Low dissolved oxygen along with nutrient deficiency leads to the growth of which organism?

The growth of filamentous bacteria is often a consequence of low dissolved oxygen levels combined with nutrient deficiencies. In aquatic environments, particularly in wastewater treatment systems, filamentous bacteria can thrive under such conditions. They are capable of forming long, thread-like structures that can impede the treatment process by causing bulking in activated sludge systems.

These bacteria typically flourish when there is an imbalance in nutrients, particularly when organic matter is present but nutrients like nitrogen and phosphorus are limited. The low dissolved oxygen further stresses the ecosystem, creating an environment where filamentous organisms are better suited to survive compared to other microbial communities.

In contrast, the other organisms listed—like rotifers, spirilla, and amoebas—are not specifically associated with low oxygen and nutrient deficiency in the same way. Rotifers and amoebas, for example, tend to thrive in more stable, well-oxygenated environments, while spirilla are known for their motility and are less dependent on specific nutrient levels compared to filamentous bacteria. Thus, the association of filamentous bacteria with scenarios of low dissolved oxygen and nutrient deficiency is critical for understanding their role in aquatic ecosystems, particularly in the context of wastewater treatment.