Final answer:
Uncontrolled growth of Lemna minor leads to reduced oxygen levels, altered water pH, and a disrupted ecosystem balance, affecting photosynthetic organisms, metabolic processes, and the food web.
Step-by-step explanation:
If the spread of Lemna minor, commonly known as duckweed, is not controlled in a body of water, there are several abiotic changes that are likely to occur:
Reduction in oxygen levels: As duckweed forms dense coverages on the surface of the water, it blocks sunlight from reaching other photosynthetic organisms. When these organisms, such as algae, cannot photosynthesize, they die, and their decomposition consumes dissolved oxygen, leading to hypoxic conditions which negatively affect fish and other aquatic animals.
Alteration of the water's pH: The death and decay of algae and other aquatic plants, as a result of the light blockage by duckweed, will lead to changes in the chemical composition of the water, particularly affecting the pH levels. This can disrupt the metabolic processes of aquatic life, potentially leading to mass deaths.
Disruption of ecosystem balance: The unchecked growth of duckweed can lead to a decline in biodiversity as it outcompetes other plants for light and nutrients. This can shift the balance of the ecosystem, leading to reductions in the populations of various organisms dependent on those plants, such as insects and amphibians, and affect the food web.