A scientometric study of the limnological societies: inferences of research collaboration and core topics based on publication networks

Scientometric analysis of limnological societies and related publications revealed complex relationships among research topics and research collaborations. We applied scientometric analysis, word networks, bibliographic coupling, and author networks analysis, to 34 777 publications related to limnology and monsoon research. We analyzed usage frequencies of limnology-related words in a Google corpus and found that usage frequencies of most limnological terms peaked during the 1980s. Social interest in the term “limnology” showed a gradually decreasing trend after the late 1990s. Monsoon research was focused in the Asian–Indian region but not in the European, African, and American regions. Word networks of limnological studies related to monsoons were mainly grouped into 3 clusters (Indian monsoons, East Asian monsoons, and monsoon assessment clusters). In the citation network of limnology journals, water quality, plankton, and invertebrate research groups generally showed strong internal citation networks. An author connection map of the limnological societies revealed strong modulators in the international societies, whereas research collaboration was rather limited to small groups within the entire network. This retrospective analysis will provide meaningful information to further develop and enhance international collaboration within limnological studies

Persistent cyanobacteria blooms in artificial water bodies : an effect of environmental conditions or the result of anthropogenic change

Algal blooms are an emerging problem. The massive development of phytoplankton is driven partly by the anthropogenic eutrophication of aquatic ecosystems and the expansion of toxic cyanobacteria in planktonic communities in temperate climate zones by the continual increase in global temperature. Cyanobacterial harmful algal blooms (CyanoHABs) not only disturb the ecological balance of the ecosystem, but they also prevent the use of waterbodies by humans. This study examines the cause of an unusual, persistent bloom in a recreational, flow-through reservoir; the findings emphasize the role played by the river supplying the reservoir in the formation of its massive cyanobacterial bloom. Comprehensive ecosystem-based environmental studies were performed, including climate change investigation, hydrochemical analysis, and bio-assessment of the ecological state of the river/reservoir, together with monitoring the cyanobacteria content of phytoplankton. Our findings show that the persistent and dominant biomass of Microcystis was related to the N/P ratio, while the presence of Aphanizomenon and Dolichospermum was associated with the high-temperature end electric conductivity of water. Together with the increase in global temperature, the massive and persistent cyanobacterial bloom appears to be maintained by the inflow of biogenic compounds carried by the river and the high electric conductivity of water. Even at the beginning of the phenomenon, the reservoir water already contained cyanobacterial toxins, which excluded its recreational use for about half the year

Opportunities and challenges for the sustainability of lakes and reservoirs in relation to the sustainable development goals (SDGs)

Emerging global threats, such as biological invasions, climate change, land use intensification, and water depletion, endanger the sustainable future of lakes and reservoirs. To deal with these threats, a multidimensional view on the protection and exploitation of lakes and reservoirs is needed. The holistic approach needs to contain not just the development of economy and society but also take into account the negative impacts of this growth on the environment, from that, the balance between the three dimensions can be sustained to reach a sustainable future. As such, this paper provides a comprehensive review on future opportunities and challenges for the sustainable development of lakes and reservoirs via a critical analysis on their contribution to individual and subsets of the Sustainable Development Goals (SDGs). Currently, lakes and reservoirs are key freshwater resources. They play crucial roles in human societies for drinking water provision, food production (via fisheries, aquaculture, and the irrigation of agricultural lands), recreation, energy provision (via hydropower dams), wastewater treatment, and flood and drought control. Because of the (mostly) recent intensive exploitations, many lakes and reservoirs are severely deteriorated. In recent years, physical (habitat) degradation has become very important while eutrophication remains the main issue for many lakes and ponds worldwide. Besides constant threats from anthropogenic activities, such as urbanization, industry, aquaculture, and watercourse alterations, climate change and emerging contaminants, such as microplastics and antimicrobial resistance, can generate a global problem for the sustainability of lakes and reservoirs. In relation to the SDGs, the actions for achieving the sustainability of lakes and reservoirs have positive links with the SDGs related to environmental dimensions (Goals 6, 13, 14, and 15) as they are mutually reinforcing each other. On the other hand, these actions have direct potential conflicts with the SDGs related to social and economic dimensions (Goals 1, 2, 3 and 8). From these interlinkages, we propose 22 indicators that can be used by decision makers for monitoring and assessing the sustainable development of lakes and reservoirs

Evaluation of lanthanum/iron oxide amended formable biochar for phosphorous and nitrogen removal in wastewater: preparation, mechanism, and application.

Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.Abstract available in PDF

Benthic Macroinvertebrates and Zooplankton Communities as Ecological Indicators in Urban Wetlands of Argentina

Urban aquatic ecosystems are important sources of fresh water for multiple uses, but often receive a point or diffuse anthropic contamination. Benthic and zooplankton invertebrates are sensitive to water quality, being good indicators of ecosystem health. In this study, the composition and structure of benthic and zooplankton communities and environmental variables were analyzed seasonally in six urban wetlands of Santa Fe City (Argentina). We present the effect of water quality on both communities as bioindicators of ecological conditions, using different community attributes, functional feeding groups, and biotic indices. For the benthic community, the Macroinvertebrate Index for Pampean Rivers (IMRP) and the Benthic Community Index (BCI) were selected. For the zoo-plankton community, abundance of rotifers/abundance of total zooplankters, microcrustaceans/total zooplankters, cladocerans/total zooplankters, and macrozooplankton/microzooplankton ratios were applied. A functional feeding groups (FFGs) classification, adapted from the literature, is proposed for zooplankters. The urban wetlands showed a gradient from the most to the least disturbed sites. Some benthic and zooplankton species were identified as excellent bioindicators of pollution, and the FFGs and biotic indices revealed the ecological condition of each urban wetland. The present study contributes to the enhancement of management practices in urban landscapes aiming to maintain ecosystem services in sustainable cities.Fil: Arias, María Julieta. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Laboratorio de Ecotoxicologia; ArgentinaFil: Vaschetto, Pablo Andrés. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Laboratorio de Ecotoxicologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Marchese Garello, Mercedes Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Regaldo, Luciana María. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Laboratorio de Ecotoxicologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Gagneten, Ana María. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Laboratorio de Ecotoxicologia; Argentin

Anthropogenic impact on phosphorus input in surface sediments of the Sergipe River hydrographic basin

Phosphorus is essential to ensure the trophic state of aquatic environments. This can be derived from natural or anthropogenic sources and its high concentration can be harmful and generate impacts on the ecosystem. In this context, it is necessary to control the concentration of phosphorus in aquatic environments. The main objective of this work is to determine and evaluate the concentration of phosphorus in surface sediments from nineteen points distributed in the hydrographic basin of the Sergipe River. For this, the methodology used was the Standards Measurements and Testing (SMT) protocol, a method adapted by Williams et al. In addition, the efficiency of the analytical method was analyzed through the limit of detection (LoD) and the limit of quantification (LoQ), which varied between 0.80 and 1.13 µg. g-1 , and 2.60 and 3.24 µg g-1 , respectively. The analytical method proved to be efficient since the agreement between certified reference material was between 98 and 105%. The mean concentrations of PT, PI, PO, PAP, PNAP, Fe, Al and MO were 162.50, 100.27, 53.84, 58.78, 34.70, 1.61, 5.31 and 1.04, respectively. The highest concentrations of total phosphorus were found in points P01, P09 and P10. Points P16, P17, and P18 presented the lowest values of total phosphorus. It is worth mentioning that the CONAMA Resolution 454/2012 establishes a maximum limit of phosphorus allowed for dredged material of 2000 mg/kg for PT. Through the principal component analysis (PCA) and hierarchical clustering (HCA), it was possible to observe that the sample points with higher concentrations of phosphorus are better grouped in PC1 and the other points showed greater dispersion. Thus, the points P01, P09 and P10 showed indicative of areas with intense agricultural and industrial exploitation, corroborating for the higher concentrations of phosphorus, and the points P16, P17 and P18 may be related to the natural origin of phosphorus in sediments.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESO fósforo é fundamental para garantir o estado trófico de ambientes aquáticos. Este pode ser derivado de fontes naturais ou antropogênicas e sua elevada concentração pode ser prejudicial e gerar impactos ao ecossistema. Neste contexto, faz-se necessário o controle da concentração de fósforo em ambientes aquáticos. Este trabalho tem como principal objetivo determinar e avaliar a concentração de fósforo em sedimentos superficiais de dezenove pontos, distribuídos na bacia hidrográfica do Rio Sergipe. Para tanto, a metodologia utilizada foi o protocolo Standards Measurements and Testing (SMT), método adaptado por Williams e colaboradores. Além disso, foi analisado a eficiência do método analítico através do limite de detecção (LoD) e o limite de quantificação (LoQ), que variaram entre 0,80 e 1,13 µg. g-1 , 2,60 e 3,24 µg g-1 , respectivamente. O método analítico mostrou-se eficiente, já que a concordância entre o material de referência certificado se apresentou entre 98 e 105%. As médias das concentrações de PT, PI, PO, PAP, PNAP, Fe, Al e MO foram,162,50, 100,27, 53,84, 58,78, 34,70, 1,61, 5,31 e 1,04 respectivamente. As maiores concentrações de fósforo total foram averiguadas nos pontos P01, P09 e P10. Já os pontos P16, P17 e P18 apresentaram os menores valores de fósforo total. Vale ressaltar que, a Resolução do CONAMA 454/2012 estabelece limite máximo de fósforo permitido para material dragado de 2000 mg/kg para PT. Através da análise de componentes principais (PCA) e Agrupamento hierárquico (HCA), foi possível observar que, os pontos amostrais com maiores concentrações de fósforo apresentam-se mais bem agrupados na PC1 e os demais pontos, apresentaram maiores dispersões. Desta forma, os pontos P01, P09 e P10 apresentaram indicativo de áreas com intensa exploração agrícola e industrial, corroborando para as maiores concentrações de fósforo, e os pontos P16, P17 e P18 pode estar relacionado a origem natural de fósforo em sedimentos.São Cristóvã

Effects of lake water level fluctuations on macrophytes and littoral macroinvertebrates

Freshwater systems are declining globally in both quality and extent and are currently losing biodiversity faster than other ecosystem types due to human impacts. Hydromorphological alterations are now the primary form of pressure on European freshwaters, occurring principally in the form of water level fluctuations (WLF) and altered flows. Modified, anthropogenic WLF remain a largely overlooked pressure on lake ecosystems, despite having a profound influence on the littoral zone, the part of a lake where biodiversity is usually concentrated. Anthropogenic alteration to lake water-level regime has been identified as a priority for investigation in order to increase understanding of ecological effects, assessment abilities and mitigation measures. There is a lack of research quantifying impacts of WLF on biota relative to other known pressures, despite the certainty that many lakes are exposed to these stressors. To address these knowledge gaps, this thesis focused on assessing the responses of littoral macrophytes and macroinvertebrates to WLFs in Scottish lakes, relative to other environmental drivers at lake and sub-lake levels. The research presented in this thesis confirms that WLFs have a dominant and overall negative association with aquatic macrophyte species richness, altering community composition, and overriding effects of other established influences (i.e. elevation, lake surface area, and phosphorus). In addition, regulation of lake water levels per se was a negative environmental factor, relative to other predictors. WLF was also the dominant and negative factor related to macroinvertebrate family richness, relative to all other significant environmental predictors, including lake elevation, perimeter, and nutrient concentrations. The range of lake WLF was also established as a key factor in explaining variation in macroinvertebrate composition. Subdivision of lakes by the morpho-edaphic index (MEI), an index formulated from lake depth and alkalinity, revealed variation in the factors associated aquatic vegetation with lake type. Macrophyte richness in lower MEI lakes, being influenced by WLFs and regulation, and with clear distinctions between plant communities in higher vs lower MEI lake types. Additional subdivision of lakes by stable or fluctuating water level regimes added further clarity. Macrophyte communities differed significantly with MEI and stability regime, with species indicative of each lake type showing contrasting life history and reproduction strategies, consistent with differences in their sensitivity to water level change. Invertebrate communities differed significantly with stability regime, with MEI having no importance. Indicator species varied by life-span, mobility and reliance on littoral vegetation. Stable regimes were characterised by Hydrachnidae, Asellidae, Haliplidae and several gastropod families, whilst Siphlonuridae were indicative of fluctuating regimes. This thesis establishes water level mediated impacts, from sub-lake factors such as littoral substrate composition and shore slope, to the robust but declining isoetid plant, Littorella uniflora. Modification of water levels resulted in uncoupling of L. uniflora from the littoral zone by way of increasing shore slope, distance, and height. Morphological traits such as root-to-shoot ratios were influenced negatively by increased wave exposure, whilst leaf length-width ratios increased with distance from the water’s edge. Biomass was negatively influenced by steeply sloping shores and sandy substrates versus coarser aggregates. This research suggests that an amplified WLF range, results in elongation of roots to access a deeper water table, may be at a cost to overall standing biomass. This thesis demonstrates that WLF is the dominant stressor on littoral zone biota, and habitat parameters, relative to other environmental factors commonly considered in studies of lakes such as elevation, perimeter, and fertility. The influence of WLF pressure should be regarded as a priority for conservationist and managers of freshwaters. In light of the expected increase in impoundments globally and high-level pressure on European freshwaters from regulation activities, as well as future projections of climate change and population growth, it is imperative to include lake water level parameters to effectively manage freshwater resources and their associated biodiversity

Development and Evaluation of a Periphytic Diatom Biomonitoring Platform of the Assessment of Cumulative Effects in Lakes of the Muskoka River Watershed, Ontario, Canada

Anthropogenic stressors such as urban development, agricultural practices and industrial activities are a growing concern throughout the Muskoka River watershed of Ontario, Canada, because they can alter physical, chemical and biological conditions of aquatic ecosystems. Cumulative effects of multiple stressors are often difficult to anticipate based on what is known about the individual effects of each stressor acting in isolation; thus, it is important to track cumulative effects on ecological integrity of our aquatic resources. Periphytic diatoms have potential to serve as an early indicator of ecological degradation in aquatic systems. Within the Muskoka River watershed there is a need to maintain the perceived naturalness of the region as it is a key driver of the tourism based economy. This thesis examines relations between diatom community composition, water chemistry and the abundance of anthropogenic stressors within the Muskoka River watershed and uses these relations to develop a bioassessment framework for tracking changes in biological integrity within lakes of the South Muskoka River Watershed. To do this, 86 lakes were examined to assess relations between diatom community composition, water chemistry and measures of nine anthropogenic stressors based on analyses by GIS. These relations were assessed using a combination of univariate and mulitvariate statistical methods. Composition of periphytic diatom communities was found to be associated with the concentration of ions from anthropogenic sources (i..e, application of road salt and dust suppressants), but relations became weaker at sites with a low abundance of anthropogenic stressors due to confounding influence of lake-water pH. Relations between periphytic diatom community composition and anthropogenic stressors were sufficiently strong to permit development of bioassessment indices for the evaluation of ecological degradation at a watershed-scale. Multiple variations of two primary indices (Eastern Canadian Diatom Index (IDEC), Index of Biological Integrity (IBI)) were developed and assessed to identify the best index for evaluating biological integrity of lakes. To reduce the cofounding influence of pH at low levels of stressors, the indices were developed separately for acidified lakes (pH 5.23-6.45) and circumneutral lakes (pH 6.52-7.47). IBI-3-Acidified and IBI-3-Circumneutral, which are based on a continuous IBI method, were found to be the best indices to assess lakes across the watershed. However, IBIs make use of only a small number of ‘indicator’ taxa, and as a result, may encounter no-analogue situations when applied to some lakes. Consequently, use of IBI-3-Acidified and IBI-3-Circumneutral is recommended for assessment of lakes within the Muskoka River watershed. But we suggest that the IDEC also be included as a backup in lakes where the IBI-3 index encounters no-analogue situations. Advantages of the use of periphytic diatom-based bioassessment protocols are presented in the thesis. By increasing ecological monitoring capacity, management agencies will be better prepared to avoid or mitigate cumulative effects of ever-evolving stressors

Cyanobakterier og cyanotoksiner i norske drikkevannskilder - (VKM)

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