian context. Using the present information as a basis, further studies including long-term population monitoring should be initiated to understand the effects of the invasive snail P. acuta in the freshwater ecosystem of West Bengal, India.

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