freshwater environments
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2022 ◽  
Vol 12 ◽  
Author(s):  
Sarah Itoïz ◽  
Sebastian Metz ◽  
Evelyne Derelle ◽  
Albert Reñé ◽  
Esther Garcés ◽  
...  

The last century has witnessed an increasing rate of new disease emergence across the world leading to permanent loss of biodiversity. Perkinsea is a microeukaryotic parasitic phylum composed of four main lineages of parasitic protists with broad host ranges. Some of them represent major ecological and economical threats because of their geographically invasive ability and pathogenicity (leading to mortality events). In marine environments, three lineages are currently described, the Parviluciferaceae, the Perkinsidae, and the Xcellidae, infecting, respectively, dinoflagellates, mollusks, and fish. In contrast, only one lineage is officially described in freshwater environments: the severe Perkinsea infectious agent infecting frog tadpoles. The advent of high-throughput sequencing methods, mainly based on 18S rRNA assays, showed that Perkinsea is far more diverse than the previously four described lineages especially in freshwater environments. Indeed, some lineages could be parasites of green microalgae, but a formal nature of the interaction needs to be explored. Hence, to date, most of the newly described aquatic clusters are only defined by their environmental sequences and are still not (yet) associated with any host. The unveiling of this microbial black box presents a multitude of research challenges to understand their ecological roles and ultimately to prevent their most negative impacts. This review summarizes the biological and ecological traits of Perkinsea—their diversity, life cycle, host preferences, pathogenicity, and highlights their diversity and ubiquity in association with a wide range of hosts.


2022 ◽  
Vol 82 ◽  
Author(s):  
M. A. Rocha ◽  
M. B. Silva ◽  
C. C. Bonecker ◽  
M. S. dos Anjos ◽  
P. A. M. C. Melo

Abstract A first checklist of Rotifera species in freshwater environments in Bahia State, in northeastern Brazil, is provided. The list includes sampling data from 26 aquatic environments (lotic and lentic) undertaken from 2010 to 2016. One hundred and fifty-five species were recorded, with 68 new records for the state. The family Brachionidae and Lecanidae were the most representative (54.8%). The greatest richness was recorded in the Colônia River (57 species). Those results reflect the low numbers of studies previously undertaken in the region, indicating more research needs to be focused on Rotifera biodiversity in Bahia, the fifth largest state in Brazil (567,295 km2) with large numbers of freshwater bodies.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260102
Author(s):  
Samantha Richardson ◽  
Alexander Iles ◽  
Jeanette M. Rotchell ◽  
Tim Charlson ◽  
Annabel Hanson ◽  
...  

Contamination of waterways is of increasing concern, with recent studies demonstrating elevated levels of antibiotics, antidepressants, household, agricultural and industrial chemicals in freshwater systems. Thus, there is a growing demand for methods to rapidly and conveniently monitor contaminants in waterways. Here we demonstrate how a combination of paper microfluidic devices and handheld mobile technology can be used by citizen scientists to carry out a sustained water monitoring campaign. We have developed a paper-based analytical device and a 3 minute sampling workflow that requires no more than a container, a test device and a smartphone app. The contaminant measured in these pilots are phosphates, detectable down to 3 mg L-1. Together these allow volunteers to successfully carry out cost-effective, high frequency, phosphate monitoring over an extended geographies and periods.


Author(s):  
Y. M. Mohammed ◽  
M. Hadizat ◽  
M. A. Umar ◽  
Y. Ibrahim ◽  
H. Mohammed ◽  
...  

Plastic pollution in aquatic ecosystems is a growing environmental concern, as it has the potential to harm ecology, imperil aquatic organisms and cost ecological damage. Although rivers and other freshwater environments are known to play an important role in carrying land-based plastic trash to the world's seas, riverine ecosystems are also directly impacted by plastic pollution. A detailed understanding of the origin, movement, fate, and effects of riverine plastic waste is critical for better quantifying worldwide plastic pollution transport and effectively reducing sources and dangers. In this review, we emphasize the current scientific state of plastic debris in rivers, as well as the existing knowledge gaps, providing a basic overview of plastics and the types of polymers commonly found in rivers and the threat they bring to aquatic ecosystems. We also go through the origins and fates of riverine plastics, as well as the mechanisms and factors that affect plastic debris transit and spatiotemporal variation. We give an overview of riverine plastic transport monitoring and modeling activities, as well as examples of typical values from throughout the world. Finally, we discuss what the future holds for riverine plastic research.


2021 ◽  
Author(s):  
Eveline Pinseel ◽  
Teofil Nakov ◽  
Koen Van den Berge ◽  
Kala M. Downey ◽  
Kathryn J. Judy ◽  
...  

The salinity gradient separating marine and freshwater environments represents a major ecological divide for microbiota, yet the mechanisms by which marine microbes have adapted to and ultimately diversified in freshwater environments are poorly understood. Here, we take advantage of a natural evolutionary experiment: the colonization of the brackish Baltic Sea by the ancestrally marine diatom Skeletonema marinoi. To understand how diatoms respond to low salinity, we characterized transcriptomic responses of S. marinoi grown in a common garden. Our experiment included eight genotypes from source populations spanning the Baltic Sea salinity cline. Changes in gene expression revealed a shared response to salinity across genotypes, where low salinities induced profound changes in cellular metabolism, including upregulation of carbon fixation and storage compound biosynthesis, and increased nutrient demand and oxidative stress. Nevertheless, the genotype effect overshadowed the salinity effect, as genotypes differed significantly in their response, both in the magnitude and direction of gene expression. Intraspecific differences included regulation of transcription and translation, nitrogen metabolism, cell signaling, and aerobic respiration. The high degree of intraspecific variation in gene expression observed here highlights an important but often overlooked source of biological variation associated with how diatoms respond and adapt to environmental change.


2021 ◽  
Vol 50 (10) ◽  
pp. 2869-2876
Author(s):  
Vipawee Dummee ◽  
Maleeya Kruatrachue ◽  
Sombat Singhakaew ◽  
Phanwimol Tanhan

The present study was undertaken to elucidate the basis of cellular reactions and to verify the suitability of Pomacea canaliculata digestive tract ultrastructure as a biomarker for assessing the Cu pollution in freshwater environments. Two-month-old P. canaliculata were exposed to 96-h lethal concentration of Cu (0.15 mg L-1) for 96 h. Electron microscope investigations showed different alterations of organelles in the epithelial cells lining the esophagus and intestine. The most striking changes were damages to the mitochondria, RER, and nucleus typified by loss of cristae and degeneration of mitochondria; degranulation and fragmentation of RER. In nucleus, karyolysis and rupture of nuclear envelope were observed. These changes were attributed to membrane destabilization and increased membrane permeability to ions under the influence of toxicants or heavy metals. These findings indicate the possibility of using the P. canaliculata as biomonitor for Cu contamination in the freshwater environment.


2021 ◽  
Vol 74 (3) ◽  
pp. 253-271
Author(s):  
Tomislav Kurečić ◽  
◽  
Marijan Kovačić ◽  
Anita Grizelj ◽  
◽  
...  

Viviparus beds are sediments deposited in lacustrine and fluvial freshwater environments (Lake Slavonia) during the Pliocene and the earliest Pleistocene. A detailed field study and mineralogical, petrographic and chemical analyses were carried out to determine their composition and origin in the area of Vukomeričke Gorice, Central Croatia. Viviparus beds are characterized by the vertical and lateral exchange of mineralogically and chemically mature pelites and sands. Pelitic sediments consist mainly of detrital quartz, calcite, dolomite and feldspar grains, with smectite as the most common clay mineral. Quartz and the most resistant lithic fragments dominate the sandy detritus. The composition of the sediments indicates their origin from the recycled orogen, while their textural immaturity suggests a short transport distance. Most of the material was re-deposited from the underlying Upper Miocene sediments, originally of Alpine provenance. A lesser proportion originated from Palaeogene sediments, Triassic carbonate rocks, basic or acidic magmatic rocks and metamorphites. The Medvednica and Žumberak Mts. were the most important source areas, while a smaller proportion of the material could have come from the Moslavačka gora Mt. and Banovina region. The uniform composition of the Viviparus beds over the entire vertical distribution of the sediments clearly indicates that the source areas did not change during their deposition. A significant change from the texturally and compositionally mature Upper Miocene clastic detritus of alpine origin, to the texturally immature material of the Viviparus beds of local origin is a consequence of compression and inversion of the previously extensional basin resulting in the uplifting and erosion of the mountains within the SW part of the Pannonian Basin System.


2021 ◽  
Vol 9 ◽  
Author(s):  
Lee J. Baumgartner ◽  
Pierre Girard ◽  
David Kaplan ◽  
Walter Collischonn

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