1.All Plants Need Iron, But Very Little Iron –
Iron is a micronutrient essential for the synthesis of enzymes required for photosynthesis. In relatively rare cases where terrestrial plants lack iron, they cannot manufacture sufficient chlorophyll, such as those to the left. The amounts plants need, however, are small; a mature two-ton tree will need about 40 grams.
2. Most Ecosystems Have More Than Enough Iron – Terrestrial plants seldom lack iron becau most soils have abundances of iron. Most ocean waters are supplied by iron from river and bottom sediments or by clouds of dust that can travel for thousands of miles. To see satellite images of Asian dust storms over the Pacific see: http://cimss.ssec.wisc.edu/goes/misc/980424.html