|Hydrogen peroxide is not the cause of fish kills associated with Chattonella marina: cytological and physiological evidence|
Tang, J.Y.M.; Anderson, D.M.; Au, D.W.T. (2005). Hydrogen peroxide is not the cause of fish kills associated with Chattonella marina: cytological and physiological evidence. Aquat. Toxicol. 72(4): 351-360
In: Aquatic Toxicology. Elsevier Science: Tokyo; New York; London; Amsterdam. ISSN 0166-445X, more
Algal blooms; Fish kill; Osmoregulation; Ultrastructure; Chattonella marina (Subrahmanyan) Hara & Chihara, 1982 [WoRMS]; Marine
|Authors|| || Top |
- Tang, J.Y.M.
- Anderson, D.M.
- Au, D.W.T.
Chattonella marina, a harmful algal bloom (HAB) causative species, was used to study the mortality, physiology, and pathology of a marine stenohaline fish, goldlined seabream exposed to the toxic alga. The median lethal time (LT50) was 3h upon exposure to 8000cells/ml of C. marina. Significant induction of filamental chloride cells (CCs) [i.e. increases in CC fractional area and in the volume density of CCs], concomitant with significant reduction of blood osmolality, were found in C. marina treated fish. To verify whether the toxicity of C. marina was mediated through oxidative stress, a hydrogen peroxide exposure experiment was carried out and the toxicity as well as cytological and physiological changes were compared with the C. marina treatment. Hydrogen peroxide at a concentration of 500 µM H2)O2, (i.e. 25 times higher than that produced by 8000cells/ml of C. marina (20 µM H2O2) was unable to induce similar CC alterations and osmoregulatory impairment in fish as observed in the C. marina treatment. Non-specific membrane damage such as severe loss of microvilli projections on the CC apical opening and rupture of epithelial membranes in the lamellae were observed. The LT50 was 6h, two times longer than that with 8000cells/ml of C. marina. Based on the cytological and physiological evidence and toxicity data, the mechanism by which C. marina kills fish appears to be very different from that caused by H2O2/ROS. Osmoregulatory distress is the major cause of fish death upon exposure to C. marina.