Copper-algae interactions: Inheritance or adaptation?

Abstract

This study evaluated the responses of wild, adult plants of Enteromorpha compressa, and their progeny, to various copper concentrations. Experiments were designed to test the hypotheses that: 1) individuals of E. compressa from Caleta Palito, a copper-enriched coastal locality, tolerate higher copper concentrations than those from a place with no history of copper pollution and 2) such copper tolerance is under genetic control and therefore, was an inherited character. Our results indicate that algae which inhabit a copper-enriched environment tolerate higher concentrations of copper than those from waters with low copper concentrations. On the other hand, our results suggest that generalizations regarding heritability of the tolerance to copper do not apply to the Chilean E. compressa, as no differences in growth or rhizoid production were found between the progeny from Caleta Palito and Caleta Zenteno. These findings are an indication that heritability and adaptation may represent alternative strategies used by different populations of the same algal species to tolerate copper.

Response of Microcystis to copper stress – Do phenotypes of Microcystis make a difference in stress tolerance?

“…However, high copper concentration is toxic to many organisms. Various sources of Cu, including industrial and domestic wastes, and copper-based pesticides have contributed to an increase of Cu concentration in aquatic environments (Ho, 1987;Nor, 1987;Correa et al, 1996), with many negative effects on algae being reported at high Cu concentrations (Harrison et al, 1977;Pandey and Singh, 1992;Kenefick et al, 1993;Okamoto and Colepicolo, 1998;Yruela et al, 2000;Bossuyt and Janssen, 2004;Nielsen and Nielsen, 2005). In response to the stress of high Cu concentration, algae display a defense mechanism, including the changed activity of superoxide dismutase (SOD) (Okamoto and Colepicolo, 1998), protein composition (Yruela et al, 2000), and so on.…”

Copper excess-induced large reversible and small irreversible adaptations in a population of Chlamydomonas reinhardtii CW15 (Chlorophyta)

“…To our best knowledge there was no investigation of algae experimental evolution on micronutrient elements, including copper. On the other hand, adaptation to high Cu 2+ concentrations was observed in natural conditions in several algal species [36][37][38]. Adaptation of biological populations to environmental changes in multigenerational time scales can be achieved by structural and functional changes at different levels of the system [39][40][41]: (i) adaptation of specimens within the framework of phenotypic plasticity; (ii) epigenetic changes; (iii) rearrangement of alleles of different genes responsible for resistance to heavy metal stress to form phenotypes with better fitness under new conditions (recombinative variability); and (iv) selection of existing populations, or newly formed alleles of sparse genes necessary for adaptation to the new environment.…”

“…Both mutations (one already present in populations and a new one) were dominant. Mechanisms of resistance to excess copper stress in the green macroalga E. compressa operated at both the hereditary and phenotypic level [37]. Because heavy metals alter the redox balance, one of the most important protective mechanisms is maintaining the high antioxidative potential of cells and their compartments [49].…”

Inter-population comparisons of copper resistance and accumulation in the red seaweed, Gracilariopsis longissima

“…Russell and Morris 1970;Reed and Moffat 1983;Anderson et al 1990;Nielsen et al 2003), and constitutive resistance (e.g. Edwards 1972;Correa et al 1996;Contreras et al 2005). Clearly, further study is required to better elucidate the responses of populations of seaweeds growing at locations that differ in their levels of metal contamination, and to clarify mechanisms of resistance in these important marine primary producers.…”