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1. PDF
Baldan D. et al. A multi-scale, integrative modeling framework for setting conservation priorities at the catchment scale for the Freshwater Pearl Mussel Margaritifera margaritifera // Science of the Total Environment. 2020. Vol. 718. P. 137369.

The identification and prioritization of sites for conservation actions to protect biodiversity in lotic systems is crucial when economic resources or available areas are limited. Challenges include the incorporation of multi-scale interactions, and the application of species distribution models (SDMs) to rare organism with multiple life stages. To support the planning of conservation actions for the highly endangered Freshwater Pearl Mussel Margaritifera margaritifera (FPM), this paper aims at developing an ecohydrological modeling cascade including a hydrological model (SWAT) and a hydraulic model (HEC-RAS). Building on hydrology and hydraulics, Random Forest models for potential risk to juveniles due to sand accumulation, SDMs for adults habitat niche, and a landscape connectivity assessment of dispersal potential were developed. The feasibility of such models integration was tested in the Aist catchment (630 km(2)) in Austria. The potential FPM habitat and the sand accumulation risk for the whole catchment were predicted with good accuracy. Results show that while the potentially suitable habitats for adults FPM cover 34% of the river network, only few habitat patches can maximize the dispersal potential (4% of the river network) and even less are showing limited impact of accumulations (3.5% of river network). No habitat patch that meets all the three criteria is available, suggesting approaches that target the patch-specific critical life stage-factors are promising for conservation. (C) 2020 The Authors. Published by Elsevier B.V.


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Chowdhury M.M.R. et al. Interaction between the endangered freshwater pearl mussel Margaritifera margaritifera, the duck mussel Anodonta anatina and the fish host (Salmo): acquired and cross-immunity // Hydrobiologia. 2018. Vol. 810, № 1. P. 273–281.

The common duck mussel Anodonta anatina can live in sympatry with-and use the same host, brown trout (Salmo trutta)-as the endangered freshwater pearl mussel Margaritifera margaritifera. Since the glochidia release of A. anatina takes place seasonally earlier than that of M. margaritifera, brown trout can be sequentially exposed first to A. anatina and then to M. margaritifera. Cross-immunity, an immune reaction induced in fish host against glochidia after the infection with glochidia of another mussel species, is possible. Thus, it was studied experimentally if brown trout can be cross immunized against M. margaritifera by earlier infection with A. anatina. In addition, the hypothesis that consecutive exposures of same glochidial species in different years in the same host may create acquired immunity was tested in brown trout against M. margaritifera. Furthermore, the dose dependence of acquired immunity against M. margaritifera glochidia in the Atlantic salmon (S. salar) was also studied. Cross-immunity was not found; suggesting that occurrence of A. anatina does not pose a threat to M. margaritifera. Instead, acquired immunity and its dose dependence were evident, emphasizing the significance of availability of 0+ age group immunologically na < ve Atlantic salmon/brown trout for efficient conservation of M. margaritifera.


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Clark S.R. et al. Stability, persistence and habitat associations of the pearl darter Percina aurora in the Pascagoula River System, southeastern USA // Endanger. Species Res. 2018. Vol. 36. P. 99–109.

The southeastern United States represents one of the richest collections of aquatic biodiversity worldwide; however, many of these taxa are under an increasing threat of imperilment, local extirpation, or extinction. The pearl darter Percina aurora is a small-bodied freshwater fish endemic to the Pearl and Pascagoula river systems of Mississippi and Louisiana (USA). The last collected specimen from the Pearl River drainage was taken in 1973, and it now appears that populations in this system are likely extirpated. This reduced the historical range of this species by approximately 50%, ultimately resulting in federal protection under the US Endangered Species Act in 2017. To better understand the current distribution and general biology of extant populations, we analyzed data collected from a series of surveys conducted in the Pascagoula River drainage from 2000 to 2016. Pearl darters were captured at relatively low abundance (2.4 +/- 4.0 ind. per collection) from 57% of 308 collections. We identified strong relationships between local habitat variables and occurrence and catch-per-unit-effort (CPUE) of pearl darters. Pearl darters were frequently encountered and in greater abundance in depositional areas characterized by low-velocity habitats and finer substrates. Patterns of occurrence and CPUE were spatiotemporally variable across years; however, repeated collections from a subset of localities collected across a decade or more indicated long-term persistence and stability, suggesting population resilience throughout the Pascagoula River drainage.


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Clements E.A., Thomas R., Adams C.E. An investigation of salmonid host utilization by the endangered freshwater pearl mussel (Margaritifera margaritifera) in north-west Scotland // Aquat. Conserv.-Mar. Freshw. Ecosyst. 2018. Vol. 28, № 3. P. 764–768.

1. The complex life cycle of the globally threatened Margaritifera margaritifera includes a parasitic stage, where glochidia attach to the gills of fishes of the genus Salmo; however, the species of Salmo used appears to vary across its range. In previous literature the reported primary host in Scotland, home to a high proportion of the world's remaining M. margaritifera populations, is the Atlantic salmon Salmo salar, and in its absence the brown trout Salmo trutta. 2. In this study, the prevalence of infection in putative Salmo hosts in eight rivers in north-west Scotland was determined. At a selected site on each river, where both S. trutta and S. salar were collected in abundance, S. trutta was the preferred host. 3. At sites where S. salar were abundant but S. trutta were at low density, however, S. salar showed a high prevalence of infection (with the exception of one river where neither S. salar nor S. trutta were infected). Thus, the primary host appears to be very site-specific in the rivers sampled. 4. We speculate that this may be because M. margaritifera have population-specific responses to cues for attachment to a host. Alternatively, it may be that host population- specific immune responses mediate infections by glochidia. In addition, larger fish were less likely to be infected than smaller fish, and gills 1 and 5 were less heavily infected than gills 2-4. 5. One consequence of this finding, for both national and international conservation management of this globally endangered species, is that any current or future management activity must take into account local population host preferences, otherwise conservation efforts may be in vain.


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Cmiel A.M. et al. Response of freshwater mussel recruitment to hydrological changes in a eutrophic floodplain lake // Science of the Total Environment. 2020. Vol. 703. P. 135467.

Although eutrophication of freshwaters is a natural process, the human impact often leads to inland waters becoming overloaded with nutrients, impoverishing many valuable and vanishing habitats, such as floodplain lakes. These changes need to be reversed if the occurrence of endangered aquatic species is to be restored. In this paper we analyse the impact of a change in the water regime of a naturally eutrophic floodplain lake, which harbours a large diversity of Unionidae (large freshwater mussels), a globally threatened taxonomic group that provides important ecosystem functions and services. We found that a slight increase in the discharge from this waterbody, following the construction of an additional outflow pipe, positively influenced recruitment in three of the five mussel species inhabiting the lake. We also found that, after the construction of this additional outflow, the niches of juveniles of Anodonfa cygnea and Unio spp. changed, revealing differences in their hydrological requirements. Our results suggest that, as in lotic habitats, complex hydraulic parameters are highly significant to unionid mussels in lentic conditions. (C) 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licensesilby/4.0/).


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Ferreira-Rodriguez N. et al. Research priorities for freshwater mussel conservation assessment // Biol. Conserv. 2019. Vol. 231. P. 77–87.

Freshwater mussels are declining globally, and effective conservation requires prioritizing research and actions to identify and mitigate threats impacting mussel species. Conservation priorities vary widely, ranging from preventing imminent extinction to maintaining abundant populations. Here, we develop a portfolio of priority research topics for freshwater mussel conservation assessment. To address these topics, we group research priorities into two categories: intrinsic or extrinsic factors. Intrinsic factors are indicators of organismal or population status, while extrinsic factors encompass environmental variables and threats. An understanding of intrinsic factors is useful in monitoring, and of extrinsic factors are important to understand ongoing and potential impacts on conservation status. This dual approach can guide conservation status assessments prior to the establishment of priority species and implementation of conservation management actions.


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Froufe E. et al. Mesozoic mitogenome rearrangements and freshwater mussel (Bivalvia: Unionoidea) macroevolution // Heredity. 2020. Vol. 124, № 1. P. 182–196.

Using a new fossil-calibrated mitogenome-based approach, we identified macroevolutionary shifts in mitochondrial gene order among the freshwater mussels (Unionoidea). We show that the early Mesozoic divergence of the two Unionoidea clades, Margaritiferidae and Unionidae, was accompanied by a synchronous split in the gene arrangement in the female mitogenome (i.e., gene orders MF1 and UF1). Our results suggest that this macroevolutionary jump was completed within a relatively short time interval (95% HPD 201-226 Ma) that coincided with the Triassic-Jurassic mass extinction. Both gene orders have persisted within these clades for similar to 200 Ma. The monophyly of the so-called "problematic" Gonideinae taxa was supported by all the inferred phylogenies in this study using, for the first time, the M- and F-type mitogenomes either singly or combined. Within Gonideinae, two additional splits in the gene order (UF1 to UF2, UF2 to UF3) occurred in the Mesozoic and have persisted for similar to 150 and similar to 100 Ma, respectively. Finally, the mitogenomic results suggest ancient connections between freshwater basins of East Asia and Europe near the Cretaceous-Paleogene boundary, probably via a continuous paleo-river system or along the Tethys coastal line, which are well supported by at least three independent but almost synchronous divergence events.


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Gomes-dos-Santos A. et al. The male and female complete mitochondrial genomes of the threatened freshwater pearl mussel Margaritifera margaritifera (Linnaeus, 1758) (Bivalvia: Margaritiferidae) // Mitochondrial DNA Part B-Resour. 2019. Vol. 4, № 1. P. 1417–1420.

The complete mitogenomes of one (M-)ale (North America), one Hermaphroditic (Europe), and two (F-)emale (North America and Europe) individuals of the freshwater pearl mussel Margaritifera margaritifera were sequenced. The M-type and F-type (Female and Hermaphroditic) mitogenomes have 17,421 and 16,122 nucleotides, respectively. All with the same content: 13 protein-coding genes, 22 transfer RNA, two ribosomal RNA genes, and one sex-related ORF. The M-type is highly divergent (37.6% uncorrected p-distance) from the F-type mitogenomes. North American and European F-type mitogenomes exhibit low genetic divergence (68 nt substitutions), and the Female and Hermaphroditic European mitogenomes are almost identical, and matching sex-related ORFs.


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Gopko M., Chowdhury M.M.R., Taskinen J. Interactions between two parasites of brown trout (Salmo trutta): Consequences of preinfection // Ecol. Evol. 2018. Vol. 8, № 20. P. 9986–9997.

Preinfection by one parasitic species may facilitate or by contrast hamper the subsequent penetration and/or establishment of other parasites in a host. The biology of interacting species, timing of preinfection, and dosage of subsequent parasite exposure are likely important variables in this multiparasite dynamic infection process. The increased vulnerability to subsequent infection can be an important and often overlooked factor influencing parasite virulence. We investigated how the preinfection by freshwater pearl mussel Margaritifera margaritifera glochidia could influence the success of subsequent infection by the common trematode Diplostomum pseudospathaceum in brown trout Salmo trutta and vice versa whether preinfection by the trematode made fish more susceptible to glochidia infection. The first experiment was repeated twice with different (low and high) exposure doses to initiate the subsequent trematode infection, while in the second experiment we varied the timing of the preinfection with trematodes. The preinfection with glochidia made fish more vulnerable to subsequent infection with trematodes. Since the trematodes penetrate through the gills, we suggest that increased host vulnerability was most likely the result of increased respiration caused by the freshwater pearl mussel glochidia encysted on gills. In turn, brown trout preinfected with trematodes were more vulnerable to the subsequent glochidial infection, but only if they were preinfected shortly before the subsequent infection (20 hr). Fish preinfected with trematodes earlier (2 weeks before the subsequent infection) did not differ in their vulnerability to glochidia. These effects were observed at moderate intensities of infections similar to those that occur in nature. Our study demonstrates how the timing and sequence of exposure to parasitic species can influence infection success in a host-multiparasite system. It indicates that the negative influence of glochidia on host fitness is likely to be underestimated and that this should be taken into consideration when organizing freshwater pearl mussel restoration procedures.


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Horky P., Slavik O., Douda K. Altered thermoregulation as a driver of host behaviour in glochidia-parasitised fish // J. Exp. Biol. 2019. Vol. 222, № 1. P. UNSP jeb184903.

Parasites alter their host behaviour and vice versa as a result of mutual adaptations in the evolutionary arms race. One of these adaptations involves changes in host thermoregulation, which has the potential to harm the parasite and thereby act as a defence mechanism. We used a model of the brown trout (Salmo trutta) experimentally parasitised with glochidia ectoparasitic larvae from the endangered freshwater pearl mussel (Margaritifera margaritifera) to reveal whether parasitisation alters fish behavioural thermoregulation. A study using radiotelemetry temperature sensors was performed during almost one year of the M. margaritifera parasitic stage. Glochidia-infested S. trutta altered their thermoregulation through active searching for habitats with different thermal regimes. The general preference for temperatures in infested fish varied and was either above or below the temperature preferred by uninfested individuals. Infested fish also preferred different temperatures across localities, whereas uninfested fish maintained their thermal preference no matter which stream they inhabited. Glochidia further induced the expression of a behavioural syndrome among S. trutta personality traits, suggesting that it might increase the probability that the fish host would occur in the glochidia temperature optimum. Our findings present the first evidence that thermoregulation plays a fundamental role in the relationship of affiliated mussels and their fish hosts. Incorporating thermoregulation as a factor in the study of this relationship can help to interpret results from previous behavioural studies, as well as to optimise management measures related to endangered mussels.


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Huang Y., Han K., Ren Q. Cloning and Analysis of Gene Expression of Two Toll Receptors in Freshwater Pearl Mussel Hyriopsis cumingii // Front. Physiol. 2018. Vol. 9. P. 133.

Toll receptors are involved in innate immunity of invertebrates. In this study, we identify and characterize two Toll genes (named HcToll4 and HcToll5) from triangle sail mussel Hyriopsis cumingii. HcToll4 has complete cDNA sequence of 3,162 bp and encodes a protein of 909 amino acids. HcToll5 cDNA is 4,501 bp in length and encodes a protein of 924 amino acids. Both deduced HcToll4 and HcToll5 protein contain signal peptide, extracellular leucine rich repeats (LRRs), and intracellular Toll/interleukin-1 (IL-1) receptor domains. Quantitative real-time PCR analysis revealed that HcToll4 and HcToll5 were largely distributed in the hepatopancreas and could be detected in the gills and mantle. HcToll4 and HcToll5 expression could respond to Staphylococcus aureus, Vibrio parahaemolyticus, White spot syndrome virus (WSSV) or Poly I:C challenge. RNA interference by siRNA results showed that HcToll4 and HcToll5 were involved in the regulation of theromacin (HcThe) and whey acidic protein (HcWAP) expression. Based on these results, HcToll4 and HcToll5 might play pivotal function in H. cumingii innate immune response.


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Karampelas S. et al. Chemical Characteristics of Freshwater and Saltwater Natural and Cultured Pearls from Different Bivalves // Minerals. 2019. Vol. 9, № 6. P. 357.

The present study applied Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) on a large number of natural and cultured pearls from saltwater and freshwater environments, which revealed that freshwater (natural and cultured) pearls contain relatively higher quantities of manganese (Mn) and barium (Ba) and lower sodium (Na), magnesium (Mg) and strontium (Sr) than saltwater (natural and cultured) pearls. A few correlations between the host animal's species and chemical elements were found; some samples from Pinctada maxima (P. maxima) are the only studied saltwater samples with Mn-55 >20 ppmw, while some P. radiata are the only studied saltwater samples with Mg-24 <65 ppmw and some of the P. imbricata are the only studied saltwater samples with Ba-137 >4.5 ppmw. X-ray luminescence reactions of the studied samples has confirmed a correlation between its yellow-green intensity and manganese content in aragonite, where the higher Mn2+ content, the more intense the yellow-green luminescence becomes. Luminescence intensity in some cases is lower even if manganese increases, either because of pigments or because of manganese self-quenching. X-ray luminescence can be applied in most cases to separate saltwater from freshwater samples; only samples with low manganese content (Mn-55 <50 ppmw) might be challenging to identify. One of the studied natural freshwater pearls contained vaterite sections which react by turning orange under X-ray due to a different coordination of Mn2+ in vaterite than that in aragonite.


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Lavictoire L. et al. Ontogeny of juvenile freshwater pearl mussels, Margaritifera margaritifera (Bivalvia: Margaritiferidae) // PLoS One. 2018. Vol. 13, № 3. P. e0193637.

The gills of juvenile freshwater bivalves undergo a complex morphogenesis that may correlate with changes in feeding ecology, but ontogenic studies on juvenile mussels are rare. Scanning electron microscopy was used to examine the ultrastructure and ontogeny of 117 juvenile freshwater pearl mussels (Margaritifera margaritifera) ranging in age from 1-44 months and length from 0.49-8.90 mm. Three stages of gill development are described. In Stage 1 (5-9 inner demibranch filaments), only unreflected inner demibranch filaments were present. In Stage 2 (9-17 inner demibranch filaments), inner demibranch filaments began to reflect when shell length exceeded 1.13 mm, at 13-16 months old. Reflection began in medial filaments and then proceeded anterior and posterior. In Stage 3 (28-94 inner demibranch filaments), outer demibranch filaments began developing at shell length > 3.1 mm and about 34 months of age. The oral groove on the inner demibranch was first observed in 34 month old specimens > 2.66 mm but was never observed on the outer demibranch. Shell length (R-2 = 0.99) was a better predictor of developmental stage compared to age (R-2 = 0.84). The full suite of gill ciliation was present on filaments in all stages. Interfilamentary distance averaged 31.3 mu m and did not change with age (4-44 months) or with size (0.75-8.9 mm). Distance between laterofrontal cirri couplets averaged 1.54 pm and did not change significantly with size or age. Labial palp primordia were present in even the youngest individuals but ciliature became more diverse in more developed individuals. Information presented here is valuable to captive rearing programmes as it provides insight in to when juveniles may be particularly vulnerable to stressors due to specific ontogenic changes. The data are compared with two other recent studies of Margaritifera development.


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Liu D. et al. Water Supply-Water Environmental Capacity Nexus in a Saltwater Intrusion Area under Nonstationary Conditions // Water. 2019. Vol. 11, № 2. P. 346.

Due to water supply increase and water quality deterioration, water resources are a critical problem in saltwater intrusion areas. In order to balance the relationship between water supply and water environment requirements, the nexus of water supply-water environment capacity should be well understood. Based on the Saint-Venant system of equations and the convection diffusion equation, the water supply-water environment capacity nexus physical equation is determined. Equivalent reliability is employed to estimate the boundary design water flow, which will then lead to a dynamic nexus. The framework for determining the nexus was then applied to a case study for the Pearl River Delta in China. The results indicate that the water supply-water environment capacity nexus is a declining linear relationship, which is different from the non-salt intrusion and tide-impacted areas. Water supply mainly relies on freshwater flow from upstream, while water environmental capacity is affected by both the design freshwater flow and the water levels at the downstream boundary. Our methods provide a useful framework for the quantification of the physical nexus according to the water quantity and water quality mechanisms, which are useful for freshwater allocation and management in a saltwater intrusion area or the tail area of cascade reservoirs.


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Marwaha J. et al. Host (Salmo trutta) age influences resistance to infestation by freshwater pearl mussel (Margaritifera margaritifera) glochidia // Parasitol. Res. 2019. Vol. 118, № 5. P. 1519–1532.

The freshwater pearl mussel (Margaritifera margaritifera) is an endangered bivalve with an obligate parasitic stage on salmonids. Host suitability studies have shown that glochidial growth and load vary significantly between host strains as well as among individuals of a suitable strain. Variation in host suitability has been linked to environmental conditions, host age and/or size, genetic composition of the host and parasite, or a combination of these factors. In our study, we wanted to investigate if brown trout (Salmo trutta) displayed an age-dependent response to glochidial infestation. We hypothesised that 1+ naive brown trout hosts tolerate glochidial infestation better than 0+ hosts. In order to test our hypothesis, we infested 0+ and 1+ hatchery reared brown trout with glochidia from closely related mothers and kept them under common garden conditions. This allowed us to observe a pure age dependent host response to infestation, as we eliminated the confounding effect of genotype-specific host interactions. We analysed the interaction between glochidial load and host condition, weight and length, and observed a significant age-dependent relationship. Glochidial load was negatively correlated to host condition in 0+ fish hosts and positively correlated in 1+ hosts. These contradictory findings can be explained by a change in host response strategy, from resistance in young to a higher tolerance in older fish. In addition, we also examined the relationship between glochidial load and haematocrit values in the 1+ hosts and observed that haematocrit values were significantly higher in heavily infested hosts. Our results have important conservation implications for the management of wild pearl mussel populations, as well as for captive breeding programmes.


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Mauvisseau Q. et al. Influence of accuracy, repeatability and detection probability in the reliability of species-specific eDNA based approaches // Sci Rep. 2019. Vol. 9. P. 580.

Environmental DNA (eDNA) barcoding has a high potential to increase the cost-efficiency of species detection and monitoring in aquatic habitats. However, despite vast developments in the field, many published assays often lack detailed validation and there is little to no commonly (agreed upon) standardization of protocols. In this study, we evaluated the reliability of eDNA detection and quantification using published primers and assays targeting the Freshwater Pearl Mussel as a model organism. We first assessed limits of detection for two different target genes (COI and 16S) following the MIQE guidelines, and then tested the reliability of quantification in a double-blind mesocosm experiment. Our results reveal that different methodological indicators, namely accuracy, repeatability and detection probability affected the reliability of eDNA measurement at the different levels tested. The selection of the optimal analytical method was mainly determined by detection probability. Both the COI and 16S assays were highly specific for the targeted organism and showed similar accuracy and repeatability, whilst the limit of detection was clearly lower for the COI based approach. In contrast, the reliability of eDNA quantification hinged on repeatability, reflected by the scattering (r(2) = 0.87) around the relationship between eDNA and mussel density in mesocosms. A bootstrapping approach, which allowed for the assignment of measures associated with repeatability of samples, revealed that variability between natural replicates (i.e. accuracy) strongly influenced the number of replicates required for a reliable species detection and quantification in the field.


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Micieli D. et al. Characterizing pearls structures using X-ray phase-contrast and neutron imaging: a pilot study // Sci Rep. 2018. Vol. 8. P. 12118.

Some cultured and natural pearls can be reliably distinguished by visual inspection and by the use of lens and microscope. However, assessing the origin of the pearls could be not straightforward since many different production techniques can now be found in the pearl market, for example in salt or freshwater environments, with or without a rigid nucleus. This wide range of products requires the use of new effective scientific techniques. Indeed, X-ray radiography has been used by gemologists since last century as the only safe and non-destructive way to visually inspect the interior of a pearl, and recently, also X-ray computed micro-tomography was used to better visualize the inner parts of the gems. In this study we analyzed samples of natural and cultured pearls by means of two non-destructive techniques: the X-ray Phase-Contrast Imaging (PCI) and the Neutron Imaging (NI). PCI and NI results will be combined for the first time, to better visualize the pearls internal morphology, thus giving relevant indications on the pearl formation process.


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Pfeiffer J.M., Breinholt J.W., Page L.M. Unioverse: A phylogenomic resource for reconstructing the evolution of freshwater mussels (Bivalvia, Unionoida) // Mol. Phylogenet. Evol. 2019. Vol. 137. P. 114–126.

Freshwater mussels (order Unionoida) are a diverse radiation of parasitic bivalves that require temporary larval encystment on vertebrate hosts to complete metamorphosis to free-living juveniles. The freshwater mussel-fish symbiosis represents a useful relationship for understanding eco-evolutionary dynamics in freshwater ecosystems but the practicality of this promising model system is undermined by the absence of a stable freshwater mussel phylogeny. Inadequate character sampling is the primary analytical impediment obfuscating a coherent phylogeny of freshwater mussels, specifically the lack of nuclear molecular markers appropriate for reconstructing supraspecific relationships and testing macroevolutionary hypotheses. The objective of this study is to develop a phylogenomic resource, specifically an anchored hybrid enrichment probe set, capable of capturing hundreds of molecular markers from taxa distributed across the entirety of freshwater mussel biodiversity. Our freshwater mussel specific anchored hybrid enrichment probe set, called Unioverse, successfully captures hundreds of nuclear protein-coding loci from all major lineages of the Unionoida and will facilitate more data-rich and taxonomically inclusive reconstructions of freshwater mussel evolution. We demonstrate the utility of this resource at three disparate evolutionary scales by estimating a backbone phylogeny of the Bivalvia with a focus on the Unionoida, reconstructing the subfamily-level relationships of the Unionidae, and recovering the systematic position of the phylogenetically unstable genus Plectomerus.


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Pradhan S. et al. Length-weight, width-weight and height-weight relationships of cultured freshwater pearl mussel, Lamellidens marginalis (Lamarck, 1819) // Indian Journal of Fisheries. 2020. Vol. 67, № 1. P. 135–137.

Lamellidens marginalis (Lamarck, 1819) is one of the important candidate species for freshwater pearl production in India. In the present study, the length-weight, width-weight and height-weight relationships of L. marginalis maintained in the farm were examined from January 2015 to September 2016. Monthly sampling was carried out and a total of 1015 specimens were analysed for the study. The length-weight, width-weight and height-weight relationships derived were W = 0.0003L(2.712), W = 0.0018L(2.708) and W = 0.0.0293L(2.210) and the value of r(2) was estimated as 0.776, 0.619 and 0.597 respectively. The values of b indicated the relative growth in body weight and superior physiological condition of the mussel. The length-weight, width-weight and height-weight relationships were found to be positive allometric and better correlation was observed in length-weight and width-weight relationships.


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Pulley S. et al. The sources and dynamics of fine-grained sediment degrading the Freshwater Pearl Mussel (Margaritifera argaritifera) beds of the River Torridge, Devon, UK // Science of the Total Environment. 2019. Vol. 657. P. 420–434.

The Freshwater Pearl Mussel (Margaritifera rnargaritifera) is an endangered organism across its entire range. It has a complex life cycle and stringent habitat requirements and is therefore an indicator species for the general ecosystem health of host rivers. Whereas historical intensive pearl fishing contributed to population declines, excess nutrient and sediment loss associated with current land use pressures in host river catchments, including modern intensive farming practices, arc now highlighted as primary contributory factors. Accordingly, this study investigated the sources and dynamics of fine-grained sediment sampled in the mussel beds of the River Torridge, SW England. Sediment source fingerprinting using a combination of calorimetric and radiometric tracers to construct different composite signatures revealed the importance of roads both as a sediment source and delivery pathway for fine-grained sediment mobilised from fields predominantly supporting lowland live-stock farming. Grassland fields with evidence of soil poaching were highlighted as important sediment sources, but equally, riparian woodland was also identified as important, especially during the latter stages of consecutive runoff events when its rainfall buttering capacity was exceeded. Bed sediment storage levels (median up to 393 g m(-2)) were found to be low (41st percentile) compared to typical values reported by a recent strategic scale survey across England and Wales, whereas elevated turbidity peaks were shown to be long duration (days) in conjunction with consecutive days of rainfall and corresponding runoff events. Hysteresis patterns varied but were generally clockwise during the largest runoff events associated with consecutive rain days; again, suggesting mobilisation of sediment from proximal woodland sources following exceedance of rainfall buffering capacity. In combination, the data assembled by this study provides a basis for planning sediment control measures for protecting the Freshwater Pearl Mussel (FPM) beds from excessive fine-grained sediment inputs associated with the intensive use of primarily grazing land. (C) 2018 The Authors. Published by Elsevier B.V.


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Sakalauskaite J. et al. “Palaeoshellomics” reveals the use of freshwater mother-of-pearl in prehistory // Elife. 2019. Vol. 8. P. e45644.

The extensive use of mollusc shell as a versatile raw material is testament to its importance in prehistoric times. The consistent choice of certain species for different purposes, including the making of ornaments, is a direct representation of how humans viewed and exploited their environment. The necessary taxonomic information, however, is often impossible to obtain from objects that are small, heavily worked or degraded. Here we propose a novel biogeochemical approach to track the biological origin of prehistoric mollusc shell. We conducted an in-depth study of archaeological ornaments using microstructural, geochemical and biomolecular analyses, including 'palaeoshellomics', the first application of palaeoproteomics to mollusc shells (and indeed to any invertebrate calcified tissue). We reveal the consistent use of locally-sourced freshwater mother-of-pearl for the standardized manufacture of 'double-buttons'. This craft is found throughout Europe between 4200-3800 BCE, highlighting the ornament-makers' profound knowledge of the biogeosphere and the existence of cross-cultural traditions.


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Sarkissian C.D. et al. Unveiling the Ecological Applications of Ancient DNA From Mollusk Shells // Frontiers in Ecology and Evolution. 2020. Vol. 8. P. 37.

The shells of marine mollusks represent promising metagenomic archives of the past, adding to bones, teeth, hairs, and environmental samples most commonly examined in ancient DNA research. Seminal work has established that DNA recovery from marine mollusk shells depends on their microstructure, preservation and disease state, and that authentic ancient DNA could be retrieved from specimens as old as 7,000 years. Here, we significantly push the temporal limit for shell DNA recovery to >= 100,000 years with the successful genetic characterization of one Portlandia arctica and one Mytilus mussel sample collected within a dated permafrost layer from the Taimyr Peninsula, Russia. We expand the analysis of ancient DNA in carbonate shells to a larger number of genera (Arctica, Cernuella, Crassostrea, Dreissena, Haliotis, Lymnaea, Margaritifera, Pecten, Ruditapes, Venerupis) from marine, freshwater and terrestrial environments. We demonstrate that DNA from ancient shells can provide sufficient resolution for taxonomic, phylogenetic and/or population assignment. Our results confirm mollusk shells as long-term DNA reservoirs, opening new avenues for the investigation of environmental changes, commercial species management, biological invasion, and extinction. This is especially timely in light of modern threats to biodiversity and ecosystems.


23. PDF
Schoene B.R. et al. Freshwater pearl mussels from northern Sweden serve as long-term, high-resolution stream water isotope recorders // Hydrology and Earth System Sciences. 2020. Vol. 24, № 2. P. 673–696.

The stable isotope composition of lacustrine sediments is routinely used to infer Late Holocene changes in precipitation over Scandinavia and, ultimately, atmospheric circulation dynamics in the North Atlantic realm. However, such archives only provide a low temporal resolution (ca. 15 years), precluding the ability to identify changes on inter-annual and quasi-decadal timescales. Here, we present a new, high-resolution reconstruction using shells of freshwater pearl mussels, Margaritifera margaritifera, from three streams in northern Sweden. We present seasonally to annually resolved, calendar-aligned stable oxygen and carbon isotope data from 10 specimens, covering the time interval from 1819 to 1998. The bivalves studied formed their shells near equilibrium with the oxygen isotope signature of ambient water and, thus, reflect hydrological processes in the catchment as well as changes, albeit damped, in the isotope signature of local atmospheric precipitation. The shell oxygen isotopes were significantly correlated with the North Atlantic Oscillation index (up to 56% explained variability), suggesting that the moisture that winter precipitation formed from originated predominantly in the North Atlantic during NAO(+) years but in the Arctic during NAO(-) years. The isotope signature of winter precipitation was attenuated in the stream water, and this damping effect was eventually recorded by the shells. Shell stable carbon isotope values did not show consistent ontogenetic trends, but rather oscillated around an average that ranged from ca. -12.00 to -13.00% among the streams studied. Results of this study contribute to an improved understanding of climate dynamics in Scandinavia and the North Atlantic sector and can help to constrain eco-hydrological changes in riverine ecosystems. Moreover, long isotope records of precipitation and streamflow are pivotal to improve our understanding and modeling of hydrological, ecological, biogeochemical and atmospheric processes. Our new approach offers a much higher temporal resolution and superior dating control than data from existing archives.


24. PDF
Silva de Souza G.R., Sabino J., Garrone-Neto D. The surprising “B-side”: description of a new foraging tactic for the pearl cichlid, Geophagus brasiliensis, in a coastal stream of the Atlantic Forest // Biota Neotrop. 2019. Vol. 19, № 3. P. e20180702.

A new foraging tactic for the pearl cichlid, Geophagus brasiliensis, is described from underwater observations performed in a coastal stream of the Atlantic Forest, Southeastern Brazil. Named "shift picking", the foraging tactic involved the manoeuvering of leaves, wood twigs and tree bark present in the substrate, with fish using its mouth to turn objects and uncover macroinvertebrates adhered to the underside of the object being picked ("B-side"). The object-shifting behaviour is rarely reported for fish and the present description seems to be the first record for a freshwater species of South America.


25. PDF
Sousa R. et al. A tale of shells and claws: The signal crayfish as a threat to the pearl mussel Margaritifera margaritifera in Europe // Sci. Total Environ. 2019. Vol. 665. P. 329–337.

The freshwater pearl mussel Margaritifera margaritifera is a highly threatened species in Europe. Several mechanisms may be responsible for the decline in distribution and abundance of European pearl mussel populations, but almost no quantitative data exists about the possible negative impacts of invasive alien species (IAS). In this study, we clearly demonstrate that the invasive signal crayfish Pacifastacus leniusculus predates pearl mussels, using a laboratorial experiment followed by in situ validation in four rivers in the North of Portugal (Mente, Rabacal, Tuela and Baceiro Rivers; Douro Basin). In the laboratory, the crayfish had a clear preference for small-sized pearl mussels but no differences in predation were found in mesocosms with and without sediment. In addition, we clearly demonstrated that the signal crayfish predates pearl mussels in natural conditions and detected a significant density dependent effect (i.e., sites with more crayfish presented higher number of pearl mussel shells with marks of predation). Given the recent introduction of the signal crayfish and the potential negative impacts on pearl mussel populations we also investigated its autoecology (distribution, abundance, size structure and sex-ratio) in the four studied rivers. Significant differences in average abundance and size of the crayfish were detected between sites and the sex-ratio was highly skewed to females. In view of the widespread distribution of signal crayfish (and other invasive crayfish species) in Europe, future management actions devoted to the conservation of pearl mussels should take in consideration the possible negative effects of these predators, especially on juveniles. (c) 2019 Elsevier B.V. All rights reserved.


26. PDF
Sousa R. et al. Die-offs of the endangered pearl mussel Margaritifera margaritifera during an extreme drought // Aquat. Conserv.-Mar. Freshw. Ecosyst. 2018. Vol. 28, № 5. P. 1244–1248.

1. Droughts may be responsible for important ecological impacts in freshwater ecosystems, including the death of rare species. 2. This study assessed the mortality of the endangered pearl mussel Margaritifera margaritifera (Linnaeus, 1758) in the Mente, Rabacal and Tuela rivers (north west of the Iberian Peninsula) during the extreme summer drought of 2017. 3. Mortality occurred as a result of the low river flow, which led to mussel stranding near the banks and consumption (by predation or scavenging) by wild boar Sus scrofa (Linnaeus, 1758). 4. Mortality differed across sites. The shell lengths of live mussels (measured before the drought) and dead mussels significantly differed in the Rabacal River, but not in the Mente and Tuela rivers. 5. Extreme droughts are predicted to increase in number and intensity in the future, and possible impacts on rare species such as M. margaritifera should be carefully monitored. Several M. margaritifera populations in Iberia (and elsewhere) may now be at increased risk, and measures should be implemented in order to mitigate the impacts of future extreme droughts.


27. PDF
Sousa R. et al. Oued Bouhlou: A new hope for the Moroccan pearl mussel // Aquat. Conserv.-Mar. Freshw. Ecosyst. 2018. Vol. 28, № 1. P. 247–251.

The freshwater pearl mussel Margaritifera marocana (Pallary, ) is an endemic species of Morocco being listed as critically endangered and it stands among the world's 100 most threatened species. An extensive survey was performed in the Sebou basin (total area of approximately 40,000km(2)), covering 26 different sites. Margaritifera marocana was found only in four sites limited to a small tributary (Oued (=River) Bouhlou). This population has a very restricted distribution (no more than 4km of river length) but appears stable with recent recruitment, since small specimens were found. Genetic analyses were performed, showing that this population has a similar diversity to that found in the River Laabid (Oum Er Rbia basin), but represents a distinct conservation unit that should be managed independently. Although this study adds a new population to the current known distribution of M. marocana, urgent conservation measures (e.g. extension of the Tazzekka National Park; better management of river flow; increase of the riparian vegetation in some stretches; establishment of national and international legislation, and engagement of local citizens) are needed given the species' restricted distribution, its rarity, and the numerous threats that impair its future survival.


28. PDF
Vikhrev I.V. et al. Fish hosts, glochidia features and life cycle of the endemic freshwater pearl mussel Margaritifera dahurica from the Amur Basin // Scientific Reports. 2019. Vol. 9. P. 8300.

Margaritiferidae is a small freshwater bivalve family with 16 species. In spite of a small number of taxa and long-term history of research, several gaps in our knowledge on the freshwater pearl mussels still exist. Here we present the discovery of host fishes for Margaritifera dahurica, i.e. Lower Amur grayling, sharp-snouted lenok, and blunt-snouted lenok. The host fishes were studied in rivers of the Ussuri Basin. The identification of glochidia and fish hosts was confirmed by DNA analysis. The life cycle of M. dahurica and its glochidia are described for the first time. The SEM study of glochidia revealed that the rounded, unhooked Margaritifera dahurica larvae are similar to those of the other Margaritiferidae. Margaritifera dahurica is a tachytictic breeder, the larvae of which attach to fish gills during the Late August -September and finish the metamorphosis in June. Ancestral host reconstruction and a review of the salmonid - pearl mussel coevolution suggest that the ancestral host of the Margaritiferidae was a non-salmonid fish, while that of the genus Margaritifera most likely was an early salmonid species or their stem lineage. The overfishing of lenoks and graylings appears to be the most significant threat for this rare mussel species.


29. PDF
Vollmer D. et al. Integrating the social, hydrological and ecological dimensions of freshwater health: The Freshwater Health Index // Sci. Total Environ. 2018. Vol. 627. P. 304–313.

Degradation of freshwater ecosystems and the services they provide is a primary cause of increasing water insecurity, raising the need for integrated solutions to freshwater management. While methods for characterizing the multifaceted challenges of managing freshwater ecosystems abound, they tend to emphasize either social or ecological dimensions and fall short of being truly integrative. This paper suggests that management for sustainability of freshwater systems needs to consider the linkages between human water uses, freshwater ecosystems and governance. We present a conceptualization of freshwater resources as part of an integrated social-ecological system and propose a set of corresponding indicators to monitor freshwater ecosystem health and to highlight priorities for management. We demonstrate an application of this new framework - the Freshwater Health Index (FHI) - in the Dongjiang River Basin in southern China, where stakeholders are addressing multiple and conflicting freshwater demands. By combining empirical and modeled datasets with surveys to gauge stakeholders' preferences and elicit expert information about governance mechanisms, the FHI helps stakeholders understand the status of freshwater ecosystems in their basin, how ecosystems are being manipulated to enhance or decrease water-related services, and howwell the existing water resource management regime is equipped to govern these dynamics over time. This framework helps to operationalize a truly integrated approach to water resource management by recognizing the interplay between governance, stakeholders, freshwater ecosystems and the services they provide. (C) 2018 The Authors. Published by Elsevier B.V.


30. PDF
Wacker S. et al. Multiple paternity promotes genetic diversity in captive breeding of a freshwater mussel // Glob. Ecol. Conserv. 2019. Vol. 17.

Captive breeding can be an important supplement to habitat restoration in the conservation of threatened species. Careful choice of breeding regimes and genetic monitoring are essential to maintain genetic integrity and genetic diversity of target populations. Many species of freshwater mussels are threatened globally, and captive breeding has been employed many places. The genetic consequences of those breeding programmes are however largely unknown, as are the mating patterns that determine offspring genetic diversity. We explored changes in genetic diversity from adult freshwater pearl mussels to offspring in two alternative breeding approaches. Genetic diversity was measured at 15 microsatellite markers and mating patterns were reconstructed by parentage analysis. In the first approach, fertilisation took place among broodstock mussels in captivity, while in the second approach, fertilisation took place in the wild. In the population fertilised in captivity, female contribution was extremely skewed. This resulted in substantial loss of genetic diversity, but many sires within female broods (multiple paternity) limited the loss of genetic diversity. Fertilisation in nature largely maintained genetic diversity in the offspring, compared to sampled adult mussels, despite a skewed female contribution. Genetic diversity was maintained because a high level of multiple paternity allowed the number of sires to largely exceed the number of dams. Our results show the potential of genetic monitoring to improve stocking of freshwater mussels. We show different success in maintaining genetic diversity between the two breeding approaches and emphasise that the choice of methods should consider conditions for fertilisation in nature and reproductive contribution of mussels in captivity. (C) 2019 Published by Elsevier B.V.


31. PDF
Wang Q. et al. The complete maternal mitochondrial genome of Acuticosta chinensis (Bivalvia: Unionoida: Unionidae) // Conserv. Genet. Resour. 2019. Vol. 11, № 2. P. 137–141.

Acuticosta chinensis is an endemic freshwater mussel in China. The natural population of A. chinensis has dramatically declined due to water pollution, overexploitation and habitat destruction. In the present study, the complete maternal mitochondrial genome of A. chinensis was sequenced and annotated (GenBank Accession No. MF687347). The circular mitogenome is 15,653bp in length. There are 13 protein-coding genes, 22 tRNA genes and 2 rRNA genes (16S rRNA and 12S rRNA). Phylogenetic analyses revealed that A. chinensis was closely related to Arconaia lanceolata and Lanceolaria grayana. These results will be essential for conservation planning and management of freshwater mussels, especially A. chinensis.


32. PDF
Wu D. et al. Molecular characterization of an inhibitor of apoptosis protein (IAPs) in freshwater pearl mussel, Hyriopsis schlegelii // Bioengineered. 2019. Vol. 10, № 1. P. 365–373.

The inhibitor of apoptosis proteins (IAPs) played important roles in inhibiting the apoptosis of tumor cells by regulating caspase activity in mammals. In this study, we first cloned the full-length cDNA sequence of IAPs gene (designated as Hs-IAPs) in Hyriopsis schlegelii. The Hs-IAPs gene contained an open reading frame of 1719 nucleotides, encoding a predicted protein of 572 amino acids. qRT-PCR assay indicated that the Hs-IAPs gene was ubiquitously expressed in different tissues, and the highest expression level was in gills. Furthermore, we purified and obtained the recombinant protein of Hs-IAPs which showed a molecular weight of 82.5 kDa. We used H2O2 stimulation experiment to explore the possible function of Hs-IAPs. The results showed that the percentage of viable cells significantly increased following the Hs-IAPs concentration. These indicated that the Hs-IAPs may play a role in anti-oxidation causing by H2O2, and its anti-oxidative may be crucial in the process of apoptosis.


33. PDF
Zhang R. et al. Molecular cloning and characterization of Pif gene from pearl mussel, Hyriopsis cumingii, and the gene expression analysis during pearl formation // 3 Biotech. 2018. Vol. 8, № 4. P. 214.

In the present study, the Pif gene of the freshwater pearl aquaculture mussel, Hyriopsis cumingii (HcPif) was successfully cloned and functionally characterized. The full sequence of HcPif gene consists of 3415 base pairs, which putatively encode two proteins, HcPif90 and HcPif80. A sequence analysis revealed that HcPif contained a von Willebrand factor type A domain and a chitin-binding domain, and shared many functional residues with other Pif homologues. A highly conserved sequence, FKGLDEIELML, at the C-terminus of Pif80s was identified as the key functional site. The corresponding peptide fragment markedly modified the morphology of calcite crystallites in CaCO3 crystallization assay and might play an essential role in the interactive binding between HcPif80 and CaCO3. Moreover, real-time PCR results showed that HcPif gene was dominantly expressed in the pearl secreting tissues and its expression changed in response to the different development status of the pearl sac during pearl aquaculture. The gene expression of HcPif was maximum 7 days after mantle grafting and declined to about the control level on day 30. Our in vitro and in vivo experimental data indicated that HcPif gene possessed the inherent characteristics of a nacre formation gene and its expression might faithfully reflect the pearl secretion status of the pearl mussels examined. Our findings may extend the understanding of the biomineralization mechanism of nacre formation and provide a potential biomarker for pearl farming.


34. PDF
Zhou Y. et al. Spectroscopic OCT: towards an effective tool for distinguishing authentic and artificial Chinese freshwater pearls // Opt. Mater. Express. 2018. Vol. 8, № 3. P. 622–628.

Distinguishing authentic and artificial Chinese freshwater pearls involves various tools and techniques, based primarily on visual inspection and spectroscopy. These methods are highly variable and thus not statistically reliable. This study investigates the capacity of spectroscopic optical coherence tomography (S-OCT) to classify authentic and artificial pearls in the NIR spectral range. The major advantage of S-OCT is that it allows spectroscopic measurements from within pearls, unlike traditional methods such as diffuse reflectance spectroscopy that primarily probe the surface. S-OCT spectral data was analyzed using principal component analysis (PCA) and partial least-squares discriminant analysis (PLSDA) to classify pearls. The implemented models successfully predicted pearl type and met performance metrics. The results show that S-OCT models could be used for more objective discrimination of authentic versus artificial pearls. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.


35. PDF
Zotin A.A., Murzina S.A., Ieshko E.P. Growth biorhythms in the freshwater pearl mussel Margaritifera margaritifera (Bivalvia, Margaritiferidae). Livojoki river population (Karelia) // Knowl. Manag. Aquat. Ecosyst. 2018. № 419. P. 44.

Individual linear growth rates were studied in freshwater pearl mussels Margaritifera margaritifera from the Livojoki River. Growth deceleration coefficients were shown to vary widely and differ significantly among individuals. The average value of the growth deceleration coefficient for the population is 0.060. The growth of mussels in the Livojoki River is accompanied by two regular biorhythms. These biorhythm periods were roughly constant both through an individual's ontogeny and among mussels, their average periods were 7.16 and 4.09 years. We discuss the possibility that these biorhythms are of thermodynamic nature.


36. PDF
Болотов И.Н., Махров А.А., Вихрев И.В., Беспалая Ю.В., Зотин А.А., Клишко О.К., Кабаков М.Б. НАУЧНОЕ НАСЛЕДИЕ В.И. ЖАДИНА И СОВРЕМЕННАЯ МАЛАКОЛОГИЯ: ОПРЕДЕЛИТЕЛЬ ПРЕСНОВОДНЫХ ЖЕМЧУЖНИЦ (BIVALVIA: UNIONOIDA: MARGARITIFERIDAE) ФАУНЫ РОССИИ // Труды Карельского научного центра Российской академии наук. 2018. № 8. С. 3-14.

Выполнен обзор современных ревизий пресноводных жемчужниц (Margaritiferidae) европейской части России, Восточной Сибири и Дальнего Востока. Фауна России насчитывает 4 вида жемчужниц, в том числе европейскую (Margaritifera margaritifera) - реки западной части страны, даурскую (М. dahurica) - бассейны Амура, Раздольной и близлежащих малых рек, Миддендорфа {М. middendorffi) - Камчатка, Сахалин, Курилы и гладкую (М. laevis) - Сахалин и Курилы. Медианная сеть гаплотипов, построенная на основе нуклеотидных последовательностей митохондриального гена, кодирующего первую субъединицу фермента цитохромоксидазы, свидетельствует, что генетические дистанции между всеми четырьмя видами жемчужниц России соответствуют уровню межвидовой дивергенции, в то время как внутривидовая генетическая изменчивость каждого из видов очень низка. Показано, что актуальная таксономия российских жемчужниц соответствует системе В. И. Жадина, которая на многие годы опередила свое время, поскольку интенсивные исследования в этом направлении начались лишь в последнее десятилетие...


37. 002190

Определены расположение и площадь нерестово-выростных участков в р. Сюскюянйоки (бассейн Ладожского оз.), а также плотность молоди пресноводной формы атлантического лосося и кумжи. Показано, что из-за непроходимой для рыб плотины ГЭС атлантический лосось стал нереститься на пороге до плотины, резко сократив свою численность, а кумжа, утратив проходную форму, сохранила жилую, распространившись по значительной части русла. Установлено, что сформировались две субпопуляции пресноводной жемчужницы, различающиеся по виду рыб-хозяев для их личинок. Отмечено, что зараженность молоди лососевых рыб личинками жемчужницы и выживаемость паразитирующих глохидиев не зависели от вида рыб-хозяев. Исследованы размерно-возрастная структура и рост пресноводной жемчужницы.


38. 002190

Обследованы ручьи бассейна р. Лопшеньга (Летний берег Белого моря). Обнаружены участки ручьев Каменного и Жемчужного с относительно большой плотностью населения европейской жемчужницы, популяции которой можно отнести к стареющим, но с высокой численностью. Отмечено, что соотношение морфологических форм европейской жемчужницы в ручьях бассейна р. Лопшеньга характерно для более южных популяций этого вида.


39. 000848
Гарькуша Д.Н., Фёдоров Ю.А., Князева Т.В., Тамбиева Н.С. НАТУРНОЕ МОДЕЛИРОВАНИЕ ЗАГРЯЗНЕНИЯ ПРЕСНОГО ВОДОЕМА КАДМИЕМ //Водные ресурсы. 2018. Т. 45. № 5. С. 514-525.

Эксперимент, проведенный в мезокосмах, установленных на рыбоводном пруду, позволил адекватно смоделировать особенности самоочищения, миграции и перераспределения кадмия и его химических форм в основных компонентах пресноводной экосистемы при поступлении его в концентрациях, значительно превышающих ПДК. Выявлено, что большая часть внесенного кадмия выводится из водной толщи в течение первых нескольких суток главным образом в составе осаждающихся на дно взвешенных частиц, в том числе остатков погибшего планктона, в виде сорбированных на взвеси ионообменных форм кадмия (37%) и форм, связанных с железомарганцевыми оксидами (41%). Скорость выведения кадмия из водной толщи определяется не только количеством оседающих на дно взвешенных веществ, но и эффективностью сорбции ими кадмия, зависящей от кислотно-щелочных и окислительно-восстановительных условий водоема.


40. PDF

Проведено исследование индивидуального линейного роста 90 особей пресноводной жемчужницы Margaritifera margaritifera путем измерения последовательных годовых колец на поверхности раковины. Установлено, что рост каждого моллюска может быть описан с помощью единого уравнения, частный случай которого – уравнение Берталанфи со средним коэффициентом замедления роста a = 0.048 год–1 и коэффициентом начальных условий d = 5.3 мм/год. Отмечено, что рост моллюсков сопровождается тремя закономерными биоритмами с периодами 13.4, 6.8 и 4.0 года, причем два первых биоритма затухающие, последний имеет постоянную амплитуду. Обнаружено, что уменьшение амплитуды затухающих биоритмов может быть описано степенны?м уравнением с одинаковыми коэффициентами. Обсуждены вопросы, связанные с природой выявленных биоритмов.


41. 005108

Показано, что индивидуальный линейный рост пресноводного двустворчатого моллюска Margaritifera margaritifera в р. Сюскюянйоки сопровождается закономерными биоритмами. Периоды биоритмов, также как и коэффициенты замедления роста, широко варьируют и различаются у разных особей. Периоды биоритмов в индивидуальном онтогенезе приблизительно постоянны. Средние значения коэффициентов замедления роста и периодов не зависят от биотопа и равны 0.114 ± 0.003 год–1 и 3.88 ± 0.06 лет соответственно. Обсуждается возможность термодинамической природы биоритмов.


42. 004393
Капаруллина Е.Н., Агафонова Н.В., Троценко Ю.А., Доронина Н.В. METHYLOPHILUS AQUATICUS SP. NOV. – НОВАЯ АЭРОБНАЯ МЕТИЛОТРОФНАЯ БАКТЕРИЯ, ВЫДЕЛЕННАЯ ИЗ ПРЕСНОГО ВОДОЕМА // Микробиология. 2018. Т. 87. № 5. С. 551-560.

Из воды небольшого пресного водоема выделен новый ограниченно-факультативный метилотроф – штамм LTKT, реализующий КДФГ-вариант рибулозомонофосфатного пути С1-метаболизма. Изолят представлен аэробными, грамотрицательными, неспорообразующими, неподвижными палочками, размножается бинарным делением, является мезофилом и нейтрофилом, синтезирует индолпроизводные. В жирнокислотном составе клеток преобладают гексадекановая (C16:0) и цис-9-гексадеценовая (C16:1?7) кислоты, основной убихинон – Q8. Доминирующими фосфолипидами являются фосфатидилэтаноламин и фосфатидилглицерин; дифосфатидилглицерин отсутствует. Не обнаружены активности ?-кетоглутаратдегидрогеназы и глутаматдегидрогеназы. Аммоний ассимилирует посредством системы ферментов глутаматного цикла. Нуклеотидная последовательность гена 16S рРНК штамма LTKT имеет высокий уровень сходства с таковыми у представителей рода Methylophilus – 99.6% с M. leisingeri DM11T и 99.4% с M. flavus ShipT, уровень ДНК–ДНК гомологии между штаммом LTKT и M. leisingeri DM11T, и M. flavus ShipT составил 47 и 40% соответственно. По совокупности полученных данных штамм LTKT отнесен к новому виду Methylophilus aquaticus sp. nov. (= VKM B-3159T = JCM 32032T = CCUG 70602T).


43. 047789

В данной работе рассмотрены видовой состав альгофлоры планктона техногенного водоема и изменения, происходящие в ней после прекращения промышленной эксплуатации на примере оз. Шламонакопительное (система Васильевских озер, Самарская область). Сравнение видового состава и таксономической структуры фитопланктона в период активной промышленной эксплуатации (1991-1992 гг.) и постэксплуатационный период (2001 г.) выявило увеличение видового богатства водорослей и усложнение таксономической структуры. Таким образом, трансформация сообщества фитопланктона имела позитивный характер. Высокая видовая специфичность альгофлоры и низкий уровень преемственности видов в каждый период исследования свидетельствовали о значительной степени трансформации экосистемы на фоне прекращения эксплуатации.В данной работе рассмотрены видовой состав альгофлоры планктона техногенного водоема и изменения, происходящие в ней после прекращения промышленной эксплуатации на примере оз. Шламонакопительное (система Васильевских озер, Самарская область). Сравнение видового состава и таксономической структуры фитопланктона в период активной промышленной эксплуатации (1991-1992 гг.) и постэксплуатационный период (2001 г.) выявило увеличение видового богатства водорослей и усложнение таксономической структуры. Таким образом, трансформация сообщества фитопланктона имела позитивный характер. Высокая видовая специфичность альгофлоры и низкий уровень преемственности видов в каждый период исследования свидетельствовали о значительной степени трансформации экосистемы на фоне прекращения эксплуатации.


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Мурзина С.А., Иешко Е.П., Зотин А.А. ПРЕСНОВОДНАЯ ЖЕМЧУЖНИЦА MARGARITIFERA MARGARITIFERA L.: МЕТАМОРФОЗ, РОСТ И ДИНАМИКА РАЗВИТИЯ ИНЦИСТИРОВАННЫХ ГЛОХИДИЕВ // Известия Российской академии наук. Серия биологическая. 2017. № 1. С. 10-18.

Исследованы рост и морфогенез глохидиев пресноводной жемчужницы Margaritifera margaritifera на жабрах атлантического лосося Salmo salar в р. Сюскюянйоки (Карелия). Проведен сравнительный анализ гистологических особенностей глохидиев в зависимости от возраста цисты и представлены результаты исследования взаимосвязи и влияния сезонных изменений температуры воды на динамику роста и морфогенез глохидиев, что имеет важное значение для адаптаций живых организмов и обеспечения устойчивости участников отношений паразит–хозяин.


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Проведено сравнительное исследование липидного статуса жабр молоди атлантического лосося, инвазированных осенью глохидиями обыкновенной жемчужницы, обитающей в реках Вуокинйоки (бассейн Белого моря) и Сюскюянйоки (бассейн Ладожского озера). В наиболее инвазированных жабрах молоди лосося и при более низкой температуре воды (1.3°C) в р. Вуокинйоки установлены более высокие содержание холестерина и значения отношения холестерин/фосфолипиды, обусловленные воздействием факторов инвазии и тем самым замедляющие биохимические процессы. Отмечено, что вариации липидного состава у молоди лосося, жабры которых заражены глохидиями, отражают развитие адаптивных реакций, обеспечивающих поддержание гомеостаза молоди в условиях инвазии.

https://www.elibrary.ru/item.asp?id=28172202 https://www.elibrary.ru/item.asp?id=28172199

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Описано девять популяций пресноводных жемчужниц из российской части Балтийского бассейна, которые малочисленны, несмотря на то что большая часть их местообитаний находится в хорошем состоянии. Установлено, что перелов рыб-хозяев – лимитирующий фактор для сохранившихся популяций. Обнаружено, что за последние 200 лет численность лососевых рыб сократилась не менее чем в 100 раз, а оценка нормального состояния системы лосось–жемчужница проблематична. Отмечено, что для предотвращения вымирания жемчужниц необходимо многократное увеличение численности лососевых рыб за счет эффективного использования особо охраняемых природных территорий.


48. PDF
Саенко Е.М., Холин С.К. МОЛЛЮСКИ ЖЕМЧУЖНИЦЫ (BIVALVIA: MARGARITIFERIDAE) РОССИЙСКОГО ДАЛЬНЕГО ВОСТОКА // Biodiversity and Environment of Far East Reserves. 2017. № 2. С. 70-85.

На основе многолетних коллекционных сборов и литературных данных проведён обзор распространения редких и исчезающих пресноводных двустворчатых моллюсков - жемчужниц родов Dahurinaia и Kurilinaia с выявлением новых мест обитания. Морфометрический анализ раковин 6 видов Dahurianaia материковой части ареала (из бассейнов рек Амур, Уссури, Раздольная и оз. Ханка) подтвердил наличие аллометрического роста у жемчужниц; установлено, что такие признаки как высота створки у макушки и выпуклость раковины имеют наибольшую дискриминирующую силу.


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Смирнов Л.П., Суховская И.В., Борвинская Е.В., Кочнева А.А. НЕКОТОРЫЕ БИОХИМИЧЕСКИЕ ПОКАЗАТЕЛИ БИОТРАНСФОРМАЦИИ КСЕНОБИОТИКОВ В ТКАНЯХ ЖЕМЧУЖНИЦЫ ЕВРОПЕЙСКОЙ MARGARITIFERA MARGARITIFERA // Известия Российской академии наук. Серия биологическая. 2017. № 1. С. 30-34.

Определена концентрация глутатиона GSH и активность глутатион S-трансферазы (GST) в жабрах и гепатопанкреасе пресноводной жемчужницы Margaritifera margaritifera L. Обнаружено, что при понижении температуры концентрация GSH в жабрах снижается, что свидетельствует о замедлении обменных процессов у этих эктотермов. Отмечено, что изменение концентрации GSH и активности GST не подвержено возрастной изменчивости, поэтому эти биохимические маркеры могут быть использованы в качестве биоиндикаторов без учета возможного влияния данного фактора. Не выявлена субстрат-специфичная активность GST в тканях жемчужницы, что может свидетельствовать об ограниченной способности этих моллюсков метаболизировать химические соединения с различной структурой.


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