there by sinking. Primary production fuelled by nitrate is, therefore, making use of a "fresh" nutrient source rather than a regenerated one. Production by nitrate is thus referred to as new production.

To sum up, production based on nitrate is using nutrient molecules newly arrived from outside the productive layer, it is termed new production. The rate of nitrate utilization remains a good measure of the new production. While if the organic matter is then eaten, respired and the nitrogen excreted as ammonia, its subsequent uptake and