Figure 6.

Unifrac analysis illustrating the genetic similarity of clone libraries based on sequences related to (a) all PPE classes, (b) Prymnesiophyceae and (c) Chrysophyceae. Coloured symbols illustrate the temperature and trophic status of the samples from which clone libraries were constructed. Circle, oligotrophic (Phosphate concentration <10 mg m⁻³); square, mesotrophic (Phosphate concentration 10–20 mg m⁻³); star, eutrophic (Phosphate concentration >20 mg m⁻³); blue, very low temperature (<10 °C); green, low temperature (10–14.99 °C); yellow, medium temperature (15–19.99 °C); orange, high temperature (20–24.99 °C); red, very high temperature (⩾25 °C).