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Freshwater Stream

Group 6. 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

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Freshwater Stream

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  1. Group 6 Freshwater Stream

  2. 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

  3. Stream Features Gradient along the transect

  4. Other features Light intensity ( Lux ) Above surface 4125 Bottom 3875 Above surface 30.5 Temperature ( degree Celsius ) Bottom 26.9

  5. Chemical oxygen demand (mg/l) Chemical factors Ammonium content(transparency) 0.5 Phosphate content(ppm) 28 6.42 pH Total dissolved solids (ppm) 25 Total suspended solids (mg/l) 0.227 3.69 Dissolved oxygen (mg/l) 8.8

  6. 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

  7. 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)

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. Marcrobrachium hainanense (海南沿蝦) • Large chelate walking leg or defence against enemies • Found in slow running water and clean water

  14. Conclusion • Different 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.

  15. Members: Cheung Lai Wan Lau Suk Yan Law Hoi Ling Lau Tsz Leung Leung Ka Man Lingnan Hang Yee Memorial School

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