What is iron?
Iron is one of the most abundant elements by mass on the earth, it is a metal found naturally throughout the earth soil and deeper making up 32.1% of the earth’s mass.
It occurs naturally in soil, sediments and groundwater and can be found in many types of rocks. It can be present in water in two forms; the soluble ferrous iron or the insoluble ferric iron. Water containing ferrous iron is clear and colorless, but when exposed to air, it turns a reddish brown color due to oxidation.
How does iron enter water?
Iron is naturally present in soil, and through this, enters rivers, lakes, and other natural water sources. Iron can also enter the water through seepage from natural deposits underground, industrial runoff containing iron, refining of iron ores, and through corroded pipe systems and other metals.
Iron in aquaculture - The good
One of the up and coming industries where iron plays a major role is aquaculture. Iron is one of the essential micronutrients for aquatic plant and animal life, both of which are a key part in the aquaculture practices.
Since most iron-bearing minerals are not very water soluble, iron occurs in very small concentrations in natural water bodies. Such small concentrations of iron are too low to support the growth of plants.
It is therefore fortunate that ferric iron reacts with major anions in water to form soluble ion pairs and complexes. These then go on to combine with the dissolved organic matter in the water to form complexes of soluble iron. These combined forms of iron greatly increase the iron concentration in water and can be used by plants.
Iron is vital to the life of all aquatic creatures, especially mollusks and green plants. Iron promotes enzyme growth and also holds an important role in photosynthesis, nitrogen binding, DNA synthesis, and many other cellular functions for aquatic plants.
Iron is also important to
The availability of iron in soil and water determines the distribution of plant species in natural ecosystems. Phytoplankton, some of the smallest ocean creatures, depend so heavily on iron that the amount of iron present in water limits or accelerates the growth of the phytoplankton bloom.
Insufficient iron uptake causes retarded growth, interveinal chlorosis, and reduced fitness.
Too much iron is, however, toxic to cells and restricts plant growth. Iron is also an essential component of many enzymes that take part in energy transformation processes in aquatic plants and animals. With regard to fish, it is an integral component of proteins involved in cellular respiration and oxygen transfer