Nanoparticles such as carbon nanotubes (CNT), which are found in an ever-increasing number of products, are ending up more and more frequently in our surroundings. If and how they affect aquatic ecosystems are questions which are still unanswered. An Empa study shows that while CNTs do not have toxic effects on green algae they do inhibit its growth by depriving the plant of light and space.

That's a bit disconcerting.  To read more, click here.