Transcript gp 4 Aquatic_Ecosystems - Xavier Institute of Management

(Source: www.iucn.org )
(Source: www.iucn.org )
(Source: www.tenbysailingclub.org.uk )
AQUATIC ECOSYSTEM
A group of interacting organisms dependent on one another and their water
environment for nutrients and shelter. Familiar examples are ponds, lakes,
rivers, oceans, wetlands, etc..
• Marine ecosystem
71% of earth’s surface
97% of planet’s water
Presence of dissolved compounds, especially salts
Two major zones: coastal zone and open ocean
• Freshwater ecosystem
0.8% of earth’s surface
0.009% of planet’s water
<1% dissolved salts
Ponds and lakes; streams and rivers; wetlands
IMPORTANCE
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Regulation of climate and rainfall
Absorption of Carbon dioxide
Treasure house of biodiversity
Flood control and groundwater recharge
Nutrient recycling
Provide food, drinking water, irrigation
Hydropower, transportation, employment
Tourism Industry
THREATS/ HUMAN IMPACTS
• Destruction of the marine resources
by bottom trawling
• The mining of corals
• Water pollution from industries
• Hydrological alterations: dams,
barrages, channelisation
• Agricultural runoff can carry
fertilizers, including traces of
antibiotics and hormones, into
waterways
ZONES OF THE OCEAN
( Source:
CORAL REEFS
• Found in shallow coastal zones of
tropical and sub-tropical oceans,
where light can penetrate
• Formed by huge colonies of tiny
organisms called polyps
• Source of foreign exchange
Threats:
 Human contact
 Pollution
 Cyanide fishing
Locations of coral reefs
( Source: www.mbgnet.net )
 Temperature variations
Mangroves
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Mangrove forests thrive near the mouths of
large rivers where river deltas provide lots of
sediment (sand and mud).
Mangroves provide a safe haven and a
nursery for a variety of fish, birds, and
shellfish
In India: Andaman&Nicobar Islands,
Sunderbans(W.B.), Bhitarkanika (Orissa)
Freshwater Wetlands
• Land surfaces covered or saturated with
water
• Control flodding, water purification and
recharging groundwater
• In danger: disappeared and fragmented by
development
( Source: www.mbgnet.net )
CHILKA LAKE
(Source: www.ramsar.org )
CHILKA LAKE
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The largest brackish lake in India
• 71 km long
• up to 32 km wide
• Unique ecosystem, that includes an impressive
range of birds both native and migratory
• About 160 species of fish, other marine creatures,
including the famous Chilka dolphin are found
(Source : www.ramsar.org)
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Bird hunting.
• For some years, many villagers from the adjoining villages had been
poaching birds from the lake as their sole means of livelihood.
• The poachers kill almost 20,000 birds every year
• This activity was a serious threat to the populations of some species and
severely disturbed many other species which roosted or fed in the lake.
Pollution.
• Fertilizer and pesticide residues from nearby agricultural fields pose a
serious problem in the northern part of the lake.
• Similarly, sewage and the waste water from the peripheral small villages
and towns, including Balugaon and Rambha, is posing a pollution
Siltation.
• Soil erosion is prevalent in the catchment of Chilka due to over-grazing, illicit felling,
cultivation along hill slopes, and clearance of vegetation for rehabilitation and
agriculture.
• About 365,000 tonnes of sediment is now added annually to the lake through streams
of various sizes. This has resulted in siltation, reducing the area of the inlet and natural
connection to the sea.
• Restriction of the hydraulic capacity of the inlet that connects the lake to the sea has
reduced flushing of the lake and has led to a decrease in salinity and the loss of some
marine and brackish water species from the ecosystem.
Weed infestation.
• Increased siltation and decreased salinity has promoted the spread of major weed
species more tolerant of fresh and brackish water. These include Eichhornia crassipes,
Azolla pinnata, and Potamogeton pectinatus.
• Weed infestation increased from 20 km2 in 1973 to nearly 400 km2 in 1993.
• It has restricted the feeding and breeding grounds of many fish of economic
importance, and has also restricted the free flow of sediment.
SOLUTIONS
The CDA was created by the Government of Orissa in 1992 with the
objective of restoring the degraded lake ecosystem of Chilika Lake.
The principal objectives of the CDA are:
i) to protect the lake ecosystem and its genetic biodiversity;
ii) to survey, plan and prepare a proposal for integrated resource
management in and around the lake;
iii) to undertake multi-dimensional and multi-disciplinary
development activities; and
iv) to cooperate and collaborate with other institutions for
development of the lake
Positive changes observed
• An increase in salinity and
• A reduction in the rate of weed expansion, and it is anticipated
that the area covered with the weed will reduce gradually.
• Fisheries (fish, prawn and crab) yields have increased
dramatically.
• Since the opening of the lead channel to the sea and the new
lake mouth, fish landings have increased from a previous average
of 1600 metric tons to 4800 metric tons during 2000-2001. In
2001-2002 (up to December 2002), total landings have been 8000
metric tons and this may reach 11,000 metric tons for the full year.
The ecological restoration of the Chilka Lake is one of the best examples of multi
sectoral collaboration with Chilka Development Authority (CDA) playing the main
role. Other Stakeholders : Fishermen, Fishing companies, NGOs
Making a Difference
• The Ramsar Convention on Wetlands, signed in Ransar,Iran, in 1971, is
an intergovernmental treaty which provides the framework for national
action and international cooperation for conservation and wise use of
wetlands and their resources. There are presently 153 contracting parties to
the convention, with 1629 wetland sites, totaling 145.6 million hectares.
• Mother of the Ocean: Elisabeth Mann Borgese
"Conditions differ from region to region. Some consist of small,
unindustrialized countries, islands with vase ocean spaces between
them; others are industrialized throughout, still others (like the
Mediterranean) contain both industrialized and developing countries.
The differences may lie in their resource base, hydrological and
climatic conditions, or institutions infrastructures; each problem
calling for solutions of its own.... But they all have one thing in
common. The protection of the marine environment is a regional as
much as a national responsibility, and co-operation in safeguarding the
ecology of all is the basis for developing the economy of each."
( Source: www.worldfederalistscanada.org )
REFERENCES
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Environmental Studies – Rajgopalan
www.downtoearth.org.in
www.wikipedia.org
www.ec.gc.ca
www.chilika.com
www.ramsar.org
www.mbg.net
THANK YOU !!!
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DHEERAJ MEHRA -12
SHUBHA-49
SHYAM DAYAL SINGH-50
SUMIT GUPTA-54