Water Quality and Pollution

Ceratium furca blooms because of coastal eutrophication. Blooms of this species cause toxic red tides (red-brown), damage fish gills and deplete dissolved oxygen causing anoxic conditions

Chlorella is very popular in Japan. It is also used as a nutritional supplement with possible effects on metabolic rate.It can reduce mercury levels in humans by chelation of the mercury to the cell wall of the organism.

Oscillatoria, is part of the Blue Green Algae (Cyanobacteria) family. It is blue greenish in colour, usually free floating, cylindrical or sometimes slightly tapering, unbranched filaments in aquatic environments.It is implicated in irritation of skin and mucous membranes suffered by people swimming.

Biological treatment of water pollution uses microorganisms like phytoplankton to consume organic pollutants. Phytoplankton (C) are microscopic aquatic organisms that help purify water naturally. Lichens are typically air quality indicators. Fungi decompose matter but are more common in terrestrial environments. None of the above is incorrect since phytoplankton is valid.

Industrial effluents contain toxic chemicals and heavy metals that contaminate water bodies. These wastes from factories and manufacturing processes are a major source of water pollution worldwide. The other options are natural processes or part of aquatic ecosystems.

Microorganisms like bacteria break down organic matter in sewage through biological treatment processes. Sewage treatment plants use these microbes to purify water before it's recycled or discharged back into water bodies. This is a natural and effective way to treat wastewater.

BOD (Biochemical Oxygen Demand) measures how much oxygen microorganisms need to decompose organic matter in water. Sugar mills discharge large amounts of organic waste that increases BOD, potentially depleting oxygen levels for aquatic life. Higher BOD indicates more severe pollution.

Water pollution reduces dissolved oxygen levels, making oxygen unavailable to aquatic organisms. When organic pollutants decompose, they consume oxygen through bacterial action. This oxygen depletion can lead to fish kills and ecosystem collapse in severely polluted waters.

Thermal discharge heats up the water, destroy aquatic life, decreases oxygenation and increase the toxicity of toxic pollutants.

Algae increase BOD (Biochemical Oxygen Demand) in water bodies. When algal blooms die and decompose, bacteria consume significant amounts of oxygen during the decomposition process, leading to higher BOD values that can harm aquatic ecosystems.

BOD (Biochemical Oxygen Demand) measures the amount of dissolved oxygen consumed by microorganisms in water. A BOD level of 5 ppm is the standard maximum acceptable limit for fresh water to maintain aquatic life and prevent oxygen depletion. Higher BOD levels indicate organic pollution and can lead to eutrophication.

Ceratium furca blooms because of coastal eutrophication. Blooms of this species cause toxic red tides (red-brown), damage fish gills and deplete dissolved oxygen causing anoxic conditions.

Oscillatoria is part of the blue-green Algae (Cyanobacteria) family. It is blue-green in colour, usually free floating, cylindrical or sometimes slightly tapering, unbranched filaments in aquatic environments. It is implicated in irritation of skin and mucous membranes suffered by people while swimming.

Continuous sewage flow introduces organic matter and nutrients that stimulate excessive bacterial growth. These bacteria consume oxygen for decomposition, leading to oxygen depletion. Eutrophication and algal blooms are earlier stages; oxygen depletion is the direct consequence that harms aquatic life.