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Effects of titanium dioxide (TiO 2 ) nanoparticles on caribbean reef‐building coral ( Montastraea faveolata )
Author(s) -
Jovanović Boris,
Guzmán Héctor M.
Publication year - 2014
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.2560
Subject(s) - coral , coral bleaching , zooxanthellae , coral reef , reef , bioaccumulation , environmental chemistry , biology , ecology , chemistry , symbiosis , bacteria , genetics
Abstract Increased use of manufactured titanium dioxide nanoparticles (nano‐TiO 2 ) is causing a rise in their concentration in the aquatic environment, including coral reef ecosystems. Caribbean mountainous star coral ( Montastraea faveolata ) has frequently been used as a model species to study gene expression during stress and bleaching events. Specimens of M. faveolata were collected in Panama and exposed for 17 d to nano‐TiO 2 suspensions (0.1 mg L −1 and 10 mg L −1 ). Exposure to nano‐TiO 2 caused significant zooxanthellae expulsion in all the colonies, without mortality. Induction of the gene for heat‐shock protein 70 (HSP70) was observed during an early stage of exposure (day 2), indicating acute stress. However, there was no statistical difference in HSP70 expression on day 7 or 17, indicating possible coral acclimation and recovery from stress. No other genes were significantly upregulated. Inductively coupled plasma mass spectrometry analysis revealed that nano‐TiO 2 was predominantly trapped and stored within the posterior layer of the coral fragment (burrowing sponges, bacterial and fungal mats). The bioconcentration factor in the posterior layer was close to 600 after exposure to 10 mg L −1 of nano‐TiO 2 for 17 d. The transient increase in HSP70, expulsion of zooxanthellae, and bioaccumulation of nano‐TiO 2 in the microflora of the coral colony indicate the potential of such exposure to induce stress and possibly contribute to an overall decrease in coral populations. Environ Toxicol Chem 2014;33:1346–1353. © 2014 SETAC