Copper toxicity and adaptation in the marine diatom Ditylum brightwellii

Abstract

1. 1. The planktonic diatom Ditylum brightwellii, grown in light-limited resp. nitrogen-limited continuous culture, has been exposed to Cu levels, comparable with those in the Scheldt estuary. 2. 2. At increasing levels D. brightwellii initially detoxified Cu, producing metal-binding ligands (amino acids), and increasing its cell volume. 3. 3. In light-limited D. brightwellii, photosynthesis could be adjusted to increasing Cu stress, division rates remained constant, and cells proved to be adaptable to 200 nM dissolved Cu. 4. 4. Nitrogen-limited D. brightwellii detoxified Cu inadequately: it stored large amounts of Cu (30–60 μM) that inhibited cell division.