Heavy Metal Bioaccumulation in the Anemone Paraphelliactis pabista Dunn, 1982 (Actiniaria: Hormathiidae) from the Hydrothermal System of Guaymas Basin, Gulf of California

Integrated biomarker responses in wild populations of the intertidal sea anemone Bunodosoma zamponii living under different anthropogenic pressures

Bunodosoma zamponii is the most abundant anemone in Mar del Plata (Buenos Aires, Argentina). Given that the presence of persistent organic pollutants (organochlorine pesticides and PCBs) and the organophosphate pesticide chlorpyrifos has recently been reported in this species, two wild populations living under different anthropogenic pressures were studied and compared regarding basic aspects of their ecology and physiological response to oxidative stress. A population from an impacted site (Las Delicias, LD) and another from a reference site (Punta Cantera, PC) were monitored seasonally (spring, summer, autumn, and winter), for one year. Anemones from PC were larger and more abundant than those from LD for most sampling periods. During winter, glutathione-S-transferase and catalase activities were higher in LD. Moreover, protein content and antioxidant defenses were higher in anemones from PC during winter as well. Taking into account their ecology (size and abundance) and biomarker responses, the population from PC was comparatively healthier. Furthermore, such differences are in agreement with recent studies indicating a higher concentration of pollutants in anemones from LD (specially during the winter sampling). In this sense, considering that B. zamponii can bioaccumulate the aforementioned pollutants, its resilience to their presence, and the fact that biomarker response differed between sites, this species can be regarded as a proper sentinel species of environmental pollution. Overall, this anemone seems to be a good bioindicator to be considered in future biomonitoring and ecotoxicological studies.

A Comparative Analysis of Sparisoma cretense in Island Environments: Unraveling Metal Accumulation Differences in the Canary Islands (Spain, NW African Waters)

This study investigates the impact of varying environmental conditions on the metal composition within the tissues of Sparisoma cretense, contributing to the understanding necessary to offer scientifically sound advice regarding the health status of this species. This knowledge extends beyond fishery production, encompassing implications for food security. The data span the years 2022 and 2023, encompassing both cold and warm climatic seasons. The concentrations of various metals, such as Al, Zn, Cd, Pb, Fe, and Cu, exhibited noteworthy variations across the islands, with significant increases recorded in 2023, particularly during the warm season. The intricate interplay between multiple factors shaped the availability of the analyzed elements in S. cretense. Factors such as rising temperatures during the warm season increased biological activity in marine ecosystems, seasonal fluctuations in weather conditions, water quality, and anthropogenic influences, all contributing to the observed variations in metal concentrations. Additionally, the geological composition of each island and the patterns of marine currents and sediment transport play pivotal roles in these differences. Comprehensive scientific research, monitoring, and environmental surveillance are essential for a holistic understanding of this variability and providing valuable insights for the conservation and management of marine ecosystems in the Canary archipelago.

Genetic adaptations of sea anemone to hydrothermal environment

Hydrothermal vent habitats are characterized by high hydrostatic pressure, darkness, and the continuous release of toxic metal ions into the surrounding environment where sea anemones and other invertebrates thrive. Nevertheless, the understanding of metazoan metal ion tolerances and environmental adaptations remains limited. We assembled a chromosome-level genome for the vent sea anemone, Alvinactis idsseensis sp. nov. Comparative genomic analyses revealed gene family expansions and gene innovations in A. idsseensis sp. nov. as a response to high concentrations of metal ions. Impressively, the metal tolerance proteins MTPs is a unique evolutionary response to the high concentrations of Fe2+ and Mn2+ present in the environments of these anemones. We also found genes associated with high concentrations of polyunsaturated fatty acids that may respond to high hydrostatic pressure and found sensory and circadian rhythm-regulated genes that were essential for adaptations to darkness. Overall, our results provide insights into metazoan adaptation to metal ions, high pressure, and darkness in hydrothermal vents.

Monitoring different sources of marine pollution in the Canarian intertidal zone using Anemonia sulcata as a bioindicator

Sea anemones have often been used as bioindicators of contamination because they are semisessile organisms that rarelly leave their niche, which is why they are conducive to affecting the ecosystem at the local level. The objective of this work is to determine whether the concentrations of heavy metals and trace elements in the anemone Anemonia sulcata vary depending on the source of contamination present. In 2021 seventy specimens were collected at five sampling points and fourteen specimens were collected in each point (Control Zone, Thermal Power Plant, Sewage Pipe, Harbour and Tourism) in 2021, on the island of Tenerife. All the areas studied characterized by a pollution condition had higher concentrations of metals and trace elements than the control area. The anemones from Harbour presented a greater number of metals with a higher concentration than the other study areas.

Manganese uptake and partitioning between the tissue of the anemone host Exaiptasia pallida and Symbiodinium spp., including assessment of stress and recovery

Manganese (Mn) is essential for global steel and Mn-iron (Fe) alloy production. The human health effects of elevated Mn concentrations have been well established, but studies on its impact on marine invertebrates are limited. This study is the first to investigate Mn uptake in the sea anemone Exaiptasia pallida after chronic exposure (0.5, 1, 10, and 100 mg/L) for 24-d. Following exposure, E. pallida were transferred to ambient seawater for 6-d to assess Mn depuration. Mn accumulation and partitioning in host tissue and symbionts (Symbiodinium spp.), tentacle retraction, and symbiont cell density were measured during exposure and depuration. Mn concentrations were substantially higher in symbionts than tissue in all treatments after 24-d. No significant difference was observed for symbiont cell density after Mn exposure. Tentacle retractions were significantly higher in all Mn exposed treatments than controls at all time points. Mn depuration was observed for both tissue and symbionts but was more rapid in symbionts. This study reveals that Symbiodinium spp. can play a role in Mn uptake and depuration in anemones, but Mn loading does not affect cell density. These results help understand metal uptake and depuration in complex relationships between Symbiodinium spp. and other host taxa like corals.

Anthropogenic radioactive isotopes in Actiniaria from the Svalbard archipelago

The abundance of radionuclides in the Arctic Actiniaria has limited study despite their environmental importance in coastal food chains. Although the Arctic has incurred relatively little contamination by anthropogenic radionuclides as a result of nuclear weapons tests, there are still detectable levels of radionuclide activity observed in marine species. In this study of anthropogenic radionuclide activity in Actiniaria from Spitsbergen we observed levels of ⁹⁰Sr from 0.92 Bq kg^-1_dw to 18 Bq kg^-1_dw and for ¹³⁷Cs from 1.2 Bq kg^-1_dw to 12 Bq kg^-1_dw. The highest values of ⁹⁰Sr and ¹³⁷Cs were observed in organisms at stations close to seabird colonies and a river mouth, suggesting that fecal material and melting glaciers may be sources of radionuclides in the Arctic environment. The body mass of individual organisms affected bioaccumulation of ⁹⁰Sr and ¹³⁷Cs in Actiniaria, with radionuclide bioaccumulation occurring most intensively in the smaller specimens.