Concurrently plants require oxygen for respiration. Additionally they require nutrients such as nitrogen and phosphorus as well as trace elements. Iron is necessary for chlorophyll synthesis. Manganese is essential for respiration and nitrogen metabolism. Copper is an important enzyme component.
Chlorophylls are the pigments of photosynthesis.
Their function is to absorb light energy, which is converted to chemical energy through the synthesis of organic compounds. Chlorophylls a and b are the most common ones. Now more than 50 chlorophylls have been identified. Free CO 2 is most readily utilized by plants, also submerged macrophytes. However, many plants are capable of utilizing bicarbonate ions when CO 2 is in very low concentrations and bicarbonate is very abundant.