Download mangrove project

Bianca Skea
10 Pn (4)
Gr 10 Assignment:
A Study of the Beachwood
Mangrove Swamp
Ecosystem
A. ABIOTIC FACTORS:
1. Water
1.1. Water temperature:
Beachwood stream: 24 °C
Umgeni River: 26°C
1.2. Clarity of the water:
The reading was not possible as the water depth was only 45cm and the
clarity was also 45cm.
2.Soil
2.1-2.4
Swamp area
Clay
Smooth, slippery and
stuck together firmly.
Soil particle size
Umgeni river bank
Sand
Coarse, rough and
crumbled when rubbed
together.
1500 microns
Soil pH
7
7
Soil type
Soil texture
100 microns
2.5
Soil type
Clay
soil
Volume added
(ml)
50
50
Volume of
water drained
(ml)
41
36
Volume of water
retained(ml)
9
14
B.BIOTIC COMPONENTS:
1. Biodiversity
1.1
Salinity: this refers to the amount of salt in the water. The animals and
autotrophs have to adapt to the change in salt in order to survive. The amount of
salt depends on where you take a reading from, there is more salt towards the
mouth of the Umgeni then there is in the Beachwood stream.
Tides: The tides affect the water levels. The animals and autotrophs have to
adapt to the changes in the water to survive. The animals and plants will have to
deal with being out of the water or in very shallow water and they will also have
to be adapted to being slightly or completely submerged I water, or they will
have to be adapted to stay out of the water.
Temperature: the mangroves experience very high temperature during the day
and the plants need to have adapted so that they don’t transpire as often. They
animals have to adapt to so they don’t over heat.
1.2
A. white mangrove plant:
1. Avicennia marina
2. A pioneer plant is the first plant to establish in that area. The white mangrove
can be a pioneer plant because it is adapted to very hot temperatures with no
shade, therefore giving the other plants shade to grow under. The white
mangrove creates a stable environment for the other plants as it stabilizes the
salinity a little bit.
3. The mangrove plant has to deal with salt as well as the heat. The leaves have
a white or light underside as to reduce transpiration in the heat by reflecting the
sunlight. The underside of the leaf also has pores that the plant excretes the salt
through.
4. The white mangrove plant has pencil roots.
5. The soil around the plant is anaerobic because of all the water, the pencil
roots therefore allow the plant to get oxygen by sticking up in the soil.
6. The seeds have an outer coating, known as a ‘jacket’. This ‘jacket’ protects
the seeds as it falls from the tree and travels with the water. Once the water
levels are low (low tide) the jacket falls off, allowing the seed to anchor itself as
quick as possible.
B. black mangrove plant:
1. Bruguiera gymnorrhiza
2. The leaves to the black mangrove are adapted to the salinity. The leaves on
the tree grow in clumps. In each clump there is one leaf that absorbs all the
excess salt, this leaf turns yellow and eventually falls off of the tree.
3. The black mangrove plants have elbow or knee roots.
4. The knee roots stick out of the ground letting the plant get oxygen because
the plant is surrounded by anaerobic soil. The knee roots also provide support
for the tree.
5. The seed is cigar shaped. There for it is adapted to drop off of the tree and
spear into the mud below, before the tides are able to wash it away.
C. Red Mangrove:
1. Rhizophora mucronata umHlume
2. The red mangrove has reddish-brown bark as well as red stipules
3. The red mangrove plants have Prop roots.
4. The prop roots against the plant and are in the soil to help the plant stand up
straight or the prop roots are in the air and the help the plant get oxygen
because of the anaerobic soil.
5. The Red mangrove’s seed is very similar to the Black mangrove’s seed as it
is also cigar shaped. However the Red mangrove’s seed is roughly 30cm in
length while the Black mangrove’s seeds are roughly 15cm in length. Unlike the
Black mangrove the Red mangrove’s seed has two parts to the seed, the cigar
shaped part that is similar to the Black mangrove’s seed and the second part of
the seed is pear shaped which is very similar to the White mangrove’s seed.
1.3
A. Mudskipper:
 The mudskipper can survive out of water for shorts periods of time but
long enough for the tides to change. It does this by retaining water in their
gill chamber.
 They are able to cling to low hanging trees and branches so that they are
not washed away with the current. This is achieved by their pelvic fins
which are adapted into a sucker
 They are a brown grey colour allowing them to camouflage.
B. Fiddler crab:
1. They mainly feed on the nutrients in the soil
2. The males have the enlarged pincher
3.
 It attracts the female crabs as a mate.

It also is used for fighting the other male fiddler crabs
C. Red mangrove crab:
1. Sesarma meinerti
2. These crabs eat the yellow leaves that have fallen from the black mangrove
trees
3. The aeration plates in their cheeks help them stay away from the water so
that they can barrow closer to the black mangroves even during low tide.
D. Mangrove snail:
The snails help as an indicator to how polluted the area. The more snails there
are the cleaner the area is, the same as the fewer there are the more polluted
the area is. This helps us identify how polluted the mangroves are.
2.Trophic relationships
MAN
GRUNTER
PELICAN
CLIMBING WHELK
FIDDLER CRAB
RED MANGROVE CRAB
DEAD ORGANIC MATERIAL
BLACK MANGROVE TREE LEAVES
3. Human influences
A. Importance of the mangroves
 The mangroves provide food to all the species living in the area as well
as around the area. If we destroy the mangroves, it will have a ripple
effect destroying many ecosystems around it.
 The mangroves help improve the quality of the water that goes to sea by
filtering the water, as the water passes through the mangroves.
 They are a habitat to many different species; if we destroy the mangroves
the species will have no breeding ground and will become extinct affecting
our ecosystem.
B. Threats to the mangrove ecosystem:
 Humans can pollute the area causing the animals and trees to die.
 By removing the plant from upstream, for farmers, creates too much water
causing the mangrove to overflow.
 We could fish or use the trees for food or medical purposes and if we use
too many of them without replacing them then the mangroves can’t
function properly.
5. Bibliography:
 In The Mangroves Of Southern Africa-Patricia Berjak, G.K. Campbell,
Barbara Huckett, N.W. Pammenter

East Coast Estuaries And Mangroves- Trevlyn Williams
 http://showme.co.za/durban/tourism/the-beachwood-mangroves-naturereserve-in-durban-north/