Nutrient analysis on D328

Paul Morris from the National Oceanography Centre, Southampton On D328 I am measuring the concentration of dissolved nutrients in the seawater. The nutrients I am interested in are nitrate, silicate and phosphate and are very similar to the fertilisers used in agriculture and gardening. These nutrients are essential for life to grow in the water and are used by the microscopic plants (phytoplankton) that live in the surface ocean, the part that is lit with sunlight. I will collect seawater from the surface right down to the seafloor, which can be as deep as 2000-3000 metres in some parts of the area where we are working. The seawater is collected in bottles that can be remotely closed and then brought back on board the ship. The seawater is then put through a machine called an auto-analyser which mixes chemicals with the seawater and turns the nitrate phosphate and silicate different colours. The intensity of the colours formed tells us how much of each nutrient is present in the seawater. All this information is stored on a computer which can then be used for scientific investigation.