Limestone is a sedimentary rock that is made up mostly of calcium carbonate which is represented by the chemical formula CaCO3. Approximately ten percent of all sedimentary rock is limestone. It is formed both by biochemical processes and inorganically. Limestone has several advantages since it is a naturally occurring mineral that dissolves easily in water. It is available in abundance and is relatively cheap. It is also non-toxic and adding it to water or soil has several effects and numerous benefits.
Types of Limestone
Due to the many ways that limestone can be produced, there are several types of limestone. One form of limestone is chalk, which is created from the skeletons of tiny marine creatures. Chalk is a porous rock best represented by the well-known cliffs of Dover. Another example of biochemically produced limestone are coral reefs which are created from the skeletal remains of invertebrates. Because it easily erodes, most cave systems are found in limestone. The stalactites and stalagmites in caves are essentially made up of inorganic limestone.
Adding limestone to water in order to neutralize it is known as "liming." When limestone is added to ponds and lakes, it has the effect of adding calcium and protecting the water from becoming too acidic. The benefit of limestone in this situation is that is restores and helps to maintain the ecology of the water and makes it supportive of aquatic life. It is also an inexpensive method of slowing down acidification. Scientists have used liming to bring dead lakes and streams back to life after they suffered the onslaught of acid rain. While liming is not a permanent solution to the problem of increased pH, it does help to prevent the damage caused by acid rain. Limestone has helped restore lakes in which life had already been obliterated by acidification.
Effects on Aquatic Life
Another of the effects and benefits of limestone is that is lowers the poisonous effects of toxic metals such as lead, cadmium, zinc and nickel which endanger both fish and human health. Liming can help the survival rate of aquatic life by not only neutralizing water that is too acidic, but by lowering the amount of metals dissolved in the water. Crayfish and mussels use the calcium provided by limestone to develop the shells that protect them. Calcium provided by limestone is also essential for the formation of scales in adult fish as well as the development of bone.
Adding limestone to acidic soils has a protective benefit as it helps to protect the soils from sudden changes in pH. Limestone is sprinkled on lawns and added to pastures, crops and gardens to provide the nutrient calcium while at the same time lowering the acidity of the soil.
When limestone is added to water, it may create cloudiness and reduce the clarity of the water. This effect is due to the limestone particle that are suspended in the water. Another short-term effect is that as phosphorous is released from the mud at the bottom of the lake, so there will be an increase in the plant life in the lake or pond.