Sampling MPs

Sampling microplastics with the Manta net

Microplastics are collected using the Manta net, a specific instrument that filters the water at the surface, trapping floating objects. The net is deployed and kept in the water for 30 minutes. It is important to note down the coordinates of the initial and final sampling location in order to measure the distance covered by the net. At the same time, to measure the volume of water sampled (needed to calculate MPs concentration) the value on the flow meter attached to the mouth of the net must be written down before and after the deployment.

Once the net is back on board, it is rinsed from the outside to gather all the pieces in the cod end. The water sampled is then sieved initially with a 5 mm mesh and then with a 300 micron mesh to exclude the pieces outside the range of MPs.

Some of the bigger pieces are used for the characterization of the microbial community attached to plastic. These pieces are divided in two parts in order to analyze them both with SEM and with DNA analysis and therefore conserved in two different ways. While the rest of the sample is kept for the identification and quantification of the MPs.