13 Fish view of a mesocosm

Six orange tubes, a roof put up like an umbrella and the collar of the plastic bag – that’s all to be seen from a mesocosm afloat.

Scientists are interested in what happens beneath the surface, well enclosed in robust, translucent special foil. The bag, which is 25 metres long and holds 55 cubic metres of water, connects to a sediment trap of two metres in which all particles sinking down from the water column are collected.

Only divers who plunge down to check or clean the bags occasionally get an idea of the huge water mass that is investigated in the experiment on ocean acidification.

Photo: Solvin Zankl