Eutrophication, or more
is the enrichment of a water body with nutrients ( normally nitrogen and
phosphorus compounds ), usually with an overabundance measure of nutrients. A
syndrome of ecosystem responses to human activities that fertilize water bodies
with nitrogen and phosphorus, frequently prompting changes in creature and
plant populations and degradation of water and habitat quality. Eutrophication
can be a natural process in lakes and streams, happening as they age through
geological time. Human activities can increase the rate at which nutrients
enter ecosystems and causes eutrophication.
Process of Eutrophication
Plants need a supply of nitrates for making their
proteins, and a source of phosphates for many chemical reactions in their
cells. The rate at which plants grow is often limited by how much nitrate and
phosphate they can obtain. In recent years, the amount of nitrate and phosphate
in our rivers and lakes has been greatly increased. This leads to an
accelerated process of eutrophication ( Refer to Appendix A.1 ).
Eutrophication is the enrichment of natural waters
with nutrients which allow the water to support an increasing amount of plant
life. This process takes place naturally in many inland waters but usually very
slowly. The excessive enrichment which results from human activities leads to
an overgrowth of microscopic algae ( Refer Appendix A.2 ).
These aquatic algae are at the bottom of the food
chain. Fertilisers are often used in farming, sometimes these fertilisers
run-off into nearby water causing an increase in nutrient levels. This causes
phytoplankton to grow and enable them to increase so rapidly that they cannot
be kept in check by microscopic animals which normally eat them. So, they die
and fall to broken down by bacteria. The bacteria need oxygen to carry out this
breakdown and the oxygen is taken from the water. So much oxygen is taken that
the water becomes deoxygenated and can no longer support animal life. Fish and
other organisms die from suffocation ( Refer to Appendix A.3 ).