major threats to freshwater ecosystem

1. Freshwater ecosystems, including rivers, lakes, wetlands, and aquifers, face numerous threats that can have detrimental effects on their
health and biodiversity. These threats are often interconnected and can exacerbate each other. Here are some major threats to
freshwater ecosystems:
1. Pollution:
 Chemical Pollution: Runoff from agricultural activities, industrial discharges, and urban areas can introduce chemicals
such as pesticides, fertilizers, heavy metals, and pharmaceuticals into freshwater ecosystems.
 Nutrient Pollution: Excessive inputs of nutrients, primarily nitrogen and phosphorus, can lead to algal blooms, oxygen
depletion, and overall water quality degradation.
2. Habitat Destruction and Alteration:
 Dams and Infrastructure: Construction of dams and other water infrastructure can alter natural flow patterns, disrupt
habitats, and impede fish migration.
 Urbanization: Expansion of urban areas often results in habitat loss, increased impervious surfaces, and altered
hydrology due to stormwater runoff.
3. Over-extraction of Water:
 Excessive Water Withdrawals: Over-extraction of water for agriculture, industry, and domestic use can lead to
lowered water tables, reduced streamflows, and the depletion of aquifers.
Threats to freshwater ecosystem

2. Cont.
Climate Change:
 Temperature Changes: Rising temperatures can impact freshwater ecosystems by affecting the
metabolism and distribution of aquatic species. It can also lead to changes in precipitation patterns,
altering water availability.
 Extreme Weather Events: Increased frequency and intensity of floods and droughts can disrupt
freshwater ecosystems, causing habitat destruction and threatening aquatic life.
Invasive Species:
 Introduced Species: Non-native species can outcompete native species, alter food webs, and disrupt
ecosystem dynamics. Some invasive species can also introduce new diseases.
Overfishing:
 Unsustainable Fishing Practices: Overfishing can deplete fish populations, disrupt food webs, and
lead to the collapse of fisheries

3. Restoration practices of freshwater ecosystem
 Protecting or restoring freshwater ecosystems can mean improving water quality,
monitoring and altering the land use around these ecosystems and avoiding or reversing
human interventions to the natural processes. Few measures that are crucial for
freshwater restoration are:
– Access: Creation of easy access points for animals to drink, boats to land and humans
to fetch water in order to reduce erosion. These measures when adopted with
community involvement could secure the vegetation and fish spawning grounds from
human intervention.
– River flow: Removal of dams that are no longer serving their original intended
purpose to reinstate the primal flow of rivers. For example, Yecla de Yeltes Dam in
western Spain was demolished in 2018 to restore the Huebra river under EU’s Water
Framework Directive.
– Water quality: Reduction and treatment of wastewater and effluent to stop
polluted water from entering the water streams.

4. Cont.
– Habitat: Insects are the main source of food for many fish. Plantation
of indigenous plants along the banks enables creation of a suitable
habitat for insects thereby positively impacting fish population.
– Fish Passage: Building fish corridors or fishways for easy movement of
fish and other species to facilitate their movement.
 Invasive Species Management: Implementing strategies to control
or eradicate invasive species helps protect native flora and fauna.
 Community Engagement and Education: Raising awareness and
involving local communities in restoration projects can contribute to
long-term success.

5. Phytoremediation
 Phytoremediation is a sustainable and environmentally friendly approach to remediate
contaminated soil, water, and air using plants. The term "phytoremediation" is derived from the
Greek words "phyto," meaning plant, and "remedium," meaning to correct or remove an
undesirable condition. This process relies on the ability of certain plants, known as
hyperaccumulators, to absorb, accumulate, and sometimes transform pollutants from the
environment.
 There are several types of phytoremediation techniques, each tailored to address specific types of
contaminants:

6. Cont.
1. Phytoextraction:
 In phytoextraction, plants are cultivated to absorb and accumulate contaminants from the soil into
their tissues.
 Hyperaccumulator plants, which can accumulate high concentrations of heavy metals or other
pollutants, are often used.
 Once the plants have absorbed the contaminants, they can be harvested and disposed of
properly, removing the pollutants from the site.
2. Phytostabilization:
 Phytostabilization aims to immobilize contaminants in the soil, preventing their movement and
reducing their bioavailability.
 Certain plants are selected for their ability to reduce the mobility of pollutants, such as heavy metals,
by promoting soil stabilization through root systems and altering the chemical conditions in the
rhizosphere (the soil zone influenced by root activity).

7. cont.
1. Phytodegradation:
 Phytodegradation involves the use of plants to break down or transform contaminants into less toxic forms through
various metabolic processes.
 Plants may produce enzymes or compounds that facilitate the degradation or transformation of organic pollutants in the soil
or water.
2. Phytovolatilization:
 In phytovolatilization, plants absorb contaminants from the soil and release them into the atmosphere in a volatile form, which
can be subsequently captured or dispersed.
 This method is often used for metalloids like selenium or certain volatile organic compounds.
3. Rhizofiltration:
 Rhizofiltration involves using the root systems of plants to filter contaminants from water.
 Plants with high water uptake and pollutant accumulation capacities are grown in areas with contaminated water, and their
roots absorb and accumulate the pollutants.