Algae blooms, a colorful threat to the aquatic ecosystem


TEHRAN – “Algal blooms” have negative effects on aquatic environments and lead to losses for the fishing sector, which are mainly caused by various factors such as climate change, rising temperatures, entry of effluents industrial, domestic, agricultural and human.

An algal bloom or algal bloom is a rapid increase or accumulation of the algal population in freshwater or marine water systems. It is often recognized by the discoloration of the water due to the pigments of the algae.

The term algae encompasses many types of aquatic photosynthetic organisms, both macroscopic multicellular organisms such as algae and microscopic single-celled organisms such as cyanobacteria. Algal bloom generally refers to the rapid growth of microscopic single-celled algae, not macroscopic algae. An example of a macroscopic algal bloom is a kelp forest.

An algal bloom is a rapid increase or accumulation of the algal population in freshwater or marine water systems. Algal blooms are the result of a nutrient, such as nitrogen or phosphorus from fertilizer runoff, entering the aquatic system and causing excessive algae growth. A proliferation of algae affects the entire ecosystem.

The consequences range from benign eating of higher trophic levels to more harmful effects like preventing sunlight from reaching other organisms, causing depletion of oxygen levels in the water and, depending on the organism. , secreting toxins into the water.

The process of excess nutrient intake leading to algae growth and oxygen depletion is called eutrophication. Blooms that can injure animals or the ecology are called “harmful algal blooms” (HABs) and can result in the death of fish, cities shutting off residents, or states shutting down fisheries.

Various factors such as increasing greenhouse gases, hydrological factors and massive changes in global climate, movement and transfer of non-native species are involved in the occurrence of algal blooms, the most of which are Important are the rise in temperatures linked to climate change and an increase in nutrients, in particular phosphorus and nitrates, which enter the seas and then the oceans, discharging industrial, domestic and agricultural effluents containing chemical fertilizers.

When algal blooms increase and spread over a large area of ​​water, they eventually lead to sedimentation and destruction of fish gills, which ultimately results in the death of fish and other aquatic organisms.

In recent years, increased algal blooms in the Caspian Sea, Persian Gulf and Arabian Sea have caused great damage to fishermen and locals, in addition to animal species and aquatic animals.

Recently, Behrouz Abtahi, director of the National Institute of Oceanography and Atmospheric Sciences, said algae blooms are having negative effects on aquatic environments. Monitoring of phenomena in northern and southern waters is therefore on the agenda.

Being of great importance, it is one of the few projects in which countries are working together to tackle the issue internationally, he added.

But over the past decade, what has made algal blooms significant has been the increase in the number and variety of such blooms, in part due to climate change and rising global temperatures.

This proliferation has negative effects on aquatic environments so that some changes caused by algal blooms are irreversible, several strategies are therefore proposed to deal with it, including the use of birds to cope with the thick cover. algal.

Manual collection of algae and the use of herbicides are known as strategies to deal with this phenomenon, he explained.


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