Sea Urchin Echinometra Lucunter Research Articles

Toxic Effects of Biogenic and Synthesized Silver Nanoparticles on Sea Urchin Echinometra lucunter Embryos.

Due to their broad-spectrum antimicrobial action and ease of synthesis, silver nanoparticles (AgNP) are one of the most widely used nanomaterials in different industrial and ecological areas. AgNP are released into marine ecosystems, nevertheless, their ecotoxicological effects have been overlooked. In this study, we evaluated the toxic effects of biogenic and synthesized AgNP (AgNPIBCLP11 and AgNPSINT) on sea urchin Echinometra lucunter embryos and compared them with the metal precursor silver nitrate (AgNO3). Fertilized eggs were exposed to five concentrations of the test compounds and a negative control for 48h under controlled conditions. The IC50-48h of AgNPIBCLP11, AgNPSINT and AgNO3 were 0.31, 4.095, and 0.01µg L-1, evidencing that both AgNP are less toxic than AgNO3, and that AgNPSINT is less toxic than the AgNPIBCLP11. Toxicity to E. lucunter embryos could be explained by the fact that Ag affects DNA replication and induces the formation of pores in the cellular wall, leading to apoptosis.

Ecotoxicological effects of personal care products on the sea urchin Echinometra lucunter

Personal care products (PCPs) are increasingly studied worldwide to understand better their ecotoxicological effects on different aquatic species. However, studies assessing their ecotoxicological effects on tropical marine aquatic organisms are still scarce. To address this information gap, this study aimed to evaluate the acute and chronic toxicity of three PCPs, methylparaben (MP), propylparaben (PP) and butylhydroxytoluene (BHT), on the tropical sea urchin Echinometra lucunter. The procedures were based on the protocols established by the US Environmental Protection Agency and the Brazilian national standard (ABNT NBR 15350). Predictive computational tools (Opera Qsar and Vega Qsar) were used to evaluate the persistence/biodegradability, bioaccumulation and mobility of PCPs. Acute exposure results showed the following ranking of toxicity: BHT (IC50 = 38.14 mg/l) > PP (IC50 = 73.20 mg/l) > MP (IC50 = 74.47 mg/l). Chronic toxicity tests indicated that BHT presented the lowest IC50 (6.85 mg/l), followed by PP (IC50 = 15.57 mg/l) and MP (IC50 = 20.09 mg/l). Additionally, in silico predictions support the findings related to the potential risks of these PCPs in aquatic ecosystems. The data obtained in this study can support future analyses of environmental risk concerning PCPs and support the establishment of concentration limits in relevant legislation.

Waterborne Toxicity to Neotropical Invertebrates and Hazard of Cigarette Butt Leachates in Marine Environments.

Cigarette butts (CBs) are the most common type of beach litter worldwide and contain a complex mixture of chemicals. Given the recent interest in this emerging problem, it is important to assess the toxicity of CB leachates to a range of species from different regions, sensitivities, and ecological traits. We evaluated the waterborne toxicity of smoked CB to tropical invertebrates. Leachates were prepared in the laboratory and characterized for trace elements (Mn, Fe, Co, Ni, Cu, Zn, As, Cd, and Pb), ammonia nitrogen, and polycyclic aromatic hydrocarbons. Then a set of toxicity tests with marine invertebrates was performed as follows: the brine shrimp Artemia sp. (nontoxic); the amphipod Tiburonella viscana (median lethal concentration [LC50] of 0.038 CB/L); the tanaid Monokalliapseudes schubarti (LC50 of 0.126 CB/L); the copepods Tisbe biminiensis (median effect concentration [EC50] of 0.038 CB/L) and Nitokra sp. (EC50 of 0.009 CB/L); pluteus stage larvae of the sea urchin Echinometra lucunter (EC50 of 0.152 CB/L); the sand dollar Mellita quinquiesperforata (EC50 of 0.054 CB/L); and D-stage larvae of the mussel Perna perna (EC50 of 0.005 CB/L). The predicted no-effect concentration was estimated using species sensitivity distribution, producing a 5th percentile hazard concentration of 0.015 CB/L. This preliminary threshold allowed us to estimate the potential impact of a single CB to 67 L of seawater via leaching, contributing to the advancement of knowledge regarding the contamination, toxicity, and ecological risks of cigarette waste. Environ Toxicol Chem 2024;43:374-384. © 2023 SETAC.

Morphological and physiological impairments in algae-infested sea urchins of the species Echinometra lucunter (Echinodermata)

Epibiotic species, which may be characterized as those living attached to the outer surface of a host (the basibiont), have hardly been described as living on echinoderms, probably because the outer surface of these latter is covered by the epidermis. Studies analyzing epibiotic associations usually focus on taxonomical and ecological aspects, while a physiological approach – even being able to reveal the costs and/or benefits of such interactions – has been neglected. Here, we not only report an unprecedented algal epibiotic association for the sea urchin Echinometra lucunter, but we mainly investigate how such kind of interaction could affect spine morphology and basibiont physiology, and consequently its health. To achieve this, we compared the spine morphology of Echinometra lucunter with and without algal infestation using histology, microcomputed tomography, and SEM. Immunological parameters, such as the number, proportion, and viability of the coelomocytes were evaluated. Algal-infested individuals showed a higher number and lower viability of coelomocytes, as well as an altered proportion of phagocytes and red spherulocytes. Additionally, spine stroma and stereom were severely degraded in comparison to non-infested ones. Thus, our findings suggest that algal-infested E. lucunter may be less efficient in carrying out routine activities than non-infested individuals, such as physical protection, anchorage, or coping with immune challenges.

Water and sediment toxicity and hazard assessment of DCOIT towards neotropical marine organisms

DCOIT is an effective antifouling biocide, which presence in the environment and toxicity towards non-target species has been generating great concern. This study evaluated the waterborne toxicity of DCOIT on marine invertebrates (i.e., survival of brine shrimp Artemia sp., larval development of the sea urchin Echinometra lucunter and the mussel Perna perna), as well as DCOIT-spiked-sediment toxicity on the fecundity rate of the copepod Nitrocra sp. And the mortality of the amphipod Tiburonella viscana. The data outcomes were used to calculate environmental hazards and risks, which were compared to their corresponding values obtained from temperate regions. Waterborne toxicity can be summarized as follows: Artemia sp. (LC50–48h = 163 (135–169) μg/L), E. lucunter (EC50–36h = 33.9 (17–65) μg/L), and P. perna (EC50–48h = 8.3 (7–9) μg/L). For whole-sediment toxicity, metrics were calculated for T. viscana (LC50-10d = 0.5 (0.1–2.6) μg/g) and Nitrocra sp, (EC50-10d = 200 (10–480) μg/kg). The DCOIT hazard was assessed for both tropical and non-tropical pelagic organisms. The predicted no-effect concentration (PNEC) for tropical species (0.19 μg/L) was 1.7-fold lower than that for non-tropical organisms (0.34 μg/L). In whole-sediment exposures, DCOIT presented a PNEC of 0.97 μg/kg, and the risk quotients (RQs) were >1 for areas with constant input of DCOIT such as ports ship/boatyards, marinas, and maritime traffic zones of Korea, Japan, Spain, Malaysia, Indonesia, Vietnam, and Brazil. The presented data are important for supporting the establishment of policies and regulations for booster biocides worldwide.

Compound Extreme Events Induce Rapid Mortality in a Tropical Sea Urchin.

AbstractThe frequency, magnitude, and duration of marine heatwaves and deoxygenation events are increasing globally. Recent research suggests that their co-occurrence is more common than previously thought and that their combination can have rapid, dire biological impacts. We used the sea urchin Echinometra lucunter to determine whether mortality occurs faster when deoxygenation events are combined with extreme heating (compound events), compared to deoxygenation events alone. We also tested whether prior exposure to local heatwave conditions accentuates the impacts of compound events. Animals were first exposed for five days to either ambient temperature (28 °C) or a warmer temperature that met the minimum criteria for a local heatwave (30.5 °C). Animals were then exposed to hypoxia, defined as oxygen levels 35% below their average critical oxygen limit, combined with ambient or extreme field temperatures (28 °C, 32 °C). Subsets of animals were removed from the hypoxic treatments every 3 hours for 24 hours to determine how long they could survive. Prior exposure to heatwave conditions did not help or hinder survival under hypoxic conditions, and animals exposed to hypoxia under ambient temperatures experienced little mortality. However, when hypoxia was coupled with extreme temperatures (32 °C), 55% of the animals died within 24 hours. On the reefs at our Panama study site, we found that extreme hypoxic conditions only ever occurred during marine heatwave events, with four compound events occurring in 2018. These results show that short durations (∼1 day) of compound events can be catastrophic and that increases in their duration will severely threaten sea urchin populations.

Biological effects caused by the pharmaceuticals losartan and diclofenac, and their mixture on marine organisms

Studies show that pharmaceuticals are being taken to the oceans causing contamination and toxicity to aquatic organisms. The present study evaluated the survival rate of microcrustaceans Artemia salina and the abnormal embryo larval development rate of sea urchin Echinometra lucunter, after exposure to the drug Losartan, an antihypertensive drug, and the drug Diclofenac, a non-steroidal antiinflammatory drug (NSAID), in addition to its mixture among its compounds. Acute toxicity tests were carried out using A. salina and chronic toxicity tests were carried out using embryos of E. lucunter. Organisms were exposed to isolated pharmaceuticals at different concentrations: 1.56 mg.L-1; 3.12 mg.L-1; 6.25 mg.L-1; 12.5 mg.L-1; 25 mg.L-1; 50 mg.L-1 and 100 mg.L-1, and their mixture at concentrations: 0.78 mg.L-1; 1.56 mg.L-1; 3.12 mg.L-1; 6.25mg.L-1; 12.5 mg.L-1; 25 mg.L-1 and 50 mg.L-1. The result obtained in the acute toxicity test did not show toxicity to A. salina. Chronic toxicity test with losartan did not show toxicity to sea urchin embryos, in contrast, the isolated diclofenac showed chronic toxicity at NOEC = 6.25 mg.L-1, LOEC = 12.5 mg.L-1 and IC50 = 62.15 mg.L-1. The result obtained with embryos exposed to the mixture of losartan and diclofenac, showed chronic toxicity at NOEC= 6.25 mg.L-1 and LOEC= 12.5 mg.L-1, not being possible to show the IC50. Our results suggest that the mixture of the two studied pharmaceuticals might decrease the toxicity, since diclofenac showed higher chronic toxicity to E. lucunter embryo larval development when it was isolated than when it was mixed with losartan. However, there is a need for further ecotoxicological studies that clarify the pathways of these pharmaceuticals in non-target organisms.

Silver-titanium polymeric nanocomposite non ecotoxic with bactericide activity.

In view of the intense interest in applications of silver nanoparticles in products for the medical field and in food preservation packaging due to their antimicrobial properties, the ecotoxicology of silver nanocomposites was evaluated in films. Test with the sea urchin Echinometra lucunter, to evaluate embryonic development and contamination by the action of silver and titanium nanoparticles in polyethylene nanocomposite films presents new results. The silver nanoparticle’s stability in polymeric materials can be enhanced by adding carriers, such as titanium dioxide and montmorillonite clay (MMT) without to producing one unfriendly material. For this research, low-density polyethylene (LDPE)/linear low-density polyethylene (LLDPE) were used processed in a twin-screw extruder, followed by gamma irradiation with 25 kGy and characterized by ecotoxicology assays, field emission scanning electron microscopy (FESEM), scanning electron microscopy and energy dispersive spectroscopy (SEM–EDX), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), Raman spectroscopy (SERS) and mechanical properties. The antibacterial properties of the LDPE films were investigated against Escherichia coli and Staphylococcus aureus. The gamma irradiation had an important effect in the synthesis of silver nanoparticles resulting in bactericidal activity and the death of 100% of the tested bacteria. The evaluation of the environment was considered with the ecotoxicological investigation carried out. The results indicated that the polymeric films with silver nanoparticles and TiO2 do not contaminate the environment and neither interfere with the larval development of Echinometra lucunter. The obtained materials can be used in various applications with antimicrobial properties.Graphical

Toxicity of Antiretrovirals on the Sea Urchin Echinometra lucunter and Its Predicted Environmental Concentration in Seawater from Santos Bay (Brazilian Coastal Zone)

Antiretrovirals (ARVs) have been detected in aquatic ecosystems throughout the world; however, studies focused on assessing their ecotoxicological effects on marine aquatic organisms are still rare. In the present study, the predicted environmental concentration (PEC) of 13 ARVs was estimated for surface seawater from Santos Bay, Brazil, according to the European Medicines Agency (EMEA) guidelines. The results indicated that all ARVs need to be assessed for their ecological effects, considering that they all exceeded the EMEA guideline limits (PEC > 0.01 µg L−1). In this sense, three ARVs (namely atazanavir, nevirapine and efavirenz) were selected for the acute and chronic tests with sea urchin (Echinometra lucunter). Furthermore, the Environmental Risk Assessment (ERA) for these three ARVs was also performed by calculating the risk quotient. The acute and chronic toxicity results showed inhibitory concentrations (IC) for the fertilization (IC50; 1 h; range: 11.46–84.61 mg L−1) and for the embryo–larval development (IC50; 42 h; range: 0.52–0.97 mg L−1) of the sea urchin, respectively. Moreover, the ERA showed that these three ARVs are potentially hazardous for aquatic life in Santos Bay, raising concerns about the continuous introduction of ARVs in aquatic ecosystems. The data presented may contribute to the provision of subsidies for the development of monitoring public policies that aim to reduce the introduction of ARVs into the aquatic environment.

Fluoxetine can make marine organisms unhappy: a study on the sub-lethal effects on marine invertebrates

The environmental effects caused by selective serotonin reuptake inhibitor drugs have been investigated for marine organisms and coastal ecosystems but are scarce in neotropical organisms. This investigation aimed to evaluate the sublethal effects of fluoxetine on the embryonic development of the sea urchin Echinometra lucunter and the survival and swimming behavior of the brine shrimp Artemia sp. The organisms were exposed to four different concentrations of fluoxetine (30, 300, 3000 and 30000 ng L-1) and to a negative control (filtered seawater), following the respective standard testing protocols. We verified a significant reduction of the embryos development to pluteus larvae, starting from 3000 ng L-1 (54.0±10.9% normal larvae), in comparison with the controls (83.5±3.1%). The non-observed effect concentration (NOEC) was estimated at 300 ng L-1, and the lowest observed effect concentration (LOEC) was 3000 ng L-1. In the behavior tests with Artemia sp, no significant adverse effects were reported for mobility, swimming speed and inactivity time. These results show that Fluoxetine can interfere on the development of species like the sea urchin E. lucunter, but short term exposure did not affected the swimming behavior of the brine shrimp Artemia sp. Fluoxetine presents thus a potential to affect marine biota and disrupt the equilibrium of the coastal ecosystems.

Impact on Fertility Rate and Embryo-Larval Development Due to the Association Acidification, Ocean Warming and Lead Contamination of a Sea Urchin Echinometra lucunter (Echinodermata: Echinoidea).

Ocean warming and acidification can cause deleterious effects on marine biota, which may be potentialized when associated with metal pollution. Thus, the aim of this work was to evaluate the effects of pH decrease, temperature increase and lead contamination on fertility rate and embryo-larval development of Echinometra lucunter. Gametes and embryos were exposed at pH 8.2 (control) and 7.5; at 26°C (control) and 28°C; and at lead concentrations of 0 (control), 125, 250 and 500μg/L. These conditions were tested individually and in combination. The fertilization rate of E. lucunter was only significantly reduced in the treatments where temperature was increased and in the treatment where pH decreased. However, the development rate of the pluteus larvae was significantly affected in the majority of treatments: metal contamination in the higher concentration; decreased pH in all metal concentrations; increased temperature in the highest metal concentration; decreased pH and increased temperature and all variables combined, which is decreased pH, increased temperature and metal contamination in relation to the control group (C). The development test was shown to be more sensitive than the fertilization test in all the studied scenarios. In general, the present study suggests that pH decrease, temperature increase and metal pollution may have a significant impact on E. lucunter reproductive cycle.

Isolation and characterization of 17 polymorphic microsatellite loci for a sea urchin (Echinometra lucunter: Echinometridae)

As a first step to establish the genetic structure of the sea urchin Echinometra lucunter lucunter throughout the Caribbean Sea, 26 microsatellite loci were isolated using Illumina paired-end sequencing, Next Generation Sequencing (NGS). We successfully optimized 17 loci for genotyping and the variation tested for 23 individuals from the Caribbean Sea and Tropical Eastern Atlantic Ocean. The allele number per locus (Na) ranged from four to 24, the observed heterozygosity (Ho) from 0.682 to 1, and the expected heterozygosity (He) from 0.609 to 0.9304. We detected no linkage disequilibrium between pairs of loci. These microsatellites will be used for the first time to detect the influence of marine barriers to genetic flow in the sea urchin E. lucunter lucunter throughout the Caribbean Sea. These new validated markers will be essential for current conservation and connectivity studies across the Caribbean Sea and the Atlantic Ocean.

The success of the fertilization and early larval development of the tropical sea urchin Echinometra lucunter (Echinodermata: Echinoidea) is affected by the pH decrease and temperature increase

The decrease in the pH of oceans and the increase in their temperature are the two main problems observed in the marine ecosystems due to the increasing emission of CO2 in the atmosphere. Both conditions can affect the ecological processes of reproduction, recruitment and survival of the marine biota. Thus, the objective of the present study was to evaluate the effects of pH decrease and temperature increase of seawater on the fertilization success and embryo-larval development of a species of tropical sea urchin. For this purpose, fertilization success (gametes) and embryo-larval development rate were determined by exposing gametes and embryos to decreasing pH values (8.0 (control), 7.7, and 7.4) and increasing temperatures (26 (control), 28, 30, 34, and 38 °C). These conditions were tested associated with each other (in synergy). The gamete test was sensitive to all investigated scenarios, the fertilization success was significantly reduced in the conditions of increased temperature (28, 30, 34, and 38 °C) associated with the ideal pH (pH 8.0) and the conditions of reduced pH (pH 7.7, and 7.4), remaining unchanged only in the ideal condition (pH 8.0 + 26 °C). However, the embryo test displayed enhanced sensitivity in the scenarios of temperature increase (28, 30, 34, and 38 °C) associated with pH decrease conditions. A significantly reduction of 29%, 23% and 10% was observed in all tested pH values at 38 °C, when compared to the control group (80%, 79.5% and 63%, respectively). Therefore, the present study suggests that the occurrence of both scenarios may have a significant impact, in the coming years, on the population of Echinometra lucunter.

Spatial Abundance and Colour Morphotype Densities of the Rock-Boring Sea Urchin (Echinometra lucunter) at Two Different Habitats

The rock-boring sea urchin Echinometra lucunter is a common echinoderm found throughout the intertidal zone along the northeastern coast of, Toco, Trinidad. Sea urchin abundance, size distribution, and colour morphotypes at two sites: Pequelle Bay (SB) and Grande L’Anse (GA) were quantified using 1 m2 quadrats, accessible during extreme low tides, and in two environments, notably low and high wave action. Percent coverage of cnidarian and macroalgae were estimated in each quadrat. Sea urchin densities were 9.9–17.8 urchins/m2 in high wave action, and 25.2–60.7 urchins/m2 in low wave action environments. Size (measured as maximum sea urchin diameter) are highest between 21 and 50 mm for both black and red colour morphotypes. Black colour morphs were significantly larger than red morphs (ANOVA, F2, 175 = 5.55, p < 0.05). Sea urchins at low energy environments were significantly larger than those found in high energy environments for all years (p < 0.05). Mean hard coral, soft coral, and macroalgae cover did not show any relationship with habitat type or urchin densities. Although sea urchin abundance and distribution were variable, larger urchins were more likely to be found in low wave action environments, and smaller urchins were mostly found in the open, and exposed to high wave action.

Disappearance of the rock-boring urchin Echinometra lucunter (Echinoidea: Echinodermata) in urchin-burrows along an extensive rock wall of Grotto Beach, San Salvador, Bahamas

The disappearance of a population of the rock-boring sea urchin Echinometra lucunter is documented along a vertical rock wall off Grotto Beach on the island of San Salvador, Bahamas. 9,960 urchin burrows were counted along a 332 m × 1 m length of the rock wall. Only one E. lucunter was found to occur per 664 available urchin holes. Likely factors that may have contributed to the disappearance of urchins include circulation patterns and elevated temperature.

Metal pollution in surface sediments from Rodrigo de Freitas Lagoon (Rio de Janeiro, Brazil): Toxic effects on marine organisms

The Rodrigo de Freitas Lagoon (RFL - Rio de Janeiro, RJ, Brazil) is a highly polluted and eutrophic lacustrine system, which has been often used for the practice of aquatic sports, including during the 2016 Summer Olympic Games. This study proposes the evaluation of metal concentrations in surface sediments from the RFL before and after urban interventions performed for the 2016 Olympics, as well as their toxicity to the benthic amphipod Tiburonella viscana and embryos of the sea-urchin Echinometra lucunter. Metal concentrations determined in 2017 were significantly higher than those obtained in 2015 (especially Cu, Cd and Ni), suggesting that the interventions performed to fulfill the requirements of the Olympics increased metal contents in sediments. The sediments from the northern sector of the RFL were muddier, more organically enriched, exhibited higher metal concentrations and were more toxic to T. viscana when compared to the sediments collected in the southern sector. This fact is particularly important since the practice of sports, including during the 2016 Olympics, has been preferably performed in the northern sector. Metal distribution was strongly correlated with organic matter and mud contents. The toxicity to E. lucunter embryos was high for both northern and southern sediments; most of the samples led to 100% lack or abnormal embryonic development. The integration of physical, chemical and ecotoxicological data indicates that the mortality to T. viscana was correlated with metal contents, whereas the toxicity to E. lucunter was apparently related to the release of ammonia from the sediment to water column. Finally, high metal concentrations and the toxicity to aquatic organisms evidence the ecological risks to the biota from RFL.

Effects of the water-soluble fraction of diesel oil (WSD) on the fertilization and development of a sea urchin (Echinometra lucunter)

Considering the high number of accidents with diesel oil spills occurring in the marine ecosystem, toxicity tests aimed at assessing the effects of this pollutant on biota are necessary and urgent. Thus, the present study aimed to evaluate the toxicity of the soluble fraction of diesel oil (WSD) in the fertilization success of gametes and pluteu larvae of the sea urchin Echinometra lucunter. To do this, gametes and embryos were exposed to concentrations of 0% (control group), 0.5%, 1.5% and 2.5% of WSD. The fertilization success of exposed gametes and embryos were reduced significantly when compared to the control group in all tested concentrations. With this finding, it is evident that diesel oil can be significantly promoted in the early and adult life stages of a particular organism, and a better way of evaluating this toxicity is through the analysis of contaminant effects throughout the reproductive cycle of a species.

Declines in plant palatability from polar to tropical latitudes depend on herbivore and plant identity.

Long-standing theory predicts that the intensity of consumer-prey interactions declines with increasing latitude, yet for plant-herbivore interactions, latitudinal changes in herbivory rates and plant palatability have received variable support. The topic is of growing interest given that lower-latitude species are moving poleward at an accelerating rate due to climate change, and predicting local interactions will depend partly on whether latitudinal gradients occur in these critical biotic interactions. Here, we assayed the palatability of 50 seaweeds collected from polar (Antarctica), temperate (northeastern Pacific; California), and tropical (central Pacific; Fiji) locations to two herbivores native to the tropical and subtropical Atlantic, the generalist crab Mithraculus sculptus and sea urchin Echinometra lucunter. Red seaweeds (Rhodophyta) of polar and temperate origin were more readily consumed by urchins than were tropical reds. The decline in palatability with decreasing latitude is explained by shifts in tissue organic content along with the quantity and quality of secondary metabolites, degree of calcification or both. We detected no latitudinal shift in palatability of red seaweeds to crabs, nor any latitudinal shifts in palatability of brown seaweeds (Phaeophyta) to either crabs or urchins. Our results suggest that evolutionary pressure from tropical herbivores favored red seaweeds with lower palatability, either through the production of greater levels of chemical defenses, calcification, or both. Moreover, our results tentatively suggest that the "tropicalization" of temperate habitats is facilitated by the migration of tropical herbivores into temperate areas dominated by weakly defended and more nutritious foods, and that the removal of these competing seaweeds may facilitate the invasion of better-defended tropical seaweeds.

Essential oil of Lippia alba as a sedative and anesthetic for the sea urchin Echinometra lucunter (Linnaeus, 1758)

The sea urchin, Echinometra lucunter, is consumed in restaurants in Europe and Asia for high prices. This study evaluated the use of the essential oil of Lippia alba (EOL) as a sedative and anesthetic in this sea urchin. Different EOL concentrations were tested (50, 100 and 150 μL L−1), in addition to a group that received ethanol and a control group. After the anesthesia and recovery from the different treatments, the coelomic fluid, gonads and intestine were collected for the analysis of oxidative stress parameters. The highest concentration tested (150 μL L−1) was determined to be the optimal concentration for anesthesia. Results suggest that EOL improved the response to oxidative stress, since a lower level of thiobarbituric acid-reactive substances and greater superoxide dismutase and catalase activities were observed in the coelomic fluid and E. lucunter gonads, making the EOL a promising anesthetic for sea urchins.

Effects of salinity on the immune system cells of the tropical sea urchin Echinometra lucunter

Human activities have caused climate changes and altered the salinity of the oceans. The reduction of the salinity is one of the factors that may limit the distribution and the survival of marine organisms. Coelomocytes are the immune system cells of the echinoderms and have been studied as biomarkers of stress. The aim of the present study was to investigate the effect of the salinity on the immune system cells of the tropical sea urchin Echinometra lucunter. Animals were collected in João Pessoa coast (Brazilian Northeast). Animals or coelomocytes were exposed to different salinities (25, 35, 45) from 4 to 24h. Phagocytic parameters, production of reactive oxygen species (ROS), mitochondrial activity and ABC transporter activity were analyzed. The phagocytic parameters did not change when animals or cells were exposed to a salinity of 25 or 45 in any time intervals monitored. However, the coelomocytes concentration increased when animals were exposed to the lower salinity. The levels of ROS were higher when cells were incubated at a salinity of 25 but lower when cells were kept at a salinity of 45. It was observed the loss of the mitochondrial inner membrane potential when coelomocytes were incubated at a salinity of 45. The activity of ABC transporters decreased when cells were incubated at the lowest salinity and increased when cells were incubated at the highest salinity tested. The present work shows that the immune system of the tropical sea urchins Ei lucunter tolerates salinity changes from 25 to 45, and suggests two cellular parameters (ROS levels and ABC transporters activity) as potential biomarkers for the monitoring of the impact of environmental salinity changes.