ABSTRACT
The present study provides new insight into the key aspects of the early formative period of the ecosystem concept in aquatic ecology. Raymond Lindeman's trophodynamics is known to be a starting point for the development of the modern concept of ecosystem. The trophodynamic approach in ecology was proposed by Lindeman in his widely cited paper of 1942. Lindeman's views are analyzed in comparison with the contemporary production studies in aquatic ecology. It is shown that a similar theoretical system has been proposed in the USSR at the end of the 1930s by Georgiy G. Vinberg. He introduced the concept of biotic balance based on the wide appraisal of the dark and light bottles method. The study shows that both Lindeman's trophodynamics and Vinberg's concept of biotic balance relied on an energy-based approach in considering the wholeness of a water body. The two scientists, however, differed in several important aspects concerning the interpretation of the role of living organisms. The holistic interpretation of ecosystem by Lindeman and Vinberg can be seen as part of the dilemma between physicalism and organicism. At the same time, the main emphasis in the concepts of both Vinberg and Lindemann was on the primary production component, a feature that was common to the first holistic systems in production hydrobiology (e.g., E. Naumann's regional limnology). It is clear that modern problems of aquatic ecology should be addressed from the perspective of the organismocentric understanding of the ecosystem, but undoubtedly at the new level of development of this view.
Subject(s)
Ecology , Ecosystem , Lakes , Animals , History, 20th Century , Hydrobiology/methods , Aquatic Organisms , Models, BiologicalABSTRACT
Owing to a long history of anthropogenic pressures, freshwater ecosystems are among the most vulnerable to biodiversity loss1. Mitigation measures, including wastewater treatment and hydromorphological restoration, have aimed to improve environmental quality and foster the recovery of freshwater biodiversity2. Here, using 1,816 time series of freshwater invertebrate communities collected across 22 European countries between 1968 and 2020, we quantified temporal trends in taxonomic and functional diversity and their responses to environmental pressures and gradients. We observed overall increases in taxon richness (0.73% per year), functional richness (2.4% per year) and abundance (1.17% per year). However, these increases primarily occurred before the 2010s, and have since plateaued. Freshwater communities downstream of dams, urban areas and cropland were less likely to experience recovery. Communities at sites with faster rates of warming had fewer gains in taxon richness, functional richness and abundance. Although biodiversity gains in the 1990s and 2000s probably reflect the effectiveness of water-quality improvements and restoration projects, the decelerating trajectory in the 2010s suggests that the current measures offer diminishing returns. Given new and persistent pressures on freshwater ecosystems, including emerging pollutants, climate change and the spread of invasive species, we call for additional mitigation to revive the recovery of freshwater biodiversity.
Subject(s)
Biodiversity , Conservation of Water Resources , Environmental Monitoring , Fresh Water , Invertebrates , Animals , Introduced Species/trends , Invertebrates/classification , Invertebrates/physiology , Europe , Human Activities , Conservation of Water Resources/statistics & numerical data , Conservation of Water Resources/trends , Hydrobiology , Time Factors , Crop Production , Urbanization , Global Warming , Water Pollutants/analysisABSTRACT
There are some tools in place that classifies and/or rank beaches according to a series of parameters. It is possible to identify a gap in the development of tools that map and describe beaches without putting the results into a classification status of good or bad. Since beaches are important from different points of views such as ecology, tourism, economy, pollution or invasive species studies and management, fisheries, estate development, protected areas, among others it is relevant to describe and understand parameters in detail. This work offers a multi-purpose and interactive beach descriptor called BeachLog. It can be used by beachgoers to keep their own records in the same way a diver uses a Diver's LogBook, managers can use the tool to support coastal management projects, long-term monitoring, and beach description baseline. Also, BeachLog can be a didactic tool to aiming to bring environmental sciences closer to technology through the use of spreadsheets and dashboards. BeachLog is based on the more frequent parameters in the literature, selected, organized, accounted for, and altered/added according to expert opinion. We created a list of 28 parameters, all of which were described in details of what is expected to be observed by the user. They were divided into 5 groups (Environmental characteristics, Services & Infrastructure, Information & Security, Planning & Management, and Descriptive). Here, we describe 14 Brazilian beaches using the BeachLog by inputting the results as parameters presence or absence (0/1) and descriptives in a table that can be transformed into an interactive dashboard for better/easier visualization. Planning & Management was absent on all 14 beaches studied, pointing out the relevance and gaps in this group. In the other groups it was possible to observe variation in the parameter occurrence, indicating that each beach is different and it is important to observe parameters individually. Beach Litter and Invasive Species parameters from the Environmental characteristics group were present in all beaches. BeachLog showed as an easy way to describe a beach and can be a tool to support diagnosis and understanding of the beach's status.
Subject(s)
Bathing Beaches , Environmental Monitoring , Brazil , Environmental Monitoring/methods , HydrobiologyABSTRACT
Euglenids are a diverse group of flagellates that inhabit most environments and exhibit many different nutritional modes. The most prominent euglenids are phototrophs, but phagotrophs constitute the majority of phylogenetic diversity of euglenids. They are pivotal to our understanding of euglenid evolution, yet we are only starting to understand relationships amongst phagotrophs, with the backbone of the tree being most elusive. Ploeotids make up most of this backbone diversity-yet despite their morphological similarities, SSU rDNA analyses and multigene analyses show that they are non-monophyletic. As more ploeotid diversity is sampled, known taxa have coalesced into some subgroups (e.g. Alistosa), but the relationships amongst these are not always supported and some taxa remain unsampled for multigene phylogenetics. Here, we used light microscopy and single-cell transcriptomics to characterize five ploeotid euglenids and place them into a multigene phylogenetic framework. Our analyses place Decastava in Alistosa; while Hemiolia branches with Liburna, establishing the novel clade Karavia. We describe Hemiolia limna, a freshwater-dwelling species in an otherwise marine clade. Intriguingly, two undescribed ploeotids are found to occupy pivotal positions in the tree: Chelandium granulatum nov. gen. nov. sp. branches as sister to Olkasia, and Gaulosia striata nov. gen. nov. sp. remains an orphan taxon.
Subject(s)
Euglenida , Euglenida/classification , Euglenida/cytology , Euglenida/genetics , British Columbia , Phylogeny , Single-Cell Gene Expression Analysis , Hydrobiology , RNA, Protozoan/geneticsABSTRACT
High-frequency water quality measurements in streams and rivers have expanded in scope and sophistication during the last two decades. Existing technology allows in situ automated measurements of water quality constituents, including both solutes and particulates, at unprecedented frequencies from seconds to subdaily sampling intervals. This detailed chemical information can be combined with measurements of hydrological and biogeochemical processes, bringing new insights into the sources, transport pathways, and transformation processes of solutes and particulates in complex catchments and along the aquatic continuum. Here, we summarize established and emerging high-frequency water quality technologies, outline key high-frequency hydrochemical data sets, and review scientific advances in key focus areas enabled by the rapid development of high-frequency water quality measurements in streams and rivers. Finally, we discuss future directions and challenges for using high-frequency water quality measurements to bridge scientific and management gaps by promoting a holistic understanding of freshwater systems and catchment status, health, and function.
Subject(s)
Hydrobiology , Water Quality , Rivers , Forecasting , Environmental MonitoringABSTRACT
The geographic ranges of marine organisms, including planktonic foraminifera1, diatoms, dinoflagellates2, copepods3 and fish4, are shifting polewards owing to anthropogenic climate change5. However, the extent to which species will move and whether these poleward range shifts represent precursor signals that lead to extinction is unclear6. Understanding the development of marine biodiversity patterns over geological time and the factors that influence them are key to contextualizing these current trends. The fossil record of the macroperforate planktonic foraminifera provides a rich and phylogenetically resolved dataset that provides unique opportunities for understanding marine biogeography dynamics and how species distributions have responded to ancient climate changes. Here we apply a bipartite network approach to quantify group diversity, latitudinal specialization and latitudinal equitability for planktonic foraminifera over the past eight million years using Triton, a recently developed high-resolution global dataset of planktonic foraminiferal occurrences7. The results depict a global, clade-wide shift towards the Equator in ecological and morphological community equitability over the past eight million years in response to temperature changes during the late Cenozoic bipolar ice sheet formation. Collectively, the Triton data indicate the presence of a latitudinal equitability gradient among planktonic foraminiferal functional groups which is coupled to the latitudinal biodiversity gradient only through the geologically recent past (the past two million years). Before this time, latitudinal equitability gradients indicate that higher latitudes promoted community equitability across ecological and morphological groups. Observed range shifts among marine planktonic microorganisms1,2,8 in the recent and geological past suggest substantial poleward expansion of marine communities even under the most conservative future global warming scenarios.
Subject(s)
Aquatic Organisms , Biodiversity , Cold Temperature , Foraminifera , Geographic Mapping , Phylogeography , Plankton , Spatio-Temporal Analysis , Animals , Aquatic Organisms/classification , Aquatic Organisms/isolation & purification , Datasets as Topic , Foraminifera/classification , Foraminifera/isolation & purification , Fossils , History, Ancient , Phylogeny , Plankton/classification , Plankton/isolation & purification , Time Factors , HydrobiologyABSTRACT
The latitudinal diversity gradient (LDG) is a prevalent feature of modern ecosystems across diverse clades1-4. Recognized for well over a century, the causal mechanisms for LDGs remain disputed, in part because numerous putative drivers simultaneously covary with latitude1,3,5. The past provides the opportunity to disentangle LDG mechanisms because the relationships among biodiversity, latitude and possible causal factors have varied over time6-9. Here we quantify the emergence of the LDG in planktonic foraminifera at high spatiotemporal resolution over the past 40 million years, finding that a modern-style gradient arose only 15 million years ago. Spatial and temporal models suggest that LDGs for planktonic foraminifera may be controlled by the physical structure of the water column. Steepening of the latitudinal temperature gradient over 15 million years ago, associated with an increased vertical temperature gradient at low latitudes, may have enhanced niche partitioning and provided more opportunities for speciation at low latitudes. Supporting this hypothesis, we find that higher rates of low-latitude speciation steepened the diversity gradient, consistent with spatiotemporal patterns of depth partitioning by planktonic foraminifera. Extirpation of species from high latitudes also strengthened the LDG, but this effect tended to be weaker than speciation. Our results provide a step change in understanding the evolution of marine LDGs over long timescales.
Subject(s)
Aquatic Organisms , Biodiversity , Foraminifera , Geographic Mapping , Plankton , Spatio-Temporal Analysis , Aquatic Organisms/classification , Aquatic Organisms/isolation & purification , Biological Evolution , Foraminifera/classification , Foraminifera/isolation & purification , Genetic Speciation , History, Ancient , Phylogeography , Plankton/classification , Plankton/isolation & purification , Temperature , Time Factors , Water/analysis , HydrobiologyABSTRACT
Aljustrel, Lousal and S. Domingos mines are located in the Iberian Pyrite Belt (IPB), one of the greatest massive sulfide ore deposits worldwide. These mines' surrounding streams are affected by Acid Mine Drainage (AMD). The main purpose of this study was to understand AMD influence in the water quality and diatom behavior. Thus, waters and diatoms were sampled in 6 sites from the 3 selected mines on winter and summer of 2016. The highest concentrations were found in acidic sites: A3 (Aljustrel-Al, Cd, Cu, Fe and Zn (and lowest pH)) and L1 (Lousal-As, Mn, Ca, Mg, SO42- and conductivity). The most abundant diatom species was Pinnularia aljustrelica with 100% of dominance in A3 and S1 acidic sites, which puts in evidence this species adaptation to AMD harsh conditions. Multivariate cluster analysis allowed us to reinforce results from previous studies, where spatial differences were more relevant than seasonal ones. In 12 years (2004-2016), and with many transformations undertaken (re-opening and rehabilitation), there is a conservative behavior in the biological species (diatoms) and physicochemical concentrations (metals, pH and sulfates) from these three mining sites. This type of biogeochemical diagnosis is necessary for the sustainable use of these waters and the prevention of the polluting process, aimed to protect the water ecosystem and its biodiversity.
Subject(s)
Diatoms , Water Pollutants, Chemical , Acids/analysis , Ecosystem , Environmental Monitoring/methods , Fresh Water , Hydrobiology , Portugal , Rivers , Water Pollutants, Chemical/analysisABSTRACT
Studying the spatial management scope of the river ecological corridor is a crucial step in effectively managing river health problems. For various purposes and needs, human beings intervene excessively in the river, resulting in the problems of unclear spatial scope, unclear ownership, and unreasonable functional utilization of the river ecological corridor. However, there is scarce research on the management scope of the river ecological corridor at present, and on the coordination relationship with territorial spatial protection planning. Therefore, in order to solve this key problem, this paper reviews and summarizes the current research status and development trends in terms of the concept, components, and other basic theories of the river ecological corridor, as well as relevant policy regulations. The relationship between the spatial scope of the river ecological corridor and the territorial spatial control line is analyzed, including the relationship with the river shoreline, aquatic ecological redline, "three control lines" and other control lines. Accordingly, this study reviewed the spatial management and control scope of the river ecological corridor. It also determined that the boundary line of the river shoreline management is the minimum line, the aquatic ecological redline, and the "three control lines" are the outermost boundary lines, in which the aquatic ecological redline has priority over other control lines. It also points out the thinking of determining the management scope in the protection and restoration of the river ecological corridor in the future. Our findings can provide a decision-making basis for the management of river ecological space.
Subject(s)
Hydrobiology , Rivers , China , Conservation of Natural Resources , Ecosystem , HumansABSTRACT
The aquatic ecological health status was focused on the Huai River Basin (HRB) from the aspects of water quantity, water quality, water ecology, river connectivity, and riparian habitat environment. Ten monitoring sections were set up in the middle and upper reaches of HRB, and 5 experiments of each section were conducted in July and December from 2012 to 2014. Thus, relevant data on the species, the density of phytoplankton, zooplankton and benthic animals, the concentration of water physicochemical variables, and riparian habitat quality were obtained. Eleven key impact factors were chosen using frequency statistics, theoretical analysis, and correlation analysis methods, forming the evaluation index system of aquatic ecological health. Then, the indicator weight value was determined by the combined weight method, and the health degree was evaluated by the comprehensive index method. On the whole, the aquatic ecological health degree of the upper sections (D1 ~ D3) of the Shaying River ranges from 0.334 to 0.927, which is generally in a "sub-healthy" state. The aquatic ecological health degree of the main section of the Huai River (D8 ~ D10) ranges from 0.362 to 0.777, which is in the "critical" or "sub-healthy" state. The Huaidian Sluice (D5) and Fuyang Sluice (D6) in the middle and lower reaches of the Shaying River had the worst aquatic ecological health. Its water ecological health range is 0.283-0.523, and most of them are under "sub-pathologic." The research results have important theoretical and practical significance. They can enrich the evaluation theories and methods of river aquatic ecological health, help to grasp the aquatic ecological health status in HRB, and provide basic support for aquatic ecological protection and water pollution control in sluice-controlled rivers.
Subject(s)
Environmental Monitoring , Rivers , Animals , China , Environmental Monitoring/methods , Hydrobiology , Water QualityABSTRACT
Lakes Sagami and Tsukui are reservoirs constructed by connecting to the Sagami River. Because of eutrophication of the lakes, cyanobacteria have appeared every year. This review deals with phenomena related to occurrence of cyanobacteria that have been observed for 40 years since 1974 at the lakes. These 40 years of observations raised three interesting issues including the retention of cyanobacteria on their surfaces. These phenomena have been attributed to the usual factors, such as illuminance, nutrition and water temperature, but our research results suggested that they cannot be resolved without the introduction of another factor. We have attempted to elucidate various phenomena involving cyanobacteria in lake ecosystems by chemical ecological methods using volatile organic compounds (VOCs) produced by the cyanobacteria as indicators. One of the VOCs, ß-cyclocitral, was significantly involved in the above phenomena, which was considered to be produced by the carotenoid cleavage dioxygenase (CCD) of the cyanobacteria. ß-Cyclocitral was not produced in the two known CCDs, but two additional CCDs to Microcystis aeruginosa participated to produce the ß-cyclocitral. These CCDs did not directly produce ß-cyclocitral, but it was accumulated in cells as their precursors. The released ß-cyclocitral underwent a Baeyer-Villiger-like oxidation. It was speculated that Microcystis activated the CCD genes through density stress and produced ß-cyclocitral, which acted as an allelopathic substance. As a result, the number of cells of cyanobacteria decreased, and the resulting nitrogen and phosphorus were fed to the living cyanobacteria. It is postulated that this "quorum sensing" was functioning in the above-mentioned issues.
Subject(s)
Cyanobacteria/physiology , Ecosystem , Fresh Water/microbiology , Hydrobiology/methods , Quorum Sensing , Aldehydes/metabolism , Cyanobacteria/enzymology , Cyanobacteria/metabolism , Dioxygenases/metabolism , Diterpenes/metabolism , Microcystis/metabolism , Nitrogen/metabolism , Oxidation-Reduction , Phosphorus/metabolism , Volatile Organic Compounds/metabolismABSTRACT
The analysis of community structure in studies of freshwater ecology often requires the application of dimensionality reduction to process multivariate data. A high number of dimensions (number of taxa/environmental parameters × number of samples), nonlinear relationships, outliers, and high variability usually hinder the visualization and interpretation of multivariate datasets. Here, we proposed a new statistical design using Uniform Manifold Approximation and Projection (UMAP), and community partitioning using Louvain algorithms, to ordinate and classify the structure of aquatic biota in two-dimensional space. We present this approach with a demonstration of five previously published datasets for diatoms, macrophytes, chironomids (larval and subfossil), and fish. Principal Component Analysis (PCA) and Ward's clustering were also used to assess the comparability of the UMAP approach compared to traditional approaches for ordination and classification. The ordination of sampling sites in 2-dimensional space showed a much denser, and easier to interpret, grouping using the UMAP approach in comparison to PCA. The classification of community structure using the Louvain algorithm in UMAP ordinal space showed a high classification strength for data with a high number of dimensions than the cluster patterns obtained with the use of a Ward's algorithm in PCA. Environmental gradients, presented via heat maps, were overlayed with the ordination patterns of aquatic communities, confirming that the ordinations obtained by UMAP were ecologically meaningful. This is the first study that has applied a UMAP approach with classification using Louvain algorithms on ecological datasets. We show that the performance of local and global structures, as well as the number of clusters determined by the algorithm, make this approach more powerful than traditional approaches.
Subject(s)
Algorithms , Environmental Biomarkers , Animals , Cluster Analysis , Hydrobiology , Principal Component AnalysisABSTRACT
In some cases, wildlife management objectives directed at multiple species can conflict with one another, creating species trade-offs. For managers to effectively identify trade-offs and avoid their undesirable outcomes, they must understand the agents involved and their corresponding interactions. A literature review of interspecific trade-offs within freshwater and marine ecosystems was conducted to illustrate the scope of potential interspecific trade-offs that may occur. We identified common pitfalls that lead to failed recognition of interspecific trade-offs, including, single-species management and limited consideration of the spatial and temporal scale of ecosystems and their management regimes. We devised a classification framework of common interspecific trade-offs within aquatic systems. The classification can help managers determine whether the conflict is species based through direct relationships (i.e., predator-prey, competition, other antagonistic relationships) or indirect relationships involving intermediate species (i.e., conflict-generating species) or whether the conflict is driven by opposing management objectives for species that would otherwise not interact (i.e., nontarget management effects). Once the nature and scope of trade-offs are understood, existing decision-making tools, such as structured decision-making and real-options analysis, can be incorporated to improve the management of aquatic ecosystems. Article Impact Statement: A synthesis of interspecific trade-offs in aquatic ecosystems supports their identification and resolution.
Un Marco de Clasificación para Compensaciones Interespecíficas en Ecología Acuática Resumen En algunos casos, los objetivos del manejo de fauna dirigidos a muchas especies pueden entrar en conflicto entre sí creando compensaciones entre las especies. Para que los manejadores identifiquen efectivamente estas compensaciones y eviten sus resultados no deseados, deben entender a los agentes involucrados y sus interacciones correspondientes. Se realizó una revisión literaria de las compensaciones interespecíficas dentro de los ecosistemas marinos y de agua dulce para ilustrar el alcance de las compensaciones interespecíficas que pueden ocurrir. Identificamos dificultades comunes que llevan al reconocimiento fallido de las compensaciones interespecíficas, incluyendo el manejo de una sola especie y sus regímenes de manejo. Diseñamos un marco de clasificación de compensaciones interespecíficas comunes dentro de los ecosistemas acuáticos. La clasificación puede ayudar a los manejadores a determinar si el conflicto está basado en las especies por sus relaciones directas (es decir, depredador-presa, competencia, otras relaciones antagonistas) o por relaciones indirectas que involucran a otras especies (es decir, efectos del manejo de especies que no son el objetivo). Una vez que se entiende la naturaleza y el alcance de las compensaciones, las herramientas de toma de decisión existentes, como la toma estructurada de decisiones y el análisis de opciones reales, pueden incorporarse para mejorar el manejo de los ecosistemas acuáticos.
Subject(s)
Conservation of Natural Resources , Ecosystem , HydrobiologyABSTRACT
A variety of mammals suppress reproduction when they experience poor physical condition or environmental harshness. In many marine mammal species, reproductive impairment has been correlated to polychlorinated biphenyls (PCBs), the most frequently measured chemical pollutants, while the relative importance of other factors remains understudied. We investigate whether reproductively active females abandon investment in their foetus when conditions are poor, exemplified using an extensively studied cetacean species; the harbour porpoise (Phocoena phocoena). Data on disease, fat and muscle mass and diet obtained from necropsies in The Netherlands were used as proxies of health and nutritional status and related to pregnancy and foetal growth. This was combined with published life history parameters for 16 other areas to correlate to parameters reflecting environmental condition: mean energy density of prey constituting diets (MEDD), cumulative human impact and PCB contamination. Maternal nutritional status had significant effects on foetal size and females in poor health had lower probabilities of being pregnant and generally did not sustain pregnancy throughout gestation. Pregnancy rates across the Northern Hemisphere were best explained by MEDD. We demonstrate the importance of having undisturbed access to prey with high energy densities in determining reproductive success and ultimately population size for small cetaceans.
Subject(s)
Nutritional Status/physiology , Phocoena/metabolism , Reproduction/physiology , Animals , Cetacea/metabolism , Conservation of Natural Resources/methods , Energy Metabolism/physiology , Female , Hydrobiology/methods , Netherlands , Polychlorinated Biphenyls/adverse effects , Polychlorinated Biphenyls/analysis , Pregnancy , Reproduction/drug effects , Sexual Behavior, Animal/drug effects , Water Pollutants, Chemical/adverse effects , Water Pollutants, Chemical/analysisABSTRACT
In this paper, we review the effects of large-scale neonicotinoid contaminations in the aquatic environment on non-target aquatic invertebrate and vertebrate species. These aquatic species are the fauna widely exposed to environmental changes and chemical accumulation in bodies of water. Neonicotinoids are insecticides that target the nicotinic type acetylcholine receptors (nAChRs) in the central nervous systems (CNS) and are considered selective neurotoxins for insects. However, studies on their physiologic impacts and interactions with non-target species are limited. In researches dedicated to exploring physiologic and toxic outcomes of neonicotinoids, studies relating to the effects on vertebrate species represent a minority case compared to invertebrate species. For aquatic species, the known effects of neonicotinoids are described in the level of organismal, behavioral, genetic and physiologic toxicities. Toxicological studies were reported based on the environment of bodies of water, temperature, salinity and several other factors. There exists a knowledge gap on the relationship between toxicity outcomes to regulatory risk valuation. It has been a general observation among studies that neonicotinoid insecticides demonstrate significant toxicity to an extensive variety of invertebrates. Comprehensive analysis of data points to a generalization that field-realistic and laboratory exposures could result in different or non-comparable results in some cases. Aquatic invertebrates perform important roles in balancing a healthy ecosystem, thus rapid screening strategies are necessary to verify physiologic and toxicological impacts. So far, much of the studies describing field tests on non-target species are inadequate and in many cases, obsolete. Considering the current literature, this review addresses important information gaps relating to the impacts of neonicotinoids on the environment and spring forward policies, avoiding adverse biological and ecological effects on a range of non-target aquatic species which might further impair the whole of the aquatic ecological web.
Subject(s)
Aquatic Organisms/drug effects , Insecticides/adverse effects , Neonicotinoids/adverse effects , Animals , Ecosystem , Hydrobiology , Insecticides/pharmacology , Invertebrates/drug effects , Neonicotinoids/pharmacology , Neurotoxins/pharmacology , Receptors, Nicotinic/drug effects , Water Pollutants, Chemical/toxicityABSTRACT
The family Marnaviridae comprises small non-enveloped viruses with positive-sense RNA genomes of 8.6-9.6 kb. Isolates infect marine single-celled eukaryotes (protists) that come from diverse lineages. Some members are known from metagenomic studies of ocean virioplankton, with additional unclassified viruses described from metagenomic datasets derived from marine and freshwater environments. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Marnaviridae, which is available at ictv.global/report/marnaviridae.
Subject(s)
Genome, Viral , Phylogeny , RNA Viruses/classification , RNA Viruses/genetics , Animals , Capsid Proteins , Eukaryota , Host Specificity , Hydrobiology , Metagenomics , RNA Virus Infections/virology , RNA Viruses/ultrastructure , RNA, Viral , Virion/classification , Virion/genetics , Virion/ultrastructure , Virus ReplicationABSTRACT
Onchocerciasis, caused by infection with Onchocerca volvulus, has been targeted for elimination by 2030. Currently, onchocerciasis elimination programs rely primarily on mass distribution of ivermectin. However, ivermectin alone may not be sufficient to achieve elimination in some circumstances, and additional tools may be needed. Vector control has been used as a tool to control onchocerciasis, but vector control using insecticides is expensive and ecologically detrimental. Community-directed removal of the trailing vegetation black fly larval attachment sites (slash and clear) has been shown to dramatically reduce vector biting densities. Here, we report studies to optimize the slash and clear process. Conducting slash and clear interventions at Simulium damnosum sensu stricto breeding sites located within 2 km of afflicted communities resulted in a 95% reduction in vector biting. Extending slash and clear further than 2 km resulted in no further decrease. A single intervention conducted at the first half of the rainy season resulted in a 97% reduction in biting rate, whereas an intervention conducted at the end of the rainy season resulted in a 94% reduction. Vector numbers in any of the intervention villages did not fully recover by the start of the following rainy season. These results suggest that slash and clear may offer an inexpensive and effective way to augment ivermectin distribution in the effort to eliminate onchocerciasis in Africa.
Subject(s)
Community Participation/methods , Insect Control/methods , Insect Vectors/parasitology , Onchocerca volvulus/pathogenicity , Onchocerciasis/prevention & control , Onchocerciasis/transmission , Simuliidae/parasitology , Animals , Humans , Hydrobiology/methods , Insect Bites and Stings/prevention & control , Onchocerciasis/epidemiology , Plants , Rain , Seasons , Simuliidae/physiology , UgandaABSTRACT
Lots of evidence has indicated that many kinds of animals can achieve goal-oriented navigation by spatial cognition and dead reckoning. The geomagnetic field (GF) is a ubiquitous cue for navigation by these animals. Inspired by the goal-oriented navigation of animals, a novel long-distance underwater geomagnetic navigation (LDUGN) method is presented in this article, which only utilizes the declination component ( D ) and inclination component ( I ) of GF for underwater navigation without any prior knowledge of the geographical location or geomagnetic map. The D and I measured by high-precision geomagnetic sensors are compared periodically with that of the destination to determine the velocity and direction in the next step. A model predictive control (MPC) algorithm with control and state constraints is proposed to achieve the control and optimization of navigation trajectory. Because the optimal control is recalculated at each sampling instant, the MPC algorithm can overcome interferences of geomagnetic daily fluctuation, geomagnetic storms, ocean current, and geomagnetic local anomaly. The simulation results validate the feasibility and accuracy of the proposed algorithm.
Subject(s)
Algorithms , Hydrobiology , Models, Biological , Spatial Navigation/physiology , Animals , Aquatic Organisms/physiology , Computer Simulation , Magnetics , Water MovementsABSTRACT
RATIONALE: Dried blood spots (DBSs) are gaining popularity for biomarker analyses in ecological research due to their advantages for use in field-based research and in remote settings; however, many DBS biomarkers remain unvalidated. We validated the application of compound-specific stable nitrogen isotope analyses of amino acids (CSIA-AAs) to field-prepared DBSs for determining trophic positions of wild-caught Arctic char (Salvelinus alpinus). METHODS: Whole blood and muscle from Arctic char were collected, and DBSs were created in the field. We measured the stable nitrogen isotope ratios (expressed as δ15 N values) of the amino acids glutamic acid (Glu) and phenylalanine (Phe) isolated from Arctic char samples using CSIA-AAs. We then compared amino acid δ15 N values from DBSs and the other sample types (whole blood and muscle) from the same specimens. We calculated and compared trophic position estimates generated from whole blood, DBSs, and muscle. RESULTS: The δ15 N values of Glu and Phe, as well as trophic position estimates from DBSs, were highly correlated with δ15 N values and estimates from both whole blood and muscle. The DBS amino acid δ15 N values and trophic position estimates agreed well with those from whole blood. Although mean differences between amino acid δ15 N values from DBSs and muscle were noted, the offsets were small and resulted in a 0.2 mean difference between trophic position estimates for DBSs and muscle. CONCLUSIONS: We demonstrate that the application of CSIA-AAs to field-prepared DBSs of Arctic char generates similar trophic position estimates to those from whole blood and muscle. We suggest that DBSs could be developed as a minimally invasive sampling technique to study feeding ecology of wild fish and perhaps other organisms of interest.
Subject(s)
Amino Acids , Dried Blood Spot Testing/methods , Dried Blood Spot Testing/standards , Nitrogen Isotopes/blood , Trout/blood , Amino Acids/blood , Amino Acids/chemistry , Animals , Gas Chromatography-Mass Spectrometry , HydrobiologyABSTRACT
Environmental DNA (eDNA) is increasingly popular as a useful non-invasive method to monitor and study biodiversity and community structure in freshwater and marine environments. To effectively extract eDNA from the filter surface is a fundamental factor determining the representativeness of the samples. We improved the eDNA extraction efficiency of an established Sterivex method by 12- to 16-fold using a larger volume of lysis buffer mix coupled with backflushing the cartridges. The DNeasy extraction column could be overloaded when the environmental sample input is high, possibly due to a higher nonspecific binding present in environmental samples, thus resulting in a relatively lower quantity measured. Therefore, we included an internal control DNA in the extraction to monitor the extraction and purification efficiencies in field samples, which is crucial for quantification of original eDNA concentration. The use of Takara Probe qPCR Mix supplemented with protein-based additives improved the robustness of the real time PCR assay on inhibitor-rich environmental samples, but prior purification by Qiagen PowerClean Pro Cleanup kit could be essential for inhibitor-rich water samples, even though the recovery rate was unexpectedly low (average 33.0%). The improved extraction and quantification complement the qualitative analyses including metabarcoding and metagenomics in field application.