Algae Overgrowth: Pollution's Unseen Impact On Aquatic Ecosystems

Algal blooms are a rapid increase in the density of algae in an aquatic system. While they sometimes occur naturally, their frequency, duration and intensity are increased by nutrient pollution. This is caused by an overabundance of nitrogen and phosphorus in waterways, which can come from industrial and wastewater treatment plant discharges, septic tanks, stormwater runoff and nutrient-enriched rainfall.

Excess nitrogen and phosphorus cause an overgrowth of algae in a short period of time

The overgrowth of algae consumes oxygen and blocks sunlight from underwater plants. When the algae die, they decompose and consume the oxygen in the water, making it impossible for aquatic life to survive. This leads to the formation of hypoxic or dead zones, which are areas of water bodies where aquatic life cannot survive due to low oxygen levels. Dead zones are generally caused by significant nutrient pollution and are a problem for bays, lakes and coastal waters since they receive excess nutrients from upstream sources.

Algal blooms are sometimes natural phenomena, but their frequency, duration and intensity are increased by nutrient pollution

Algal blooms can turn the water noticeably green, although other colours can occur. Some species of algae grow in clumps covered in a gelatinous coating and have the capability to float, allowing cells to stick together into large surface scums in calm weather.

The overgrowth of algae consumes oxygen and blocks sunlight from underwater plants. When the algae die, the oxygen in the water is consumed, making it impossible for aquatic life to survive. This creates dead zones, which are areas of water bodies where aquatic life cannot survive because of low oxygen levels. Dead zones are generally caused by significant nutrient pollution and are primarily a problem for bays, lakes and coastal waters since they receive excess nutrients from upstream sources.

Dead zones are caused by significant nutrient pollution and are primarily a problem for bays, lakes and coastal waters

Dead zones are areas of water where aquatic life cannot survive due to low oxygen levels. They are generally caused by significant nutrient pollution, particularly an overabundance of nitrogen and phosphorus. These nutrients enter waterways from point sources, such as industrial and wastewater treatment plant discharges, and nonpoint sources, such as septic tanks and stormwater runoff from urban areas, farms and residential areas. When the concentrations of nitrogen and phosphorus increase in a water body, the right combination of temperature, sunlight and low flow can trigger an algal bloom.

Algal blooms are a rapid increase in the density of algae in an aquatic system. They can turn the water noticeably green and sometimes form large surface scums. The overgrowth of algae consumes oxygen and blocks sunlight from underwater plants. When the algae die, they further deplete the oxygen in the water, making it impossible for aquatic life to survive.

Dead zones are primarily a problem for bays, lakes and coastal waters since they receive excess nutrients from upstream sources. The frequency and duration of dead zones have increased since they were first noticed in the 1970s, impacting clear water, recreation, businesses and property values.

The overgrowth of algae consumes oxygen and blocks sunlight from underwater plants

Algal blooms are caused by an overabundance of nitrogen and phosphorus in the water. This can be caused by nutrient pollution, which comes from point sources such as industrial and wastewater treatment plant discharges, nonpoint sources such as septic tanks and stormwater runoff from urban areas, farms and residential areas, and from nutrient-enriched rainfall. When the concentrations of nitrogen and phosphorus increase in a water body, the right combination of temperature, sunlight and low flow can trigger an algal bloom.

Nutrient pollution can enter waterways from point sources (such as industrial and wastewater treatment plant discharges) and nonpoint sources (such as septic tanks and stormwater runoff)

Nutrient pollution can enter waterways from point sources, such as industrial and wastewater treatment plant discharges, and nonpoint sources, such as septic tanks and stormwater runoff. Point sources are defined as single, identifiable sources of pollution that discharge pollutants into a waterway. These sources can include industrial facilities, such as factories or power plants, and wastewater treatment plants, which release treated or untreated sewage into water bodies. Nonpoint sources, on the other hand, are more diffuse and challenging to identify. They include runoff from urban areas, farms, and residential areas, as well as septic tanks, which can leak nutrients into the groundwater that eventually reaches waterways.

Nutrient pollution, specifically the excess of nitrogen and phosphorus, is a significant contributor to algal blooms. These nutrients act as fertilisers, promoting the rapid growth of algae. When there is an overabundance of these nutrients in the water, often due to the sources mentioned above, the right combination of temperature, sunlight, and low flow can trigger an algal bloom.

Algal blooms can have detrimental effects on aquatic ecosystems. As the algae proliferate, they consume oxygen and block sunlight from reaching underwater plants, disrupting the delicate balance of the ecosystem. When the algae eventually die, their decomposition further depletes the oxygen levels in the water, creating hypoxic or "dead zones" where aquatic life cannot survive.

The impact of nutrient pollution and algal blooms extends beyond the ecological realm. Thick, green muck formed by algal blooms can affect clear water, impacting recreational activities, businesses, and property values. Additionally, the frequency and duration of dead zones have increased since they were first noticed in the 1970s, underscoring the urgency of addressing nutrient pollution and its consequences.

Frequently asked questions