Monterey Bay Aquarium Research Institute
Chemical Sensor Program
In Situ Ultraviolet Spectrophotometer (ISUS)

Nitrate (µM - blue) and Temperature (°C - red) measured at the M0 mooring in Monterey Bay are plotted versus the Year Day.    As temperature goes down, the concentration of nitrate rises. Decreasing temperature indicates upwelling of cold deep water that is also rich in nutrients.