1. Mangrove Estuary

2. Mangrove Estuary Swamp Investigation
Aim: To compare the biotic and abiotic factors in two distinct mangrove swamp communities.

3. Abiotic Factors
In this lab, you will identify and measure the abiotic factors on the rocky shore.
- some of the factors that you will investigate are:
Salinity, substrate, exposure to light, temperature, turbidity and more…

4. Abiotic Factors in the Mangrove Estuary Swamp
SUBSTRATE surface material
The muddy substrate is composed of detritus, and fine inorganic particles.
Some organisms burrow under the mud and live there. (we will not disturb them in our study).
The mangrove roots go deep into the muddy substrate.
Different species have specific root forms; many have aerial or buttress roots.

5. Abiotic Factors on the Shore
TEMPERATURE
Immersion in water buffers against temperature change.

6. Abiotic Factors on the Shore
LIGHT
Needed for photosynthesis.
Water will filter off some of the wavelengths of light and reduce the intensity.
Small algae, e.g. some of the red algae, will photosynthesise with very little light and occur under other larger algae.
Mangrove trees provide shade for species underneath.

7. Some Abiotic Factors in the Mangrove Estuary Swamp
TURBIDITY is the cloudiness of the water.
Large amounts of plankton, detritus, or sewage pollution can increase the turbidity. This restricts the light reaching the algae on the rocks.

8. Using Quadrats for sampling
We cannot count all of the organisms in the two mangrove swamp communities. Instead we can take samples.
We will imagine quadrats which are small square areas (usually 1m x 1m--ours are approx. 0.5m x 0.5m), and counting all of the organisms of each kind inside of these quadrats.
We will do this at each of the stations in our mangrove ecosystems.

9. Identification and Abundance of Organisms
As you observe the organisms of the estuary, you will count the individuals and record their abundance. The number of each species will be recorded as…
A=abundant, C=common, F=frequent,
O=occasional, R=rare, N=absent.
(Known as the “ACFOR(N) Scale”)
There are scales that will help guide you in determining the abundance for various types of organisms.

10. Organisms to look for in the estuary swamp…
Mangroves: These interesting trees dominate the mangrove ecosystem. There are several species in Thailand, two of which we will see easily, with a few others scattered about. Watch for differences in tree morphology, leaf structure, seed pods, and the root systems.
Lichens: The symbiotic algae-fungi organisms grow on many surfaces.

11. Organisms that you might find in the estuary swamp…
Mudskippers – These fish are able to survive out of the water for short bouts of time by storing water inside of their gill chambers and breathing through their wet skin. They can be seen near the roots of the mangrove trees.
Blue crabs -- These crustaceans may be seen on the mangrove roots or near burrows. If lucky, you will see them foraging!
Snails: You will see a number of snails in the mangroves.