Sea Urchin Research Articles

Post-synthetic modification of covalent organic framework for efficient adsorption of organochlorine pesticides from cattle's milk

Analysis of organochlorine pesticides (OCPs) residues in milk faces a significant challenge. Herein, a sea urchin structured covalent organic framework bearing boric acid groups named COF-B(OH)2 was synthesized and applied as a coating material for solid-phase microextraction (SPME) of the OCPs in cattle’s milk. Its performance was superior to that of three commonly used commercial SPME fibers, which could be due to the coexistence of hydrogen bonding, halogen bonding, π-stacking and electrostatic interactions. Besides, the fiber coating displayed good stability and reusability. After optimization, a COF-B(OH)2 based SPME coupled with gas chromatography-electron capture detection was established for the sensitive detection of the OCPs from milk samples. The limits of detection (S/N = 3) were between 0.04 and 1.0 μg kg−1. Satisfactory accuracy was achieved with the method recoveries in the range of 87.5 % to 112.5 %. These results manifest the feasibility of the COF-B(OH)2 coated fiber for the enrichment of the trace OCPs from milk samples.

Investigating the timing of spawning of two sea urchins (Tripneustes gratilla and Toxopneustes pileolus)

AbstractMany marine organisms broadcast gametes for external fertilization, thus conspecifics need to concentrate the time of gamete release through synchronization with environmental factors. We investigated the timing of spawning in two sea urchin species, Tripneustes gratilla and Toxopneustes pileolus, by assessing the spawning potential of individuals using both surveys and experiments in southern Taiwan from March to November 2010. We developed a new method to observe the spawning potential without sacrificing any individuals, defining those individuals‐initiated spawning within 30 min after 10 s of exposure to air as having the spawning potential. We discovered that the percentage of individuals with spawning potential, that is, the spawning ratios of the population, varied greatly from 0% to 80% in To. pileolus and from 0% to 50% in Tr. gratilla within the reproductive seasons. We evaluated the possibility of a lunar/semilunar rhythm of spawning ratios of the population and tested three environmental factors, that is, light intensity, tide, and temperature that could potentially affect the spawning potential of the sea urchins by experiments. Individuals with spawning potential were neither randomly nor evenly distributed among days but were aggregated on certain days; however, no lunar/semilunar rhythm of the spawning ratios was detected within the reproductive season. The possible role of the tidal factor within a day was not found in experiments in either species. However, when water temperature was >27°C in our surveys, significantly higher spawning ratios were observed in To. pileolus, but not in Tr. gratilla in the reproductive season. A further temperature experiment in To. pileolus supported the positive role of high temperature on the spawning ratios of individuals. In addition, To. pileolus was more likely to spawn during the day than at night, and the light/dark experiments suggested that the spawning potential was controlled by an endogenous biological clock rather than by the ambient light conditions directly. The lack of rhythmic pattern and yet concentrated spawning of these sea urchins may be adaptive to avoid predation.

Asymmetric segregation of maternal mRNAs and germline-related determinants in Cephalochordate embryos: implications for the evolution of early patterning events in chordates.

How animal embryos determine their early cell fates is an important question in developmental biology. In various model animals asymmetrically localized maternal transcripts play important roles in axial patterning and cell fate specification. Cephalochordates (amphioxus), which have three living genera (Asymmetron, Epigonichthys, Branchiostoma), are an early branching chordate lineage and thus occupy a key phylogenetic position for understanding the evolution of chordate developmental mechanisms. It has been shown that in the zygote of Brachiostoma amphioxus, which possess bilateral gonads flanking both sides of their trunk region, maternal transcripts of germline determinants form a compact granule. During early embryogenesis this granule is inherited by a single blastomere that subsequently gives rise to a cluster of cells displaying typical characteristics of primordial germ cells (PGC). These PGCs then come to lie in the tailbud region and proliferate during posterior elongation of the larva to join in the gonad anlagen at the ventral tip of the developing myomeres in amphioxus larvae. However, in Asymmetron and Epigonichthys amphioxus, whose gonads are present only on the right side of their body, nothing is known about their PGC development or the cellular/morphogenetic processes resulting in the asymmetric distribution of gonads. Using conserved germline determinants as markers, we show that similarly to Brachiostoma amphioxus, Asymmetron also employ a preformation mechanism to specify their PGCs, suggesting that this mechanism represents an ancient trait dating back to the common ancestor of Cephalochordates. Surprisingly, we found that Asymmetron PGCs are initially deposited on both sides of the body during early larval development; however, the left side PGCs cease to exist in young juveniles, suggesting that PGCs are eliminated from the left body side during larval development or following metamorphosis. This is reminiscent of the PGC development in the sea urchin embryo, and we discuss the implications of this observation for the evolution of developmental mechanisms.

Evolutionary and biogeographic patterns in the deep-sea echinoid families Pourtalesiidae Agassiz 1881 and Ceratophysidae fam. nov. (Echinoidea)

Abstract The sea urchin family Pourtalesiidae is primarily an abyssal taxon, exhibiting extremely modified morphologies that have emerged as an adaptation for burrowing in soft sediment. Here, we present the first detailed molecular phylogeny of the family Pourtalesiidae. Both morphological and molecular evidence support the establishment of the family Ceratophysidae fam. nov. to accommodate seven former pourtalesiid genera. The name Pourtalesiidae is retained for the group of genera Cystocrepis and Pourtalesia. Based on morphological data, the fossil genus Galeaster is transferred to the monotypic family Galeasteridae fam. nov.. Families Pourtalesiidae and Ceratophysidae are each characterized by a unique pattern of plastron plating. Reconstructions indicate that elongated tests, as well as other adaptations for burrowing, evolved independently in these families. The evolutionary histories of pourtalesiids and ceratophysids are complex and include several instances of increase and decrease in this specialization. Molecular data support the Antarctic origin of Pourtalesiidae and Ceratophysidae, although for the latter the support is limited. The initial dispersal of pourtalesiids from the Antarctic occurred in the northward direction and included distribution of the least specialized forms throughout the eastern Pacific. Broad radiation of the more specialized forms apparently occurred later. The biogeographic history of the family Ceratophysidae is more complex and at present cannot be reconstructed reliably.

ROCK and the actomyosin network control biomineral growth and morphology during sea urchin skeletogenesis

Biomineralization had apparently evolved independently in different phyla, using distinct minerals, organic scaffolds, and gene regulatory networks (GRNs). However, diverse eukaryotes from unicellular organisms, through echinoderms to vertebrates, use the actomyosin network during biomineralization. Specifically, the actomyosin remodeling protein, Rho-associated coiled-coil kinase (ROCK) regulates cell differentiation and gene expression in vertebrates’ biomineralizing cells, yet, little is known on ROCK’s role in invertebrates’ biomineralization. Here, we reveal that ROCK controls the formation, growth, and morphology of the calcite spicules in the sea urchin larva. ROCK expression is elevated in the sea urchin skeletogenic cells downstream of the Vascular Endothelial Growth Factor (VEGF) signaling. ROCK inhibition leads to skeletal loss and disrupts skeletogenic gene expression. ROCK inhibition after spicule formation reduces the spicule elongation rate and induces ectopic spicule branching. Similar skeletogenic phenotypes are observed when ROCK is inhibited in a skeletogenic cell culture, indicating that these phenotypes are due to ROCK activity specifically in the skeletogenic cells. Reduced skeletal growth and enhanced branching are also observed under direct perturbations of the actomyosin network. We propose that ROCK and the actomyosin machinery were employed independently, downstream of distinct GRNs, to regulate biomineral growth and morphology in Eukaryotes.

ROCK and the actomyosin network control biomineral growth and morphology during sea urchin skeletogenesis

Biomineralization had apparently evolved independently in different phyla, using distinct minerals, organic scaffolds, and gene regulatory networks (GRNs). However, diverse eukaryotes from unicellular organisms, through echinoderms to vertebrates, use the actomyosin network during biomineralization. Specifically, the actomyosin remodeling protein, Rho-associated coiled-coil kinase (ROCK) regulates cell differentiation and gene expression in vertebrates’ biomineralizing cells, yet, little is known on ROCK’s role in invertebrates’ biomineralization. Here, we reveal that ROCK controls the formation, growth, and morphology of the calcite spicules in the sea urchin larva. ROCK expression is elevated in the sea urchin skeletogenic cells downstream of the Vascular Endothelial Growth Factor (VEGF) signaling. ROCK inhibition leads to skeletal loss and disrupts skeletogenic gene expression. ROCK inhibition after spicule formation reduces the spicule elongation rate and induces ectopic spicule branching. Similar skeletogenic phenotypes are observed when ROCK is inhibited in a skeletogenic cell culture, indicating that these phenotypes are due to ROCK activity specifically in the skeletogenic cells. Reduced skeletal growth and enhanced branching are also observed under direct perturbations of the actomyosin network. We propose that ROCK and the actomyosin machinery were employed independently, downstream of distinct GRNs, to regulate biomineral growth and morphology in Eukaryotes.

Local and regional variation in kelp loss and stability across coastal British Columbia

Kelp forests are among the most abundant coastal marine habitats but are vulnerable to climate change. The Northeast Pacific has experienced recent large-scale changes in kelp abundance and distribution, but little is known about changes north of the British Columbia (BC)-Washington border. Here, we assessed whether and how floating canopy kelp (Macrocystis pyrifera, Nereocystis luetkeana) distributions have changed in recent decades along the extensive coast of BC. We assembled and analysed available kelp distributional data, comparing snapshots of kelp linear extent from 1.5-3 decades ago (1994-2007) to recently collected data (2017-2021) across 11 different subregions spanning the province. We then leveraged timeseries, where available (n = 7 data sets), to contextualise patterns of change. In aggregate, the data suggest that kelp forests have declined considerably in some parts of the province, but with variable patterns of change across BC. In the warmest areas (southern BC), kelp persistence was negatively correlated with mean summer sea surface temperatures, which at times exceeded known thermal tolerances. In contrast, in northern subregions, top-down control by sea urchins and otters appeared to modulate kelp dynamics, with declines occurring in 2 subregions despite cool ocean temperatures. Timeseries data suggest that many declines occurred around the 2014-2016 marine heatwave, an event associated with sustained warming and altered trophic dynamics. Our results suggest that the extent of BC’s kelp forests has declined in some places in recent decades, but that regional and local-scale factors influence their responses to environmental change.

Sea Urchin Food Waste into Bioactives: Collagen and Polyhydroxynaphtoquinones from P. lividus and S. granularis

Approximately 75,000 tons of different sea urchin species are globally harvested for their edible gonads. Applying a circular economy approach, we have recently demonstrated that non-edible parts of the Mediterranean Sea urchin Paracentrotus lividus can be fully valorized into high-value products: antioxidant pigments (polyhydroxynaphthoquinones—PHNQs) and fibrillar collagen can be extracted to produce innovative biomaterials for biomedical applications. Can waste from other edible sea urchin species (e.g., Sphaerechinus granularis) be similarly valorised? A comparative study on PHNQs and collagen extraction was conducted. PHNQ extraction yields were compared, pigments were quantified and identified, and antioxidant activities were assessed (by ABTS assay) and correlated to specific PHNQ presence (i.e., spinochrome E). Similarly, collagen extraction yields were evaluated, and the resulting collagen-based biomaterials were compared in terms of their ultrastructure, degradation kinetics, and resistance to compression. Results showed a partially similar PHNQ profile in both species, with significantly higher yield in P. lividus, while S. granularis exhibited better antioxidant activity. P. lividus samples showed higher collagen extraction yield, but S. granularis scaffolds showed higher stability. In conclusion, waste from different species can be successfully valorised through PHNQ and collagen extraction, offering diverse applications in the biomedical field, according to specific technical requirements.

Multi‐omic analysis reveals genes and proteins integral to bioactivity of Echinochrome A isolated from the waste stream of the sea urchin industry in Aotearoa New Zealand

AbstractEvechinus chloroticus (commonly known as kina) is a sea urchin species endemic to New Zealand. Its roe is a culinary delicacy to the indigenous Māori and a globally exported food product. Echinochrome A (Ech A) is a bioactive compound isolated from the waste product of kina shells and spines; however, the molecular mechanisms of Ech A bioactivity are not well understood, partly due to Ech A never being studied using unbiased genome‐wide analysis. To explore the high‐value pharmaceutical potential of kina food waste, we obtained unbiased functional genomic and proteomic profiles of yeast cells treated with Echinochrome A. Abundance was measured for 4100 proteins every 30 min for four hours using fluorescent microscopy, resulting in the identification of 92 proteins with significant alterations in protein abundance caused by Ech A treatment that were over‐represented with specific changes in DNA replication, repair and RNA binding after 30 min, followed by specific changes in the metabolism of metal ions (specifically iron and copper) from 60–240 min. Further analysis indicated that Ech A chelated iron, and that iron supplementation negated the growth inhibition caused by Ech A. Via a growth‐based genome‐wide analysis of 4800 gene deletion strains, 20 gene deletion strains were sensitive to Ech A in an iron‐dependent manner. These genes were over‐represented in the cellular response to oxidative stress, suggesting that Ech A suppressed growth inhibition caused by oxidative stress. Unexpectedly, genes integral to cardiolipin and inositol phosphate biosynthesis were required for Ech A bioactivity. Overall, these results identify genes, proteins, and cellular processes mediating the bioactivity of Ech A. Moreover, we demonstrate unbiased genomic and proteomic methodology that will be useful for characterizing bioactive compounds in food and food waste.

Interactive effects of chronic ocean acidification and warming on the growth, survival, and physiological responses of adults of the temperate sea urchin Strongylocentrotusintermedius

To investigate the interactive effects of chronic ocean acidification and warming (OAW) on the growth, survival, and physiological responses of sea urchins, adults of the temperate sea urchin Strongylocentrotus intermedius were incubated separately/jointly in acidic (ΔpHNBS = −0.5 units) and thermal (ΔT = +3.0 °C) seawater for 120 days under lab-controlled conditions based on the projected ocean pH and temperature for 2100 put forward by the Intergovernmental Panel on Climate Change (IPCC). Survival rate (SR), average food consumption rate (FCR), gut index (GuI), specific growth rate (SGR), digestive capability, energy production, and antioxidant capability were subsequently determined. The results showed that 1) the SR, FCR, GuI and SGR decreased sharply under OAW conditions. Significant interactive effects of OAW on SR and SGR were observed at 120 days post-incubation (dpi), and on FCR this occurred at 90 dpi. 2) OAW altered the activities of both digestive and antioxidant enzymes. There were significant interaction effects of OAW on the activities of amylase, trehalase, and superoxide dismutase. 3) The relative gene expression levels and activities of key enzymes involved in glycometabolism pathways (i.e., glycolysis and the tricarboxylic acid cycle) were significantly affected by OAW, resulting in an alteration of the total ATP content in the sea urchins. Interaction effects of OAW were observed in both relative gene expression and the activity of enzymes involved in glycolysis (hexokinase), the transformation of glycolysis end-products (lactate dehydrogenase), the tricarboxylic acid cycle (citrate synthetase), and ATP production (Na+/K+-ATPase). The data from this study will enrich our knowledge concerning the combined effects of global climate change on the survival, growth, and physiological responses of echinoderms.

Genomic signatures of exceptional longevity and negligible aging in the long-lived red sea urchin

The red sea urchin (Mesocentrotus franciscanus) is one of the Earth's longest-living animals, reported to live more than 100 years with indeterminate growth, life-long reproduction, and no increase in mortality rate with age. To understand the genetic underpinnings of longevity and negligible aging, we constructed a chromosome-level assembly of the red sea urchin genome and compared it to that of short-lived sea urchin species. Genome-wide syntenic alignments identified chromosome rearrangements that distinguish short- and long-lived species. Expanded gene families in long-lived species play a role in innate immunity, sensory nervous system, and genome stability. An integrated network of genes under positive selection in the red sea urchin was involved in genomic regulation, mRNA fidelity, protein homeostasis, and mitochondrial function. Our results implicated known longevity genes in sea urchin longevity but also revealed distinct molecular signaturesthat may promote long-term maintenance of tissue homeostasis, disease resistance, and negligible aging.

Phylogenetic Relationship of Diadema: Emphasis on The Two Distinct Clades of D. Setosum With The Inclusion of Long Spine Black Sea Urchin From Malaysian Borneo

Diadema urchins (family Diadematidae) are ecologically important bioindicators of coral reef ecosystems and seagrass beds. Diadema urchins which are widely distributed and broadcast spawners, have been frequently utilized as model invertebrate species for zoogeography research of the Indo-West Pacific region. So far, Malaysian Borneo, located at the geographic center of Maritime Southeast Asia, has been under-sampled. This study aims to fill this sampling gap and provide the first record of Diadema setosum from Malaysian Borneo using genetic diagnostics to conclusively establish the clade-level identity of the species. According to Cytochrome Oxidase I gene analysis, Diadema is monophyletic. Seven species of Diadema namely Diadema palmeri, Diadema clarki, Diadema mexicanum, Diadema antillarum, Diadema paucispinum, Diadema africanum, and Diadema savignyi, formed their subclades with strong bootstrap values, demonstrating interspecific variation. The findings of this study provide further evidence for the presence of two distinct monophyletic clades, with all D. setosum individuals forming a monophyletic clade that later split into two distinct subclades, dividing Red Sea population (D. setosum-b) and Indo-West Pacific populations (D. setosum-a), supported by a significant genetic divergence value ranging from 6.3% to 9.1%. This study also revealed notable levels of nucleotide and population subdivision between the D. setosum from the Indo-West Pacific and the Red Sea populations (Nst = 0.891; Fst = 0.886) with a low number of migrants per generation (Nm = 0.065). This may suggest geographic isolation due to ecological factors preventing each other from surviving in the territory of the other, or that the two clades of D. setosum were a separate species. Additional morphological and molecular analysis is required in the future to ascertain the level of divergence and further resolve the taxonomic confusion within the genus Diadema.

Rab35 Is Required for Embryonic Development and Kidney and Ureter Homeostasis through Regulation of Epithelial Cell Junctions.

Rab35 is a member of a GTPase family of endocytic trafficking proteins. Studies in cell lines have indicated that Rab35 participates in cell adhesion, polarity, cytokinesis, and primary cilia length and composition. Additionally, sea urchin Rab35 regulates actin organization and is required for gastrulation. In mice, loss of Rab35 in the CNS disrupts hippocampal development and neuronal organization. Outside of the CNS, the functions of mammalian Rab35 in vivo are unknown. We generated and analyzed the consequences of both congenital and conditional null Rab35 mutations in mice. Using a LacZ reporter allele, we assessed Rab35 expression during development and postnatally. We assessed Rab35 loss in the kidney and ureter using histology, immunofluorescence microscopy, and western blotting. Congenital Rab35 loss of function caused embryonic lethality: homozygous mutants arrested at E7.5 with cardiac edema. Conditional loss of Rab35, either during gestation or postnatally, caused hydronephrosis. The kidney and ureter phenotype were associated with disrupted actin cytoskeletal architecture, altered Arf6 epithelial polarity, reduced adherens junctions, loss of tight junction formation, defects in EGFR expression and localization, disrupted cell differentiation, and shortened primary cilia. Rab35 is essential for mammalian development and the maintenance of kidney and ureter architecture. Loss of Rab35 leads to non-obstructive hydronephrosis, making the Rab35 mutant mouse a novel mammalian model to study mechanisms underlying this disease.

The viability of seagrass ecosystems for supporting dugong recovery in Kenya

Seagrasses are the primary source of food for dugongs and a good indicator of marine ecosys- tem health. The East African dugong (Dugong dugon) population is listed as critically endan- gered under the IUCN Red List. This study aimed to document the status of seagrass beds and evaluate their potential for supporting dugong recovery in Kenya. A cross-sectional survey was conducted in December 2016 to March 2017, with data gathered through desktop reviews, inter- views, beach surveys and aerial surveys. Seven seagrass species were found at sampled sites, namely Syringodium isoetifolium, Thalassodendron ciliatum, Halophila ovalis, Zostera capensis, Thal- assia hemprichii, Cymodocea serrulata, and Halodule uninervis. Halodule and Halophila seagrass spe- cies are important in the diet of dugongs. Two dugongs were sighted during the aerial survey. The spread of sea urchins, unplanned infrastructure development, Illegal, Unreported and Unregulated fishing, and boat anchors negatively affected seagrass ecosystems and hence dugong distribution in Kenya.

A Triply-Periodic-Minimal-Surface Structured Interphase based on Fluorinated Polymers Strengthening High-energy Lithium Metal Batteries.

The challenge of constructing a mechanically robust yet lightweight artificial solid-electrolyte interphase layer on lithium (Li) anodes highlights a trade-off between high battery safety and high energy density. Inspired by the intricate microstructure of the white sea urchin, we first develop a polyvinyl fluoride-hexafluoropropylene (PVDF-HFP) interfacial layer with a triple periodic minimal surface structure (TPMS) that could offer maximal modulus with minimal weight. This design endows high mechanical strength to an ordered porous structure, effectively reduces local current density, polarization, and internal resistance, and stabilizes the anode interface. At a low N/P ratio of ~3, using LiFePO4 as the cathode, Li anodes protected by TPMS-structured PVDF-HFP achieve an extremely low capacity-fading-rate of approximately 0.002 % per cycle over 200 cycles at 1 C, with an average discharge capacity of 142 mAh g-1. Meanwhile, the TPMS porous structure saves 50 wt % of the interfacial layer mass, thereby enhancing the energy density of the battery. The TPMS structure is conducive to large-scale additive manufacturing, which will provide a reference for the future development of lightweight, high-energy-density secondary batteries.

A Triply‐Periodic‐Minimal‐Surface Structured Interphase based on Fluorinated Polymers Strengthening High‐energy Lithium Metal Batteries

AbstractThe challenge of constructing a mechanically robust yet lightweight artificial solid‐electrolyte interphase layer on lithium (Li) anodes highlights a trade‐off between high battery safety and high energy density. Inspired by the intricate microstructure of the white sea urchin, we first develop a polyvinyl fluoride‐hexafluoropropylene (PVDF‐HFP) interfacial layer with a triple periodic minimal surface structure (TPMS) that could offer maximal modulus with minimal weight. This design endows high mechanical strength to an ordered porous structure, effectively reduces local current density, polarization, and internal resistance, and stabilizes the anode interface. At a low N/P ratio of ~3, using LiFePO4 as the cathode, Li anodes protected by TPMS‐structured PVDF‐HFP achieve an extremely low capacity‐fading‐rate of approximately 0.002 % per cycle over 200 cycles at 1 C, with an average discharge capacity of 142 mAh g−1. Meanwhile, the TPMS porous structure saves 50 wt % of the interfacial layer mass, thereby enhancing the energy density of the battery. The TPMS structure is conducive to large‐scale additive manufacturing, which will provide a reference for the future development of lightweight, high‐energy‐density secondary batteries.

Another New Species of the Cyrtodactylus annulatus Complex (Squamata: Gekkonidae) from Maratua an Adjacent Island to Borneo, Indonesia

The region of Borneo is very interesting in its diversity of gekkonid lizards of the genus Cyrtodactylus. Until now, it is known to harbor 14 described species. Herein, we described a new member of this genus from the adjacent island of Maratua. Cyrtodactylus tehetehe sp. nov. is named after the specialty of the traditional cuisine of the Derawan Islands (sticky rice with coconut milk and a little salt wrapped in sea urchin skin, Echinoidea spp.). The new species forms a tight phylogenetic clade with Philippine taxa allied to C. annulatus and is sister to the Palawan species C. tautbatorum, a biogeographic surprise, given that C. jambangan and C. annulatus occur closer geographically, in the Sulu Archipelago. The new species can be distinguished from all other congeners by a combination of characters including maximum SVL, number of supralabials, infralabials, longitudinal dorsal tubercle rows, paravertebral tubercles, ventral scale rows, subdigital lamellae on fourth toe, by having tubercles on ventrolateral body folds, a single precloacal pore and enlarged precloacal scales, lacking tubercles on upper arm, enlarged femoral scales and respective pores, precloacal depression, and transversely enlarged median subcaudals.  

Urchins CuCo2S4/Carbon composites with abundant defects and hetero-interfaces for optimized impedance matching and broadened effective band width

This work adopts a composite strategy combining “large anisotropic structure” and “strong dielectric material”, which is a pioneer work reported on urchins CuCo2S4/C absorber. An environmentally friendly (eco-friendly) CuCo2S4/C composites were prepared through a facile route including an ion exchange method and a simple physical grinding process. The resultant CuCo2S4/C composites exhibit an urchins-like morphology with carbon nanoparticles anchored randomly on the tentacles of the urchins. The urchins CuCo2S4/C composites display an optimal reflection loss value of −44.2 dB at the thickness of 2.2 mm, and the effective bandwidth with RL < −10 dB reaches 7.12 GHz at a thickness of 2.4 mm. The outstanding electromagnetic (EM) wave absorption performance is mainly benefited from the synergistic effects between the anisotropic structure of CuCo2S4 and conductive carbon particles. By adjusting the component ratio during the grinding process, an optimized combination of conduction loss and polarization loss can be achieved, and the impedance matching level can be regularly controlled and improved while increasing the effective absorption bandwidth. These results indicate that the sea urchin CuCo2S4/C composite material designed in this work can serve as an ideal candidate for high-performance electromagnetic wave absorption and has certain reference significance for the development of more sulfide semiconductor based absorbing materials.

How do sea urchins prepare offspring to face ocean acidification? Gamete intraspecific differences and adaptability

IntroductionDue to their relevant ecological position and well-studied biology, sea urchins are reference organisms for ocean acidification studies, at both within- and trans-generational levels. In this study, we examined gamete quality in specimens exposed to future predicted (-0.4 units) pH conditions during gametogenesis.MethodsEgg physical characteristics, biochemical composition, and fatty acid profiles were assessed after two and six months of exposure, while sperm viability and velocity were analyzed after six months of exposure. Considering the documented intraspecific variability in response to ocean acidification, this study involved two populations of Paracentrotus lividus. One population was sampled from the highly variable lagoon of Venice (Site 1), while the other was obtained from a coastal area (Site 2) characterized by more stable environmental conditions and facing minimal anthropogenic stress.ResultsA different response was highlighted in the two sites. Noteworthy trends emerged, especially in the fatty acid profile and sperm traits. Although adults were fed the same diet, Site 1 eggs contained more high-energetic fatty acids than Site 2, potentially boosting the survival odds for the next generation. Moreover, Site 1 sperms displayed higher viability but slower motility compared to those from Site 2. Within sites, a significant difference between time points and a change in the fitness strategy of sea urchin females emerged when comparing eggs spawned after two and six months of exposure to reduced pH. The effects of time and exposure pH are more pronounced in animals from Site 1, suggesting a higher adaptability of this population rather than negative effects of ocean acidification.DiscussionOverall, our findings suggest that sea urchins have the potential to acclimate to reduced pH and to produce gametes of the same quality as controls held at the currently natural pH. Our findings emphasize the relevance of combining investigations of gamete quality characteristics, particularly egg biochemistry and fatty acid composition, and considering site variability to fully understand the transgenerational response potential of sea urchins to ocean acidification.

Edible Sea urchins Echinus esculentus from Norwegian waters- Effect of season on nutritional quality and chemical contaminants

This study aimed to characterize Echinus esculentus gonads in terms of biometric parameters and nutritional quality at two sites in Mid-Norway at four different seasons. The chemical contamination of the gonads was also investigated for the first time through the evaluation of 28 macro- and trace elements and 32 components from the emerging and persistent group per- and polyfluoroalkyl substances (PFAS). The spawning period was determined in summer, given that the gonad index was the lowest in this season for both sites. Protein concentrations were constant (8%–10%). However, lipid contents (1%–3%) were noticed to be higher in gonads during autumn and winter. The gonads had high contents of PUFA mainly EPA and DHA, followed by SFA, and MUFA year around for both locations. E. esculentus gonads constitute a good source of fatty acids, macro, and trace elements. This species could also be a bioindicator for the monitoring of marine environments.