Shell Calcification Research Articles

LITHOPEDION: A CASE REPORT

This article presents a case of lithopedion, a rare condition characterized by the calcification of a deceased fetus within the mothers abdomen. The objective is to highlight the clinical features, diagnostic challenges, and management strategies associated with this phenomenon. We describe the case of a 34-year-old patient, gravida 2 para 1 (G2P1), in whom lithopedion was incidentally discovered during a cesarean section.A lithopedion, also known as a stone baby, refers to the calcification of a fetus following intra-abdominal fetal demise. This occurs when the non-viable fetus is encased in a calcified shell, a process termed fetal mummification. It is an exceptionally rare outcome of a failed intrauterine or ectopic pregnancy [1].Our case is unusual, as the lithopedion was discovered incidentally during a cesarean section in a woman with a history of infertility. The newborn presented in a breech position, likely due to the reduced intrauterine space caused by an adnexal mass.

Fluorescent imaging and bio-cellular uptake assessment of gold-near infrared dye conjugated cockle shell calcium carbonate nanoparticle

Fluorescent imaging and bio-cellular uptake assessment of gold-near infrared dye conjugated cockle shell calcium carbonate nanoparticle

Fluorescent imaging and bio-cellular uptake assessment of gold-near infrared dye conjugated cockle shell calcium carbonate nanoparticle

Fluorescent imaging and bio-cellular uptake assessment of gold-near infrared dye conjugated cockle shell calcium carbonate nanoparticle

Development observed in the field of the Antarctic bivalve mollusc Aequiyoldia eightsii at Signy Island, South Orkney Islands

ABSTRACT The embryonic development of marine ectotherms has been shown to be strongly temperature dependent across the world's oceans. However, at the coldest sites, in the polar regions, development is even slower than would be predicted on the basis of the temperature dependence of development in warmer waters, and this is thought to be a consequence of changes in physical characteristics of cytoplasm near 0 °C—such as viscosity and osmolyte packing that slow protein folding and increase the likelihood of interference by charged particles, and their effect on protein synthesis. The overwhelming majority of studies of rates of embryonic development have been laboratory-based, with animals either collected directly from the sea and spawned in the laboratory or held first in the laboratory and preconditioned to set environments before spawning. Few studies have assessed development from regularly collected samples and assessed field development, especially from polar latitudes. Here we present data for the Antarctic bivalve mollusc Aequiyoldia eightsii, tracking its development from spawning on 25/26 May to hatching of pelagic veligers on 12 June and the disappearance of pediveliger larvae from the water column at the end of September or early October, 108–114 days later. Larval dry mass was constant at 16.7 µg (SE = 0.19) across the pelagic phase, except for the initial few days after hatching when it was 9.55 µg (SE = 0.60). The difference was likely the calcification of the larval shell. The development time to trochophore was 189 h, and this was in line with previous studies showing larval development at temperatures around 0 °C is around 4–22 times slower than would be predicted from the general effect of temperature on development rates.

Potential nutrient, carbon and fisheries impacts of large-scale seaweed and shellfish aquaculture in Europe evaluated using operational oceanographic model outputs

Large-scale seaweed and shellfish aquaculture are increasingly being considered by policymakers as a source of food, animal feed and bioproducts for Europe. These aquacultures are generally thought to be low impact or even beneficial for marine ecosystems as they are ‘extractive’ – i.e., growing passively on foodstuff already available in seawater, and with potential habitat provision, fisheries, climate mitigation and eutrophication mitigation benefits. At some scale however, over-extraction of nutrients or chlorophyll could potentially have a negative effect on natural systems. Understanding the likely impacts of aquaculture production at scale is important to identify when safe limits are being approached. Taking seaweed aquaculture as the primary focus, this work uses operational oceanographic model outputs to drive prognostic growth models to predict the likely optimal distribution of seaweed farms across European waters to meet different production scenarios. A novel nutrient transport scheme is then used to model the interacting ‘footprints’ of nutrient drawdown from aquaculture facilities to demonstrate the likely spatial impact of large-scale aquaculture. Evaluation of both seaweed and shellfish contributions to CO2 balance under large scale production, and the potential impact on fisheries are also considered. The study finds that the impact of intensive seaweed aquaculture on nutrient availability could be significant where many farms are placed close together; but at the regional/basin scale even the highest level of production considered does not significantly impact total nutrient budgets. Seaweed aquaculture has the potential to extract large amounts of carbon dioxide, but the impact on carbon budgets depends on the end-use of the extracted seaweed. Shellfish aquaculture is a net source of CO2 due to the impact of calcification of shells on the carbonate system (i.e., alkalinity removal). However, gram-for-gram the CO2 impact of shellfish production is likely to be less than the impact of land-based meat production. Whilst operational oceanographic models are useful for taking a ‘broad brush’ approach to likely placement and impacts of aquaculture, reliable yield predictions for individual locations across European waters would require models integrating more physical and biogeochemical factors (wave environment, local currents, riverine inputs) at a finer scale than currently achievable.

Nitrogen fixation and calcium activation of oyster shell during composting and its performance on acidic soil amendment

Chicken manure, corn straw and oyster shell powder (OSP) were used as raw materials for organic-inorganic combined composting. Experiments were designed by adding different amounts of OSP (0 %, 20 %, and 40 %), designed as CK, T1, and T2, respectively. In final composts, the pH value increased to 8.72–9.08, and the electrical conductivity ranged from 2.08–3.82 mS·cm−1. The co-composting could effectively reduce ammonia emissions by 54.65 % and could activate the calcium component by 37.5 %. Addition of OSP promoted the humification and the humic acid could increased 86.1 %. This calcium-based compost of oyster shells (OSs) activated by composting was used to plant Brassica napus by pot experiment. Compared with the addition of OSP after composting, the calcium-based compost activated by composting significantly promoted the growth of Brassica napus because of more nitrogen, humus and available calcium in the calcium-based compost. In addition, this calcium-based compost significantly increased pH, organic matter (OM) and exchangeable calcium content in the acidic soil. In general, composting is an effective method to realize the fertilizer utilization of OSs. This composting process could make full use of calcium in oyster shells to achieve nitrogen retention and humification enhancement during composting, meanwhile calcium morphology in oyster shells can be activated and high-quality acidic soil conditioner can be obtained.

Hydric Environment and Chemical Composition Shape Non-avian Reptile Eggshell Absorption.

The amniotic egg fulfils a critical role in reproduction by serving as an interface between the external environment and the embryo. Because non-avian reptiles are rarely incubated, they must be heated by, and absorb water from, the oviposition site for the developing embryo. The mechanisms by which they absorb sufficient, but not excess, water and how these mechanisms vary with local habitat is largely unknown, despite its significance to their evolution. Here, we first performed histology, Fourier-transform infrared spectroscopy and dynamic vapor sorption experiments to elucidate the mechanisms of eggshell absorption for 56 reptile species. Then, we used phylogenetic comparative analysis to test the hypothesis that the absorptive capacity of reptile eggshells increases with aridity of the environment. We found that water absorption increases in the presence of a superficial mucopolysaccharide layer and decreases with increased calcium content. We found that eggs from arid environments have highly absorbent eggshells, but only in species with weakly calcified shells. Our results suggest that reptile eggshells have over evolutionary time tuned absorptive capacity to environmental moisture level. Since these eggs often must sustain conflicting constraints, they may serve as inspirations for new biomimetic materials, such as water filtering membranes or humidity sensors.

Experimental Study on Ecological and Biogeochemical Role of Calcimycocavites in Understanding Carbon Fluxes in the Age of Global Warming and Climate Change

The present work reports the results of calcimycocavitological studies on the seashells from beaches of north Goa, India yielding distinct microfungal forms known as calcimycocavites which are important in global climate change studies. SEM studies of the calcareous shell fragments revealed the micro tunneling behavior of the fungi. Digital analysis of SEM images using Mountain Premium 7.2 software revealed the fine topography of calcimycocavites hyphae along with unidentified presumptive biomineral encrustations. The biodegradation of mycocavitogenic insoluble Calcium Oxalate by oxalotrophic members of bacterial communities may occur using bacterial Oxalate decarboxylase and formate dehydrogenase finally releasing Carbon Di Oxide and water and Calcium oxide to the local nutrient pool. Calcimycocavites may be thus involved in the biogeochemical cycling of Carbon and Calcium in the Ocean-Beach environment. The ecological, biological, and biogeochemical implications of the findings are presented concerning the possible role of calcimycocavites in Calcium and Carbon cycling by breakdown of the calcareous shells and release of inorganic and organic components in the ecosystem. The role of calcimycocavites is stressed in global climate studies.

Comparative Evaluation of Bioavailability, Efficacy and Safety of MICROCORE NESC® with Calcium Carbonate and Calcium Citrate Malate in Osteopenic and Osteoporotic Patients: A Randomized Clinical Trial.

Osteoporosis is a skeletal disease characterized by loss of bone mass, reduced bone strength and increased bone fragility predisposing to fractures. This study was planned to evaluate the efficacy, safety and relative bioavailability of Microcore NESC® (Natural Egg Shell Calcium) in osteopenia and osteoporotic patients. This was a randomized, open label, parallel group interventional clinical trial which included 60 study participants with osteopenia and osteoporosis who were randomized into three groups (20 each). Group 1-Microcore NESC®, Group 2-Shelcal and Group 3-CCM with 12weeks treatment period. The participants were evaluated for relative oral bioavailability, bone mineral density (BMD), serum osteocalcin, change in VAS pain scale and quality of life-Questionnaires. There was significant improvement in the BMD T scores-post-treatment with MICROCORE NESC® and Shelcal. Higher percentage of improvement in calcium absorption as depicted by an increase in serum calcium levels (10.23%) in the MICROCORE NESC®-treated group when compared to Shelcal (7.7%) and CCM (7.2%). The relative bioavailability of MICROCORE NESC® with respect to Shelcal was 93%. MICROCORE NESC®, has shown a better oral relative bio availability of calcium (93%), better improvement of BMD T score compared to Shelcal and CCM. The general health status has improved to very good/excellent in 83% of patients in MICROCORE NESC®-treated group. Thus, MICROCORE NESC® can be considered a better and safe calcium supplement, as there are very few side effects observed without any clinically significant abnormalities in lab parameters.

Nano‐Calcium Carbonate with Core–Shell Structure was Prepared by Dopamine Chelation Using Pluronic F‐127 as Template

AbstractHerein, a new template carbonization method is used to prepare calcite‐type nano‐calcium carbonate (CaCO3) with a core–shell structure using calcium hydroxide as a solute and Pluronic F‐127 as a templating and pore‐forming agent. Dopamine hydrochloride is added to control the size of calcium hydroxide particles. The morphology, particle size, and crystal type of CaCO3 are characterized via transmission electron microscopy, X‐ray diffraction, nanoparticle size, and zeta potentiometer. The creation of core–shell calcium carbonate nanoparticles is examined in relation to reaction circumstances (i.e., additive sequence, additive amount, and additive mixing time), carbonization temperature, liquid flow rate, and templates with varying chain lengths. Furthermore, a discussion is held regarding the formation mechanism of spherical core–shell calcium carbonate that is created using the innovative template carbonization method. The results show that the order, amount, liquid flow rate, and template type of additives have a significant effect on the crystal shape of calcium carbonate nanoparticles. The mixing time of additives has a significant effect on the particle size of calcium carbonate nanoparticles. Interestingly, the thickness of the shell depends on the carbonization temperature, and too slow or too fast flow rate will lead to the formation of cyclic calcium carbonate nanoparticles.

The effectiveness of Bio-plus2B®, Techno Mos® and their mixture on the rate of egg production, egg characteristics, retention of nutrients and blood metabolites through the early period of production

BackgroundThe trend of using probiotic, prebiotic and their mixture as alternative feed additives which works as growth promoters in poultry diets to increase the productive performance and the immunity of the flock still have an importance consideration. So that the aim of this study is to estimate the impact of Bio-plus2B® (probiotic), Techno Mos® (prebiotic) or their mixture (synbiotic) on egg production, egg and shell quality, some blood metabolites and retention of nutrients between 28 and 40 weeks of age. The hens (ISA brown laying) were allocated randomly in 40 cages; 10 cages/treatment with two hens each. The treatments were the control (T1), T2 (Probiotic: 1 g Bio-plus2B® (Bacillus licheniformis plus Bacillus subtilis)/kg feed), T3 (Prebiotic: 1 g Techno Mos® (Mannanoligosaccarides (MOS) and 1,3 B-glucan) /kg feed) and T4 (Synbiotic: 1 g Bio-plus2B® plus 1 g Techno Mos®/ kg feed).ResultsHen-day egg production% and mass were significantly increased (P < 0.05) with T2 and T4 treatments. The experimental treatments recorded an increase in albumen index, Haugh unit (P < 0.01), shell thickness (P < 0.05), the retention of crude protein (CP), crude fiber (CF) and ether extract (EE) (P < 0.05), plasma globulin, albumin and total protein (P < 0.001) versus to the untreated group, while egg weight was not affected. Synbiotic treatment showed a significant (P < 0.001) increase in shell calcium content. T3 and T4 treatments were significantly decreased plasma cholesterol (P < 0.001) and low density lipoprotein (LDL) (P < 0.05). Alanine transaminase (ALT) was significantly (P < 0.001) decreased and estradiol hormone was increased (P < 0.001) in the experimental groups versus to the control.ConclusionsIt concluded that adding probiotic and/or prebiotic in the early age laying hens diets had beneficial effects for productivity with improving the egg shell thickness.

Physiological impacts of climate change on juvenile American lobster Homarus americanus (Decapoda: Astacidea: Nephropidae), a commercially important species

Abstract The American lobster, Homarus americanus, H. Milne Edwards, 1837 is an ecologically, economically, and culturally valuable marine resource for the coastal communities in the Gulf of Maine. Lobsters in the Gulf of Maine are experiencing the effects of rapid warming and acidification due to climate change. Lobster shells are comprised of chitin with precisely precipitated minerals (calcite, amorphous calcium carbonate, and carbonate apatite) that provide structural integrity to the shell and protection against predators and microbial intrusion. We examined the combined effects of ocean warming and acidification on shell mineralogy, epibiont abundance, and growth in early benthic juveniles. Lobsters were grown under six different temperature/pCO2 treatment conditions over 52 days (three replicates per treatment) aligned with environmentally relevant as well as predicted future extremes. Elevated pCO2 and temperature led to a decrease in shell calcium and magnesium content, suggesting that these environmental stressors inhibit shell biomineralization. There was an interactive effect of the stressors on epibiont abundance with the probability of epibiont coverage increasing with increasing pCO2 and temperature. Elevated pCO2 alone was significantly correlated (P = 0.002) to decreased growth, but only for female lobsters. Ocean acidification and warming significantly affect shell integrity in juvenile lobster, increasing risk to injury and disease with potential downstream consequences for the lobster fishery.

Glacial-Holocene variability in sediment accumulation and erosion along submarine blind canyons: A case study from Eastern Mediterranean Sea

Submarine canyons serve as important sediment transport conduits from littoral zones to the deep sea, with strong impacts on the sedimentation patterns in marginal areas of the ocean. Moreover, such canyons can be major geohazards for submarine infrastructure, warranting a good understanding of their past and current behavior.Here, we present a study of the geological history and the recent activity of the Nahariya submarine canyon, the longest of a system of ∼15 small blind canyons located in the eastern Mediterranean Sea, offshore Israel. Two piston cores retrieved from the middle and outlet of the canyon, at 650 m and 915 m water depth, respectively, were the focus of a multi-proxy study aiming to characterize sediment transport and deposition along the canyon during the Last Glacial and up to the present.Both cores reveal a sequence of homogenous sediment of late last glacial age, which are capped by an unconformity overlying by fine laminated sediment dated to the last ∼200 years. Thus, the deglacial and most of the Holocene intervals are absent from the record. Evidence for down canyon sediment transport are abundant and include a 70 cm interval of mud clasts with disordered glacial ages that appears immediately below the hiatus, as well as broken calcareous shells of dead benthic foraminiferal species of shallow marine habitats, which are abundant throughout both cores. Similarly, shelf-derived living benthic foraminiferal species were found in the core-tops, indicating that active sediment transport persists along this canyon today.We conclude that the history of Nahariya submarine canyon includes a period of sediment accumulation that lasted until the last deglaciation. Thereafter, the canyon was dominated by an erosive regime that persisted throughout the Holocene. Sediment accumulation resumed ∼200 years ago. We suggest that the recent resumption of sediment-accumulation is a result of anthropogenic amplification of on-land soil erosion accompanied by a wet period that persisted in the region and enhanced land to sea sediment transport.

Https://www.micropress.org/microaccess/micropaleontology/issue-404/article-2385

Ostracod crustaceans are among the most abundant microfossils in the geological record, thanks to their strongly calcified shell. Most of the fossils belong to the suborder Cytherocopina, which also has a rich diversity of living species. Unfortunately, many of the living representatives are known only by their shell morphology. Soft body always provides valuable insights into the phylogeny, and sometimes conflicts with currently accepted systematics of this group. We provide a complete description of Coquimba ishizakii Yajima 1978, collected from Jeju Island, South Korea. This is the first report on soft body morphology for the entire genus Coquimba Ohmert 1968, and the first record of this genus from Korea. Its soft body morphology is similar to other representatives of the family Hemicytheridae, where Coquimba currently belongs. After reviewing all records of C. ishizakii, we propose that several of them belong to different species, such as all those from Taiwan (modern and fossil). We also provide 18S rRNA and 28S rRNA sequences for this species, the latter being reported for the first time for the entire family Hemicytheridae.

A Novel Kunitz-Type Serine Protease Inhibitor (HcKuSPI) is Involved in Antibacterial Defense in Innate Immunity and Participates in Shell Formation of Hyriopsis cumingii.

Serine protease inhibitors (SPIs) are abundantly reported for its inhibition against specific proteases involved in the immune responses, but SPI data related to calcareous shells are scarce. Previously, our research group has reported the proteome analysis of non-nucleated pearl powder, and a candidate matrix protein containing two Kunitz domains in the acid soluble fraction caught our attention. In the present study, the full-length cDNA sequence of HcKuSPI was obtained from Hyriopsis cumingii. HcKuSPI was specifically expressed in the mantle, with hybridization signals mainly concentrated to dorsal epithelial cells at the mantle edge and weak signals at the mantle pallium, suggesting HcKuSPI was involved in shell formation. HcKuSPI expression in the mantle was upregulated after Aeromonas hydrophila and Staphylococcus aureus challenge to extrapallial fluids (EPFs). A glutathione S transferase (GST)-HcKuSPI recombinant protein showed strong inhibitory activity against the proteases, trypsin and chymotrypsin. Moreover, HcKuSPI expression in an experimental group was significantly higher when compared with a control group during pellicle growth and crystal deposition in shell regeneration processes, while the organic shell framework of newborn prisms and nacre tablets was completely destroyed after HcKuSPI RNA interference (RNAi). Therefore, HcKuSPI secreted by the mantle may effectively neutralize excess proteases and bacterial proteases in the EPF during bacterial infection and could prevent matrix protein extracellular degradation by suppressing protease proteolytic activity, thereby ensuring a smooth shell biomineralization. In addition, GST-HcKuSPI was also crucial for crystal morphology regulation. These results have important implications for our understanding of the potential roles of SPIs during shell biomineralization.

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The biodiversity of benthic foraminifera around the coral communities and the concentration of heavy elements (e.g., Mn, Fe, Cr, Cu, Ni, Pb, Zn, Cd, and Co) in Miskan Island and Al-Khiran coastline of Kuwait are used as an ecological indicator for the environmental and anthropogenic stresses occurred from February 2018 to February 2019. The study resulted in identifying 19 families, 6 orders, 29 genera, and 94 species. Using R-mode cluster analysis results in four assemblages and using Q-mode principal component analysis (PCA) distinguished three groups depending on the deep. The three main assemblages refer to different depths, Group A from 20 cm to 1 m depth; Group B from 1.5 to 2 m depth, Group C from 6 to 8 m depth. Al-Khiran coastline is characterized by anoxic conditions, confirmed by the existence of pyrite. Additionally, high water turbidity because of anthropogenic effects. The low number of benthic foraminifera on Miskan Island is due to the dissolution and calcification of foraminifera shells. The Island characterized by freshwater runoff from Iraq meets saltwater in the gulf, affecting the salinity. The turbidity is caused by sediment runoff and eutrophication. Both sites were considered relatively unpolluted compared with the nearest Iranian coast. However, the relatively high potentially toxic elements in some locations are due to the semi-restricted geographic characteristic and high anthropogenic activity. There is no clear abnormality in the identified species showing normal aperture, coiling, shape, and size.

A Comparative Study of Calcium Metabolism between Quail and Domestic Rabbits

The existing study was conducted to evaluate calcium; vitamin D and calcitonin concentration in two types of amniotes that live in the Iraqi environment include the local rabbit and the Japanese quail. The study included 18 female Japanese quail Coturnix coturnix, weighing 145.5 ± 34.341 g, they were 16 weeks in ages and 18 female local rabbits, Oryctolagus cuniculus, at the age of one years and 1438.5 ± 284.988 g in weight. The results showed that the mean serum calcium concentration in bird and rabbit were 8.134±0.450 (mg/dl) and 7.267±1.761 (mg/dl) respectively and it was significantly at at 0.066 higher in bird in comparison to rabbit, the mean of vitamin D in bird and rabbit were 24.22± 3.159 (ng/ml) and 28.43±4.632 (ng/ml) respectively and it was significantly higher in rabbit than bird at 0.007 while the mean serum calcitonin concentration in bird and rabbit were 1.354±0.1960 (mg/dl) and 1.676±0.4151 (mg/dl) respectively and it was significantly at 0.009 higher in rabbit in comparison to bird. Egg laying, shell calcification and medullary bone formation induce more extra demand of calcium in birds while the high rate of teeth erupting demand extra calcium in rabbits, the metabolism of vitamin D will be altered indirectly by these process which associated with increased requirements for calcium. The study showed an increase in the level of calcium in both rabbits and quail birds, and that this increase will change the metabolism of vitamin D, and many physiological processes will occur.

Abstract 17504: Revisiting the Etiology of a Non-Ischemic Cardiomyopathy

Introduction: In the era of REVIVED-BCIS2 and ISCHEMIA clinical trials, the role of routine invasive coronary angiography for treatment of coronary artery disease (CAD) in the setting of left ventricular dysfunction has come into question. While the majority of heart failure (HF) patients undergo some form of non-invasive ischemic evaluation, there are a wide range of opinions on which testing modality is the most appropriate. Case: This is a 53 year-old man with a history of HTN, HLD, and presumed non-ischemic cardiomyopathy and LVEF of 15-20%, first diagnosed in 2009. He had a family hx of heart disease in several distant relatives, thus the etiology was presumed familial. In 2022, he had NYHA class II symptoms and a routine echo showed a LVEF of 25% with anteroseptal hypokinesis. Given these findings, a coronary CTA was obtained. This demonstrated infarct in the LAD territory and a proximal left main to mid-LAD aneurysm measuring up to 7 mm with a partially calcified shell and peripheral thrombus, consistent with prior Kawasaki’s disease (KD). He was initiated on a DOAC to prevent further embolic events and aspirin. He is now undergoing serial monitoring of the aneurysm size, thrombus burden, and functional testing to monitor for ischemia. Discussion: Non-invasive anatomic testing to evaluate for CAD in HF patients can provide useful information over a functional assessment. KD is a rare disease with an estimated incidence rate of ≈25 per 100,000 children less than 5 years of age. KD can lead to coronary artery aneurysms, which often contain thrombi, and subacute/chronic myocarditis. The affected arteries can become stenotic over time or even occlude, leading to ischemic injury later in life. Early recognition of this rare disease is important to initiate appropriate treatment and prevent thromboembolic complications. Conclusion: KD is a rare cause of adult cardiomyopathy. Anatomic testing was essential to appropriately diagnose and treat this patient’s cardiomyopathy.

Exceptional Early Jurassic fossils with leathery eggs shed light on dinosaur reproductive biology.

Our understanding of pre-Cretaceous dinosaur reproduction is hindered by a scarcity of evidence within fossil records. Here we report three adult skeletons and five clutches of embryo-containing eggs of a new sauropodomorph from the Lower Jurassic of southwestern China, displaying several significant reproductive features that are either unknown or unlike other early-diverging sauropodomorphs, such as relatively large eggs with a relatively thick calcareous shell formed by prominent mammillary cones, synchronous hatching and a transitional prehatching posture between the crocodilians and living birds. Most significantly, these Early Jurassic fossils provide strong evidence for the earliest known leathery eggs. Our comprehensive quantitative analyses demonstrate that the first dinosaur eggs were probably leathery, elliptical and relatively small, but with relatively long eggshell units, and that along the line to living birds, the most significant change in reptilian egg morphology occurred early in theropod evolution rather than near the origin of Aves.

From reproductive behaviour to responses to predators: Ocean acidification does not impact the behaviour of an herbivorous marine gastropod

Ocean acidification (OA), which reduces ocean pH and leads to substantial changes in seawater carbonate chemistry, may strongly impact organisms, especially those with carbonate skeletons. In marine molluscs, while the physiological effects of OA are well known, with a reduction of growth and shell calcification, there are few studies on behavioural effects. A large marine gastropod, Haliotis tuberculata, was exposed to ambient (pHT 8.0) or low pH (pHT 7.7) during a 5-month experiment. Because animal fitness can be affected through various behavioural changes, a broad spectrum of behavioural parameters was investigated, including situations involving no stress, responses to predators, righting to evaluate indirectly the level of energy reserves, and finally, reproductive behaviour. In addition, we measured the expression profile of the GABA A-like and serotonin receptor genes, often described as central neuromodulators of sensory performance and behaviour and known to be affected by OA in molluscs. No significant effect of low pH as compared to ambient pH was observed on abalone behaviour for any of these behavioural traits or gene expressions after either one week or several months of exposure to OA. The significance tests were corroborated by estimating the size of pH effects. The behaviour of this mollusc appears not to be affected by pH decrease expected by the end of the century, suggesting some resilience of the species to OA at the adult stage. This is probably related to the ecological niche of this abalone, where important pH variations can be observed at tidal, diurnal or seasonal scales.