Tetrapygus niger pdf

The PLI was calculated and used to compare the pollution status of the sites. This index is used to demonstrate the availability of metals in the water column and, therefore, the status of coastal health. Depending on the values obtained for both factors i.

Prior to this, descriptive analyses were performed to evaluate the normality and homogeneity of variance. Three replicates were performed for both the algal tissue and sea urchin gonads.

All the analyses were performed in R [59]. For both the toxicity indices and factors, statistical analyses were not performed; rather, the ratios between the treatments and matrices were compared. Results In Macrocystis pyrifera tissues, the concentrations of most analyzed PAHs were under the detection limit, except for naphthalene NAF , whose concentrations were above its detection limit 0.

For the PAH concentrations in the T. Figure 3. Each treatment comprised three replicates. Since the PAH concentrations in the T. Toxics , 9, 8 of 16 In both the M. Regarding Cu concentration in the HIZ samples, the measured concentrations were 0. For As, the measured concentrations were 1. Finally, the concentrations of Cd in the algal tissue were 0. Figure 4. Notably, the pattern of Pb concentrations in both sites differed from those of the previously mentioned metals.

Concentrations of 1. However, these factors could not be calculated in the NIZ for Cu and As since their concentrations were under the detection limit. The largest transfer recorded to T. Toxics , 9, 9 of 16 Table 1. Index Treatment Water Column M. This polluted condition is similar to those reported by other studies, such as [60], who studied the concentrations of different metals in the Gulf of Chabahar, where a landing port is located.

In this context, the differences in the impact of the zones are discussed below. As such, given the absence of other PAHs in the tissue of Macrocystis pyrifera, the high concentrations of naphthalene NAF alone are probably not indicative of the exclusive presence of NAF in the seawater. The NAF levels in M. In that study, the same compounds were analyzed in algal tissue, and whereas the concentrations of the other PAHs were above the detection limit, the concentrations of NAF in M.

Algarrobo NIZ shows no indication of an environmental impact due to pollutants from industrial activities, but the high level of NAF in M. Nonetheless, the high concentration of NAF found in M. As previously established [63], small molecules such as NAF can permeate phospholipid membranes, with diverse naphthalene derivatives exhibiting different preferences for the hydrophilic or hydrophobic domain of phospholipids. This mechanism may explain the high NAF levels observed in M.

Conversely, just as some hydrocarbons can be syn- thesized by marine organisms, PAHs can also be degraded, as was determined in Chlorella sorokiniana and Ulva fasciata [64]. This process is the result of enzymatic activity in the presence of molecular oxygen, which catabolizes the benzene rings that are characteristic of these compounds [65,66]. The authors suggested that this portion was metabolized by the algae, as described in other studies [68,69].

The high levels of NAF in algal tissue may be because M. In addition, the results of this study do not provide evidence of the transfer of NAF through the food chain that is, through M.

For the sea urchin T. However, again, this does not mean that these pollutants are not being ingested by the herbivore, as they may also be metabolized. It was reported that both fish and other marine organisms can metabolize PAHs through a group of enzymes dedicated to the oxygenation of these compounds and that the cytochrome P monooxygenases Ps of fishes are able to oxygenate PAHs [71].

When the crab Sylla serrata was directly exposed to sublethal concentrations of NAF, its enzymatic activity in the hemolymph was found to increase, which indicates that its mechanisms of tolerance to NAF occur through its metabolization [72]. Nonetheless, the detection limit for NAF 0. Further research in T. Alternatively, assuming an absence of PAHs in T. However, more information is required to determine the possible events or mechanisms that explain the low detected levels of NAF in T.

Although the negative effects of PAHs have been demonstrated in sea urchins, few studies have examined the bioaccumulation and dynamics of pollutant transfer from their diet [75,76]. It is worth mentioning that due to the physicochemical properties of PAHs, they can precipitate and remain in the solid fraction according to their structural differences [80,81]; then, an analysis of the marine sediments must be considered in future studies. In our case, for most PAHs the concentration measured in the alga and the sea urchin were below the instrumental detection limit, which could have resulted from the precipitation of these compounds in the marine sediments.

Toxics , 9, 11 of 16 4. One study [37] demonstrated that the concentrations of HMs in M. Additionally, heavy metal concentrations in the seawater and sediment have risen considerably in the HIZ during the last two decades, probably extending its pollution load to northern coastal sites according to Oyarzo-Miranda [23].

As in the case of NAF in M. In this sense, to better understand this phenomenon, it is necessary to conduct further research on the combined effects and the dynamic uptake of these metals when they co-occur. Some metals, such as Pb, are not only derived from industrial activity but also domestic and transport sources, and the main form of entry of Pb into the water is through the atmosphere as particulate matter [82].

This means that the distribution of Pb along the coastline is ubiquitous, presenting focal points of higher pollution in the presence of human settlements [82,83], which also explains the important pollution load observed in the NIZ both for NAF in M.

This is further evidence of the chemical interaction between toxic elements and their possible effects on marine organisms. The heavy metals Cu, As, and Cd are characteristic pollutants in industrial zones, primarily resulting from mining activity and the burning of fossil fuels. Through metabolic mechanisms, algae can actively bioconcentrate metals at the intracellular level, but initially, rapid and passive adsorption occurs on their surfaces [86].

During the active phase, metal ions are transported through and toward the cytoplasm, a process which may accelerate upon combination with intracellular compounds such as glutathione [35,87], thus accumulating within the cell. The excess bioaccumulation of heavy metals in algae, as previously mentioned, induces the rapid accumulation of ROS, generating oxidative stress.

The accumulation of ROS above the upper limit of tolerance in the algal species may, in turn, damage macromolecules and cell structures [20,21], and the heavy metals may be transferred to herbivores, such as T. As a result, heavy metals generate direct and indirect effects on higher organisms in the food web.

Nonetheless, brown algae such as Dictyota kuntii possess diverse mechanisms to counteract metal excess, such as metal accumulation, the activation of antioxidant enzymes, and inducing the release of metal-binding compounds in their exudates [88].

Such mechanism may allow M. Given this feeding behavior, and according to the TTF of T. The concentrations of metals in sea urchin gonads increase during the feeding stage because of the greater ingestion of pollutants through its food. The individuals from Algarrobo NIZ had higher concentrations of Cd and Pb, which are transferred more easily through the food web in the absence of other metals. Therefore, compared to other pollutants e. Alternatively, the high accumulation of Cu compared to the relatively low accumulation of Cd in both M.

The results obtained in this research reflect not only an environmental but also a socio-environmental problem. The concentrations of heavy metals found in both the algal tissue and the gonads exceed the limits stipulated in Codex Alimentarius Norm , FAO for human and animal consumption.

In addition, the International Agency for Research on Cancer IARC assigned naphthalene to Group 2B—possibly carcinogenic to humans—because there is sufficient evidence for the carcinogenicity of this compound in experimental animals. Therefore, in organisms with eating behaviors similar to those of T. However, any conclusion regarding this requires further analysis, though should be considered with caution. Finally, it is worth mentioning that for both the calculation of the MPI and PLI, the data sets used regarding metals concentrations in the water column were those reported by previous studies.

This could have affected the magnitude of these pollution indices and of the interpretation of the bioconcentration of the pollutants in M.

Then, future studies in this zone will have to consider a synchronous measurement of HMs or PAHs both in the water column and in these two types of organisms to more strongly confirm the pollution patterns observed.

Nonetheless, neither the clear difference of the concentrations nor ecotoxicological indexes patterns of toxics between HIZ an NIZ should change in future studies. On the other hand, as pointed out by studies such as [96], heavy metals can be transported by airborne particles, which can be driven far away from their sites of emission. Accordingly, it would also be useful to investigate the heavy metals content in airborne particles from the Quintero Bay industrial and surrounding areas, to better define the sources of pollutants in the HIZ and the NIZ.

This difference in the level of pollution stems mainly from the higher concentrations of heavy metals and NAF in the seawater and biological matrices of the HIZ than NIZ. Nonetheless, as previously mentioned, the high bioaccu- mulation of Cd 1. In general, an order of increasing metal concentrations was verified in seawater, M. The former findings are important because these pollutants may have direct and indirect harmful effects on algae and their herbivores, as demonstrated previously for early developmental stages and adult individuals of kelps and sea urchin.

Toxics , 9, 13 of 16 Author Contributions: Conceptualization, N. All authors have read and agreed to the published version of the manuscript. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Derived data supporting the findings of this study are available from the corresponding author L. This involves detach- moved down to the bottom climbed up the sides of ment from the bottom, making it more likely to be the boulders once the sea stars were removed.

Phillips , found cifics under a strong unidirectional flow and ob- that the gastropods Acmaea spp. Finally, diving observations by et al. Dayton et al. Thus, detach- ple urchins often form grazing fronts at the edge of ment and use of water flow may be a common kelp beds or aggregate on algal debris that has been strategy used to limit predatory attacks.

About half of the predators that could aggregates on drift kelp Macrocystis pyrifera, and be identified during these trials were sea stars. It is thus unlikely that the micro- small urchins 20 to 30 mm without causing damage, distribution of T. Boulder tops are devoid of fleshy algae stars encountered during an extensive benthic sur- and any macroalgal debris present usually sinks to vey Gaymer showed that the most common depressions in the bottom.

The present study indicates helianthus. In their survey the sizes of urchins con- that this choice of microhabitat represents an adapta- sumed by M.

Occupying elevated surfaces might in- urchins. Although tethering undoubtedly reduces crease exposure to pelagic predators such as fish. In Chile, the abun- feeding on T. These included the because of overfishing Godoy et al. Thus, the blennid fish Scartichthys viridis, the gastropods decrease in fish predators may have led to increased Tegula atra and Crassilabrum crassilabrum, and her- numbers of urchins on elevated surfaces and an mit crabs Pagurus spp.

Bonaviri et al. In contrast H. Responses of T. Such studies would at the same time indicate helianthus; the urchin severs contact faster with M.

We are grateful to E. Harvey also helped in the field work. The paper was fur- en las comunidades submareales rocosas del norte de ther improved by comments from C. Dumont, H. Gud- Chile, proyecto Fondecyt Johnson, H. Feder, J. Qiu and 3 anony- Chile mous reviewers. Mar Environ Res yan lagoon. Lawrence Estuary, eastern Canada. Invest Strongylocentrotus purpuratus Stimpson. Mar can sun-star Heliaster helianthus. Fish algae throughout the Canarian Archipelago.

A reinterpre- the sea urchins Paracentrotus lividus and Arbacia lixula tation. Mar Ecol actions in Chilean subtidal communities: a review. Related Papers Responses of the black sea urchin Tetrapygus niger to its sea-star predators Heliaster helianthus and Meyenaster gelatinosus under field conditions By Carlos Gaymer.

Scales of detection and escape of the sea urchin Tetrapygus niger in interactions with the predatory sun star Heliaster helianthus By Tatiana Manzur. New body metrics to determine asteroid size and weight directly in the field By Francesco Di Trapani. Download PDF. For example, numerous studies show that sea stars can saponins; Paine, ; Estes et al. Natural selection should lead predators to select prey that Rochette et al.

The diverse behavioral Covich, ; Covich et al. Chemical signals from predatory sea Wooster, ; Rochette et al. For example, numerous chemical defenses Cronin and Hay, ; Terlau et al. Godin, Urriago et al. The a. Several niger to varying degrees of proximity with the predatory sea stars M.

However, this hypothesis is contested because the back-and-forth wave movement. Methods Thompson et al. All ; Mann et al. At both sites the sea stars H. During our trials, water temperature Snyder, ; Rosenthal and Chess, ; Dayton et al. In all experiments, divers collected sea stars Bernstein et al.

Andrew and MacDiarmid, ; Vadas and Elner, An ability to In each trial different sea stars, urchins and urchins aggregations were identify the risk associated with different predatory sea stars has been used. Responses to different sea stars Mahon et al. One in and examined the ability of the urchin to differentiate among study executed in northern Chile reports escape responses of intertidal different sea stars representing varying degrees of predatory risk. For limpets resulting from contact with sea stars under wave conditions this, we recorded the responses of isolated urchins 5—6 cm in Espoz and Castilla, No studies have examined distance diameter to simulated attacks by H.

For each simulated attack, the sea urchin Tetrapygus niger in central and northern Chile. This sea urchin star one arm in attacks with M. The The two predators most frequently observed feeding on T. Preliminary trials indicated that if there was a response it Barrios et al. These sea stars would occur within s. For each attack, we recorded if and when the have been described as keystone predators in shallow rocky urchin 1 raised its spines, 2 started displacing, and 3 severed communities in northern Chile Gaymer and Himmelman, ; contact with the sea star.

In this way, 20—26 simulated attacks were Barahona and Navarrete, The multi-armed sea star H. The proportion of is a generalist predator that consumes prey according to availability urchins responding and reaction times for each of the three Gaymer and Himmelman, ; Barahona and Navarrete, , parameters were analyzed separately.

The same body-size range of whereas M. Dayton et al. Responses relative to the level of risk of predatory sea stars responses of the commercially-harvested urchin Loxechinus albus. They mention that T. In this case, no transformation was maximum of 50 cm. In each trial the sea star was placed at the desired necessary to meet the normality assumption. To test if the mean distance along the axis of the wave activity and held there until the response time of urchins varied in the trials with different levels of urchin responded or for a maximum of s.

For each sea star we predatory risk from M. The MIXED procedure was also and 14—15 times for each of the distances new sea stars and urchins used because of the heterogeneity observed in each combination of were used in every trial at each threat level, including at each predatory risk test SAS, The log-transformation was used to distance. These experiments were conducted on a relatively smooth meet the normality assumption.

Density effects on the sea urchin's response proportion of urchins leaving the circular area using a generalized linear model GENMOD procedure as described above.

Trials in which no urchins left the hoop the time to respond to a sea star being placed nearby for urchins at were not included in the analysis. No circular hoop made with 5-mm thick wire around urchins found on transformation was necessary. Then we placed 3.

Responses to different sea stars a sea star, collected haphazardly from the surrounding area, in the empty space at the center of the hoop the sea star was always at least The simulated attacks with three species of sea stars and the mimic 5 cm from the urchins and recorded the departure times for urchins sea star showed that the sea urchin T.

The predatory and non predatory sea stars Fig. The sea star was response to H. This procedure which occurred after about 3 s of exposure.

Displacement followed was repeated 5 times with M. The urchins used their spines and podia to move densities of T. An away from the sea stars. There were no differences in the numbers of increased response at a higher density would imply that the urchins urchins responding and response times for the trials with the two sea were responding to some sort of alarm signal.

Podia extension took pairwise comparisons using protected Fisher least square difference place in about 8. These two analyses were performed separately for each in attacks by M. Data were displacement began in the trials with simulated attacks made in Normality was tested using the Shapiro— 3. Responses relative to the level of risk of predatory sea stars Wilk's test SAS, and homogeneity of variances using the Levene test Snedecor and Cochran, Then, with further was then used to compare the proportion of urchins responding to increases in distance and decreased risk the percent displacing different levels of predatory risk represented by the two predatory sea declined.

The decrease was more rapid in the trials with H. This analysis was only applied to the data for helianthus was placed at 30 cm from the urchin, whereas This sequence and similar reaction times have 60 A been reported for the sea urchin Strongylocentrotus droebachiensis in response to contact with its predators, the sea stars Leptasterias polaris a 40 a and Crossaster papposus Legault and Himmelman, They do B B b b not report the time when contact with the sea star was severed.

Each variable was analyzed separately; bars not sharing the same letter are different p b 0. Our trials using simulated attacks demonstrate that T. The at 50 cm. In contrast, urchins was rapid and similar for the two sea star predators, but the with mere contact the response time was notably more delayed in the urchins tended to sever contact more rapidly with H. At with M. Only a few urchins responded to the mimic sea distances of 10 and 20 cm response times to the two sea stars were star, and the reaction time for those that did respond was very slow.

Commu- ground and a kelp bed: are populations regulated by nity development following removal of sea urchins, settlement or post-settlement processes? Scheibling, R. E , Hamm, J. Changes in sea urchin populations predators in field and laboratory experiments.

Biol Larrain, A. Los echinoideos regulares fosiles y Sokal, R. Biometry, 2nd edn. On the relationships between marine Tegner, M. Sea urchin recruitment plants and sea urchins. Science Moreno, C. Nicho alimentario de la 'Vieja negra' Tegner, M. Population structure, Graus nigra Philippi. Ojeda, F. Dearborn, J. Feeding ecology of ben- Mar. Spiny lobsters and sea ence in rocky subtidal communities of the Gulf of Maine.

J exp. Comunidades de Lessonia nigrescens Phaeophyta in central Chile. Pearse, J. Marine waste disposal and sea urchin Zamora, S. Comparaciones inter e intraespecificas ecology. California Inst. Efflclency estimates for various quadrat Echinoidea en dos localidades de la IV Region, sizes used in benthic sampling.

Coqulmbo, Chile. Are kelp holdfasts islands on the ocean floor? Kelp forest ecosystems: biodiversity, stability, resilience and future By Michael Graham and Robert Steneck. Download PDF.