Final answer:
Algal blooms can cause oxygen depletion leading to 'dead zones,' produce toxins harmful to humans and the economy, and change the pH of water affecting multiple organisms' metabolic processes.
Step-by-step explanation:
One of the significant negative effects of algal blooms on the environment is the depletion of oxygen in the water, leading to the creation of 'dead zones.' When algae proliferate excessively, they eventually die and sink to the bottom, where their decomposition by bacteria consumes a substantial amount of the available oxygen. This process can create an environment where fish and other aquatic animals are unable to survive due to the lack of oxygen. Furthermore, some algal species produce harmful toxins that affect human health and the economy by contaminating seafood and causing the closure of fisheries.
The resulting dead zones and toxic effects also alter the pH of the water, which can interfere with metabolic processes for many organisms. The change in pH levels can further lead to detrimental effects on the ecosystem, impacting species diversity and functionality. Additionally, the significant alteration of the ecosystem can affect photosynthetic and non-photosynthetic organisms, depending on the type of algal bloom and the resulting environmental conditions.