The Algal Apocalypse: How We Are Fueling Eutrophication

The biological implications of a rise in nutrient concentration are described as eutrophication. The term 'nutrients' refers to the ingredients required for primary production by plants and other photosynthetic organisms. Or in a way we can say everything starts when nutrients enter lakes and oceans. Remember that what we consider rubbish might be sustenance for plants and other animals.

Nutrients, like other plants, feed algae. Algae multiplies and obstructs sunlight. Plants die in the absence of sunlight. The algae eventually die as well. Bacteria consume the dead plants, depleting oxygen and emitting carbon dioxide. Eutrophication can happen in any aquatic system whether it is freshwater or marine, and the term is what is used to explain the process through which nutrient-enriched soil water affects terrestrial vegetation.

Nutrient richness stages -> Oligotrphic >mesotrophic >eutrophic >hypertrophic

Can Eutrophication occur naturally?

Without human intervention, habitat eutrophication can also occur. Nutrient enrichment can have an impact on habitats of any initial trophic status, resulting in unique alterations in plant and animal groups.

The process of primary succession is typically related with the progressive eutrophication of a place as nutrients are obtained and retained by vegetation in the soil as living tissue & organic matter.

There is a theory known as natural eutrophication. All lakes, large or small ponds, and reservoirs have a finite lifespan, ranging from a few years for shallow amounts of water to thousands of years for deep crater lakes formed by Earth's crustal processes.

They progressively fill in with silt and become shallow enough for plants anchored in bed sediment to predominate, at which time they evolve into a closed marsh or fen and are eventually colonized by terrestrial flora.

The addition of sediment, rainfall, and the death of resident animals and plants, as well as their excreta, all contribute to nutrient enrichment.

Beginning from an oligotrophic phase with low productivity, a typical temperate lake's productivity rises relatively rapidly as nutrients accumulate, eventually attaining a constant state of eutrophy that can endure for a very long time (perhaps hundreds of years).

It is possible, however, for a water body's nutritional status to change over time and for its trophic state to change as a result.

How are humans responsible?

Although eutrophication occurs regardless of human activity, it is increasingly being caused or exacerbated by it.

Human activities are producing unprecedented levels of pollution in water sources and soils, resulting in a variety of symptomatic changes in the water quality as well as species and communities of related creatures.

Human accelerates the process due to the various activities they perform like the use of fertilizers for agricultural purposes.

The fertilizers are firstly absorbed by the soil, then when the soil reaches the saturation level, the excess amounts gets washed to the water bodies in the vicinities. This adds up the nutrient level in those water bodies.

Other things like dumping of wastes in the water bodies like lakes or ponds in the localities also fuels up the process of eutrophication.

This not only occurs in local municipal areas but also in those places where industries dispose of their wastes uncontrollably, amplifying the level of nutrients, and increasing the organic load deliberately.

How can it be managed?

There are many methods and options which can be used to reduce eutrophication. Here are few of the useful methods which can work.

• It may be possible in some cases to divert sewage effluent away from a body of water in order to minimize nutrient burdens. The sewer system might be altered to redirect effluent away from the lake. Effluent diversion should be considered only if the effluent to be redirected does not form a significant portion of the water supply for the aquatic body. Otherwise, the residence durations of water and nutrients will be extended, thereby negating the benefits of diversion.

• It is believed that sewage treatment plants contribute up to 45 percent of total phosphorus loadings to freshwater in the UK. This input can be greatly reduced (by 90% or more) by doing phosphate stripping. The effluent is pumped into a tank and treated with a precipitant, which mixes with phosphate in solution to form a solid that settles out and can be collected.

• Buffer strips can be used to minimize the amount of nutrients that reach water bodies as a result of runoff or leaching. They typically take the shape of vegetated strips of land adjacent to bodies of water: grassland, woodland, and wetlands have all been proved to be helpful in various conditions.

• Water oxygenation is used to restore ecological conditions by minimizing the negative impacts of the eutrophic process, such as oxygen scarcity and the generation of hazardous chemicals from anaerobic metabolism.

• Chemical phosphorus precipitation occurs when iron or aluminum salts or calcium carbonate are added to water, causing the precipitation of the respective iron, aluminum, or calcium orthophosphates, minimizing the deleterious effects associated with the high amount of phosphorus in the sediments.