EUTROPHICATION
A process in which nutrients and sediments from near
water or environment enter into a waterbody and increase in its fertility and
make it shallower. But due to human activities and other reason this natural
process gets faster and cause aging of lakes and making it less recreative for
sustaining life due to more algal blooms and plant growth.
Eutrophication is actually the aging process of lakes
which is natural. The natural eutrophication occurs after thousands of years
when the lake gets old but human speed up this process by discharging the
nutrients into the lakes which cause Lake Eutrophication.
The causes of Lake Eutrophication are:
Fertilizers
When human keep on using nitrate and phosphate
fertilizers on the golf courses, fields and on lawns these nutrients get washed
by the rain water and runs into the rivers, lakes and oceans. The algae,
plankton and the aquatic plants fed on them and through this they increase the
photosynthetic activity. As a result algal blooms grow and increase in the
plant life which results in Lake Eutrophication.
Animal Feeding Operations
Concentrated Animal Feeding operations discharge nutrient
that easily find their way to the lakes, nearby water bodies, rivers and oceans
and there they accumulate causing the production of algal Blooms and
Cyanobacteria.
Sewage and Industrial Water Discharge
Sewage water system is not very advanced in the
developing countries, they discharge their water directly into oceans, lakes
and river. The sewage water contains high amount of the different nutrients
which cause the high growth of aquatic plants and nutrients which cause harm to
the fishes and all the aquatic animals. The same results are with the discharge
of industrial waste water. It shows the same outcomes because it contains large
amount of chemical nutrients which causes Lake Eutrophication.
Aquiculture
The Aquiculture is the technique to grow the fishes,
aquatic plants and shell fishes in the controlled environment without soil
which contains nutrients for their growth. If the Aquiculture is not properly
managed this can cause lake eutrophication. The nutrients and the food
particles which are not fully consumed along with the fish excretion when
discharged in the water bodies it causes the synthesis of Algal blooms and the
microscopic floating plant.
Natural Events
Some of the natural events like flood causes the flow of
nutrients from the land to the water bodies and cause the growth of algal
blooms.
Reduction of Self Purification Capacity
When the lakes grow old over the years, they accumulate
the large quantity of sediments (solid material transported by water). These
sediments are able to absorb nutrients and pollutants. Over time these
sediments start filling the basin and increase the interaction of water with
these sediments which causes the resuspension of nutrients that are present at
the bottom is facilitated. This harms the water quality and cause lake
eutrophication.
Accumulation of Inorganic Contents
The process of eutrophication happens due to
phytoplankton and inorganic nutrients accumulation in the water body. Inorganic
nutrients such as nitrogen and phosphorus, play an active role in the process.
Some of this nutrient accumulation is caused by periodic flooding and rains,
which bring different type of chemicals to the water. However, the main culprit
for spread inorganic chemicals is human interference, including run-off from
lawns or fertilizer manufacturers. The introduction of nitric and phosphoric
acids makes the environment a temporarily acidic nutrient haven for plant life.
SIDE-EFFECTS OF EUTROPHICATION
The most notable effects of eutrophication on lakes are increase
in toxic content and decrease in the overall biodiversity in the area.
·
Phytoplankton (microscopic algae) can grow out
of control due to the increased nutrient content made available through
photosynthesis. Sucking off the nutrients, and leaving none for other
organisms.
·
Along with phytoplankton which are plant in
nature, zooplanktons and gelatinous zooplanktons find eutrophic waterbodies as a
safe haven and an opportunity for them to grow faster.
·
Both type of algae (epiphytic and bethnic) is
observed to grow in number an where bethnic algae may serve as a food source,
increased quantities only elevate the toxicity levels of the lake. The water loses
its transparency and develops a bad smell and color. The treatment of this
water becomes difficult.
·
Eventually, this leads to bad odor and taste,
since the pH is disturbed, leading towards a more untreatable situation.
·
The oxygen that is naturally being produced within
the water and is taken from the air is consumed forcibly by the algal blooms, leaving
nothing behind for fishes and pioneer species in the area, leading to the
eradication of oxygen.
·
Native species like white fishes in Europe
get exiled from their territories due to unlivable environment.
·
The situation is also bad from an economic
point of view, since many fish farms or people making a living out by selling
fresh marine lives as the number of harvestable oysters and shellfishes are
lowered.
·
Above all the aesthetic nature of the lake is
destroyed.
Ecological Effects
Generally, natural water, with an undisturbed pH, ranges
somewhere between oligotrophic (no nutrients) and eutrophic (nutrient rich).
The vertical structure of lakes is often affected by eutrophication. Human activities
play a key role in disturbing the ecological balance of lake.
Primary producers (algae) are the biggest cause of eutrophication.
They are provided the chance to ‘bloom’ when nutrients (artificial or natural
means) present themselves on the lake side in surplus amounts. The algal blooms
then do two very important things, firstly they suck off all the dissolved oxygen
leaving behind an uninhabitable waterbody and secondly form an impermeable
sheet that does not allow sunlight to reach the marine life beneath it. The
effect of these algal blooms are witnessed, when the water body reaches a
hypoxic level for oxygen. Eventually, the biodiversity starts to diminish as a hypoxic
level of eutrophication induces suffocation and death on the marine life.
A variety of algae prove to be toxic for the environment.
Algae like cyanobacteria are told to have neurotoxin and hepatotoxin effects on
plants and animals. It is understood that due to food chain, many of these
toxic deleterious effects can move up towards marine life and also land animals
and plants. Humans consume seafood as a luxurious food item and also because of
its unrivaled nutrient content. Still, toxic algal blooms can lead to more harm
than good as they are responsible for being neurotoxic, paralytic, as seen in
diarrhetic shellfish poisoning.
REMEDIAL SOLUTIONS TO THE ISSUE OF EUTROPHICATION
Once algal blooms are established, it becomes more
difficult to treat them. So, the main control mechanism of the eutrophic
process should be focused on prevention techniques. The major factor leading
towards the eutrophication is the discharge of excessive nutrients into the
water bodies. The wastewater should be filtered before releasing it into a lake
or stream.
Reduction of Phosphorus Contents in Detergents
Frequent use of detergents causes excess of phosphates which
in turn increases eutrophication of the water bodies. Fluctuation of phosphorus
loads in wastewater is noted with respect to consumption of phosphate in
detergents. So, we can say that removal or decrease of phosphorus in detergents
can be beneficial in management of eutrophication. Now industries use decrease
amount of phosphate in detergents, but if we want to decrease phosphorus load
on lakes in future, we should ban completely phosphorus use in detergents that
will lessen 30% more phosphorus from sewage. Therefore, the utmost need is improvement
of quality of water by using different environmental techniques for control of discharged
wastewater from treatment plants, replacing phosphorus with some suitable
element in detergents, education of consumers so that they can select washing
products having a smaller number of pollutants.
Biological Solutions
Addition of periphytons in waterbodies help greatly in
decreasing eutrophication. They actually help by consuming excess nitrogen and
phosphorus from water and decline eutrophication. In the process of
photosynthesis, they increase pH of the surrounding environment and as a result
calcium phosphate precipitates are formed so phosphorus is buried for long term
and eutrophication process is lowered or inhibited.
There are some species of macrophytes that seems helpful
in case of eutrophication problem. Eichhornia crassipes, Salvinia auriculata,
and Phragmitis communis are known to cause reduction of phosphorus and nitrogen
in waterbodies. So, they can be helpful in managing eutrophication process in
lakes. Duckweeds are also beneficial for treatment of waterbodies and removing
excess ammonia and nutrients from it.
RECOMMENDATIONS FOR RECOVERY OF WATHER
BODIES/ LAKES
Following are some recommendations for recovery of
affected lakes and safety of other waterbodies.
·
For recovery and protection of waterbodies,
public education campaigns should be organized in which causes of
eutrophication and how public can play their roles should be demonstrated.
·
Protection from nitrates and phosphorus
should be carried out by safe farming practices and there should be check and
balance on them by government.
·
Water discharge from industries and urban
sector should be handled and treated properly before its entry into waterbodies
to lower the eutrophication process.
·
Government should introduce macrophyte plants
in such lakes and also encourage public to do so.
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This article has been shared by
the following authors to PAKAGRIFARMING.
Authors: Noorulain, Rameesha
Abid, Kainat Tariq & Raed Muhammad Sajjad Al Qazi
