Biogeochemical Cycles Introduction The relationships between agriculture and nature have always been painful. While agriculture and animal breeding were the reliable sources of plant and animal food, nature was suffering the consequences of human unreasonable approaches to fertilization. Strong increase in food production and population growth in conjunction with the increasing fertilizers and pesticides use strengthened the impact to the environment, in particular to water bodies (Nierenberg, 2001).
Fertilizers that contain high amounts of nitrogen and phosphorous compounds have altered the earths natural biogeochemical cycles. As a result, the whole nations were compelled to review their agricultural policies and their impact on aquatic systems. Fertilizers are inexhaustible sources of nitrogen and phosphorus. Fertilizers tend to break the balance of nutrients in aquatic ecosystems, increasing the availability of inorganic nitrogen and phosphorous compounds in water.
These, in turn, lead to the intensification of plankton production and the formation of toxic ammonia in rivers (Kumar, 2003). Big amounts of nitrogen-containing materials shift the balance of total ammonia and result in the excessive formation of unionized ammonia, which is toxic to fish and aquatic plants (eutrophication). Another effect of the eutrophication is, among, others, a possible rise in water level by an excessive growth of macrophyta in conjunction with increasing friction (Kumar, 2003).
Lakes appear more vulnerable to external contamination than rivers: lakes do not have an outflow and are likely to remain contaminated during much longer than rivers and seas. Green belts are the direct results of over-fertilization in lakes; under the impact of fertilizers, lakes experience organic materials mineralization. Excessive amounts of organic nutrients subsequently lead to uncontrolled growth of phytoplankton that covers the lakes surface and creates anoxic conditions, killing plants and animals, and slowly destroying the whole ecosystem.
Conclusion In general, the effects of fertilization on aquatic ecosystems are mostly indirect. Fertilization is the element that makes agriculture responsible for the damage is causes to all types of aquatic ecosystems. Simultaneously, agriculture possesses vast potential for controlling and decreasing the amount of fertilizers that distort biogeochemical balance on earth. References Kumar, A. (2003). Aquatic ecosystems. APH Publishing. Nierenberg, D. (2001). Toxic fertility (nitrogen). World Watch, 14 (2): 30-34.