scholarly journals The scent of fear makes sea urchins go ballistic

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Jordi F. Pagès ◽  
Frederic Bartumeus ◽  
Javier Romero ◽  
Teresa Alcoverro
Keyword(s):  
Sea Urchin ◽  
Linear Models ◽  
Sea Urchins ◽  
Movement Patterns ◽  
Paracentrotus Lividus ◽  
Predator Prey ◽  
Predator Cues ◽  
Ballistic Motion ◽  
Key Species ◽  
Predator Prey Models

Abstract Background Classic ecological formulations of predator–prey interactions often assume that predators and prey interact randomly in an information-limited environment. In the field, however, most prey can accurately assess predation risk by sensing predator chemical cues, which typically trigger some form of escape response to reduce the probability of capture. Here, we explore under laboratory-controlled conditions the long-term (minutes to hours) escaping response of the sea urchin Paracentrotus lividus, a key species in Mediterranean subtidal macrophyte communities. Methods Behavioural experiments involved exposing a random sample of P. lividus to either one of two treatments: (i) control water (filtered seawater) or (ii) predator-conditioned water (with cues from the main P. lividus benthic predator—the gastropod Hexaplex trunculus). We analysed individual sea urchin trajectories, computed their heading angles, speed, path straightness, diffusive properties, and directional entropy (as a measure of path unpredictability). To account for the full picture of escaping strategies, we followed not only the first instants post-predator exposure, but also the entire escape trajectory. We then used linear models to compare the observed results from control and predators treatments. Results The trajectories from sea urchins subjected to predator cues were, on average, straighter and faster than those coming from controls, which translated into differences in the diffusive properties and unpredictability of their movement patterns. Sea urchins in control trials showed complex diffusive properties in an information-limited environment, with highly variable trajectories, ranging from Brownian motion to superdiffusion, and even marginal ballistic motion. In predator cue treatments, variability reduced, and trajectories became more homogeneous and predictable at the edge of ballistic motion. Conclusions Despite their old evolutionary origin, lack of cephalization, and homogenous external appearance, the trajectories that sea urchins displayed in information-limited environments were complex and ranged widely between individuals. Such variable behavioural repertoire appeared to be intrinsic to the species and emerged when the animals were left unconstrained. Our results highlight that fear from predators can be an important driver of sea urchin movement patterns. All in all, the observation of anomalous diffusion, highly variable trajectories and the behavioural shift induced by predator cues, further highlight that the functional forms currently used in classical predator–prey models are far from realistic.

scholarly journals Contrasting recruitment seasonality of sea urchin species in Gran Canaria, Canary Islands (eastern Atlantic)

2014 ◽  
Vol 15 (3) ◽  
pp. 475 ◽  
Author(s):  
S. GARCIA-SANZ ◽  
P. G. NAVARRO ◽  
F. TUYA
Keyword(s):  
Community Structure ◽  
Seasonal Variation ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Late Summer ◽  
Paracentrotus Lividus ◽  
Abundant Species ◽  
Late Winter ◽  
Gran Canaria ◽  
Arbacia Lixula

Despite sea-urchins can play an important role affecting the community structure of subtidal bottoms, factors controlling the dynamics of sea-urchin populations are still poorly understood. We assessed the seasonal variation in recruitment of three sea-urchin species (Diadema africanum, Paracentrotus lividus and Arbacia lixula) at Gran Canaria Island (eastern Atlantic) via monthly deployment of artificial collectors throughout an entire annual cycle on each of four adjacent habitat patches (seagrasses, sandy patches, ‘urchin-grazed’ barrens and macroalgal-dominated beds) within a shallow coastal landscape. Paracentrotus lividus and A. lixula had exclusively one main recruitment peak in late winter-spring. Diadema africanum recruitment was also seasonal, but recruits appeared in late summer-autumn, particularly on ‘urchin-grazed’ barrens with large abundances of adult conspecifics. In conclusion, this study has demonstrated non-overlapping seasonal recruitment patterns of the less abundant species (P. lividus and A. lixula) with the most conspicuous species (D. africanum) in the study area.

scholarly journals Diverse Transformers (Trf) Protein Family in the Sea Urchin Paracentrotus lividus Act through Collaboration between Cellular and Humoral Immune Effector Arms

2021 ◽  
Author(s):  
Iryna Yakovenko ◽  
Asaf Donnyo ◽  
Or Ioscovich ◽  
Benyamin Rosental ◽  
Matan Oren
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Paracentrotus Lividus ◽  
Protein Family ◽  
Immune Gene ◽  
Immune Effector ◽  
E Coli ◽  
Purple Sea Urchin ◽  
Humoral Immune ◽  
Extended Families

Sea urchins are long-living invertebrates with a complex immune system which includes extended families of immune receptors. A central immune gene family in the sea urchins encodes for the Transformer (Trf) proteins. The Trf family was so far studied mainly in the purple sea urchin Strongylocentrotus purpuratus. In this study, we explored this protein family in the Mediterranean Sea urchin Paracentrotus lividus. The PlTrf genes and predicted proteins were found to be highly diverse and showed a typical Trf size range and structure. We found that P. lividus coelomocytes and hemolymph contain different PlTrf protein repertoires with a shared subset which specifically bind E. coli bacteria. Using FACS, we identified five different P. lividus coelomocyte sub-populations with cell surface Trf protein expression. The relative abundance of the Trf-positive cells sharply increased following immune challenge with E. coli bacteria, but not following challenge with LPS or sea urchin pathogen V. penaeicida. Finally, we demonstrated that the phagocytosis of E. coli bacteria by P. lividus phagocytes is mediated through the hemolymph and is inhibited by blocking Trf activity with anti-Trf antibodies. Together, our results suggest collaboration between cellular and humoral Trf-mediated effector arms in the P. lividus specific immune response to pathogens.

scholarly journals Complex Mixture-Associated Hormesis and Toxicity: The Case of Leather Tanning Industry

Dose-Response ◽  
2008 ◽  
Vol 6 (4) ◽  
pp. dose-response.0 ◽  
Author(s):  
Giovanni Pagano ◽  
Giuseppe Castello ◽  
Marialuisa Gallo ◽  
Ilaria Borriello ◽  
Marco Guida
Keyword(s):  
Growth Inhibition ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Complex Mixture ◽  
Algal Growth ◽  
Paracentrotus Lividus ◽  
Selenastrum Capricornutum ◽  
Tannery Effluent ◽  
Developmental Defects ◽  
Algal Growth Inhibition

A series of studies investigated the toxicities of tannery-derived complex mixtures, i.e. vegetable tannin (VT) from Acacia sp. or phenol-based synthetic tannin (ST), and wastewater from tannin-based vs. chromium-based tanneries. Toxicity was evaluated by multiple bioassays including developmental defects and loss of fertilization rate in sea urchin embryos and sperm ( Paracentrotus lividus and Sphaerechinus granularis), and algal growth inhibition ( Dunaliella tertiolecta and Selenastrum capricornutum). Both VT and ST water extracts resulted in hormetic effects at concentrations ranging 0.1 to 0.3%, and toxicity at levels ≥1%, both in sea urchin embryo and sperm, and in algal growth bioassays. When comparing tannin-based tannery wastewater (TTW) vs. chromium-based tannery effluent (CTE), a hormesis to toxicity trend was observed for TTW both in terms of developmental and fertilization toxicity in sea urchins, and in algal growth inhibition, with hormetic effects at 0.1 to 0.2% TTW, and toxicity at TTW levels ≥1%. Unlike TTW, CTE showed a monotonic toxicity increase from the lowest tested level (0.1%) and CTE toxicity at higher levels was significantly more severe than TTW-induced toxicity. The results support the view that leather production utilizing tannins might be regarded as a more environmentally friendly procedure than chromium-based tanning process.

scholarly journals The impact of ocean acidification and warming on the skeletal mechanical properties of the sea urchin Paracentrotus lividus from laboratory and field observations

2015 ◽  
Vol 73 (3) ◽  
pp. 727-738 ◽  
Author(s):  
Marie Collard ◽  
Samuel P. S. Rastrick ◽  
Piero Calosi ◽  
Yoann Demolder ◽  
Jean Dille ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Laboratory Experiment ◽  
Young’S Modulus ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Young's Modulus ◽  
Paracentrotus Lividus ◽  
Low Ph ◽  
Fracture Force ◽  
The Impact

Abstract Increased atmospheric CO2 concentration is leading to changes in the carbonate chemistry and the temperature of the ocean. The impact of these processes on marine organisms will depend on their ability to cope with those changes, particularly the maintenance of calcium carbonate structures. Both a laboratory experiment (long-term exposure to decreased pH and increased temperature) and collections of individuals from natural environments characterized by low pH levels (individuals from intertidal pools and around a CO2 seep) were here coupled to comprehensively study the impact of near-future conditions of pH and temperature on the mechanical properties of the skeleton of the euechinoid sea urchin Paracentrotus lividus. To assess skeletal mechanical properties, we characterized the fracture force, Young's modulus, second moment of area, material nanohardness, and specific Young's modulus of sea urchin test plates. None of these parameters were significantly affected by low pH and/or increased temperature in the laboratory experiment and by low pH only in the individuals chronically exposed to lowered pH from the CO2 seeps. In tidal pools, the fracture force was higher and the Young's modulus lower in ambital plates of individuals from the rock pool characterized by the largest pH variations but also a dominance of calcifying algae, which might explain some of the variation. Thus, decreases of pH to levels expected for 2100 did not directly alter the mechanical properties of the test of P. lividus. Since the maintenance of test integrity is a question of survival for sea urchins and since weakened tests would increase the sea urchins' risk of predation, our findings indicate that the decreasing seawater pH and increasing seawater temperature expected for the end of the century should not represent an immediate threat to sea urchins vulnerability.

The Relation Between Lobster Abundance, Sea Urchins, and Kelp Beds

1972 ◽  
Vol 29 (5) ◽  
pp. 603-605 ◽  
Author(s):  
K. H. Mann ◽  
P. A. Breen
Keyword(s):  
Sea Urchin ◽  
Food Supply ◽  
Sea Urchins ◽  
Critical Density ◽  
Eastern Canada ◽  
Kelp Beds ◽  
Key Species

When subtidal communities are disturbed and sea urchin populations expand, they frequently overgraze their food supply, eliminating large seaweeds from considerable areas. The hypothesis is advanced that the lobster is a key species, controlling sea urchin populations in eastern Canada, and that reduction of lobster populations below a critical density has led to overgrazing of seaweeds in many places.

scholarly journals Green Extraction Strategies for Sea Urchin Waste Valorization

2021 ◽  
Vol 8 ◽  
Author(s):  
Stefania Marzorati ◽  
Giordana Martinelli ◽  
Michela Sugni ◽  
Luisella Verotta
Keyword(s):  
Fatty Acids ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Food Resource ◽  
Paracentrotus Lividus ◽  
Added Value ◽  
Physical Parameters ◽  
Widespread Application ◽  
Green Extraction ◽  
Successive Extraction

Commonly known as “purple sea urchin,” Paracentrotus lividus occurs in the Mediterranean Sea and the eastern Atlantic Ocean. This species is a highly appreciated food resource and Italy is the main consumer among the European countries. Gonads are the edible part of the animal but they represent only a small fraction (10–30%) of the entire sea urchin mass, therefore, the majority ends up as waste. Recently, an innovative methodology was successfully developed to obtain high-value collagen from sea urchin by-products to be used for tissue engineering. However, tissues used for the collagen extraction are still a small portion of the sea urchin waste (<20%) and the remaining part, mainly the carbonate-rich test and spines, are discarded. Residual cell tissues, tests, and spines contain polyunsaturated fatty acids, carotenoids, and a class of small polyphenols, called polyhydroxynaphthoquinones (PHNQ). PHNQ, due to their polyhydroxylated quinonoid nature, show remarkable pharmacologic effects, and have high economic significance and widespread application in several cosmetic and pharmaceuticals applications. A green extraction strategy aimed to obtain compounds of interest from the wastes of sea urchins was developed. The core strategy was the supercritical CO2 technique, characterized by low environmental impacts. Fatty acids and carotenoids were successfully and selectively extracted and identified depending on the physical parameters of the supercritical CO2 extraction. Finally, the exhausted powder was extracted by solvent-based procedures to yield PHNQ. The presence of Spinochrome A and Spinochrome B was confirmed and extracts were characterized by a remarkably high antioxidant activity, measured through the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. Overall, the selective and successive extraction methods were validated for the valorization of waste from sea urchins, demonstrating the feasibility of the techniques targeting added-value compounds.

scholarly journals Sibling Bald Sea Urchin Disease affecting the edible Paracentrotus lividus (Echinodermata: Echinoidea) in Sardinia, Italy

2019 ◽  
Author(s):  
Daniele Grech ◽  
Ivan Guala ◽  
Simone Farina
Keyword(s):  
Mediterranean Sea ◽  
Infection Rate ◽  
Sea Urchin ◽  
Environmental Changes ◽  
Sea Urchins ◽  
Paracentrotus Lividus ◽  
Pathogen Transmission ◽  
Microbiological Analysis ◽  
Genetic Population ◽  
Sampling Campaign

Different species of echinoids and bivalves are suffering infectious diseases as the effect of ocean warming. In Sardinia (Western Mediterranean Sea) the keystone sea urchin species Paracentrotus lividus (Lamarck 1816) is widely appreciated as edible resource. Recently, a number of individuals were found to be infected by a no specified bacterial morphologically matching to a “bald sea urchin disease” (Fig. 1). In February 2019, a sampling campaign took place in two locations in the West and East Coast, inside and in proximity of local Marine Protected Areas. Field samplings were approved by the Regione Autonoma Sardegna (Fishing License for scientific purposes n.310/AP SCIE/N.1 10/01/2019). Samplings were carried out at the end of February 2019, when water temperature was 13°C. For each sampled site we performed two replicates of fast 50 m belt transects to estimate the infection rate as the total individuals infected on the total counted. The estimated infection rate was around 5% in both of sampled locations. A higher level of preyed sea urchins was observed, compared to natural predatory level previously observed in all the surveyed sites. Moreover, an unusual amount of dead sea urchins has been observed stranded on the storm berm, neighbouring one of the sampled sites. Microbiological analysis puts in evidence bacterial infection as the potential causal agent that could be temperature-related. Previous mass mortalities of sea urchins due to this infection were reported in the northwestern Mediterranean Sea in the past, where populations of shallow waters sharply declined until 75% during the summer period. A number of papers argued global warming might be linked to the occurrence of catastrophic events in the Mediterranean Sea, which could alter the host/pathogen range and modify pathogen transmission rates. Thus, the spread of the infection could cause important consequences at genetic, population, community and ecosystem level. In the study area, it seems already evident how predatory pressure on populations sampled was increased probably due to the lowering of the natural defences of the sea urchin preys as consequence of the infection. Accordingly, the outbreak of this infection probably related with environmental changes could determine important effects on trophic interactions and generating unpredictable cascading effects. In this area, an increasing of the sea urchin disease and related mortality is expected in the next months with the temperature increasing. A long-term monitoring across the summer season will be crucial to understand the extent and magnitude of the phenomenon as its implications.

scholarly journals Interspecific Analysis of Sea Urchin Adhesive Composition Emphasizes Variability of Glycans Conjugated With Putative Adhesive Proteins

2021 ◽  
Vol 8 ◽  
Author(s):  
Lisa Gaspar ◽  
Patrick Flammang ◽  
Ricardo José ◽  
Ricardo Luis ◽  
Patrício Ramalhosa ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Secretory Granules ◽  
Paracentrotus Lividus ◽  
Single Species ◽  
Lectin Histochemistry ◽  
Additional Species ◽  
Adhesive Organs ◽  
Adhesive Proteins ◽  
Tube Feet

Sea urchins possess specialized adhesive organs, tube feet. Although initially believed to function as suckers, it is currently accepted that they rely on adhesive and de-adhesive secretions to attach and detach repeatedly from the substrate. Given the biotechnological potential of their strong reversible adhesive, sea urchins are under investigation to identify the protein and glycan molecules responsible for its surface coupling, cohesion and polymerization properties. However, this characterization has only focused on a single species, Paracentrotus lividus. To provide a broader insight into sea urchins adhesion, a comparative study was performed using four species belonging to different taxa and habitats: Diadema africanum, Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis. Their tube feet external morphology and histology was studied, together with the ultrastructure of their adhesive secretory granules. In addition, one antibody and five lectins were used on tube foot histological sections and extracts, and on adhesive footprints to detect the presence of adhesion-related (glyco)proteins like those present in P. lividus in other species. Results confirmed that the antibody raised against P. lividus Nectin labels the adhesive organs and footprints in all species. This result was further confirmed by a bioinformatic analysis of Nectin-like sequences in ten additional species, increasing the comparison to seven families and three orders. The five tested lectins (GSL II, WGA, STL, LEL, and SBA) demonstrated that there is high interspecific variability of the glycans involved in sea urchin adhesion. However, there seems to be more conservation among taxonomically closer species, like P. lividus and S. granularis. In these species, lectin histochemistry and lectin blots indicated the presence of high molecular weight putative adhesive glycoproteins bearing N-acetylglucosamine residues in the form of chitobiose in the adhesive epidermis and footprints. Our results emphasize a high selective pressure for conservation of functional domains in large putative cohesive proteins and highlight the importance of glycosylation in sea urchin adhesion with indications of taxonomy-related conservation of the conjugated glycans.

scholarly journals The challenge of managing the commercial harvesting of the sea urchin Paracentrotus lividus: advanced approaches are required

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10093
Author(s):  
Simone Farina ◽  
Maura Baroli ◽  
Roberto Brundu ◽  
Alessandro Conforti ◽  
Andrea Cucco ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Paracentrotus Lividus ◽  
Current Speed ◽  
Predatory Fish ◽  
Bottom Current ◽  
Environmental Constraints ◽  
Calcareous Rock ◽  
Commercial Size

Sea urchins act as a keystone herbivore in marine coastal ecosystems, regulating macrophyte density, which offers refuge for multiple species. In the Mediterranean Sea, both the sea urchin Paracentrotus lividus and fish preying on it are highly valuable target species for artisanal fisheries. As a consequence of the interactions between fish, sea urchins and macrophyte, fishing leads to trophic disorders with detrimental consequences for biodiversity and fisheries. In Sardinia (Western Mediterranean Sea), regulations for sea urchin harvesting have been in place since the mid 90s. However, given the important ecological role of P. lividus, the single-species fishery management may fail to take into account important ecosystem interactions. Hence, a deeper understanding of population dynamics, their dependance on environmental constraints and multispecies interactions may help to achieve long-term sustainable use of this resource. This work aims to highlight how sea urchin population structure varies spatially in relation to local environmental constraints and species interactions, with implications for their management. The study area (Sinis Peninsula, West Sardinia, Italy) that includes a Marine Reserve was divided into five sectors. These display combinations of the environmental constraints influencing sea urchin population dynamics, namely type of habitat (calcareous rock, granite, basalt, patchy and continuous meadows of Posidonia oceanica), average bottom current speed and predatory fish abundance. Size-frequency distribution of sea urchins under commercial size (<5 cm diameter size) assessed during the period from 2004 to 2007, before the population collapse in 2010, were compared for sectors and types of habitat. Specific correlations between recruits (0–1 cm diameter size) and bottom current speeds and between middle-sized sea urchins (2–5 cm diameter size) and predatory fish abundance were assessed. Parameters representing habitat spatial configuration (patch density, perimeter-to-area ratio, mean patch size, largest patch index, interspersion/juxtaposition index) were calculated and their influence on sea urchin density assessed. The density of sea urchins under commercial size was significantly higher in calcareous rock and was positively and significantly influenced by the density and average size of the rocky habitat patches. Recruits were significantly abundant in rocky habitats, while they were almost absent in P. oceanica meadows. The density of middle-sized sea urchins was more abundant in calcareous rock than in basalt, granite or P. oceanica. High densities of recruits resulted significantly correlated to low values of average bottom current speed, while a negative trend between the abundance of middle-sized sea urchins and predatory fish was found. Our results point out the need to account for the environmental constraints influencing local sea urchin density in fisheries management.

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