What happens if there is reduced oxygen concentration in water?

Reduced oxygen concentration in water significantly impacts the respiration of aquatic organisms. Aquatic animals, such as fish and invertebrates, rely on dissolved oxygen for cellular respiration—a process essential for converting food into energy. When oxygen levels drop, these organisms struggle to obtain sufficient oxygen, leading to decreased rates of respiration. This can result in diminished energy production, affecting their growth, reproduction, and overall survival.

In contrast, increased aquatic plant growth typically requires higher levels of dissolved oxygen, as plants also benefit from photosynthesis, which produces oxygen. Enhanced filtration processes are not directly influenced by oxygen levels; rather, they depend on water movement and the presence of filter-feeding organisms. Increased bacterial activity can occur in low-oxygen environments, particularly in decomposing organic matter, but this does not directly relate to the respiration of aquatic beings. Therefore, the key consequence of reduced oxygen concentration is the decreased ability of aquatic organisms to perform respiration effectively.