A team from Plymouth Marine Laboratory (PML) visits the wetlands every two to three months.

On each visit the PML team work over a 6-hour tidal cycle at the Calstock breach. Every 30 minutes a sample of water is collected from the channel which feeds water from the River Tamar into the site.

This allows the team to measure what is coming in and out of the wetland with the rise and fall of the tide.

The temperature and salt content of the water are recorded before dividing it into 11 smaller samples.

These samples are then taken back to Plymouth Marine Laboratory where they are analysed for nutrients which include nitrate and phosphate, greenhouse gas concentrations, pH, dissolved and suspended carbon, bacteria, algae, and DNA.