Toxicity of naturally occurring complex mixtures of organic pollutants (OP) to temperate and polar phytoplankton communities from the Mediterranean Sea, North East Atlantic Ocean and Southern Ocean was tested.
Toxicity was observed at significantly lower relative concentrations than simple OP mixtures, i.e., as low as 5 fold the oceanic concentrations.
Overall, smaller sized picocyanobacteria (< 2 μm diameter) of temperate seawaters were the most affected.
In some cases, larger sized Antarctic phytoplankton (> 20 μm diameter) showed higher sensitivity to OPS than Mediterranean picophytoplankton.
Results suggest that current concentrations of OPs present in seawater are impacting natural marine phytoplankton communities.