Changes in zooxanthellae density, morphology, and mitotic index in hermatypic corals and anemones exposed to cyanide

• Published in: Marine pollution bulletin Vol. 46; no. 5; pp. 573 - 586
• Main Authors: Cervino, J.M, Hayes, R.L, Honovich, M, Goreau, T.J, Jones, S, Rubec, P.J
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-05-2003; Elsevier
• Subjects: Acropora millepora; Aiptasia pallida; Animal, plant and microbial ecology; Animals; Anthozoa; Anthozoa - anatomy & histology; Anthozoa - physiology; Applied ecology; Biological and medical sciences; Bleaching; Cell Division; Chemical pollution; Cyanide toxicity; Dose-Response Relationship, Drug; Ecotoxicology, biological effects of pollution; Eukaryota - physiology; Euphyllia divisa; Favites abdita; Fisheries; Fundamental and applied biological sciences. Psychology; Goniopora; Heliofungia actinformis; Histopathology; Marine and brackish environment; Mitosis; Mitotic indices; Mortality; Plerogyra; Poisons - adverse effects; Population Dynamics; Protein Biosynthesis; Protein synthesis; Scarophyton; Sea Anemones - anatomy & histology; Sea Anemones - physiology; Sodium Cyanide - adverse effects; Symbiosis; Trachyphyllia; Trachyphyllia geoffrio; Asia; South east Asia; Southeast Asia; Chemical pollution; Mitotic indices; Cyanide toxicity; Histopathology; Bleaching; Protein synthesis; Algae; Mortality; Coral reef; Cyanides; Sodium Cyanides; Fishing; Marine environment; Coelenterata; Density change; Mitotic index; Dinophyta; Coral; Morphology; Reef animal; Cnidaria; Pollutant effect; Invertebrata; Non target organism; Population density; Thallophyta
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/S0025-326X(03)00071-7

Sodium cyanide (NaCN) is widely used for the capture of reef fish throughout Southeast Asia and causes extensive fish mortality, but the effect of NaCN on reef corals remains debated. To document the impact of cyanide exposure on corals, the species
Acropora millepora,
Goniopora sp.,
Favites abdita,
Trachyphyllia geoffrio,
Plerogyra sp.,
Heliofungia actinformis,
Euphyllia divisa, and
Scarophyton sp., and the sea anemone
Aiptasia pallida were exposed to varying concentrations of cyanide for varying time periods. Corals were exposed to 50, 100, 300, and 600 mg/l of cyanide ion (CN
−) for 1–2 min (in seawater, the CN
− forms hydrocyanic acid). These concentrations are much lower than those reportedly used by fish collectors. Exposed corals and anemones immediately retracted their tentacles and mesenterial filaments, and discharged copious amounts of mucus containing zooxanthellae. Gel electrophoreses techniques found changes in protein expression in both zooxanthellae and host tissue. Corals and anemones exposed to cyanide showed an immediate increase in mitotic cell division of their zooxenthellae, and a decrease in zooxanthellae density. In contrast, zooxanthellae cell division and density remained constant in controls. Histopathological changes included gastrodermal disruption, mesogleal degradation, and increased mucus in coral tissues. Zooxanthellae showed pigment loss, swelling, and deformation. Mortality occurred at all exposure levels. Exposed specimens experienced an increase in the ratio of
gram-negative to
gram-positive bacteria on the coral surface. The results demonstrate that exposure cyanide causes mortality to corals and anemones, even when applied at lower levels than that used by fish collectors. Even brief exposure to cyanide caused slow-acting and long-term damage to corals and their zooxanthellae.