Question

Explain the difference between oligotrophic and eutrophic waters. Describe the sequential process of eutrophication.

Short answer

Oligotrophic waters have low nutrients and support less life, usually have a clear-blue appearance while eutrophic waters have high nutrients, supporting more life and appearing greenish due to algal growth. Eutrophication is the process of nutrient enrichment of water bodies leading to a shift from oligotrophic to eutrophic condition, accompanied by algal blooms, depletion of oxygen and creation of 'dead zones'.

Step-by-step solution

Defining Oligotrophic and Eutrophic Waters

Oligotrophic waters are bodies of water that have a low concentration of nutrients, while eutrophic waters have a high concentration of nutrients. In oligotrophic waters, conditions are such that aquatic life is usually scarce due to the lack of necessary nutrients. In contrast, eutrophic waters are typically rich in nutrients, fostering a vibrant water ecosystem with abundant plant and animal life.

Characteristics of Oligotrophic and Eutrophic Waters

Oligotrophic waters most often have a clear blue appearance due to the low levels of phytoplankton present and are home to species that can survive in nutrient-poor conditions. Eutrophic waters, on the other hand, are more green and murky due to the higher levels of algae and phytoplankton. The biodiversity in these waters tends to be lower as some species can't survive in such nutrient-rich conditions.

Explanation of Eutrophication Process

Eutrophication is a process where water bodies become enriched with nutrients, potentially leading to an overgrowth of plant life, especially algae. The sequence of eutrophication begins with nutrient run-off, often from human activities like agriculture or sewage disposal, entering the water. This nutrient enrichment promotes the growth of algae (algal bloom), which deprives other aquatic life of necessary light. When this large amount of algae dies, it fuels the growth of decomposers, which consume the remaining oxygen in the water, creating 'dead zones' where few organisms can survive.