Unio Pictorum Research Articles

The state of the intestinal bacterial community in mollusks for assessing habitat pollution in the gulf of Finland (Baltic Sea)

In this study, we investigated the abundance and diversity of bacteria in the digestive tract of the bivalve mollusks Unio pictorum after 30-day exposure in experimental cages and field-collected gastropod mollusk Radix balthica in the eastern Gulf of Finland, Baltic Sea. Contamination of water and sediments with petroleum hydrocarbons had a significant impact on the intestinal bacterial community of mollusks stimulating the growth of hydrocarbon-oxidizing bacteria. The abundance of the intestinal hydrocarbon-oxidizing bacteria correlated with the concentration of the total hydrocarbons in the water of the coastal sites in the Gulf, where the mollusks were exposed. Metagenomic analysis revealed significant differences in the intestinal microbial community composition between polluted and unpolluted sites. The increased abundance of members of the phylum Gammaproteobacteria, including species of Aeromonas, Acinetobacter, Arenimonas, Pseudomonas, Rheinheimera, and Shewanella, and Bacteroidetes (Flavobacterium and Pedobacter) in the intestinal tracts of mollusks Unio pictorum were found at hydrocarbon-contaminated site: therefore, these bacteria are key players in the adaptation of intestinal community to this kind of pollution and hydrocarbon degradation. Our study suggests that hydrocarbon-oxidizing bacteria have the potential as a sensitive bioindicator for the further monitoring and ecological assessment of marine ecosystems.

The gill transcriptome of threatened European freshwater mussels

Genomic tools applied to non-model organisms are critical to design successful conservation strategies of particularly threatened groups. Freshwater mussels of the Unionida order are among the most vulnerable taxa and yet almost no genetic resources are available. Here, we present the gill transcriptomes of five European freshwater mussels with high conservation concern: Margaritifera margaritifera, Unio crassus, Unio pictorum, Unio mancus and Unio delphinus. The final assemblies, with N50 values ranging from 1069–1895 bp and total BUSCO scores above 90% (Eukaryote and Metazoan databases), were structurally and functionally annotated, and made available. The transcriptomes here produced represent a valuable resource for future studies on these species’ biology and ultimately guide their conservation.

Helobdella stagnalis (Hirudinea: Glossiphoniidae), the first facultative mussel-associated leech in Europe

The ecological group of mussel-associated freshwater leeches (Hirudinea) contains facultative and obligate inhabitants of the mantle cavity of freshwater mussels (Unionida) from Asia, Africa, North America, and South America. Here, we report on the record of a mussel-associated leech in Europe and present a list of its freshwater bivalve hosts. The widespread leech species Helobdella stagnalis (Glossiphoniidae) was recovered as a facultative inhabitant of the mantle cavity of the native Anodonta anatina, Unio pictorum, and U. tumidus, and the non-native Sinanodonta woodiana (Unionidae). Globally, the freshwater mussel-associated leech assemblage contains 17 species, including four Helobdella representatives: H. lineata and H. modesta in North America, H. adiastola in South America, and H. stagnalis in Europe.

АНАЛИЗ ЗАГРЯЗНЕНИЯ ТЯЖЕЛЫМИ МЕТАЛЛАМИ МЯГКИХ ТКАНЕЙ ДВУСТВОРЧАТЫХ МОЛЛЮСКОВ В ВОДОЕМАХ Г. ГОМЕЛЯ И ПРИЛЕГАЮЩИХ ТЕРРИТОРИЙ

Currently, observations of the components of aquatic ecosystems - hydrobionts and bottom sediments with the ability to deposit pollutants - are of particular importance. Comprehensive studies of the behavior of heavy metals in aquatic ecosystems are relevant and make it possible to provide an integral assessment of the state of the water body, determine the probability of secondary pollution, find out the migration paths of pollutants, and therefore their implementation is relevant. The article deals with the analysis of quantitative data on the content of heavy metals in the soft tissues of mollusks living in the reservoirs of Gomel and adjacent territories. An array of data was obtained for the period of research in 2010-2021, on the basis of which the choice of an ordinary pearl barley (Unio pictorum L.) as an object of monitoring studies of the ecological state of water bodies was justified. The change in the content of copper, lead and nickel in the tissues of the studied mollusk species during the period of research from 2010 to 2021 indicates a change in the physicochemical conditions in the studied reservoirs, as well as a change in the content of biologically accessible metal forms in water and bottom sediments of aquatic ecosystems. This fact confirms the presence of different routes of entry of heavy metals into the body of different species of bivalve mollusks, as well as the different availability of metal compounds in components of the same aquatic ecosystem for different species of mollusks. As a result of the analysis of the array of data obtained from 2010 to 2021, the authors determined the background concentrations of heavy metals in the tissues of common pearl barley living in the reservoirs of Gomel and adjacent territories: for lead - 0.17 mg/kg, zinc - 19.20 mg/kg, copper - 0.71 mg/kg, manganese - 1084.22 mg/kg, cobalt - 0.25 mg/kg, chromium - 0.71 mg/kg, nickel - 0.95 mg/kg. Patterns of change in the quantitative content of heavy metals in the soft tissues of molluscs are shown.

Global Crystallographic Texture of Freshwater Bivalve Mollusks of the Unionidae Family from Eastern Europe Studied by Neutron Diffraction.

The crystallographic texture of the whole valves of bivalve mollusks from the family Unionidae Unio pictorum Linnaeus, 1758 and Anodonta cygnea Linnaeus, 1758 is studied using pole figures measured using neutron diffraction. The use of neutron diffraction, in contrast to X-rays, makes it possible to study the valves without destroying them. Thus, we can discuss the study of the global texture of the entire valve. It was revealed that the pole figures of aragonite in the valves repeat their shape. The pole density maxima for U. pictorum from the Danube Delta and the Gulf of Finland in the Baltic Sea, living at different salinities and temperatures, differs by 0.41 mrd. The maximum value of the crystallographic texture for A. cygnea from the Danube Delta was also measured (5.07 mrd). In terms of texture sharpness, it surpasses the shell of marine bivalve mollusks, which are partially or completely composed of aragonite. Although U. pictorum and Mya arenaria Linnaeus, 1758 have different microstructures, their pole figures are very similar in isolines pattern, but differ in pole density maxima. No relationship was found between the crystallographic texture and the microstructure in U. pictorum. In addition, we report good qualitative agreement between aragonite X-ray pole figures of Sinanodonta woodiana Lea, 1834 from the Czech river Luznice, and neutron pole figures of U. pictorum from the Danube Delta.

Effects of Diclofenac on the Reproductive Health, Respiratory Rate, Cardiac Activity, and Heat Tolerance of Aquatic Animals.

Diclofenac is an important pharmaceutical present in the water cycle of wastewater treatment and one of the most distributed drugs in aquatic ecosystems. Despite the great interest in the fate of diclofenac in freshwaters, the effects of environmentally relevant concentrations on invertebrates are still unclear. Two species of freshwater invertebrates, the amphipod Gmelinoides fasciatus and the bivalve mollusk Unio pictorum, were exposed to diclofenac concentrations of 0.001-2 μg/L (environmentally relevant levels) for 96 h. A set of biological endpoints (survival, fecundity, embryo abnormalities, respiration and heart rates, heat tolerance, and cardiac stress tolerance) were estimated in exposed invertebrates. Effects of diclofenac on amphipod metabolic rate and reproduction (number and state of embryos) and adaptive capacity (cardiac stress tolerance) in both species were evident. The oxygen consumption of amphipods exposed to diclofenac of 0.1-2 μg/L was 1.5-2 times higher than in the control, indicating increased energy requirements for standard metabolism in the presence of diclofenac (>0.1 μg/L). The heart rate recovery time in mollusks after heating to critical temperature (30 °C) was 1.7 and 9 times greater in mollusks exposed to 0.1 and 0.9 μg/L, respectively, than in the control (24 min). A level of diclofenac >0.9 μg/L adversely affected amphipod embryos, leading to an increase in the number of embryos with impaired development, which subsequently died. Thus, the lowest effective concentration of diclofenac (0.1 μg/L) led to increased energy demands of animals while reducing cardiac stress tolerance, and at a level close to 1 μg/L reproductive disorders (elevated mortality of the embryos) occurred. Environ Toxicol Chem 2022;41:677-686. © 2021 SETAC.

Comparative Characteristics of Glutamate Dehydrogenase Functioning in Cyprinus carpio and Unio pictorum under the Impact of Elevated Metal Ions Concentrations

Comparative Characteristics of Glutamate Dehydrogenase Functioning in Cyprinus carpio and Unio pictorum under the Impact of Elevated Metal Ions Concentrations

The First Record of Dreissena polymorpha (Pallas, 1771) and Unio pictorum (Linnaeus, 1758) in Demirköprü Dam Lake and Evaluation of Some Biometric Parameters

Manisa İli sınırları içerisinde yer alan Demirköprü Baraj Gölü’nde yaşayan Dreissena polymorpha (Pallas, 1771) ve Unio pictorum (Linnaeus, 1758) türlerine ait bazı biyometrik özellikler çalışılmıştır. Çalışma alanında toplanan bireylere ait uzunluk (mm), genişlik (mm), yükseklik (mm) verileri dijital kumpas ile; bireylerin ağırlıkları (g) hassas terazi kullanılarak ölçülmüştür. Bireylere ait veriler sırasıyla; ortalama kabuk uzunluğu 30.48±5.40 ve 61.02±7.78 mm, kabuk genişliği 14.48±2.33 ve 32.01±4.48 mm, kabuk yüksekliği 14.72±3.02 ve 17.87±3.43 mm ve ağırlığı 5.19±0.94 ve 23.08±2.90 g olarak belirlenmiştir. Temel bileşenler analizine göre, her iki tür için kabuk yüksekliği, kabuk genişliği, kabuk uzunluğu ve ağırlık arasında güçlü bir ilişki olduğu belirlenmiştir. Toplam varyansın U. pictorum ve D. polymorpha türleri için % 97.913 ve % 94.379’luk kısmının iki temel bileşen tarafından açıklanmış olduğu tespit edilmiştir. D. polymorpha ve U. pictorum türü bu çalışma ile Demirköprü Baraj Gölü’nden ilk defa rapor edilmiştir.

Behavioural responses of Anodonta anatina and Unio pictorum to temperature and algal concentration

ABSTRACT Using time-lapse photography in a laboratory setting, we exposed Anodonta anatina and Unio pictorum for 4 h to algal (Chlorella vulgaris) concentrations ranging from 0.5 to 20.0 mg ash-free dry mass l−1 and to three different temperatures (11 ± 1, 15 ± 1 and 19 ± 1 °C). We analysed the proportion of mussels in locomotion, duration of locomotory activities, posterior tip movement and valve opening behaviour. The proportion of mussels in locomotion was significantly higher for A. anatina and for A. anatina was significantly lower at 11 °C. For both species, the proportion of mussels in locomotion, the duration of locomotion and movement of the posterior tip decreased with increasing algal concentration. The locomotory duration was significantly shorter in U. pictorum. In both species, valve opening peaked at intermediate algal concentrations, with the deviation from the peak being more prominent in A. anatina. Finally, we recorded a contrasting locomotory strategy for the two species (A. anatina crawled on the sediment surface, whereas U. pictorum moved through the sediment) and identified potential density dependence in behavioural adaptation.

Impacts of native and invasive crayfish on three native and one invasive freshwater mussel species

Abstract Freshwater mussels and crayfish provide important ecosystem functions and services. In both groups, global declines of native species are paralleled by invasions of non‐native species. Knowledge on differences in predation susceptibility of native and invasive freshwater mussels exposed to native and invasive crayfish is essential for understanding their ecological interactions and for conservation management. In this study, we compared the predation impact of the native European noble crayfish (Astacus astacus) and the invasive signal crayfish (Pacifastacus leniusculus) on three native (Anodonta anatina, Anodonta cygnea, and Unio pictorum) and one invasive (Sinanodonta woodiana) mussel species in controlled laboratory experiments. We repeated the same experiments with the same crayfish specimens to investigate a potential learning effect of crayfish and assessed the in situ impacts in a natural stream. Mussel predation and damage caused by P. leniusculus was significantly higher than by A. astacus. Irrespective of the crayfish species, susceptibility was greater in native mussel species compared to invasive S. woodiana. Predation and damage was greatest in the thick‐shelled U. pictorum, suggesting that other factors such as shell shape are more important in explaining susceptibility than shell thickness. A predation learning effect from previous co‐exposure was evident, being most pronounced for A. astacus. Even if our experimental findings could not be confirmed in the field, the experimental results suggest that crayfish may have a negative impact on mussels and this impact will likely increase with the ongoing spread of P. leniusculus replacing A. astacus populations in Europe. The co‐occurrence of invasive P. leniusculus with the invasive S. woodiana could potentially exacerbate declines of endangered native mussel populations.

Species diversity of unionid mussels (Mollusca: Bivalvia: Unionidae) as a bioindicator of the state water environment of river basins of Ukraine

Species diversity and frequency index of bivalve mollusks’ of unionid family are researched within river basins of Ukraine. The largest frequency index of mussels is identified in the Prypiat and Desna basins (84 and 79% respectively), then (as the indicator declines) – the Dnieper and Severskiy Donets basins (74 and 67%), the Southern Bug and Danube (47 and 46%), the Southern and Western Bug (47 and 28%), the Crimea (17%). No mollusks were found in the Azov basin at all. Most often (33%) there were found groups consisting of only three unpretentious species (Unio pictorum, U. tumidus, Anodonta anatina). In general, settlements from one to three species make up 70% of all researched collecting sites. Settlements formed by four species are identified only in 23% of habitats. Only 6% of settlements consisted of five aboriginal species and about 1% – of six. Locations where six species lived together were identified only in the Danube and Prypiat basins. There are no settlements of five species in the Western Bug and Desna basins at all, and there are not any even four species settlements in the Crimea. The obtained data can be used for organizing environmental activities and assessing water environment quality

Complex Assessment and Forecasting of Chemical Pollution of Small Rivers by Economic and Mathematical Modelling Methods


 
 
 The purpose of this work is to determine the hydrochemical parameters of the water of the river Seret and the features of the accumulation of heavy metals by bivalve molluscs Unio pictorum L. to predict the chemical contamination of the reservoir in the near future. Water samples for the study were taken in spring (April) and summer (July) from the Seret River at two points: above and below Ternopil. It is established that the chemical composition of the water of the river Seret is formed under the influence of a number of factors, but seasonal and anthropogenic factors play a dominant role. In the spring season, a number of hydrochemical indicators (pH, water hardness, concentration of ΝΟ 2-, ΝН4+, Сl- ions and metals) have lower values than in the summer. In addition, there is an increase in the amount of organic matter, ammonium cations, nitrite ions, chloride ions, phosphate ions and a decrease in oxygen concentration below Ternopil, especially in the summer season. This is evidence that the Seret River is under significant anthropogenic impact. An increase in the concentration of metals (Mn, Cu and Pb) in summer below Ternopil was revealed, which may be due to the discharge of insufficiently treated wastewater. The series of metal concentrations in the water of the Seret River looks as follows Mn → Zn → Pb → Cd → Cu, and the series of accumulation of metals in the tissues of molluscs Unio pictorum L. has the form Zn → Mn → Cu → Pb → Cd. On the basis of bioaccumulation coefficients of heavy metals by molluscs, a prediction of the situation on their content in water for the short term based on the theory of Markov chains was made. This theory allows us to make forecasts of a factor, taking into account the possibility of accidental influences on the environment, and to investigate the highest probability of finding a factor in a certain numerical parameter. The possibility of using economic and mathematical modelling tools and statistical methods based on correlation-regression analysis using modern Matlab information systems to identify correlations between chemical indicators of water quality and biological molluscs for modelling the environmental situation of the river Seret and assessing the contribution of the studied indicators in pollution of small rivers is shown.
 
 

Importance of substratum quality for potential competitive niche overlap between native and invasive unionid mussels in Europe

Infaunal freshwater mussels are highly threatened and declining worldwide. One of the potential threats to mussels consists of biological invasions. We intended to investigate the habitat overlap and behavioural differences between native (Unio pictorum, Unio tumidus, Anodonta anatina, Anodonta cygnea) and invasive (Asian Sinanodonta woodiana) unionid bivalves to determine potential sources of competition. Furthermore, we investigated differences between S. woodiana from the established population in artificially heated waters and from the recent population in a natural thermal regime. We used pairwise choice tests on mud, medium, coarse and very coarse sand, mixture of medium and coarse sand, fine, medium and coarse gravel, and observed mussel locomotion and burrowing in preferred and non-preferred substrata. All species generally preferred fine-grained materials. The widest preference range was exhibited by S. woodiana (both populations), whereas A. cygnea was the most selective. The preferences of the cold-water population of S. woodiana were shifted towards coarser materials compared to conspecifics from the heated waters, and highly overlapped with the preferences of the native species. Anodonta cygnea most often moved horizontally and spent the shortest time deeply burrowed. Both Unio species were deeply burrowed for the largest amount of time and the horizontal locomotion of U. tumidus was the lowest among the test species. Sinanodonta woodiana, especially from the heated water population, exhibited relatively weak locomotion (compared to A. cygnea) and burrowing (compared to Unio spp. and A. anatina). Deep burrowing was more common on fine-grained materials. Our results suggest that the native mussels can be threatened by S. woodiana due to their overlapping habitat preferences, potentially hindering habitat separation. However, mobile native mussels may be capable of migrating and avoiding competition. Accumulating knowledge of the biology and ecology of freshwater mussels could contribute to the creation and improvement of conservation plans to protect these threatened animals.

Shifted mineral ions transport in the mollusk Unio pictorum exposed to environmental concentrations of diclofenac

Previous studies showed that diclofenac (DCF), when released in the environment, can be toxic to aquatic animals (fish and mollusks), affecting gills, which are the main organ of ionic regulation. This study focuses on detecting the effects of relevant environmental concentrations of DCF (0.1–1 μg L−1) on the transport of main mineral cations, i.e. sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg), by widely distributed freshwater bivalve mollusks Unio pictorum. After 96-h exposure to river aerated water at 25 °C with DCF concentrations of 0 (control), 0.1 (treatment I), and 1 μg L−1 (treatment II), the mollusks were transferred to deionized water, and daily (for 7 days) concentrations of these cations in the medium have been measured. Animals exposed to 1 μg L−1 DCF maintained the ionic balance between the organism and the diluted medium at a significantly higher level of Na, K, and Mg ions in water compared to the control and animals exposed to 0.1 μg L−1 DCF. At 0.1 μg L−1 DCF, the greater loss concerning the control (p < 0.05) was found only for Na ion. There were no differences in the dynamics of Ca ions between control and both treatments. This study showed that detectable environmental concentrations of DCF in natural waters can influence the transport of main cations required by freshwater animals to maintain their ionic balance, and the observed effect (elevated ion loss) is ion-specific and also dose-dependent.

Operativnyy analiz stvorochnoy aktivnosti mollyuskov v avtomatizirovannykh sistemakh ekologicheskogo biomonitoringa

The article describes features of the operational analysis of valve activity of freshwater (Unio pictorum) and marine (Black Sea mussel Mytilus galloprovincialis) bivalve molluscs for created automated systems of bioelectronic environmental control. The studies used measuring data obtained from long-term field and laboratory experiments using instruments developed by the author. The assessment of the mollusc general behavioral characteristics expressed in the dynamics and amplitude of group valve activity as a response to various effects made it possible to determine typical behavioral response models of toxic effects in the aquatic control environment. For the operational analysis, the main statistical indicators are identified, which are used to create software algorithms for automatic decision-making of the environmental biomonitoring system. As these indicators are used first of all the group time-sliding estimates of the synchronism of mollusc reactions, the data of valve activity averaged in different time intervals and the gape level (group and individual). The existence of established models, specified calculated numerical indicators and their permissible limits will ensure the standardization of the approach to detection of toxic factors and further implementation of such biomonitoring systems at control points.

Возможности анализа хронических загрязнений водных источников с помощью биоэлектронных систем с двустворчатыми моллюсками

An independent experimental experience of observations of marine mussels (Black Sea mussel Mutilus galloprovincialis) since 2008 in the coastal zone and of freshwater mussels (pearl Unio pictorum) since 2014 at the river water intake point when developing and maintaining automated bioelectronic complexes at control facilities allowed accumulating data on valve activity in various natural conditions. The analysis of the data obtained determined statistical and methodological regional (Crimea) estimates of the valve activity of biosensor mollusks, including annual seasonal and climatic variability, daily and semi-daily periodicity and attenuation against the background of chronic toxicosis, starvation and physiological aging. Studies show that the main indicator of chronic pollution in water bodies for the developed automated biomonitoring systems is the level of group valve activity, which, in case of environmental toxicity, has a pronounced trend towards decline. Inter-annual variability can be analyzed by meeting a number of requirements for the composition and conditions of use of reference groups of mollusks, as well as by considering climate changes. The informativity, from the point of view of autonomous long-term automation of the control process, daily and semi-daily seasonal rhythms is quite doubtful, because they are unstable in the natural environment and depend on a number of natural factors unrelated to toxic pollution. It can be concluded that the main purpose of bioelectronic monitoring systems remains operational analysis and integrated indication of sudden impacts.

Oxygen consumption during digestion in Anodonta anatina and Unio pictorum in response to algal concentration

The metabolic activity of unionid mussels influences the oxygen fluxes and other physical and chemical characteristics in aquatic systems. Unionid oxygen consumption rate during digestion and its dependency on food availability is understudied. In laboratory conditions, we quantified the oxygen consumption rate of Anodonta anatina and Unio pictorum in response to algal concentration—0.05, 6.0 and 12.0 mg of Ash Free Dry Mass of Chlorella vulgaris L−1—and mussel dry soft-tissue mass at 19 ± 1°C. Following a 5-h feeding-period, the oxygen consumption rate (mg O2 h−1) increased with algal concentration and mussel dry mass in both species during a 2-h digestion-period. The mean oxygen consumption per gram of dry mass (mg O2 gDM−1 h−1) increased with the algal concentration in both species. The oxygen consumption rate of A. anatina was significantly greater than that of U. pictorum at a given algal concentration. The A. anatina oxygen consumption per gram of dry mass decreased with increasing dry mass. Oxygen consumption rate during digestion shows inter-specific differences and is dependent on food availability. The findings inform the species-specific quantification of oxygen consumption, and validation is required in in situ conditions.

Lake-stream transition zones support hotspots of freshwater ecosystem services: Evidence from a 35-year study on unionid mussels

Securing adequate supply of high-quality water is of increasing global importance and relies in large part on ecosystem services provided by freshwater biota. Unionid mussels are important keystone species and habitat engineers that shape freshwater ecosystems through water filtration, nutrient cycling and provision of habitats; their rapid global declines result in dramatic losses of ecosystem functions. Maintenance and enhancement of the services they provide depend on the identification of their crucial habitats. Following theoretical assumptions, this study analyses the importance of lake-stream transition zones for unionid mussels, based on data collected in 1984 and 2019 from an undisturbed stream flowing through five consecutive lakes. Mussel distribution matched the distribution of host fish and was strongly influenced by lakes: densities were highest near lake outlets, reaching 290 ind. m−2 (14.7 kg m−2) in 2019, and declined with downstream distance following a negative power function. This pattern was spatially consistent and sustained over time. All six unionid species native to north-central Europe were present, but common species (Anodonta anatina, Unio pictorum, U. tumidus) contributed about 80% of individuals and were responsible for most of the ecosystem services provided by unionid mussels. Estimated 1.9 × 106 mussel individuals inhabiting 3.2 km of stream length filtered a water volume equivalent to the total stream discharge approximately 2.5 times daily. Aggregations of spent shells, up to 17 kg m−2, accumulated downstream of lakes, forming extensive shell and mussel beds, providing habitats and contributing shell hash that improved stream-bed conditions. Globally invasive Dreissena polymorpha was present at low densities and did not spread or increase in abundance, indicating a long-term biotic resistance of the natural native community. Our study underscores the importance of undisturbed lake outlets, longitudinal connectivity of riverine ecosystems, and of common mussel species in maintaining freshwater ecosystem functionality and provision of vital services.

Dynamics of topological defects and structural synchronization in a forming periodic tissue

Living organisms form a large variety of hierarchically structured extracellular functional tissues. Remarkably, these materials exhibit regularity and structural coherence across multiple length scales, far beyond the size of a single cell. Here, synchrotron-based nanotomographic imaging in combination with machine-learning-based segmentation is used to reveal the structural synchronization process of nacre forming in the shell of the mollusc Unio pictorum. We show that the emergence of this highly regular layered structure is driven by a disorder-to-order transition achieved through the motion and interaction of screw-like structural dislocations with an opposite topological sign. Using an analogy to similar processes observed in liquid-crystalline systems, we demonstrate that these microstructural faults act as dissipative topological defects coupled by an elastic distortion field surrounding their cores. Their mutual annihilation results in structural synchronization that is simulated using the classical Kuramoto model. The developed experimental, theoretical and numerical framework provides a comprehensive physical view of the formation of biogenic materials. Molluscs assemble layers of material in the shells around them with a high level of control. Here the authors observe the structural evolution of layer formation and propose a mechanism reminiscent of topological defect dynamics in liquid crystals.

Proximate Composition of Freshwater Mussels (Unio Pictorum, Linnaeus 1758) in Karasustream, Sinop

The effects of environmental factors and reproductive activities on proximate composition of freshwater mussels, Unio pictorum, was investigated from February 2013 to February 2014 in Sinop, Turkey. Environmental parameters including total particulate matter, inorganic matter and organic matter, chlorophyll-a and temperature were determined monthly during the experimental period. Mean protein, lipid, moisture and meat yield were 56.03±0.79%, 4.42±0.31%, 82.19±0.21% and 21.75±0.91%, respectively. The obtained data indicate that the proximate composition of mussels is highly correlated with environmental factors and reproduction cycle. In conclusion, freshwater mussel based protein should be evaluated an alternative source of protein for the feed industry.