The introduction of Galba truncatula samples, each comprising 5, 10 or 20 snails, in 25 slope rushes and 24 ditches on acidic soil allowed the development of new populations in 10 sites (out of 21) where samples of 5 snails each were used and in the other 28 sites when each sample included 10 or 20 snails.
The present work investigated histological changes in skeletal muscles of zebrafish (Danio rerio) caused by fonofos, an organophosphate insecticide. Fonofos-induced fibrosis, intramyofibrillar vacuoles, disintegrated myofibrils, splitting of myofibers, atrophic and disappeared fibers, histoarchitectural loss, necrosis and progressive decrement in glycogen content were noted. Muscle fiber diameter measurements showed that the fiber diameters of all fonofos exposed groups were decreased in a concentration-dependent manner. These results suggested that fonofos caused significant myoarchitectural impairments in non-target freshwater zebrafish.
This paper builds on community ecology, evaluating spatial and temporal fluctuations in species composition of the protist ciliates community, in rural and urban streams. Particularly, we show that distinct species composition were found in rural and urban streams, considering the main source of impact of each type of stream. Moreover, temporally, the species composition changed between the two periods of the year, considering the limnological distinctions drove by the temperature and rainfall regime.
Depending on the increase in agricultural production, the use of pesticides has also increased worldwide. Imidacloprid is a neonicotinoid pesticide and one of the most widely used in the world. In this study, it was aimed to investigate the histopathological changes in zebrafish ovary and testis tissue caused by imidacloprid, which pollutes the aquatic ecosystem in various ways. It has been shown that imidacloprid causes histopathological changes in the gonads by causing deterioration in the structure of reproductive cells.
Pesticides used to protect plants and animals against the competition of unwanted insects, diseases, and weeds, and pests play a delicate role in living systems. It has adverse effects on the environment and health. The most adverse effects of pesticide derivatives are the reduction in biodiversity, water pollution, and health risks. Mancozeb is an ethylene bis dithiocarbamate (EBDC) pesticide containing manganese and zinc. These pesticides are included in the fungicide group because they are used for treating fungal diseases. In this study, the structure of oocytes developing in female zebrafish exposed to different doses of mancozeb (5 mgL−1, 7.5 mgL−1) was examined. Compared with the control group, it was determined that the number of developing oocytes reduced in the experimental groups. There was a significant increase in atretic oocytes, an increase in the level of degenerate oocytes in a dose-dependent manner, and deformation in oocytes became prominent.
The main objective of this study was to determine the age, growth, mortality, and population structure of the silver carp Hypophthalmichthys molitrix (Valenciennes, 1844) in the middle and lower Pearl River. This work will benefit conservation of the species and to sustainably develop this valuable fishery.
The present study deals with the phytoplankton dynamics, biomass and physicochemical features in freshwater reservoir, Tillari, western India. The reservoir experience seasonal stratification and mixing associated and changes in the biogeochemical aspects especially the phytoplankton community and chlorophyll a. Depth affected the behavior of the phytoplankton associations. Buildup in phytoplankton biomass was observed in the upper strata of the water column (epilimnion) during the monsoon period (June-July) and winter (December) as a result of nutrient enrichment from the hypolimnion. Among nutrients, nitrate was associated with buildup of Chl a during summer in the epilimnion (r2 = 0.7). A total of about 91 phytoplankton species were identified with major contribution by charophytes and chlorophytes. The dominant phytoplankton species belonged to genera Staurastrum, Cosmarium, Aulacoseira, Nephrocytium and Shroederia. Charophytes made a remarkable presence during the whole study period in the well oxygenated epilimnion as well as in the hypolimnion with relatively low oxygen. Diatom, the major silica sinking group was relatively less abundant. Keeping the importance of the reservoir in view, the understanding phytoplankton community from this poorly explored reservoir with respect to influencing factors is a very vital baseline information. Thus, to design and evaluate the management strategies for the reservoir, continuous monitoring and processes studies is warranted.
Determining the factors responsible for cyanobacterial blooms is a key issue for scientists and lake stakeholders. This article provides a complete explanation for a recent bloom of Planktothrix rubescens that occurred in Lake Bourget (France) accompanied by a plausible scenario, likely to be used as a predictive tool in the future.
In this study, we used the phytoplankton functional group index, survival strategies and environmental conditions in the Zhushuqiao reservoir to detect overall phytoplankton survival strategies (C-S-R) in the entire reservoir water column, and assess quantitative relationships between phytoplankton survival strategies and environment, which may help for future reservoir management.
This study found that intermittent disturbance combined nitrogen and phosphorus adding promoted colony size and abundance increase of Microcystis flos-aquae. This result suggest that intermittent disturbance combined N and P adding plays an important role in the formation of Microcystis blooms in freshwater ecosystems.
This study provides evidence of the historical dynamic of hydrometeorological and hydrological indicators related to water availability in Cozumel island and emphasizes the need of updated information analysis as part of an adequate water management based upon an integrative approach that can be replicated on islands with a similar geohydrological settings.
The current environmental conditions of La Redonda lagoon favor recovery largemouth bass population. The reintroduction of the species into this lagoon will be important for recreational fishing (tourism) and economic incomes to Cuba.
It is important to determine the water quality of the creeks in the Lake Sapanca basin since it is used for drinking water supply. For this purpose, environmental parameters and diatom assemblages as biological quality components were investigated to determine the ecological status of eight creeks with monthly intervals between March 2015 and February 2016. A total of 132 diatom taxa were identified in eight creeks of the Lake Sapanca basin during the studied period. 19 taxa increased their relative abundance higher than 30% in at least one sample and showed a different seasonal pattern. Environmental parameters [nitrate-nitrogen, orthophosphate, total phosphorus (TP), specific conductance, temperature, pH, and dissolved oxygen] were effective on the distribution of diatom assemblages. The ecological status of the creeks was characterized by using four different diatom indices (TIT, EPI-D, IPS, and TDI), however, only Trophic Index Turkey (TIT) represented significant positive correlations with log (TP) gradient. Both environmental parameters, the relative abundance of indicator species, and TIT index results stated that 1st, 2nd, 3rd, 5th, 7th, and 8th stations had moderate, while 4th and 6th stations had good water quality. The good correlation of TIT index with log (TP), and its compatibility with the presence of indicator species at different stations indicates that this index could be used in the Lake Sapanca basin, and Sakarya basin where the lake basin is located.
The Functional Feeding Groups (FFGs) of ciliates responded the fluctuations of food resources, since these vary according to seasonality and types of environments, reinforcing that the FFGs can be a great indicator of the responses to environmental fluctuations, helping to understand the structure communities in freshwater environments.
This work allows us to analyze the changes in invertebrate communities of the Luján River basin in an urbanization gradient and to determine the specific indicator taxa of urbanized habitats.
The aim of the study is to determine the effects of Bentagran on growth and oxidative effects to Chlorella vulgaris and Arthrospira platensis and to evaluate the herbicide toxicity on primary producers of aquatic ecosystems. Bentagran effected to the biomass accumulation and chlorophyll-a content in a dose-dependent manner and it caused the oxidative stress in both organism.
This study adds additional knowledges about the taxonomy of the stonel loach Barbatula spp. Several cryptic evolutionary lineages were previously highlighted by molecular data. Here we revalidate Barbatula hispanica, previously considered a junior synonym of B. quignardi. This species is found in the Ebro drainage and in Cantabria (Spain) as well as in the Adour drainage (Southwestern France). This is important for the conservation and for a region with a high rate of endemicity.
The objective of this study was to identify the presence of morphotypes L. bulla strains from Quintana Roo, México and their life history traits. Our results indicated that L. bulla has two morphotypes: large morphotype and small morphotype. The large presented short life expectancy, intrinsic positive growth, short generational time and low number of descendants, that reach sexual maturation in an accelerated manner, while in the small the opposite occurred. In conclusion, this study indicates the possible coexistence in the same geographical bioregion of two different morphotypes of L. bulla, one is a small-sized distributed in the northwest of Quintana Roo and another large-sized in the southwest.
This study analyzed the population structure and habitat use of the Japanese eel (Anguilla japonica) and the marbled eel (Anguilla marmorata) in the Pearl River based on data collected from 2015 to 2018. A total of 181 Japanese eels and 56 marbled eels were collected, over half of which were middle-sized eels between 255 and 600 mm in length. Although they are sister species, Japanese eels mainly inhabit complex river habitats characterized by high river fractals and coefficients of fluvial facies, while marbled eels mainly inhabit wider and deeper river sections. The results of this study showed that wild Anguilla spp. resources in the Pearl River were extremely low and there was an urgent need for conservation and management of eel resources in south China.
Understanding the genetic diversity and population structure of fish species is crucial for the sustainable use and protection of fish germplasm resources. Hemibagrus guttatus (Bagridae, Siluriformes) is widely distributed in the large subtropical Pearl River (China) and is a commercially important fish. H. guttatus populations have been declining due to over-fishing, water pollution, and hydraulic constructions, it is now a wild animals under second class national protection. However, the genetic diversity of wild H. guttatus is not clear, despite its important ecological significance and its significance for conservation. In this paper, genes mitochondrial cytochrome c oxidase subunit I (COI) and cytochrome b (Cyt b) were used to analyze the genetic structure and found that there is degradation in germplasm resources of H. guttatus that could destabilize the sustainable use of this species.
Triclosan (TCS) is a broad-spectrum antimicrobial agent found in personal care, household, veterinary, medical, and industrial products. TCS has been detected in soil, sediment, and surface water. In the current work, the effects of acute exposure to TCS on gill and liver tissues of zebrafish were evaluated and the results indicated that TCS caused distinct histopathological alterations.
The depressive effect of salinization on detritus processing in streams overrides the potential buffer capacity of aquatic hyphomycetes higher richness, main drivers of litter decomposition. These findings, suggest that this stressor is as worldwide threat for stream ecosystem functioning independently of the fungal species abundance.
Investigating freshwater fish introductions in French Guiana revealed the presence of 11 non-native species. Four are established and one is rapidly increasing its spatial range. Five other species are known from few specimens, but belong to highly invasive species, making those first occurrences an early warning for potential establishment and spread.
This study examines the effects of bottom-up (physical-chemical) and top-down (predation) factors on the phytoplankton functional groups in a eutrophic lake. The study revealed that the bottom-up effects of physical-chemical variables on some phytoplankton functional groups was stronger than the top-down effects of zooplankton. The study further showed that zooplankton functional groups were positively correlated with phytoplankton biomass implying that the top-down control of phytoplankton by the zooplankton in Lake Hulun is not strong enough to produce a negative effect. These finding serve as a basis for identifying how phytoplankton dynamics are influenced, which have implications for developing sustainable management strategies and conserving services of Lake Hulun and other eutrophic fresh water lakes.
Our study on trait-environment relationship of co-occurring water beetles in anthropogenic ponds revealed that submerged vegetation, odonate nymphs, calcium hardness, salinity and chironomid larvae affected body size, swimming traits and functional feeding groups of the beetles in assemblages.
The exploitation of phosphate mines contributes to the eutrophication of the Foum-Gleita reservoir (Mauritania), leading to the appearance of cyanobacterial blooms. Microcystis aeruginosa and Dolichospermum flos-aquae are the two dominant species during the hot season (May to September), and only the microcystin-LR congener was detected for the first time in a freshwater ecosystem in Mauritania with a peak at 3.55 μg L−1.
