Does the survivorship of activated resting stages in toxic environments provide cues for ballast water treatment?

Abstract

The toxic effects of three inorganic metals (Cu, Cr, Hg), three organic (phenol, formalin, ammonium) chemicals, ozone-enriched water and peroxides (H2O2) on embryonic development were tested in 8 species from the Porifera, Bryozoa and Crustacea. Toxicants with lower molecular weight showed stronger negative impacts on post-diapause embryos than chemicals with higher molecular weight if related to the toxicity of the chemicals to active adult stages. Only few embryos of the cladoceran Moina macrocopa and none of the cladoceran Wlassicsia pannonica treated with peroxides at concentration 0.3% developed further. Ozone-enriched water had no significant effect on post-diapause embryonic development in cladocerans. Ammonium (the product of NH4OH dissociation) in concentration 100mg/l and higher killed all embryos of M. macrocopa inside protective membranes. Peroxides and ammonium are suggested for the purification of ship ballast waters as effective, non-expensive and non-persistent toxic chemicals. Resting stages of invertebrates including at least Crustaceans, Porifera and Bryozoa seem to allow not only dispersal among toxic industrial environments such as ship ballast compartments, but may also endure serious pollution events common in seaports and estuaries. Artemia cysts due to their strong protection against different toxic substances are recommended as a model for studies of toxic effects in diapausing stages in polluted estuaries and marine environments.