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Freshwater Stream
Introduction• Date : 14/9/2005• Site location : Chuen Lung• Time : 1:00 p.m to 3:00 p.m• Weather condition : Sunny and Dry• Water transparency : Fairly Clear• Smell : No Special Smell• Floating matters: Plastic bags, tin
cans, glass bottles, decayed leaves
Stream FeaturesGradient along the transect
Distance (m)
0 0.5 1 1.5 2 2.5 3
Water depth(cm)
6 11 17 15 10 18 10.5
26.9Bottom
30.5Above surfaceTemperature ( degree Celsius )
3875Bottom
4125Above surfaceLight intensity( Lux )
Other features
Chemical oxygen demand (mg/l)
Chemical factors
Ammonium content(transparency)
Phosphate content(ppm)
pH
Total dissolved solids (ppm)
Total suspended solids (mg/l)
Dissolved oxygen (mg/l)
0.5
28
6.42
25
0.227
3.69
8.8
Paramestorition hongkongensis (香港瘰螈 )Large, brownish newt
Under with red blotches
A predator of various invertabrates
Commonest in stream from September to March, when breeding take place
Most of the time spent on land
Pseudogastromyzon myersi
( 麥氏擬腹吸鰍 )
Strongly flattened fish
Mouth on the underside of the head
Dorsal fin yellow with red border
Food: grazes algae any oyanobacteria (藻青菌 )
Ptilomera tigrina (水黽 )
Long-legged bugs with raptorial front limbs and a slender beak.
Live in the most rapid part of riffles, especially numerous around the base of waterfalls
Strong jumpers that easily avoid capture
Euphaea decorate (豆娘若蟲 )
Found under stones
Have gills along the sides of abdomen
Colour: Dark grey to black
Development takes one year
Euphaea decorate (豆娘 )
Males have a black band across the hindwings
Females have more yellow stripes on the body and lack the wing band
Common found between April and October
Heptageniidae (蜉蝣若蟲 )
Tends to remain clinging to stones picked out of the water
Distinctly flattened with oral heads and plate-like gills
Brotia hainanesis (海南蜷螺 )
Streamlined shell reduces impact of water current
Hard shell protects against predator
Operculum(厴能 ) protects against predator
Found in fast running water and clean water
Marcrobrachium hainanense (海南沿蝦 )
Large chelate walking leg or defence against enemies
Found in slow running water and clean water
ConclusionDifferent animals have different features in order to adapt the environment.
As the light intensity is relatively low, there are only small number of plants.
There are many microhabitats along the transect line, e.g under stones.
More animals can be found in slow running water.
It is extremely important for us to protect the environment.
Cheung Lai Wan
Lau Suk Yan
Law Hoi Ling
Lau Tsz Leung
Leung Ka Man