Wetlands'nature's kidneys’

Definition of wetland(s) -Lands covered with water all or part of a year

-Interface between Terrestrial and aquatic ecosystems- They have been called as 'nature's kidneys’ Characteristics of wetlands

• There are three characteristics that describe a wetland:1. Hydrology

– There must be water at or near the surface of the land for a designated amount of time.

2. Soils – Must be hydric or saturated with water to create an anaerobic

(oxygen-free environment).3. Plants

– Must be “wetland plants,” meaning that they require lots of water and the anaerobic conditions that the hydric soil creates. (Smith & Smith, 2001)

Two components of hydrology

1. Physical Characteristics

– Precipitation, surface and subsurface flow, direction, chemistry, and kinetic energy of the water.

2. Hydroperiod– Duration, frequency,

depth, and flood season

Hydrology

• Basin Wetlands (lakes and ponds)– Physical: Water flow is vertical

(precipitation)– Hydroperiod: Long with floods during

periods of high rainfall.

Classification of wetland on the basis of hydrology

• Riverine Wetlands (periodically flooded banks of rivers and streams)– Physical: Water flow is both vertical

and horizontal (precipitation and stream/river flow)

– Hydroperiod: Have short periods of flooding with stream/river flow.

Basin Wetlands

Riverine Wetlands

• Fringe Wetlands (along coastal areas of large lakes and oceans)

– Physical: Water flow is both vertical and horizontal (precipitation and tidal flow)

– Hydroperiod: May be short and regular. Is not seasonal like basin wetlands.

Classification of wetland on the basis of hydrology

Three types of soils

1. Sandy soils– Contain mineral grains ranging from 0.05-2 mm

in diameter.2. Silt soils

– Soils that have grains ranging from 0.002-0.05 mm in diameter.

3. Clay soils– Contain mineral grains smaller than 0.002 mm in

diameter.

Soil

Soil Properties

• Sandy soils– Has good drainage and aeration– Does not store water well– Is not suitable for most plants

• Silt Soils– Soils made from minerals– Granule sizes are between sandy and

clay.– Also known as “rock flour” or “stone

dust” when produced by glaciers

• Clay soils- Hold water very well- Do not drain water easily- Do not have space for air- Is not suitable for most plants

Sandy soils

Silt Soils

Clay soils

• If a plant is native to a particular area, then it is originally from that area

– Native plants provide food and habitat for native animals. Without this, the native animals may be forced to migrate to areas.

– Native plants also keep local genes viable and in the gene pool.

Wetland Plants

• Exotic plants were not originally in the area and have been carried to the area in some way.

– Exotic plants can become invasive where they dominate the ecosystem preventing opportunities for growth for the native plants.

– Exotic plants also out grow native plants because they have no native predators.

– Invasive exotic species are the second leading cause of native species extinction (habitat loss being number one).

Native vs. Exotic

Benefits of Aquatic Plants

• Primary Production– Wildlife Food– Oxygen Production

• Shelter– Protection from predation for small fish

• Fish Spawning– Several fish attach eggs to aquatic macrophytes– Some fish build nests in plant beds

• Water Treatment– Wetland plants are very effective at removing

nitrogen and phosphorous from polluted watersPhytoremediation

Submerged macrophytes can provide shelter for young fish as well as house an abundant food supply.

Some fish will attach their eggs to aquatic vegetation.

Alligators also build nests from vegetation.

Wetland Life – The Protists

• One celled organisms (algae, bacteria)– Often have to deal with a lack of oxygen

• Desulfovibrio – genus of bacteria that can use sulfur, in place of oxygen, as a final electron acceptor– Produces sulfides (rotten-egg smell)

• Other bacteria important in nutrient cycling– Denitrification

Phytoplankton

• Single celled• Base of aquatic food web• Oxygen production

CO2 + H20 H2CO3 H+ + HCO3- 2H+ + CO3

2-

As CO2 is removed from the water pH increases.

Solar Energy + CO2 + H20 C6H12O2 + O2

Photosynthesis:

General Types of Aquatic Macrophytes

• Submergent – Plants that grow entirely under water. Most are rooted at the bottom and some may have flowers that extend above the water surface.

• Floating-leaved – Plants rooted to the bottom with leaves that float on the water surface. Flowers are normally above water.

• Free Floating – Plants not rooted to the bottom and float on the surface.

• Emergent – herbaceous or woody plants that have the majority of their vegetative parts above the surface of the water.

Floating-Leaved Plants

Free Floating Plants

Emergent

Plants

Human-made wetlands

– Aquaculture ponds (e.g., fish/shrimp); – Irrigated land (rice fields);– Seasonally flooded agricultural land (pastures); – Salt exploitation sites;– Water storage areas; – Excavations (gravel/brick/ clay pits);– Canals and drainage channels; – Wastewater treatment areas;

Freshwater Marshes

• Very diverse group• Non-tidal, freshwater systems• Dominated by grasses, sedges, and other

freshwater emergent hydrophytes (non-forested)

• High productivity• Approximately 20% of world’s wetlands

Description of some wetlands

Freshwater Marshes Photo/ Example

Freshwater Marshes

Chemical Functions of Wetlands

• Pollution Interception– Nutrient uptake by plants– Settle in anaerobic soil and become reduced– Processed by bacterial action

• Toxic Residue Processing– Buried and neutralized in soils, taken up by

plants, reduced through ion exchange– Large-scale / long-term additions can exceed a

wetland’s capacity– Some chemicals can become more dangerous

in wetlands (Mercury)

Mercury Chemistry

• Elemental mercury (Hg0) – Most common form of environmental mercury – High vapor pressure, low solubility, does not

combine with inorganic or organic ligands, not available for methylation

• Mercurous Ion (Hg+)– Combines with inorganic compounds only– Can not be methylated

• Mercuric Ion (Hg++)– Combines with inorganic and organic

compounds– Can be methylated CH3Hg

Methylation

• Basically a biological process by microorganisms in both sediment and water– Mono- and dimethylmercury can be formed– Dimethylmercury is highly volatile and is not

persistent in aquatic environments• Influenced by environmental variables that affect both

the availability of mercuric ions for methylation and the growth of the methylating microbial populations.– Rates are higher in anoxic environments,

freshwater, and low pH – Presence of organic matter can stimulate growth

of microbial populations, thus enhancing the formation of methylmercury

Methylmercury Bioaccumulation

• Mercury is accumulated by fish, invertebrates, mammals, and aquatic plants.

• Inorganic mercury is the dominate environmental form of mercury, it is depurated about as fast as it is taken up so it does not accumulate.

• Methylmercury can accumulate quickly but depurates slowly, so it accumulates– Also biomagnifies

• Percentage of methylmercury increases with organism’s age.

Chemical Functions of Wetlands

• Waste Treatment• High rate of biological activity

• Can consume a lot of waste• Heavy deposition of sediments that bury waste• High level of bacterial activity that breaks down and

neutralizes waste

• Several cities have begun to use wetlands for waste treatment

Biological Functions of Wetlands

• Biological Production– 6.4% of the Earth’s surface 24% of total global

productivity– Detritus based food webs

• Habitat– 80% of all breeding bird populations along with

>50% of the protected migratory bird species rely on wetlands at some point in their life

– 95% of all U.S. commercial fish and shellfish species depends on wetlands to some extent

What happens when wetlands are destroyed?• Destruction of wetlands can cause many problems such

as:– Increased floods– Water quality problems– Population decrease in plants and animals that live in

wetlands

Water storage and purification Biodiversity protection Sediment retention Groundwater replenishment Climate change mitigation Recreation/tourism Cultural value

Wetland helps

Loss of wetlands• Building of dams • Channelization of riverbeds • Overexploitation of wetlands resources• Introduction of invasive species• Developmental activities and population pressure• Water pollution and dumping of waste

• We have lost an estimated 50% of our original wetlands in the world.

Area Estimates of Wetlands of India (in million ha)

(Source: Directory of Asian Wetlands, IUCN, 1989)

Wetlands in India There are 19 different types of wetlands in India. It includes mangroves, high-altitude lakes, marshes and ponds. It covers an estimated 3 percent of India's land area.

Various wetlands in India

Various wetlands in India cont..

Projects on Wetland Conservation in Uttarakhand

• The two conservation reserves – Jhilmil Jheel in Haridwar and Asan Barrage in DehraDun districts – are being established under the 2003 parliamentary amendment made in the Wildlife (Protection) Act 1972 with a view to seek greater community involvement in protecting extremely critical wildlife.

• FRI Dehradun is engaged in a Wetland Conservation project.

• A special project undertaken by ZSI Northern Regional Circle, Dehradun for conservation of Swamp Deer.

• Wild life institute of India Dehradun also played a pivotal role in Swamp Deer conservation

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