Comparative study of radioactivity levels and radionuclide fingerprints in typical marine ecosystems of coral reefs, mangroves, and hydrothermal vents

Abstract

As a key environmental parameter to induce radiation dose and effect on non-human species, radioactivity level is rarely evaluated in typical ecosystems of coral reefs, mangroves, and hydrothermal vents. In this study, naturally occurring radionuclides (²³⁸U, ²²⁶Ra, ²²⁸Ra, and ⁴⁰K) in carbonate, silicate, and sulfide sediments collected from coral reefs, mangroves, and hydrothermal vents were simultaneously measured using high purity germanium (HPGe) γ spectrometry. Radioactivity levels and radionuclide fingerprints (²²⁶Ra/²³⁸U and ²²⁸Ra/²²⁶Ra) were interpreted and explored for tracking sources and formation processes of marine sediments in distinct marine ecosystems. Additionally, ionizing radiation dose rate on representative marine biotas (mollusc-bivalve, crustacean, polychaete worm, benthic fish, and pelagic fish) was evaluated using the ERICA tool with an increasing rank in coral reefs < mangroves < hydrothermal vents. Polychaete worm received the highest radiation dose relative to other marine biotas. We also emphasized the dominant contribution of ²¹⁰Po to total radiation dose rate on marine biotas.

Keywords: Coral reefs; ERICA; Hydrothermal vents; Mangroves; Non-human species; Radiation dose.