Blue Mussel Shells Research Articles

Biorenewable Calcite as an Inorganic Filler in Ionic Liquid Gel Polymer Electrolytes for Supercapacitors.

Supercapacitors play a crucial role in the global shift toward cleaner, renewable energy and away from fossil fuels. Ionic liquid electrolytes have a larger electrochemical window than some organic electrolytes and have been mixed with various polymers to make ionic liquid gel polymer electrolytes (ILGPEs), a solid-state electrolyte and separator combination. One way to improve the conductivity of these electrolytes is to add inorganic materials such as ceramics and zeolites to increase their ionic conductivity. Herein, we incorporate a biorenewable calcite from waste blue mussel shells as an inorganic filler in ILGPEs. ILGPEs composed of 80 wt % [EMIM][NTf2] and 20 wt % PVdF-co-HFP are prepared with various amounts of calcite to determine the effect on the ionic conductivity. The optimal addition of calcite is 2 wt % based on the mechanical stability of the ILGPE. The ILGPE with calcite has the same thermostability (350 °C) and electrochemical window (3.5 V) as the control ILGPE. Symmetric coin cell capacitors were fabricated using ILGPEs with 2 wt % calcite and without calcite as a control. Their performance was compared using cyclic voltammetry and galvanostatic cycling. The specific capacitances of the two devices are similar, 110 and 129 F g-1, with and without calcite, respectively.

국내 소비 수산자원 및 가공품 중의 비타민 A 및 E vitamers 분석 및 검증

Simple simultaneous alkaline extraction (saponification) coupled with HPLC was validated and applied for the analysis of ten vitamers of A (retinol and β-carotene) and E (α-, β-, γ-, and δ-tocopherols (T) and corresponding tocotrienols (T3)) in seafood. Limits of detection for retinol, β-carotene and α-T were 0.380 μg/100 g, 0.602 μg/100 g and 0.0002 mg/100 g, respectively. Analysis precision was excellent for all vitamers (RSD: repeatability <2.4%, reproducibility <4.5%). Recoveries of vitamers ranged from 92% to 110%, showing good accuracy. Total vitamin A and E activities varied among seafood types, with ranges of 0.00-311.77 μg retinol activity equivalent/100 g and 0.01-0.62 mg α-tocopherol equivalent/100 g, respectively. β-Carotene was found in some seafoods such as shellfish (ark shell, blue mussel and spiny top shell) and crustacean (gazami crab) samples as well as marine algae due to the presence of intestinal organ containing algae in edible parts. The highest β-carotene content (689.84±29.86 μg/100 g) was observed in seasoned oyster whereas the retinol content was highest in blackthroat seaperch (311.77±7.99 μg/100 g). α-T was found in all samples and ranged from 0.07 to 4.72 mg/100 g. This study provides reliable vitamin A and E profiles for domestic seafood in Korea.

The 'Shellome' of the Crocus Clam Tridacna crocea Emphasizes Essential Components of Mollusk Shell Biomineralization.

Molluscan shells are among the most fascinating research objects because of their diverse morphologies and textures. The formation of these delicate biomineralized structures is a matrix-mediated process. A question that arises is what are the essential components required to build these exoskeletons. In order to understand the molecular mechanisms of molluscan shell formation, it is crucial to identify organic macromolecules in different shells from diverse taxa. In the case of bivalves, however, taxon sampling in previous shell proteomics studies are focused predominantly on representatives of the class Pteriomorphia such as pearl oysters, edible oysters and mussels. In this study, we have characterized the shell organic matrix from the crocus clam, Tridacna crocea, (Heterodonta) using various biochemical techniques, including SDS-PAGE, FT-IR, monosaccharide analysis, and enzyme-linked lectin assay (ELLA). Furthermore, we have identified a number of shell matrix proteins (SMPs) using a comprehensive proteomics approach combined to RNA-seq. The biochemical studies confirmed the presence of proteins, polysaccharides, and sulfates in the T. crocea shell organic matrix. Proteomics analysis revealed that the majority of the T. crocea SMPs are novel and dissimilar to known SMPs identified from the other bivalve species. Meanwhile, the SMP repertoire of the crocus clam also includes proteins with conserved functional domains such as chitin-binding domain, VWA domain, and protease inhibitor domain. We also identified BMSP (Blue Mussel Shell Protein, originally reported from Mytilus), which is widely distributed among molluscan shell matrix proteins. Tridacna SMPs also include low-complexity regions (LCRs) that are absent in the other molluscan genomes, indicating that these genes may have evolved in specific lineage. These results highlight the diversity of the organic molecules – in particular proteins – that are essential for molluscan shell formation.

The positive effect of coexisting ecosystem engineers: a unique seaweed-mussel association provides refuge for native mud crabs against a non-indigenous predator.

In marine sedimentary bottoms, mussels and macroalgae have long been recognized as important autogenic engineers that create habitat and modify abiotic conditions. The structural complexity added by bivalves and macroalgae may also mediate intraguild predation amongst marine decapod crustaceans. While spatial distributions of these ecosystem engineers frequently overlap, there is limited understanding of compounded effects when more than one engineer is present. Here we demonstrate that the coexistence of two ecosystem engineers may create habitat valuable for the survival of a small native species, the Atlantic mud crab (Panopeus herbstii), in the presence of the invasive green crab (Carcinus maenas). Using laboratory and field habitat mimics, we measured mud crab survival rates as a proxy for refuge quality. We compared the refuge provided by a unique association between shells of blue mussels (Mytilus edulis) and the giant strain of Irish moss (Chondrus crispus) to that provided by bare substrate, and by each engineer alone. These experiments revealed that the association of giant Irish moss with blue mussel shells positively and non-additively increased mud crab survival compared to the other less complex habitat mimics. In contrast, parallel experiments revealed that high habitat complexity was less important for young green crabs to survive predation from large conspecifics. These results suggest that the impact of ecosystem engineers on trophic dynamics should be considered in a broader, whole-community context encompassing multiple habitat-forming species present.

Hard to Soft: Biogenic Absorbent Sponge-like Material from Waste Mussel Shells

Summary Mussel shells are a source of renewable CaCO3 and can be obtained from aquaculture waste streams. Valorization of waste shells relieves strain on landfills and aligns with the goals of a circular economy. Here, we present the preparation of an absorbent CaCO3 material, soft calcite (SC), prepared from waste blue mussel shells under mild conditions. Calcite is the only polymorph present in SC, despite the presence of aragonite in the shell. SC has a nest-like morphology, unlike the highly ordered calcite in the shell. SC is formed by the reassembly of calcite prisms and may be held together by the organic matrix “glue” from the original shell as evidenced by NMR spectroscopy. This inorganic sponge adsorbs dyes from aqueous solution and absorbs crude oil from seawater with good recyclability. Our results demonstrate how a natural structure can be modified in a sustainable fashion to yield a higher-value material.

Trace elemental fingerprinting of shells and soft tissues can identify the time of blue mussel (Mytilus edulis) harvesting

Reliance on seafood for a source of animal protein is growing globally and this is likely to continue as Earth's population continues to rise. An active shift towards farmed produce over wild caught is occurring, attributed to dwindling wild populations, increased productivity potential and increased food security needs. Although production is rising, producers and regulators are continually challenged as passive filter feeding shellfish such as mussels are impacted by disease outbreaks, toxic algae blooms, pollution and food fraud that pose a risk to the market. This risk can manifest as mortality events and loss of stock, but also via consumer safety and subsequent loss of trust. To combat this threat, accurate and reliable traceability tools are necessary to give regulators power to maintain consumer safety and subsequently, trust. Recent research has demonstrated that trace element fingerprints (TEFs) based on the shell and soft tissues can identify the site of harvest of blue mussels (Mytilus edulis) (Bennion et al., 2019. Trace element fingerprinting of blue mussel (Mytilus edulis) shells and soft tissues successfully reveals harvesting locations. Science of The Total Environment, 685, 50–58) and king scallops (Pecten maximus) (Morrison et al., 2019. Spatio-temporal trace element fingerprinting of king scallops (Pecten maximus) reveals harvesting period and location. Science of The Total Environment, 697, 134121) with 100% success. Here, we test the temporal stability of trace element fingerprints (TEFs) of blue mussels within the aquaculture sphere, over five harvesting dates spanning two years. Computational models constructed using the trace element signatures of shells and soft tissues show near absolute temporal differences of TEFs between harvesting dates. However, TEFs based on a combination of both the shell and periostracum of mussels enabled 96% of all individuals to be correctly assigned to their date of harvest indicating that this method can not only identify the location but also the date of harvest of bivalve shellfish. This technique offers a reliable scientific-based traceability tool for regulators to uphold food safety standards and can prove an invaluable asset within the seafood regulatory arsenal.

Mesoporous Mg-doped hydroxyapatite nanorods prepared from bio-waste blue mussel shells for implant applications

The most important problem in post orthopedic surgery is implant infections developed by infectious micro-organisms. An alternative strategy needs to resolve this problem through creating a biomaterial with the addition of potential antibacterial activity. The foremost objective of this study is to develop magnesium (Mg)-doped mesoporous hydroxyapatite (HAp) nanorods using polyvinylpyrrolidone-assisted microwave synthesis by utilizing seashell bio-wastes to inhibit implant infections. The XRD, Raman spectroscopy, and FT-IR results expose that the produced HAp nanoparticles possesses hexagonal crystal structure. The morphological topographies corroborate that the acquired pure HAp consists of mesoporous nanorods with size of 10–15 nm (width) and 50–90 nm (length). Further, Mg-doped HAp nanoparticles, namely, MgHAp-1, MgHAp-2, and MgHAp-3 were also found alike mesoporous nanorods; however, with variations in sizes of 5–10, 10–15, 15–20 nm width and 50–65, 50–70, 50–80 nm length, respectively. Specific surface area was 47.2, 49.3, 113.0, and 25.7 m2 g−1, and with pore diameters of 3.79, 3.96, 6.07, and 7.77 nm, respectively, for the produced pure HA, MgHAp-1, MgHAp-2, and MgHAp-3 particles. The cytotoxicity and antibacterial analyses confirm that Mg-doped HAp nanorods are non-toxic with effective antibacterial properties. Therefore, it is clear that polyvinylpyrrolidone-assisted microwave synthesis method is an excellent way for the rapid manufacturing of HAp nanoparticles with diverse ranges and mesoporous morphology for its application as implant materials.

Introduced marine ecosystem engineers change native biotic habitats but not necessarily associated species interactions

Introduced bioengineering organisms may fundamentally change native coastal ecosystems by modifying existing benthic habitat structures and thereby habitat-specific species interactions. The introduction of the Pacific oyster Magallana gigas into the sedimentary coastal area of the south-eastern North Sea and its preferred settlement on native blue mussel shells caused a large-scale shift from monospecific Mytilus edulis beds to current mixed reefs of mussels and oysters. To investigate whether the newly developed biotic habitat affects the occurrence of associated native key organisms and their ecological functions, we studied the long-term density trajectory of the gastropod Littorina littorea and its grazing activity on barnacles attached to Pacific oyster reefs in the northern Wadden Sea. We found no significant correlation between oyster and snail densities on blue mussel beds in the last two decades, which spans a time-period from the beginning of Pacific oyster establishment to today's oyster dominance. A manipulative field experiment revealed that snail density significantly affects the recruitment success of barnacles Semibalanus balanoides on oyster shells with the highest number of barnacle recruits at snail exclusion. Thus, density and grazing activity of the snail L. littorea may control barnacle population dynamics on epibenthic bivalve beds in the Wadden Sea. This interspecific interaction was already known for blue mussel beds before the oyster invasion and, therefore, we conclude that despite the strong modifications that non-native ecosystem engineers cause in native biotic habitats, the ecological functions of associated key species can remain unchanged.

Natural Antireflective Microstructure of Blue Mussel Shells and Biomimetic Replication.

Nature provides various exquisite photonic structures of antireflection. Here, we investigate the color and structure of the inner surface of the shell edge (ISSE) of blue mussel shells, using a fiber optical spectrometer, scanning electron microscope (SEM), and X-ray diffraction (XRD). We demonstrate that the structurally assisted black color of the ISSE is produced by a pyramidal microstructure. Furthermore, we use the two-step biotemplate (TSBT) method to successfully replicate this microstructure. Particularly, we modify this method by using a poly(vinyl alcohol) (PVA) film as the negative replica and an epoxy resin film as the positive replica both fabricated without vacuum treatment. We show that the natural and replicated structures show a reflectivity of ∼4% and of ∼3% in the visible wavelength. Finally, we hope our investigation can provide basic data for the study of the bioinspired antireflective structures, which have a promising application in smart windows and optical devices.

Modelling crushing crab predation on bivalve prey using finite element analysis

ABSTRACT Amongst the many adaptive features of a bivalve shell, valve shape has been hypothesised to increase structural stability and to aid in withstanding crushing predation. Using Finite Element Analysis we modelled the crushing attack of a crab on a hard clam, soft clam, and blue mussel, assessing the effect of shell shape, size and thickness on their structural performance. Nanoindentation tests provide data on material properties. The hard clam is best suited to distribute applied loads evenly over a thick shell. Blue mussel shells work well when they are thin, and an increase in size is structurally disadvantageous. The soft clam accumulates the highest stresses; change in none of the tested variables improves its performance. The material properties and life habits of these taxa complement the structural responses of their shell shapes to crushing predation. Soft clams are poorly adapted to withstand crushing attacks, avoiding predators by living deeply burrowed in the substrate. Hard clams live shallower in the sediment, relying more on their thick valves to withstand attacks; these organisms are well adapted to disperse loads over a brittle shell. Epifaunal blue mussels absorb more energy than more brittle shells serving the organism well when small and thin.

Proteomic investigation of the blue mussel larval shell organic matrix

Shell matrix proteins (SMPs) are occluded within molluscan shells and are fundamental to the biological control over mineralization. While many studies have been performed on adult SMPs, those of larval stages remain largely undescribed. Therefore, this study aimed to characterize the larval shell proteome of the blue mussel for the first time and to compare it to adult mussel shell proteomes. Following development of a method for cleaning larval shells of tissue contaminants, 49 SMPs were identified using shotgun proteomics. Twenty-one proteins were independently identified in all samples indicating that they form a subset of the core larval shell proteome. These included: the blue mussel shell protein, a peroxidase domain-containing sequence, a laminin G domain-containing sequence, a ZIP domain-containing sequence and a ferric-chelate reductase 1-like sequence. Additional SMP domains identified were: fibronectin type III, BPTI/Kunitz, chitin-binding type 3, thyroglobulin and EF-hand. While key predictable molluscan shell matrix functions are identified, 67% of sequences remain unknown or uncharacterized, indicating that this shell proteome is unique to mussel larvae. Specifically, comparison with adult mytilids reveals that nine domains are exclusive to the larval shell proteome and only four domains are conserved among species and developmental stages. Thus, strong species-specific and ontogenetic variation exists in shell proteome composition.

Trace element fingerprinting of blue mussel (Mytilus edulis) shells and soft tissues successfully reveals harvesting locations

Globally, aquaculture products are expected to account for >60% of total seafood produce by 2030. In the European Union, the seafood sector is of considerable economic importance to member states with household spending on seafood produce totalling €54.8 billion in 2016. Within the EU, shellfish aquaculture supports livelihoods and employment in many rural communities throughout the region. Harmful algal blooms pose considerable risk to consumer safety and in turn, stability of the shellfish market. If contaminated produce was to make it to the market the health risk to the public could be considerable, but the damage to the sector through loss of trust in producers would also be significant. Mytilus edulis account for a considerable portion of the aquaculture sector in the Northeast Atlantic. At present, no scientific tool is available to industry regulators, to allow them to trace mussel produce to its source, uphold food safety standards and ensure consumer confidence. The present study uses chemical analysis of shells and soft tissues to classify individual M. edulis to their site of harvest. The use of random forest classification of trace element composition has revealed location specific elemental signatures for all examined sites. This led to the correct classification of 100% of individuals sampled to their respective harvesting locations, including two sites located just 6 km apart within the same bay. The protocol demonstrated here provides the basis for a scientifically driven traceability framework for shellfish produce.

Wealth from waste: blue mussels (Mylitus edulis) offer up a sustainable source of natural and synthetic nacre

Inner and outer layers of blue mussel shell separate easilyviaheat treatment allowing isolation of biogenic nacre and calcite.

Blue mussel shell shape plasticity and natural environments: a quantitative approach

Shape variability represents an important direct response of organisms to selective environments. Here, we use a combination of geometric morphometrics and generalised additive mixed models (GAMMs) to identify spatial patterns of natural shell shape variation in the North Atlantic and Arctic blue mussels, Mytilus edulis and M. trossulus, with environmental gradients of temperature, salinity and food availability across 3980 km of coastlines. New statistical methods and multiple study systems at various geographical scales allowed the uncoupling of the developmental and genetic contributions to shell shape and made it possible to identify general relationships between blue mussel shape variation and environment that are independent of age and species influences. We find salinity had the strongest effect on the latitudinal patterns of Mytilus shape, producing shells that were more elongated, narrower and with more parallel dorsoventral margins at lower salinities. Temperature and food supply, however, were the main drivers of mussel shape heterogeneity. Our findings revealed similar shell shape responses in Mytilus to less favourable environmental conditions across the different geographical scales analysed. Our results show how shell shape plasticity represents a powerful indicator to understand the alterations of blue mussel communities in rapidly changing environments.

Impact of Chinese mitten crab Eriocheir sinensis on blue mussel Mytilus edulis trossulus – laboratory studies of claw strength, handling behavior, consumption rate, and size selective predation

Summary We examined the claw strength, handling behavior, consumption rate, and size selective predation of the invasive Chinese mitten crab Eriocheir sinensis feeding on native Baltic Sea blue mussels Mytilus edulis trossulus during 24 h laboratory experiments. Single starved crabs were offered 15 mussels (five mussels in three length classes) at a time. The total number of mussels consumed by a single crab increased significantly ( P −1 h −1 after 4 h to 0.2 ± 0.7 # mussels crab −1 h −1 after 24 h. The highest consumption rate was observed within the first 4 h, and it decreased significantly ( P E. sinensis can also harm blue mussel shells by crushing them without further consumption. The mean daily damage, and not consumption, by a single crab was 0.9 ± 1.4 of 11–40 mm mussels. The claw strength of E. sinensis ranged from 1.50 to 20.43 N (mean 8.51 ± 5.93 N) and was significantly correlated ( P E. sinensis may be able to impact the native M. edulis trossulus population abundance in the coastal Baltic waters either through direct predation or indirect mortality by damaging (crushing) the shell.

Effects of live and post-mortem shell structures of invasive Pacific oysters and native blue mussels on macrofauna and fish

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 518:123-138 (2015) - DOI: https://doi.org/10.3354/meps11044 Effects of live and post-mortem shell structures of invasive Pacific oysters and native blue mussels on macrofauna and fish P. Norling1,3,*, M. Lindegarth2, S. Lindegarth2, Å. Strand2 1Norwegian Institute for Water Research, Gaustadalléen 21, 0349 Oslo, Norway 2Department of Biology and Environmental Sciences - Tjärnö, University of Gothenburg, 452 96 Strömstad, Sweden 3Present address: Swedish Agency for Marine and Water Management, Box 11 930, 404 39 Gothenburg, Sweden *Corresponding author: pia.c.norling@gmail.com ABSTRACT: Blue mussels Mytilus edulis and the invasive Pacific oyster Crassostrea gigas are both ecosystem engineering species which modify the environment, thus having large effects on associated species. With the introduction of the Pacific oyster, a new biogenic structure has been added to subtidal sediment habitats in Scandinavia. By conducting a field experiment, the effects of live and post-mortem shell structures of C. gigas and M. edulis on associated infauna, epibenthic fauna and fish on the Swedish west coast were evaluated. Plots with 5 different treatments (live Pacific oysters, oyster shells, live blue mussels, mussel shells and sand control) were constructed on bare sandy sediment at 2 subtidal localities. Epibenthic macrofauna and fish were sampled with a drop trap, and sediment and infauna samples were collected with sediment cores. Live bivalve treatments had significant effects on organic content of the sediment; however, no treatment effects on infauna were found. In contrast, abundance and biomass of epibenthic fauna increased 4 to 8 times and species richness increased in the presence of the bivalves or their shells, compared to the sand control. Epibenthic fauna abundance and biomass was higher in the oyster shell treatment compared to the live bivalve treatments, which in turn had higher abundance and biomass than the mussel shell treatment. In general, the mussel shell treatment favoured small crustaceans, while the oyster shell and live bivalve treatments favoured fish and larger invertebrate species. Based on these results, we conclude that further establishment of the Pacific oyster in Swedish waters will cause large changes to community structure of benthic macrofauna and fish. KEY WORDS: Non-indigenous species · Ecosystem engineering · Habitat modification · Macroinvertebrates · Infauna · Epibenthic fauna · Sediment community · Crassostrea gigas · Mytilus edulis Full text in pdf format Supplementary material PreviousNextCite this article as: Norling P, Lindegarth M, Lindegarth S, Strand Å (2015) Effects of live and post-mortem shell structures of invasive Pacific oysters and native blue mussels on macrofauna and fish. Mar Ecol Prog Ser 518:123-138. https://doi.org/10.3354/meps11044 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 518. Online publication date: January 07, 2015 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2015 Inter-Research.

Evaluation of composition and in vitro solubility rate of by-products of the Atlantic shellfish industry as alternative calcium sources

SUMMARY Mineral composition and in vitro solubility rates for 14 different Atlantic calcium (Ca) sources were assessed. Fourteen test Ca sources [commercial limestone, granular limestone, shell mix, AIM-limestone, oyster shell, crab shell (CS), lobster shell (LS), blue mussel shell, blue mussel shell–clean, surf-clam shell, soft-clam shell, scallop shell, quahog shell, abalone shell, and whelk shell] were separated into their particle size groups that ranged from 1.0 to 1.41 to <2.83 mm. Average concentration of Ca was 36 g/kg in all Ca sources (except CS and LS). Calcium content was 20.35 and 20.32% in CS and LS, respectively. The mineral composition analysis showed values of P varying from 0.03 to 1.8%, Mg from 0.01 to 1.2%, K from 0.005 to 0.32%, Na from 0.02 to 0.81%, Mn from 7.22 to 2168 mg/kg, Zn from 23.8 to 120.5 mg/kg, Fe from 0 to 37.9 mg/kg, Cu from 10.4 to 41 mg/kg, and boron from 0 to 163 mg/kg. There was significant interaction (P < 0.05) between Ca sources and time for solubility for different particle size of Ca sources. In vitro solubility was dependent upon Ca source and particle size (P < 0.0001) with small particle generally having a greater in vitro solubility than large particle at the same time. The in vitro solubility rate of these Ca sources would provide a new and adequate source of Ca and a steady rate of Ca during the dark period. It was concluded that the observed mineral concentration and in vitro solubility differences between the examined Ca sources could be exploited to ensure optimum supply of Ca and most minerals, but lower in vitro solubility and Ca content of CS and LS would likely limit the use of CS and LS.

Unsuitable habitat patches lead to severe underestimation of dynamics and gene flow in a zooplankton metapopulation

Migration and re-colonization enable organisms to persist in metapopulations. Re-colonization success may be limited by the number of arriving migrants or by patch quality. In a well-studied rock pool Daphnia metapopulation, it is frequently assumed that re-colonization is limited by the number of arriving migrants, and that all patches are equally suitable for colonization. This assumption strongly influences how observations about dynamics, epidemiology and population genetics for the entire metapopulation are interpreted. Here we test this assumption. In 627 rock pools, we found that high pH, high Ca(++) and high water conductivity were positively correlated with the presence of D. magna. The experimental release of D. magna into randomly chosen natural pools revealed the highest colonization success in pools with high pH. Next, we elevated pH and Ca(++) concentrations in natural pools by adding a system-specific natural source of calcium carbonate (either from crushed oyster shells or from eider duck droppings, which contain blue mussel shells). These treatments led to a rapid increase in pH and Ca(++) and strongly raised the likelihood that introduced D. magna would establish persistent populations. Therefore, we conclude that low pH and Ca(++) result in unsuitable colonization conditions in two-thirds of the untreated pools. A further experiment revealed that natural colonization rates were about five times higher in calcium-treated pools than in untreated pools. Finally, we observed that eider droppings are more frequently found in the catchment area of occupied pools, than they are in those of unoccupied pools, suggesting that the blue mussel shells contained in the eider droppings play an important role in making pools suitable for colonization and in enabling D. magna to persist. Thus, eider ducks are ecosystem engineers in this system. We recalculate typical metapopulation parameters to account for the unsuitable pools, resulting in a much more dynamic picture of this metapopulation than previously believed, with colonization rates and gene flow three to five times higher. These results have strong implications for metapopulation persistence, local and global genetic diversity, genetic rescue, gene flow and local adaptation. Our results emphasize that without verifying patch suitability, estimated rates of metapopulation dynamics can severely underestimate the true rates.

Identification and Characterisation of a Calcium Carbonate‐Binding Protein, Blue Mussel Shell Protein (BMSP), from the Nacreous Layer

The nacreous layer of molluscan shells consists of a highly organised, layered structure comprising calcium carbonate aragonite crystals, each surrounded by an organic matrix. In the Japanese pearl oyster Pinctada fucata, the Pif protein from the nacreous layer functions in aragonite binding, and plays a key role in nacre formation. Here, we investigated whether the blue mussel Mytilus galloprovincialis also has a protein with similar functions in the nacreous layer. By using a calcium carbonate-binding assay, we identified the novel protein blue mussel shell protein (BMSP) 100 that can bind calcium carbonate crystals of both aragonite and calcite. When the entire sequence of a cDNA encoding BMSP 100 was determined, it was found that BMSP is a preproprotein consisting of a signal peptide and two proteins, BMSP 120 and BMSP 100. BMSP 120 contains four von Willebrand factor A (VWA) domains and one chitin-binding domain, thus suggesting that it has a role in maintaining structure within the matrix. Immunohistochemical analysis revealed that BMSP 100 is present throughout the nacreous layer with dense localisation in the myostracum. Posttranslational modification analysis indicated that BMSP 100 is phosphorylated and glycosylated. These results suggest that there is a common molecular mechanism between P. fucata and M. galloprovincialis that underlies the nacreous layer formation.

Disentangling the biological and environmental control of M. edulis shell chemistry

Blue mussel individuals (Mytilus edulis) were cultured at four different salinities (17, 20, 29, and 34). During the course of the experiment, temperature was gradually increased from 6°C to 14°C. Mg/Ca and Sr/Ca ratios of the shell calcite portions produced during the 9 weeks of experimental treatment as well parts that were precipitated before the treatment phase were measured by laser ablation–multicollector–inductively coupled plasma–mass spectrometry. Mg/Ca ratios show a positive correlation with temperature for individuals cultured at salinity 29 and 34 (Mg/Ca (mmol/mol) ∼ (0.2–0.3)*T (°C)), while for individuals cultured at low salinities (17, 20) no trend was observed. Sr/Ca ratios were not affected by temperature but strongly by salinity. The data show very strong biological influence (“individual differences” and “physiological variability”) on elemental ratios (79% on Mg/Ca and 41% on Sr/Ca) in M. edulis calcite. The results challenge the use of blue mussel shell data as environmental proxies.