Estuary: In simple terms, it is a brackish water body between marine and river environments. The transition zone between the marine environment and the river environment is called an ecotone. The streams and rivers flow into the partially enclosed water body of the estuary which is connected to the sea from one side.
The various factors that influence the salinity and density of estuaries are tides, waves, climate, etc. An estuary varies with salinity making it a unique habitat for particular biodiversity. Some dry areas between land and sea that are exposed to tidal action/waves often act as estuaries.
Estuaries of Pakistan
There are a number of estuaries present in Pakistan located along the Indus River that leads up to the Indus Delta. Freshwater from the river flows into these estuaries and merge with saline water from the Arabian Sea.
Location of Estuaries in Pakistan
The coasts of Pakistan have three major estuaries. One out of three is present along the coastline of Sindh while others are located along with coastal areas of Baluchistan.
The two estuaries in Baluchistan are known as Dash and Hingol. Both estuaries are dependent on seasonal variations forming small deltas and have minimal to no vegetation at all. Check out Dire Need of Sea Water Desalination Plants in Baluchistan Pakistan
The estuary in Sindh is known as the Indus estuary that finishes up in the Indus Delta. The Indus delta is present at the inlet of the Indus River. This delta is covering approximately the total coastal area of Sindh primarily south of Karachi. It makes a landform that has mudflats. Narrow creeks of old Indus estuaries are intervening in these mudflats formed by Indus Delta.
Importance of Estuaries
The ecosystem of estuaries supports a diverse variety of biodiversity including animals, aquatic plants, shellfish, fishes, etc. Estuaries are protected water that provides ranges of habitats to many species. The biodiversity includes sea lions, sea turtles, seagrass, pelicans, etc.
Estuaries have huge economic importance due to their presence along coastal areas as well as fishes are being caught for livelihoods. The Indus Delta enriched with fishes is more often used as a hub for seafood export.
Estuaries play an important role in marine and aquatic ecosystems because it filters pollutants. The pollutants include heavy metals, herbicides, pesticides, etc. These estuaries act as natural filters for environmental pollutants.
Environmental Degradation of Estuaries
There are a number of factors accountable for the environmental degradation of estuaries in Pakistan. These are human activities and natural events. Natural events are floods and sea storms. Human activities that degrade estuaries include urbanization and coastal development.
Other factors that are threatening the ecosystem of estuaries include increased level of sedimentation, nutrients flow resulting in algal bloom, climate change, invasive species, pollutants and toxins, unsustainable use of estuaries for economic benefits, etc.
Any part of the ecosystem if subjected to environmental degradation will definitely trigger the adverse consequence. The biodiversity-rich estuaries in Pakistan are important transitional zone between the land and marine ecosystem. It is a natural resource that gives value to the economy of the nation. Estuaries should be protected from environmental degradation in order to preserve the natural ecosystem.
Also, check out Marine Pollution – Its Risky Effects on Marine Life & Humans
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– MS Environmental Science
– Content Writer
Researcher, Nature Lover, and Environmentalist