Sinanodonta Woodiana Research Articles

Biometric conversion factors as a unifying platform for comparative assessment of invasive freshwater bivalves

Abstract Invasive bivalves continue to spread and negatively impact freshwater ecosystems worldwide. As different metrics for body size and biomass are frequently used within the literature to standardise bivalve‐related ecological impacts (e.g. respiration and filtration rates), the lack of broadly applicable conversion equations currently hinders reliable comparison across bivalve populations. To facilitate improved comparative assessment among studies originating from disparate geographical locations, we report body size and biomass conversion equations for six invasive freshwater bivalves (or species complex members) worldwide: Corbicula fluminea, C. largillierti, Dreissena bugensis, D. polymorpha, Limnoperna fortunei and Sinanodonta woodiana, and tested the reliability (i.e. precision and accuracy) of these equations. Body size (length, width and height) and biomass metrics of living‐weight (LW), wet‐weight (WW), dry‐weight (DW), dry shell‐weight (SW), shell free dry‐weight (SFDW) and ash‐free dry‐weight (AFDW) were collected from a total of 44 bivalve populations located in Asia, the Americas and Europe. Relationships between body size and individual biomass metrics, as well as proportional weight‐to‐weight conversion factors, were determined. For most species, although inherent variation existed between sampled populations, body size directional measurements were found to be good predictors of all biomass metrics (e.g. length to LW, WW, SW or DW: R2 = 0.82–0.96), with moderate to high accuracy for mean absolute error (MAE): ±9.14%–24.19%. Similarly, narrow 95% confidence limits and low MAE were observed for most proportional biomass relationships, indicating high reliability for the calculated conversion factors (e.g. LW to AFDW; CI range: 0.7–2.0, MAE: ±0.7%–2.0%). Synthesis and applications. Our derived biomass prediction equations can be used to rapidly estimate the biologically active biomass of the assessed species, based on simpler biomass or body size measurements for a wide range of situations globally. This allows for the calculation of approximate average indicators that, when combined with density data, can be used to estimate biomass per geographical unit‐area and contribute to quantification of population‐level effects. These general equations will support meta‐analyses, and allow for comparative assessment of historic and contemporary data. Overall, these equations will enable conservation managers to better understand and predict ecological impacts of these bivalves.

Ingestion and Toxicity of Polystyrene Microplastics in Freshwater Bivalves.

The ubiquity of microplastics in aquatic ecosystems has raised concerns over their interaction with biota. However, microplastics research on freshwater species, especially mollusks, is still scarce. We, therefore, investigated the factors affecting microplastics ingestion in the freshwater mussel Dreissena polymorpha. Using polystyrene spheres (5, 10, 45, 90 µm), we determined the body burden of microplastics in the mussels in relation to 1) exposure and depuration time, 2) body size, 3) food abundance, and 4) microplastic concentrations. D. polymorpha rapidly ingested microplastics and excreted most particles within 12 h. A few microplastics were retained for up to 1 wk. Smaller individuals had a higher relative body burden of microplastics than larger individuals. The uptake of microplastics was concentration-dependent, whereas an additional food supply (algae) reduced it. We also compared the ingestion of microplastics by D. polymorpha with 2 other freshwater species (Anodonta anatina, Sinanodonta woodiana), highlighting that absolute and relative uptake depends on the species and the size of the mussels. In addition, we determined toxicity of polystyrene fragments (≤63 µm, 6.4-100 000 p mL-1 ) and diatomite (natural particle, 100 000 p mL-1 ) in D. polymorpha after 1, 3, 7, and 42 d of exposure, investigating clearance rate, energy reserves, and oxidative stress. Despite ingesting large quantities, exposure to polystyrene fragments only affected the clearance rate of D. polymorpha. Further, results of the microplastic and diatomite exposure did not differ significantly. Therefore, D. polymorpha is unaffected by or can compensate for polystyrene fragment toxicity even at concentrations above current environmental levels. Environ Toxicol Chem 2021;40:2247-2260. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Effects of water temperature on glochidium viability of Unio crassus and Sinanodonta woodiana: implications for conservation, management and captive breeding

ABSTRACT The global decline of freshwater bivalves (Unionida) has prompted many programmes for their conservation and augmentation, which often include a captive breeding component. One key point to such programmes is the collection, maintenance and use of mussel glochidium larvae, which require attachment to a fish host in a sensitive parasitic stage of their life cycle. Understanding the thermal limits of glochidia can increase knowledge of mussel larval survival and ultimately aid in the development of conservation programmes. Glochidia of the endangered thick-shelled river mussel Unio crassus and the non-native Chinese pond mussel Sinanodonta woodiana were observed for active clamping ability at 5, 15, 17, 20 and 25 °C over the course of a 7-d period. The results from this study confirm that an inverse relationship between water temperature and larval viability can be observed in both species. Additionally, the significantly higher thermal tolerance of S. woodiana indicates that the species exhibits competitive invasive behaviour beginning from the larval stage. These findings also suggest that the collection and transportation of glochidia from genetically important yet distant populations is feasible if the larvae can be maintained at temperatures between 5 and 15 °C.

Texture Study of Sinanodonta Woodiana Shells by X-Ray Diffraction

Texture Study of Sinanodonta Woodiana Shells by X-Ray Diffraction

Intrinsic Mechanical Properties of Individual Biogenic Mineral Units in Biomineralized Skeletons.

A bioinspired study on replicating the superior damage tolerance of bioceramic composites requires a detailed understanding of the intrinsic properties of biogenic mineral units. Here, we investigate and compare the intrinsic properties of biogenic calcite (Atrina rigida) and aragonite (Sinanodonta woodiana) by conducting microbending experiments on the separated prismatic building blocks. Analyzed bending results indicate that the biogenic calcite has a higher modulus (36.24 ± 14.4 GPa for A. rigida vs. 29.9 ± 10.5 GPa for S. woodiana) and strength (446.5 ± 141.5 MPa for A. rigida vs. 338.6 ± 63.2 MPa for S. woodiana) than the biogenic aragonite, while the nanoindentation results indicate the opposite trend. Further systematic fractographic analysis suggests that the biogenic calcite fractures like amorphous glass, while the biogenic aragonite resembles polycrystalline ceramics. These contradictory behaviors of biogenic calcite and aragonite under tension-dominated (microbending) and indentation loading conditions are attributed to their different intrinsic structures, i.e., intracrystalline organic inclusions in single-crystal calcite vs. interlocked nanograins in polycrystalline aragonite.

First insights into oxidative stress and theoretical environmental risk of Bronopol and Detarox® AP, two biocides claimed to be ecofriendly for a sustainable aquaculture

Bronopol and Detarox® AP are broad spectrum antimicrobial biocides of growing interest for the aquaculture sector. While their effectiveness against aquatic pathogens has been demonstrated, toxicity data on wild or farmed species are still lacking, as is information on their potential environmental risk for aquatic ecosystems. With this study, we assessed the acute and sublethal toxicity of Bronopol and Detarox® AP in the freshwater bivalve Sinanodonta woodiana and their theoretical risk for aquatic ecosystem. The 96-h median lethal concentration (LC50) was determined using the acute toxicity test, while for the sublethal toxicity test the bivalves were exposed to two concentrations for 14days of Bronopol (2.5 and 50mg/L) and Detarox® AP (1.11 and 22.26mg/L) followed by a 14-day withdrawal period. Biocide-mediated oxidative processes were investigated via a panel of oxidative stress biomarkers (malondialdehyde, superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase). Theoretical environmental risk assessment of both biocides, with predicted concentration of no effect (PNEC), expected theoretical concentration (TEC) in the environment, and risk quotient (RQ) was performed. TEC was calculated using a model based on the size of the aquaculture facility and the receiving basin, the estimated quantity of biocide dissolved in water, and published data on biocide stability in water. Although the LC50 was higher for Bronopol (2440mg/L) than for Detarox® AP (126mg/L), fluctuations in oxidative stress biomarkers levels indicated that both biocides exert a slight oxidative pressure on S. woodiana. Theoretical environmental risk assessment suggested a muted risk with Detarox® AP and greater eco-sustainability compared to Bronopol.

Study of bivalvia habitat in the mangrove area of Aceh Jaya District, Aceh Province

One of the biota that utilizes the mangrove ecosystem as its habitat is a group of Bivalvia belonging to the Phylum Mollusca Class Pelecypoda (Bivalvia). Shellfish have relatively high economic and nutritional value, so that the collection of shellfish in Aceh Jaya District continues. The research was conducted to study the biological components, analyze the habitat preferences, and management patterns of shellfish in the mangrove area of Aceh Jaya Regency. The research was conducted by using purposive sampling method, by determining 12 stations in 6 districts. Shellfish samples were taken three times with an interval of 15 days. The results found 5 species of shellfish with a dominance index of 0.002 to 0.255 with a low dominance level. The frequency of the presence of shellfish species is very rare (accidental) to rare (constant). The lowest presence level was Centrocardita rosulenta with a value of 8.33% and the highest was Sinanodonta woodiana with a value of 58.33. Habitat preference Sinanodonta woodiana has a salinity range between 3-7ppt and clay soil texture class, while Geloina habitat preference likes salinity with a range of 12 to 25 ppt with sand, loamy sand and sandy loam soil texture classes.

Physicochemical characteristics of surimi-like material made from the muscle tissues of freshwater mussels (Sinanodonta woodiana Lea, 1834)

The aim of the study was to determine selected characteristics of surimi-like material (SLM) made from the muscle tissues of Sinanodonta woodiana (Lea, 1834) freshwater mussels. The research material consisted of unwashed mussel muscle homogenate as the control sample—C, mussel muscle tissue twice washed with water (SLM-W) and sample washed with NaCl at a concentration of 0.169 mol/L as well as water (SLM–S). A raw control sample and surimi like-materials were analysed using the SDS-PAGE technique. They were also tested using the DMTA method (dynamic mechanical thermal analysis) while heating the samples up to 80 °C and cooling to 20 °C. The thermal drip and texture of gels after heating (75 °C, 30 min) were also determined. The washing procedure had a significant impact on the protein composition of the SLMs. A significantly (p < 0.05) higher percentage of proteins with molecular weights of 270–273 kDa and 105–110 kDa (corresponding to specific filamin isoforms), as well as 42–43 kDa (corresponding to actin), were found in the SLMs compared to sample C. Ccorrelation analysis confirmed a strong positive relationship between the percentage share of the above proteins and the values of the elasticity modulus (r ≥ 0.84) and firmness (r ≥ 0.88) of SLM gels. The SLM-S sample was characterised by the lowest significant (p < 0.05) thermal drip values. During heating, the rheological traits of all samples changed at two stages: from 20 to 50 °C and over 50 °C. The highest dynamics of variation in the elasticity modulus (G′) value were noticed at temperatures exceeding 50 °C in all samples. The G′ values in the SLM samples were significantly greater than the values in sample C. The analysis revealed a strong correlation (r ≥ 0.81) between the determinants of the texture of the SLM samples and their rheological parameters. Sample SLM-W was the one with the highest firmness and elasticity values. The analysis showed that the textural properties of the SLM samples mainly resulted from the reaction of spatial matrices to mechanical interactions.

Effects of in vitro metamorphosis on survival, growth, and reproductive success of freshwater mussels

Captive breeding is an effective conservation strategy, but it has risks, especially when a life history stage of an organism is bypassed. Freshwater mussels (Unionida) are critically imperiled, and their larvae are parasites on fishes. Traditional mussel captive breeding involves artificially infesting fishes with larvae (in vivo), but increasingly used in vitro methods allow larval metamorphosis in culture media, bypassing the parasitic stage. We provide the first comparisons of mussel performance between in vitro and in vivo methods in the wild and throughout the mussel life cycle using two mussel species. In six streams, survival and growth did not differ between in vitro- and in vivo-produced Lampsilis cardium. Metamorphosis of Sinanodonta woodiana differed sharply between two in vitro protocols (methods 1 and 2), but metamorphosis for method 2 was twice as high as in vivo. Survival and growth after eight days was lower for in vitro method 1 than method 2 and in vivo, showing that suboptimal in vitro protocols can have lingering effects on juvenile performance. However, survival and growth did not differ among methods by the end of the first and second growing seasons. Most importantly, in vitro-produced mussels survived, grew to maturity, and produced F2 juveniles naturally on fishes, all at rates that did not differ from in vivo-produced mussels. We detected no strong side effects of bypassing the mussel host-fish stage, but this study illustrates the importance of assessing consequences of captive breeding methods for any organism in a variety of environmental and life history contexts.

Analisis Scanning Electron Microscopy pada Nacre Sinanodonta (Anodonta) woodiana (Lea, 1834)

Chinese pond shell, Sinanodonta (Anodonta) woodiana (Lea, 1834), is a freshwater bivalve that has essential ecological and economic functions. The microstructure of the nacre is of great interest and is the main attraction for the development of pearl farming. This study aims to describe the microstructure and composition of biomineral elements of the nacre at several shell sizes of S. woodiana. The shell is cut with a small forcepon the ventral margin with a size of 3-5 mm for Scanning Electron Microscpy (SEM). SEM images display that a shell layer consists of periostracum, prismatic and nacre layers. The surface of the nacre layer is an irregular or labyrinth patterned. The nacre tablets are hexagonal, glued to each other, so the nacre tablets become polygonal. Moreover, the microstructure of the nacre tablets is like a brick wall, and the thickness of tablets from 0.43 μm to 0.59 μm. The composition of the biomineral elements are C, O, Ca, and the mineralization mechanism is under the control of aquatic environmental factors that help the process of microstructure formation in nacre.

Interactive effects of bitterling fish and mussel on the community structures of plankton and benthic macroinvertebrates

放养河蚌，提高水体透明度以促进沉水植物生长，是湖泊生态修复中的常用手段之一.而小型杂食性鱼类鳑鲏依赖河蚌繁殖，河蚌放养可能会促进鳑鲏种群的发展；而鳑鲏与河蚌交互作用对水生态系统的影响仍研究较少.于2018年11—12月通过原位受控实验，设置对照组、河蚌组、鳑鲏组和河蚌+鳑鲏组，研究了鳑鲏（大鳍鱊Acheilognathus macropterus）与河蚌（背角无齿蚌Sinanodonta woodiana）对水质、浮游生物和底栖生物的影响.结果表明：鳑鲏显著增加了上覆水总氮、总磷、悬浮质和叶绿素a（Chl.a）浓度；但并未显著影响无机悬浮质的浓度，说明鳑鲏对沉积物的扰动作用较弱.此外，鳑鲏显著增加了浮游植物生物量和蓝藻的比例.浮游动物总生物量并未受鳑鲏的影响，但显著增加了浮游动物的丰度，其中以轮虫为主.鳑鲏组的底栖动物总丰度（主要为水丝蚓）显著高于对照组，说明鳑鲏对水丝蚓的摄食压力较低.鳑鲏与河蚌交互作用对总磷、Chl.a、浮游植物和浮游动物丰度具有显著影响：具体表现为河蚌虽然抵消了部分鳑鲏对水质（如氮、磷和悬浮质浓度，以及Chl.a浓度和浮游植物生物量等）的负面影响，但其对浮游动物和水丝蚓生物量的影响不显著.在湖泊生态修复和管理中，需要关注和重视鳑鲏等此类小型杂食性鱼类对水生态系统可能产生的负面影响，通过物理（网簖等）或生物（放养肉食性鱼类）等方式将其控制在较低密度水平，从而降低这些鱼类对水质、浮游生物和底栖生物群落可能产生的负面影响，维持生态修复效果的长效与稳定运行.;In restoration of shallow eutrophic lakes based on recovery of submerged macrophytes, stocking of the filter-feeding mussels has been commonly used for improving water clarity, thereby enhancing the growth of submerged macrophytes. However, the small omnivorous bitterling fish has to rely on mussels for breeding. Thus, the increased abundance of mussels may enhance the population development of bitterling. Nevertheless, the effects of bitterling (Acheilognathus macropterus) and their host mussels (Sinanodonta woodiana) on the aquatic ecosystems are, so far, not well-studied. We conducted a mesocosm experiment to study the effects of bitterling, mussels, and their interactions on water quality and the community structures of phytoplankton, zooplankton and benthic macroinvertebrates, respectively. Our results showed that bitterling did not substantially affect the concentration of inorganic suspended solids (ISS) indicating weak effects on sediment resuspension. However, the concentrations of total nitrogen and total phosphorus were significantly enhanced by bitterling. Consequently, both the abundance and biomass of phytoplankton were enhanced in the bitterling-only mesocosms, and cyanobacteria dominated the phytoplankton community at the end of the experiment. However, rotifers dominated the zooplankton community leading to a higher abundance of zooplankton in the bitterling-only treatment, while the total biomass of zooplankton did not differ significantly between the control and bitterling-only treatments. Moreover, bitterling significantly increased the total abundance of benthic macroinvertebrates compared with the controls, while the biomass of macroinvertebrates was not pronouncedly affected. The presence of mussels significantly eliminated the negative effects induced by bitterling, such as reducing the concentrations of nutrients, suspended solids and chlorophyll-a and phytoplankton biomass. However, the biomass of zooplankton and benthic macroinvertebrates were not substantially affected by the presence of mussels. Our results suggest that bitterling alone can induce significantly negative effects on water quality though mussels can eliminate part of these impacts under our experimental bitterling-to-mussel biomass ratio. Therefore, in the restoration and management of shallow lakes, more attention should be paid on the effects of small omnivorous fish, like bitterling, on aquatic ecosystems. The biomass of these small omnivores should be controlled at a relatively low level by physical (e.g., trap net) or biological (e.g., stocking of effective piscivorous fish) methods to minimize the negative effects of the fish on lake ecosystems.

Population structure and symbiotic relationships of the invasive speciesSinanodonta woodiana(Lea, 1834) in water bodies of Ukraine

Understanding the process of penetration and distribution of the invasive speciesSinanodonta woodianais important for predicting associated changes in biodiversity and the structure of freshwater communities. The biomass, density, age and sex structure of mollusk populations were analyzed. An increase in the size of Chinese pond mussels was noted after the introduction: the shell length of individuals from a pond (Romanivka village, 2017) was 24,2% more than of mollusks from the Velyka Repida river (Matroska village, 2004), and in 2019 it increased by another 14,7% (by 42,5% compared to the shell length of the mollusks from the Velyka Repida river). The body weight ofS. woodianafrom the river was 125,3 g, while in the pond there was a 2,13-fold increase in body weight in 2017, with a further increase in this indicator by another 23,6% in 2019 and another 37,7% in 2020. The relative number ofS. woodianaand native speciesUnio pictorumandAnodonta anatinain 2017 was 26,3%, 47,4% and 26,3%, in 2020 – 64,0%, 16,0% and 20,0% respectively. Ciliates of the genusConchophthirusandTrichodina,Aspidogaster conchicola,Helobdella stagnalis, larvae ofChironomussp. are in a symbiotic relationship withS. woodiana. The most commonConchophthirussp. – in 21,6% of individuals. Further spread ofS. woodianato the cold regions of Ukraine and the formation of new populations in the already developed regions should be expected.

Freshwater molluscs fauna of Western Ukraine and its representation in museum collections of Lviv

Based on the literary and personal data, as well as collections of the State Museum of Natural History of the NAS of Ukraine and the Zoological Museum of the Ivan Franko National University of Lviv, the taxonomic composition and peculiarities of the spatial distribution of gastropods and bivalve molluscs in Western Ukraine have been analyzed. Species lists have been drawn up for the Volhynian (Western) Polissia, Volhynian Upland, Male Polissia, Roztochya and Opillya, Western Podillia, Central (Northern) Podillia, Prut-Dnister interfluve, Ciscarpathian, Transcarpathian lowland and mountainous part of the Ukrainian Carpathians. It is established that in the west of Ukraine, 74 autochthonous and 6 adventitious freshwater molluscs with generally recognized species status, belonging to 35 genera and 15 families, can be considered as reliably registered. Adventitious to Western Ukraine are Potamopyrgus antipodarum, Physella acuta, Menetus dilatatus, Dreissena polymorpha, D. bugensis, Sinanodonta woodiana. Additional confirmation requires the presence of Lithoglyphus pyramidatus, Omphiscola glabra, Physella heterostropha, Planorbis carinatus, Pisidium conventus, P. tenuilineatum. Not taking into account the Central Podillia, poorly researched by malacologists, a distinctly pronounced decrease in the species richness of freshwater molluscs is observed only in the mountainous part of the Ukrainian Carpathians (38 species, 17 genera, 8 families), with the presence of some specific components of freshwater molluscs complexes (small gastropods of the genera Bythinella і Paladilhiopsis). The richest taxonomic composition of freshwater molluscs was noted for Volhynian Polissia: 67 species, 29 genera, 15 families. It has been found that most freshwater molluscs are evenly distributed throughout the plain and foothill territories of Western Ukraine. Only few species can be considered as specific components of freshwater malacocomplexes for one of the physical-geographical areas or river basins. A number of species that are not present in the malacological collection of SMNH NASU, as well as the territories poorly represented in it, have been identified. The results obtained will be taken into account when further collecting the museum collection.

First records of Sinanodonta woodiana (Lea, 1834) and Corbicula fluminea (O. F. Müller, 1774) (Mollusca, Bivalvia) from the Adriatic part of Croatia

Sinanodonta woodiana (Lea) and Corbicula fluminea (O. F. Müller) are among the most invasive aquatic molluscs found in Europe. Both species were recorded in the Adriatic part of Croatia for the first time in 2019 although in the Danubian Croatia they were more common. An abundant population of S. woodiana was found in an oxbow of the Cetina River; mussels with shell length of ca. 12–17 cm dominated. A population of C. fluminea was recorded in the freshwater section of the Zrmanja River above the Jankovića Buk waterfall which forms the border between the brackish and the freshwater sections of the river. Possible pathways of their introduction and reasons for their rare occurrence in contrast to the Danubian Croatia are discussed.

New evidence on the relationships between Hypnophila Bourguignat, 1859 and Gomphroa Westerlund, 1902 (Gastropoda: Eupulmonata: Azecidae)

Sinanodonta woodiana (Lea) and Corbicula fluminea (O. F. Müller) are among the most invasive aquatic molluscs found in Europe. Both species were recorded in the Adriatic part of Croatia for the first time in 2019 although in the Danubian Croatia they were more common. An abundant population of S. woodiana was found in an oxbow of the Cetina River; mussels with shell length of ca. 12–17 cm dominated. A population of C. fluminea was recorded in the freshwater section of the Zrmanja River above the Jankovića Buk waterfall which forms the border between the brackish and the freshwater sections of the river. Possible pathways of their introduction and reasons for their rare occurrence in contrast to the Danubian Croatia are discussed.

Comparative analysis of gut microbiota diversity in endangered, economical, and common freshwater mussels using 16S rRNA gene sequencing.

Freshwater mussels are both among the most diverse and endangered faunas worldwide. The gut microbiota of species plays a key role in nutrition and immunity, such as preventing it from pathogen invasion, synthesizing beneficial secondary metabolites, and contributing to the digestion of complex nutrients. Information on the gut microbiota could have significant implications for conservation biology, especially for threatened or endangered species. However, there is relatively little study into the gut microbiota of freshwater mussels. Here, the gut microbiota diversity was analyzed in endangered (Solenaia carinata), economical (Sinohyriopsis cumingii), and common (Sinanodonta woodiana) freshwater mussels using 16S rRNA gene sequencing. This study represents the first to compare the gut microbiota diversity of endangered, economical, and common Chinese freshwater mussels. The results showed that 13,535 OTUs were found in S. carinata, 12,985 OTUs in S. cumingii, and 9,365 OTUs in S. woodiana. The dominant phylum in S. carinata and S. cumingii was Fusobacteria, and was Firmicutes in S. woodiana. Alpha diversity indices indicated that S. carinata and S. cumingii had a higher abundance and diversity of gut microbiota than S. woodiana. The composition of gut microbiota was different among three freshwater mussels, but their composition variation was not significant. This study provides insight for the conservation of freshwater mussel biodiversity, which will not only help conserve these vulnerable groups but also, will offer wider benefits to freshwater ecosystems.

Bioremediation with freshwater bivalves: A sustainable approach to reducing the environmental impact of inland trout farms

Integrated multi trophic aquaculture (IMTA) is well developed in seawater, while the only suitable organisms for bioremediation in freshwater are bivalves. The aim of this research has been to investigate a novel system, based on freshwater bivalves integrated with rainbow trout, for the bioremediation of inland aquaculture systems. The Unionid species selected for the experiments was Sinanodonta woodiana. Five mesocosm experiments were conducted to evaluate the efficiency of mussels in filtering the total bacteria and Aeromonas hydrophila, as well as their clearance efficiency on trout farm wastewater. The temperatures, dissolved oxygen, nitrates, and phosphates were monitored and were all within the physiological tolerance range of the species in all the experiments. The feasibility of bioremediation with S. woodiana in trout farming has thus been demonstrated, and among the tested rearing densities (3.75; 7.5; 15; 30 and 60 kg m−3) that of 7.5 kg m−3 was found to be optimal. The net reduction of the total bacterial concentration was as much as 72%, while that of A. hydrophila reached a level of 95–98%. No relevant effects of the mussels on particulate suspended material or sedimented material was observed, regardless of the temperature. The efficiency of freshwater bivalves in reducing the bacterial load, in particular toward A. hydrophila, indicates a bioremediation system with the possibility of interesting applications on inland fish farms, and as a biotechnological tool against the diffusion of antibiotic resistance in aquaculture.

Association of microbiota in the stomach of Sinanodonta woodiana and its cultured soil.

The current study aimed to investigate the association of microbial characteristics in the stomach of Sinanodonta woodiana (S. woodiana) and its cultured soil. S. woodiana stomach and its cultured soil were collected in winter 2019. The V3 + V4 regions of the 16S rRNA gene were sequenced to detect microbial diversity. The differences in the dominant species between S. woodiana and soil were also discussed. The results showed that the diversity and richness indices in S. woodiana were significantly higher than those in cultured soil (P < 0.01). At the phylum level, the dominant bacterial community compositions in the two groups were similar and included Proteobacteria, Firmicutes, Bacteroidetes, Cyanobacteria, Fusobacteria, and Acidobacteria. However, the abundance of these phyla was significantly different between the two groups (P < 0.05 or P < 0.01), and Proteobacteria was the most abundant phylum. At the genus level, a total of 1001 genera were identified in the two groups, of which 890 genera were detected in the cultured soil and 549 were detected in the S. woodiana stomach; 452 were unique to the cultured soil, and 111 were unique to the S. woodiana stomach. This result indicated great differences in the bacterial genera between the two groups. Moreover, 17 out of the 20 dominant bacterial genera exhibited statistically significant differences between the two groups (P < 0.05 or P < 0.01). Cupriavidus was the absolute dominant genus in the stomach of S. woodiana, followed by Sphingomonas and Burkholderia. The microorganisms in the stomach of S. woodiana formed a certain inherent bacterial system and were affected by the environment, which is beneficial to nutrition and health. In conclusion, the bacterial compositions were mostly the same between the stomach of S. woodiana and cultured soil, but the relative abundances of the bacterial communities were different. This study will greatly enhance the understanding of the microbial characteristics between the stomach of S. woodiana and the cultured environment, and provide guidance for healthy aquaculture in freshwater.

Integrated Monitoring with Moss-Bag and Mussel Transplants in Reservoirs

For the first time, transplants with moss-bags and mussels together were applied to study the water quality in standing water bodies. The tested species: Fontinalis antipyretica Hedw. and Sinanodonta woodiana (Lea, 1834) were collected from unpolluted sites and analyzed to obtain background levels. Then, the moss and mussels were left in cages for a period of 30 days in three reservoirs where both are not present naturally. Two of the reservoirs suffer from old industrial contamination and one is affected by untreated wastes. Twenty-four compounds were studied, among them trace elements Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Zn and organic priority substances: six polybrominated diphenyl ethers (PBDEs) congeners and short-chain chlorinated paraffins (SCCPs). The trace element accumulation was significant after the exposition period in all studied stations. PBDEs and SCCPs were also accumulated up to two times more in the moss tissues. PBDEs in the mussels exceeded the environmental quality standard (EQS). The applied combined transplants, and especially the moss-bags, revealed severe contamination with heavy metals not detected by the water samples. The moss and the mussel followed a different model of trace element and PBDEs accumulation. The SCCPs levels were alarmingly high in all plant samples. The study confirmed PBDEs and SCCPs as bioaccumulative compounds and suggested that an EQS for SCCPs in biota needs to be established.

Selection of assay, organism, and approach in biomonitoring significantly affects the evaluation of genotoxic potential in aquatic environments.

In this study, few different evaluation concepts were used for the assessment of genotoxic potential at the stretch of the Danube River identified as a significant hotspot of pollution originated through the untreated wastewaters. Three sites were chosen: one site upstream of the wastewater outlet in Novi Sad (Serbia), one at the outlet of wastewaters, and one site few kilometer downstream. Ex situ approach comprised prokaryotic SOS/umuC test on Salmonella typhimurium TA1535/pSK1005 and comet assay on human hepatoma cell line (HepG2). In situ approach was based on the active monitoring (cage approach) using freshwater mussels Sinanodonta woodiana and fish Cyprinus carpio. The comet and micronucleus assays were selected for evaluation of DNA damage in mussel haemocytes and fish blood cells. Within the ex situ part of the study, our results indicated that the eukaryotic model system is more sensitive compared to the prokaryotic one. In situ bioassays are recommended for obtaining a better insight into ecosystem status and in the case of our study the complete insight of genotoxic pressure. However, the choice of animals as bioindicators also has a significant impact on the quality of the obtained information. Differential response between fish and mussels was observed at the highly polluted site suggesting possible involvement of additional protective mechanism such as valve closure in mussels.