Scallop Research Articles

Effects of material composition and face block exposure on the long-term (2014-2018) colonisation of an intertidal RECIF Artificial Reef in the Bay of Seine

An experimental artificial reef (AR) with the incorporation of crushed seashells of the queen scallop Aequipecten opercularis was initiated on the intertidal zone of the Bay of Seine in the framework of the INTERREG IVa RECIF project for a everyone year monitoring observations from March 2014 to April 2018. Three block types were operated: eco-friendly material with 20% or 40% of crushed queen scallop shells, and ordinary concrete made from natural aggregates. On the seven blocks analysed at the end of the experiment in 2018, 74 taxa including 32 sessile and 42 motile fauna have been accounted; no difference of taxonomic richness was observed between material and immersion time. The sessile fauna was identified for the six external faces of two blocks aged of four years: horizontal above face (FAB), horizontal below Face (FBE), face oriented offshore (FOF), face oriented inshore (FIN), vertical face oriented west (FEW) and vertical face oriented east (FEA). FBE showed higher taxonomic richness and abundance than the other block faces. FAB exposed to the light showed the lowest abundances. Our observations showed the efficiency of such AR on the intertidal zone accessible at each spring tide, which was easier to survey than in the subtidal zone, where divers must be mobilised to sample blocks.

Antibacterial mechanism of biogenic calcium oxide and antibacterial activity of calcium oxide/polypropylene composites

In this study, biogenic calcium oxide (CaO) was developed as a natural antibacterial agent. After the thermal treatment of waste scallop shell powder, a CaO antibacterial agent was obtained. In addition, the crystal phase and morphology of the calcined product were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The antibacterial mechanism indicated that the alkaline environment caused by CaO hydration plays a vital role in the antibacterial action, in addition to the secondary sterilization of reactive oxygen species (ROS) by ·OH. CaO/polypropylene (PP) composites were prepared to examine the effectiveness of CaO as a bactericidal agent. Results revealed that the addition of CaO enhances the antibacterial activity of the composites and renders low toxicity. Such an eco-friendly natural inorganic antibacterial material demonstrates potential application prospects for sterilization.

Spatiotemporal distribution characteristics of yessotoxins and pectenotoxins in phytoplankton and shellfish collected from the southern coast of South Korea

The distribution characteristics of lipophilic marine biotoxins (LMTs), such as yessotoxins (YTXs) and pectenotoxins (PTXs) in phytoplankton, mussels, and commercial seafood were determined for the southern coast of South Korea. Gonyaulax spinifera and Dinophysis acuminata, which are the causative microalgae of YTXs and PTXs, were recorded during summer. Homo-YTX and PTX-2 were predominantly detected in phytoplankton (max: 5.7 μg g−1 ww), whereas only YTXs were detected in mussels (max: 1.1 μg g−1 ww). LMT concentrations in mussels were positively correlated with those in phytoplankton. However, there was a 1-month time gap in maximum LMT concentrations between mussels and phytoplankton. Homo-YTX was detected in commercial seafood, including red scallop and comb pen shell. However, homo-YTX concentrations in shellfish were below the recommended value of the European Food Safety Authority (3.75 mg YTX equivalents kg−1); thus, the consumption of this seafood was not considered to be a significant risk for human health.

Synthesis and characterization of ferric@nanocellulose/nanohydroxyapatite bio-composite based on sea scallop shells and cotton stalks: adsorption of Safranin-O dye

In the present study, four solid adsorbents were prepared via green synthesis sources, namely, nanohydroxyapatite (NHAP), nanocellulose (NC), nanocellulose/nanohydroxyapatite composite (NPC), and ferric@nanocellulose/nanohydroxyapatite composite (FNPC). Synthesis procedures were based on natural sources such as sea scallop shells and cotton stalks. All the prepared solid adsorbents were characterized by TGA, XRD, nitrogen adsorption/desorption isotherm, FTIR, pHPZC, SEM, and TEM. FNPC exhibited a higher surface area (358.32 m2/g), mesoporous surface (pore diameter, 12.29 nm), TEM particle size of 45 nm, and the availability of various surface functional groups. Static adsorption of Safranin-O (SO) dye was investigated for all the prepared solid adsorbents under different application conditions. Maximum adsorption capacity (239.23 mg/g) was achieved by FNPC after 24 h of equilibrium time, at pH 7, 2 g/L as adsorbent dosage, and 40 ℃. Adsorption of Safranin-O onto all the samples well-fitted Langmuir, Temkin, Freundlich, Dubinin–Radushkevich, pseudo-second-order, and Elovich models. Thermodynamic and kinetic parameters proved that Safranin-O adsorption is favorable, spontaneous, endothermic, and physisorption. Desorption studies confirmed that hydrochloric acid (0.03 mol/L) achieved the maximum desorption efficiency (92.8%). Reusability of FNPC showed a decrease in the adsorption capacity after five cycles of adsorption and desorption by only 7.8%.

Malleable Patterns from the Evaporation of a Colloidal Liquid Bridge: Coffee Ring to the Scallop Shell.

The present article highlights an approach to generating contrasting patterns from drying colloidal droplets in a liquid bridge configuration, different from well-known coffee rings. Reduction of the confinement distance (the gap between the solid surfaces) leads to systematized nanoparticle agglomeration yielding spoke-like patterns similar to those found on scallop shells instead of circumferential edge deposition. Alteration of the confinement distance modulates the curvature that entails variations in the evaporation flux across the liquid-vapor interface. Consequently, flow inside different liquid bridges (LBs) varies significantly for different confinement distance. Small confinement distance results in the stick-slip motion of squeezed liquid bridges. On the contrary, the stretched LBs exhibit pinned contact lines. The confinement distance determines the characteristic length scales of the thin film formed near the contact line, and its theoretical estimations are validated against the experimental observations using reflection interferometry, further exhibiting good agreement (in order of magnitude). We decipher a proposition that a drying liquid thin film (height ∼ O(10-7)m) present during dewetting near the three-phase contact line is responsible for the aligned deposition of particles. The coupled interplay of contact line dynamics, evaporation induced advection, and dewetting of the thin film at a three-phase interface contributes to the differences in deposition patterns.

Valorization of queen scallop shells in the preparation of metakaolin-based geopolymer mortars

This paper aims to assess the effect of the seashell waste (SW) incorporation on the performance of MK-based geopolymer mortar. The SW powder was introduced as partial replacement of MK with a substitution rate of 0, 10, 20 and 30%. Its effect on setting time, water porosity, mechanical strengths and both drying and autogenous shrinkage was investigated. A special attention was also devoted to the evaluation of the efflorescence stability. The obtained results show that partial replacement of MK by SW powder leads to limit considerably the water demand of the binder resulting in mortars with higher mechanical strengths and lower porosity and shrinkage. In addition, SW powder allows to accelerate the setting time of geopolymer mortars. The autogenous shrinkage was found to increase with increasing SW percentage. However, the total shrinkage was dominated by the drying shrinkage that represents around 85% of the total strain at 90 days regardless the SW replacement rate. In terms of efflorescence stability, the lowest efflorescence formation was attributed to the geopolymer mixture formulated with 30% of SW powder.

Economical and Environmentally Friendly Track of Biowaste Recycling of Scallop Shells to Calcium Lactate.

The scallop shell waste (Pectinidae, one of saltwater clams) was used as a raw material (precursor) to prepare calcium lactate (Ca(C2H4OHCOO)2), and the physicochemical properties of scallop-derived calcium lactate were then investigated. The scallop waste was first ground to obtain calcium carbonate (CaCO3) powder, and the calcium lactate compounds were successfully synthesized by the reactions between shell-derived CaCO3 and lactic acid (C2H4OHCOOH). The short preparation time, high percentage yield, and low-cost production are the preferred manners, and, in this research, it was the reaction of 70 wt % lactic acid and scallop-derived CaCO3. The thermal decompositions of both CaCO3 precursor and all prepared calcium lactates resulted in the formation of calcium oxide (CaO), which is widely used as a catalyst for biodiesel production. By comparing with the literature, the results obtained from the characterization instruments (infrared spectrophotometer, X-ray diffractometer, thermogravimetric analyzer, and scanning electron microscope) confirmed the formation and crystal structure of both CaCO3 and its calcium lactate product. The morphologies of calcium lactate show different sizes depending on the acid concentration used in the reaction process. Consequently, this work reports an easy, uncomplicated, low-cost technique to change the cheap calcium compound product (scallop CaCO3) derived from shellfish waste to the valuable compound (calcium lactate), which can be used in many industries.

Eco‐friendly method for rearing sea cucumber ( Apostichopus japonicus ) larvae

Seed production plays an important role in aquaculture. The sea cucumber Apostichopus japonicus is an important marine aquaculture species in many Asian countries. By 2020, the annual total seed production of A. japonicus reached 551 billion individuals in China. However, the traditional method of culturing A. japonicus larvae is cost intensive and causes environmental pollution. In this study, we developed an eco-friendly method for rearing sea cucumber larvae. We designed a cage system to provide a suitable living environment for larvae in open-air outdoor ponds, and then, we identified 0.2 larvae per ml as the optimal stocking density for larval rearing. We also found that substrates made of oyster and scallop shells were optimal for larval settlement. A. japonicus larvae showed good survival, growth, development and settlement when cultured using this low-cost and non-polluting method. Our results can be applied to support sustainable development of the sea cucumber industry.

Potential Uses of Scallop Shell Powder as a Substrate for the Cultivation of King Oyster Mushroom (Pleurotus eryngii)

Scallop shells are currently a major form of waste generated in the Chinese fishing industry. However, they have the potential to be used as important industrial products. This study was conducted to assess the utility of scallop shell powder (SSP) supplementation in improving the growth of king oyster mushrooms (Pleurotus eryngii) grown on sawdust and sugarcane bagasse substrates. The outcomes of interest included mycelial growth, yield, biological efficiency, fruiting body traits, nutrient supply, and the mineral composition of P. eryngii. Supplementation with SSP accelerated the mycelial growth of P. eryngii. The yield of fruiting bodies (399.5 g/bag) and the biological efficiency (84.6%) were 14% higher after supplementation of the substrate with 2% SSP compared with those of mushrooms grown on substrates not supplemented with SSP (349.8 g/bag and 74.0%, respectively). Moreover, the crude protein and fiber contents of the fruiting bodies significantly improved after growth with SSP. Furthermore, supplementation with 2% SSP increased the calcium (Ca) content of the fruiting bodies of P. eryngii by 64% (to 67.2 ± 15.7 mg kg−1) compared with that of mushrooms grown on a control substrate (41.0 mg kg−1). This study revealed that P. eryngii can efficiently use the Ca provided by raw SSP, generating higher Ca contents in their fruiting bodies. Our results demonstrate that the supplementation of substrates with SSP can be useful for enhancing both the yield and nutritional content of P. eryngii.

Discard Mortality of Sea Scallops Placopecten magellanicus Following Capture and Handling in the U.S. Dredge Fishery

AbstractDiscard mortality can represent a potentially significant source of uncertainty for both stock assessments and fishery management measures. While the family Pectinidae is considered to be robust to the capture and handling process, understanding species‐specific discard mortality rates is critical to characterize both population dynamics and to develop regulatory measures to meet management objectives. The discard mortality rate for the U.S. dredge fishery of sea scallop Placopecten magellanicus was estimated empirically via a retention study aboard industry vessels under commercial conditions. Over 16,000 sea scallops were assessed via a composite index of scallop vitality that consisted of semiqualitative measures of both overt trauma (shell damage) and response to stimuli. Results indicate that overall sea scallop discard mortality was 21% and consistent with the values currently assumed in the stock assessment. Survival mixture models support the utility of a simple metric of physical trauma as an effective predictor of mortality. Exposure time was also identified as a positively correlated factor that was important in describing the discard mortality process. Application of experimental results highlight the need to consider some operational characteristics of the fishery to reduce potential discard mortality.

Rendering of Beef Tallow for Biodiesel Production: Microwave versus Boiling Water and Acetone Fat Extraction

Biodiesel can substitute for conventional diesel fuel and contribute to the decarbonization of the transportation sector. To improve biodiesel sustainability and decrease production costs, low-grade fats such as non-edible animal fats must be used. Animal fats are mixed with tissues which must be removed before alcoholysis to avoid biodiesel contamination with nitrogen and phosphorus-containing compounds. Biodiesel was produced by the methanolysis of beef tallow and beef tallow/soybean oil mixtures over calcium heterogeneous catalysts obtained by the calcination of scallop shells. The tallow from fatty bovine tissues was extracted using boiling water, dry microwave treatment, and acetone extraction. The thermal stability and the moisture content of the extracted fats were evaluated by thermogravimetry. The thermograms of fats revealed that microwave treatment, which was faster (3 min instead of 40 min for boiling water and 240 min for acetone extraction) and had the lowest energy consumption, led to a dry fat with a thermal stability analogous to that of fats extracted with boiling water and acetone. All the extracted fats behaved similarly in the methanolysis reaction over calcium catalyst, with biodiesel yield (61–62%) being 30% lower than the analogous obtained from soybean oil (88%). Co-processing the extracted tallow with soybean oil overcomes the drawback related to the low-grade fats.

Complex Modulation of Rapidly Rotating Young M Dwarfs: Adding Pieces to the Puzzle

Abstract New sets of young M dwarfs with complex, sharp-peaked, and strictly periodic photometric modulations have recently been discovered with Kepler/K2 (scallop shells) and TESS (complex rotators). All are part of star-forming associations, are distinct from other variable stars, and likely belong to a unified class. Suggested hypotheses include starspots, accreting dust disks, corotating clouds of material, magnetically constrained material, spots and misaligned disks, and pulsations. Here, we provide a comprehensive overview and add new observational constraints with TESS and SPECULOOS Southern Observatory photometry. We scrutinize all hypotheses from three new angles: (1) We investigate each scenario’s occurrence rates via young star catalogs, (2) we study the feature’s longevity using over one year of combined data, and (3) we probe the expected color dependency with multicolor photometry. In this process, we also revisit the stellar parameters accounting for activity effects, study stellar flares as activity indicators over year-long timescales, and develop toy models to simulate typical morphologies. We rule out most hypotheses, and only (i) corotating material clouds and (ii) spots and misaligned disks remain feasible—with caveats. For (i), corotating dust might not be stable enough, while corotating gas alone likely cannot cause percentage-scale features and (ii) would require misaligned disks around most young M dwarfs. We thus suggest a unified hypothesis, a superposition of large-amplitude spot modulations and sharp transits of corotating gas clouds. While the complex rotators’ mystery remains, these new observations add valuable pieces to the puzzle going forward.

Deep neural network-based optimal selection and blending ratio of waste seashells as an alternative to high-grade limestone depletion for SOX capture and utilization

• Wet flue gas desulfurization process was optimized using waste oyster shell. • Deep neural network–based surrogate model is used to cost optimization. • Seashells with low-grade limestone could fully replace high-grade limestone. • At an optimal blending ratio, total annualized cost could be reduced by US$788,469. • The results facilitate cost-effective and eco-friendly SO x capture and utilization. In wet flue gas desulfurization system, the resource depletion of high-grade limestone, used as conventional SO x absorbent, is becoming serious for SO x capture and utilization. This paper proposes optimal selection and blending ratio of waste seashells as an alternative to high-grade limestone depletion using a deep neural network (DNN)-based surrogate model. Cost optimization proceeds as follows: data generation, data preprocessing, development of DNN-based surrogate model, and derivation of cost optimal selection and blending ratio. First, a process model is developed to generate the datasets, which are gypsum purity according to selection and blending ratio of each seashell and limestone. In addition, a mathematical model is proposed to calculate the total annualized cost (TAC) considering the pretreatment cost of seashell, and the TAC is added to the datasets to predict the gypsum purity as well as TAC. Second, the generated datasets are preprocessed to intensify prediction performance of the DNN-based surrogate model using the z-score normalization method. Third, a DNN-based surrogate model is developed to predict the gypsum purity and TAC according to the selection and blending ratio. Finally, the cost optimal selection and blending ratio are derived from 2.4 billion data generated by the developed DNN-based surrogate model under two constraints: gypsum purity and total SO x absorbent consumption. As a result, the derived selection and optimal blending ratios are low-grade limestone (80.86%), oyster shells (10.78%), scallop shells (0.216%), cockle shells (0.323%), clam shells (2.426%), and mussel shells (5.391%), reducing the TAC by US$788,469.

Utilization of Scallop Shells (Placuna placenta) for Potential Water Filter Prototype in Jaring Halus Village, Jaring Halus-Langkat District and the Characterization Test

Indonesia is a maritime country that has abundant marine wealth. Unfortunately, most fishers still live in poor conditions, including Jaring Halus Village, Secanggang District, Langkat Regency, North Sumatra Province. Previous research has shown that there is much coastal waste, such as Scallop Shells (Placuna placenta), that are not treated, even though it has the potential to help people who are experiencing water crises to get clean water sources. This study aimed to characterize the shells of Scallops and produce calcium carbonate as an activated carbon product to produce clean water. The method used to characterize the mashed scallop shells is X-Ray Diffraction (XRD). In this study, three different sizes, namely 25 μm, 90 μm, and 150 μm, will be compared, and the size and quality selected to produce the best calcium carbonate were tested at different temperatures, namely 800°C, 900°C, 1000°C, and 1100°C. In the x-ray diffraction analysis test, the smallest particle is 25 μm, which has the highest intensity compared to other sizes. The best particle size, which is heated/calcined at a temperature of 1100, has the highest intensity, which can remove all impurities and produce natural calcium carbonate, which is more stable. Based on the study results, it can be concluded that the best calcium carbonate is produced from particles with a size of 25 μm which are calcined at the highest temperature of 1100°C.

Cryofouling avoidance in the Antarctic scallop Adamussium colbecki

The presence of supercooled water in polar regions causes anchor ice to grow on submerged objects, generating costly problems for engineered materials and life-endangering risks for benthic communities. The factors driving underwater ice accretion are poorly understood, and passive prevention mechanisms remain unknown. Here we report that the Antarctic scallop Adamussium colbecki appears to remain ice-free in shallow Antarctic marine environments where underwater ice growth is prevalent. In contrast, scallops colonized by bush sponges in the same microhabitat grow ice and are removed from the population. Characterization of the Antarctic scallop shells revealed a hierarchical micro-ridge structure with sub-micron nano-ridges which promotes directed icing. This concentrates the formation of ice on the growth rings while leaving the regions in between free of ice, and appears to reduce ice-to-shell adhesion when compared to temperate species that do not possess highly ordered surface structures. The ability to control the formation of ice may enable passive underwater anti-icing protection, with the removal of ice possibly facilitated by ocean currents or scallop movements. We term this behavior cryofouling avoidance. We posit that the evolution of natural anti-icing structures is a key trait for the survival of Antarctic scallops in anchor ice zones.

Biomechanical Characterization of Scallop Shells Exposed to Ocean Acidification and Warming.

Increased carbon dioxide levels (CO2) in the atmosphere triggered a cascade of physical and chemical changes in the ocean surface. Marine organisms producing carbonate shells are regarded as vulnerable to these physical (warming), and chemical (acidification) changes occurring in the oceans. In the last decade, the aquaculture production of the bivalve scallop Argopecten purpuratus (AP) showed declined trends along the Chilean coast. These negative trends have been ascribed to ecophysiological and biomineralization constraints in shell carbonate production. This work experimentally characterizes the biomechanical response of AP scallop shells subjected to climate change scenarios (acidification and warming) via quasi-static tensile and bending tests. The experimental results indicate the adaptation of mechanical properties to hostile growth scenarios in terms of temperature and water acidification. In addition, the mechanical response of the AP subjected to control climate conditions was analyzed with finite element simulations including an anisotropic elastic constitutive model for a two-fold purpose: Firstly, to calibrate the material model parameters using the tensile test curves in two mutually perpendicular directions (representative of the mechanical behavior of the material). Secondly, to validate this characterization procedure in predicting the material’s behavior in two mechanical tests.

Preparation and characterization of self-suspended CaCO3 nanoparticles derived from scallop shells

In this study, self-suspended CaCO3 nanoparticles (M-SCC) derived from thermal activated scallop shells were prepared through the hydration–carbonation reaction and surface modification with sodium hexametaphosphate (SHMP). The characterization results proved the successful synthesis and modification of cubic-like CaCO3 particles. Suspension stability of CaCO3 particles was improved greatly after modification. The effects of additive amount of SHMP, modification temperature and time on degradation of SHMP and interaction between SHMP and CaCO3 were discussed using settling height, particle size distribution, zeta potential and viscosity measurements, and the optimum modification sample (M-SCC-OP) with excellent suspension stability was obtained under the condition of 3.0% of SHMP, 55 °C and 40 min. Zeta potential results indicated that surface charge property of CaCO3 was changed from positive to negative, and low viscosity (6.62 mPa·s) for the suspension of M-SCC-OP (23.8 wt.%) further proved strong composite forces among particles. Compared with original CaCO3 particles, suspension rate in a dietary calcium simulation system was improved from 14.2% to 67.6%. This study may help to solve the problem of limited application of CaCO3 in granule products for low solubility and poor suspension stability.

Characteristics of Hydrothermal Synthesis of Hydroxyapatite using Scallop Shells

Characteristics of Hydrothermal Synthesis of Hydroxyapatite using Scallop Shells

Quantitative proteomic analysis reveals the molecular mechanism of the Yesso scallop (Patinopecten yessoensis) in response to Polydora infection

The Yesso scallop is a large and ancient molluscan group with great economic value; however, it has recently suffered severe cases of Polydora infection. Polydora parasitizes the shells of scallops, badly damaging shell structures and affecting growth and mortality. To investigate the molecular mechanism of Yesso scallops’ response to Polydora infection, proteomic profiling changes in the mantle tissues of Polydora-infected (diseased) and healthy scallops were systematically analysed by tandem mass tags (TMT) labelling technology in this study. A total of 519 differentially expressed proteins (DEPs) were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed most innated immune-related functions and pathways were significantly downregulated in diseased scallops, except the phagocytosis pathway, indicating an important role of phagocytosis in response to Polydora infection. DEPs involved in the phagocytosis pathway were associated with phagocytic receptor recognition, phagosome biogenesis and pathogen degradation, and they were further verified by quantitative real-time PCR. The results elucidate the molecular components of phagocytosis in molluscs for the first time. Polydora can be encapsulated by melanization with an obvious appearance in shells; indeed, melanization-related DEPs were upregulated in diseased scallops. Inhibition of apoptosis and nervous modulation may be also involved in the response mechanism, with some highly associated proteins significantly differentially expressed. Finally, a protein–protein interaction network was constructed to provide a global view of the interaction relationships of the DEPs. The study predicts the molecular response mechanism of Yesso scallops to Polydora infection, and lays a theoretical foundation for Polydora disease control.

Esterification of Tripalmitin Using Calcined Scallop Shell as a Heterogeneous Basic Catalyst

Esterification of Tripalmitin Using Calcined Scallop Shell as a Heterogeneous Basic Catalyst