With an average nitrogen content between 0.3% and 0.5% in the tissues and a nitrogen removal cost between USD 10 and USD 30, the harvesting of 1 million tonnes equated to between 3 000 and 5 000 tonnes of nitrogen removal for a NTC value between USD 30 and 150 million! Additional NTCs of USD 1.6 million for the removal of 400 tonnes of phosphorus, and CTC of USD 900 000 for the removal of 30 000 tonnes of carbon should also be factored in. In 2009, there was another green tide event covering at least 17 400 km2 of the Yellow Sea.