Salt marshes are coastal wetlands flooded by salt water brought in by tides. They contain deep mud and peat made of decomposing plant matter. Salt marshes worldwide provide habitat for over 75% of fisheries species and protect shorelines from erosion. The salt marshes in Mannar district contain various plant species that have adapted to the saline soil conditions and fluctuating tides. Common plant species observed include Suaeda maritima, Suaeda monica, and Holosaciaindicum. Salt marshes are productive ecosystems that filter water and absorb flood waters, while also providing habitat for crabs, fish, and birds. However, they face threats from coastal development, erosion, and potential impacts of

1. H.M.N.P HERATH
University of Peradeniya
SALT MARSHES IN MANNAR

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Objectives
 To identify the salt marshes in mannar district
 To identify the flora and fauna in the salt marshes
 To identify the threads in the salt marshes in mannar
 To identify the importance of salt marshes
Introduction
Salt marshes are coastal wetlands that are flooded and drained by salt
water brought in by the tides. They are marshy because the soil may be
composedof deep mud and peat. Peat is made of decomposing plant
matter that is often several feet thick. Peat is waterlogged,root-filled,
and very spongy.Because salt marshes are frequently submergedby
the tides and contain a lot of decomposing plant material, oxygen levels
in the peat can be extremely low—a condition called hypoxia. Hypoxia is
caused by the growth of bacteria which produce the sulfurous rotten-egg
smell that is often associated with marshes and mud flats.
Salt marshes occur worldwide, particularly in middle to high latitudes.
Thriving along protected shorelines,they are a commonhabitat
in estuaries. These intertidal habitats are essentialfor healthy fisheries,
coastlines,and communities—and they are an integral part of our
economyand culture. They also provide essential food,refuge,or
nursery habitat for more than 75 percentof fisheries species,including
shrimp, blue crab, and many finfish.
Salt marshes also protectshorelines from erosionby buffering wave
action and trapping sediments.They reduce flooding by slowing and
absorbing rainwater and protectwater quality by filtering runoff, and by
metabolizing excess nutrients.

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Figure 1-salt marshes
The Gulf of Mannar lies between the southeastern tip of India and the
northwestern coast of Sri Lanka.
Figure 2- Location of the Gulf of Mannar
There are three types of salt marshes. Temperate countries have
marshes which covered by the tide most of the time during the day and
there vegetation is covered by grass species . Spartina alterniflora is the
major species.Most of the time they covered by grasses and grass grow

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very thin and soil is tightly bound the roots of the grasses and because
of there are lot of grasses dead leaves falls on the ground and they
decay. They form peat. Sulfur compounds produced because present of
the sulfur bacteria.
Values of a Salt Marsh
Salt marshes are important transitional habitat between the ocean and
the land; they are estuaries where fresh and salt water mix. Salt marsh
plants (halophytes) are salt tolerant and adapted to water levels that
fluctuate with the tide. Tides carry in nutrients that stimulate plant growth
in the marsh and carry out organic material that feeds fish and other
coastal organisms. Over time, salt marshes accumulate organic material,
forming into a dense layer called peat. Salt marshes are among the most
productive ecosystems on earth, rivaling that of an Iowa cornfield. The
position of salt marshes on the landscape and their productivity makes
them important not only as a part of the natural world but also to
humans.
 Act as a giant sponge
-The salt marsh absorbs large volumes of water, thus minimizing the
impacts of flooding and erosion and recharging groundwater. Salt marsh
plants help purify water by absorbing toxins and in some cases
metabolizing them into harmless substances. Most productive food
factories on earth.
 Recreation
-Kayaking, fishing, crabbing, boating, birding
 Economy
– Fishing industry
– Jobs in education, conservation, recreation, etc.
 Water Quality

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Water is filtered through grasses, roots, and soil.
– Filter feeders (like mussels and oysters) also filter the water)
Flood/Erosion Control
– Marshes act like giant sponges on the coast, absorbing water and
releasing it slowly.
 Habitat
Nursery habitat for blue crab, sharks, shrimp, fish
etc.
– Permanent home for Spartina, fiddler crabs, etc.
 Productivity
– Bacteria break down wrack into detritus
– This decompositionproduces hydrogensulfide (the rotten egg smell).
 Protection Against Waves and Sea Level Rise
Over the past 6,000 years, the ocean has risen many feet in elevation. It
is not uncommon to dig in a salt marsh and find the stumps of cedar
trees preserved underneath. Because salt marshes trap nutrients and
sediment, and build organic matter to form peat, they are able to grow
and keep pace with the rising ocean. Current forecasts call for the sea
level to rise at least another foot in the next 100 years. The salt marshes
will keep pace with this rise if we let them. The marshes also slow the
velocity of waves before they reach land and mitigate storm surges. In
places where marshes have been destroyed, winter storms are more
damaging
Zonation Salinity of water and soil determines zonation of
plants
often divided into two zones:
 Upper marsh (high marsh)

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-flooded irregularly. At least 10 days continuous exposure
 Lower marsh (intertidal marsh)
-flooded almost daily. No more than 9 days continuous exposure
Figure 3 –profile of a salt marsh
Characteristic feathers of salt marshes
 Saltmarsh dynamics
 Seasonal growth and dieback
 Halophytes and Glycophytes
 Seasonal biomass accumulation
 Rainfall and salinity affects vegetation cover/survival
 Seasonal behavior in animals e.g. birds
 Impact of grazing on plants and succession
 Biomass, productivity and energy flow
 Algal productivity: creek sides, plant stems
Physical and Chemical Variables
Important physical and chemical variables that determine the structure
and function of the salt marsh include: Salinity of water and soil ,Tidal
flooding frequency and duration Nutrient limitation

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Salinity
Salinity in the marsh soil and water depend on several factors:
 Frequencyof tidal inundation
 Rainfall
 Tidal creeks and drainage slopes
 Soil texture
 Vegetation
 Depth to water table
 Fresh water inflow
 Fossilsalt deposits
Lower marsh soils that are flooded frequently tend to have a fairly
constant salinity approximation that of the flooding seawater. ON the
other hand, the upper marsh that is only occasionally flooded experience
long periods of exposure that may lead to either higher or lower salt
concentrations. Frequent rainfall tends to leach the upper sill in the high
marsh of its salts; frequent periods of drought, on the other hand lead to
higher concentrations in the soil. The presence of tidal creeks and steep
slopes that drain away saline water can lead to lower soil water salinity
than that which would cover under poorly drained conditions. Silt and
clay materials tend to reduce drainage rates and retain more salt that
does sand. The vegetation itself has an influence on soil salinity.
Evaporation of water from the marsh surface is reduced by vegetation
cover, but transpiration is increased.The net effect depends on the type
of vegetation and the environmental setting. When groundwater is close
to the surface, soil water salinity fluctuations are less.The inflow of fresh
water in rivers, as overland flow, or in groundwater tends to dilute the
salinity in both the salt marsh and the surrounding estuary. The early
spring-flood periods along much of the eastern US coastal plain lead to
significant reductions in the salinity of downstream coastal marshes the
presence of fossil salt deposits in the substrate can increase salt
concentrations in the root zone
Frequency of tidal inundation-the lower salt marshes retain a consistent
salinity close to that of sea water. Rainfall-high rainfall tends to lower
salinity while periods of drought will increase salinity because of

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evaporation .Tidal creeks and drainage slopes-lower salinity because
they allow saline water to drain
Soil texture-silt and clay soils reduce drainage rates and retain more salt
than clay soils. Vegetation-evaporation is reduced by vegetation and
transpiration is increased. Depth to water table-when groundwater is
close to the surface, salinity is lower and more stable. Fresh water
inflow-reduces salinity. Fossil salt deposits-increase salinity in the root
zone
Salinity of Soil
In the lower marsh, the soil salinity is relatively constant and rarely
exceeds that of the flooding water. IN the upper marsh, there is more of
an influence from flooding and the climate. High rainfall will reduce soil
salinity. During dry periods, evaporation increases soil salinity.
Sometimes to the point that a salt crust will form
Water in tidal marshes is often brackish
Influence of freshwater from rivers and creeks and salt water from
ocean. Water table is near or above the soil surface. Influenced by ebb
and flow of tides.Little or no wave action
Influence of Tides
The environmental feature which distinguishes coastal salt marshes from
terrestrial habitats is tidal submergence
Tides control soil salinity degree of water logging carry sediment into the
marshes
Anaerobic Soil
When water fills in pore spaces in soils, rate at which oxygen can diffuse
through the soil is reduced. It is estimated that the diffusion of oxygen is
10,000 slower in flooded soil than in an aqueous solution

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Anaerobic Soil Surface –thin layer oxygenated soil
Lower layers-have decreased oxygen levels .prevents plants from
carrying out normal aerobic root respiration .as the oxygen concentration
declines, the carbon dioxide concentration increases. Peat formed
anaerobic conditions. High biomass-becomes trapped .does not
completely decompose compacted into peat
Human Impacts
The biggestthreats to salt marsh habitats are the Illegal encroachment.
Coastal erosion and storm damage also effects. These threats are
likely to continue or increase in the twenty first century due to climate
change
Observations
Plant speies obseverd in the field visit
Figure 4- Suaeda maritima

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Figure 5- Suaedamonica
Figure 6- Holosaciaindicum

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figure 7- salicornia brachiata
figure 8 -suaeda vermiculata
Figure 9- mangrove associated plant

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Animal species observed in the field visit
Figure 10- puththalam ass and there dung
Figure 11- chicoreus ramosus

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Figure 12- Cerithidea cingulata
Figure 13-unkown bird species
Figure 14-apple snail

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Figure 15-Gafrarium sp
Figure 16- whelk shell
Discussion
Salt marshes are found near mangroves, and are also adapted to flow
— in and out — of the daily tide. Plants that grow in salt marshes are
adapted to tolerate water flooding and changes in saltiness.
Salt marshes can be seen in Kaladi, Vankalai, Arrippu, inside the
Wilpattu, Ailay at Illuvankulam, inside the Mannar Island and in
Pallimunai.
In this region, most of the Salt Marshes are covered by non-woody,
small plants. These areas become extremelydry during the very long dry

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period and lose a lot of water, with the result that the area become very
salty. Often, salt can be seen in these habitats during the dry season.
Vegetation in salt marshes includes o Umiri (Scientific name: Suaeda
maritima and Suaeda vermiculata ).
These habitats are important for many reasons. Hiding among these
plants are animals in various stages of life. Umiri is used as a leafy
vegetable.
Suaeda maritima is an annual growing to 0.3 m (1ft). It is in flower from
July to October, and the seeds ripen from August to October. The
species is hermaphrodite (has both male and female organs) and is
pollinated by Wind. The plant is self-fertile. Suitable for: light (sandy) and
medium (loamy) soils. Suitable pH: neutral and basic (alkaline) soils and
can grow in very alkaline and saline soils.
It cannot grow in the shade. It prefers moist soil. The plant can tolerate
maritime exposure. Young leaves - raw or cooked. A pleasant salty
flavor, they make a nice addition in small quantities to a salad. They are
often mixed with other vegetables in order to reduce their saltiness. The
young shoots are pickled in vinegar and eaten on their own or used as a
relish. Seed - raw or cooked. The ashes of the plant provide a soda that
is used in making glass and soap. Plants for a Future can not take any
responsibilityfor any adverse effectsfrom the use of plants. Always seek
advice from a professional before using a plant medicinally.
Suaeda monicasmall tree or shrub to 3m.stem much branched .the
branches erect or assending,with the prominent leaf scares.
Suaeda vermiculata is a shrub and can grow up to between 0.4–1 m,
with woody stems at its base, very branched. Salt-tolerant plant
(halophytes).
Salicornia species are small annual herbs. They grow prostrate to erect,
their simple or branched stems are succulent, glabrous, and apparently
jointed. Older stems may be somewhat woody basally. It is used
in Phytoextraction, it is highly effective at removing selenium from soil,
which is absorbed by the plant and then released into the atmosphere to
be dispersed by prevailing winds.

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