The researchers studied the nutrient levels in a type of aquatic plant in a lake to see if harvesting the plants could help remove excess nutrients. They found that plants near pollution sources had more nitrogen and phosphorus. Iron and aluminum levels were high near a storm sewer. Phosphorus was the most limited nutrient. Late August was the best time to harvest plants to remove nutrients. Harvesting could remove about 16% of nitrogen and 37% of phosphorus entering the lake each year. Harvesting can help reduce nutrient pollution in the lake, but it doesn't solve the problem completely.