1. The effect on species diversity by water current

2. Controlled Variables Water depth River bed substrate composition
Light intensity
Abundance of water plants
Temperature

3. Dependent variable Independent variable Animal species
Rate of water flow

4. Hypothesis
Current has direct effect on the distribution of organisms.The biodiversity may be inversion related to the speed of the water current

5. Materials and methods Light meter: measure the light intensity
Digital thermometer: measure the temperature
Forceps: pick out the species attached to the surfaces
Water flow meter: measure the speed of the water flow

6. Materials and methods
Tray: temporarily hold the species for investigation
Brush pen: discard the species onto the tray
Metal sieve: catch the species which are difficult to catch by using forceps flowing with the water current.
Meter: measure water depth

7. Method to control the variables
Measure one-by-one by using the apparatus. Carry out experiment at regions with same water depth, river bed substrate, light intensity, temperature and abundance of water plants.

8. Methods of measuring water flow rate
Using water flow meter to measure the water flow rate at the shallow and stony part of the stream where we did animal survey. Make a few measurements at different points and then take average of the readings.

9. Method to record the data of dependent variables
Using quadrant sampling method to find out animal species.

10. Experiments Fair test Temperature: 22.5 Degree Celsius
Water depth: 8cm
Light intensity: 9920
Substrate: by observation

11. Results (1) Water flow rate: 0.16m/s
Species in different sizes are present, ranging from 1mm to 2cm
Greater abundance of species in smaller size
E.g. Dragonfly nymph, small stream leech, mayfly nymph, bloodworm, water penny

12. Results(2) Water flow rate: 0.21m/s Absence of species in large size
Presence of species in smaller size, particularly Caddisfly larva attached to the rock surfaces
E.g. Caddisfly larva, large stream snail

13. Results(3) Water flow:0m/s
Presence of species in different sizes, ranging from 1mm to 5cm
E.g. Canton bee shrimp, toothed bee shrimp, large stream snoil, Toby

14. Analysis
Species smaller in size are present in both high and low water current.

15. Analysis
Species which are greater in size are present in lower water current, while absent in greater water current.

16. Analysis
Species in greater size may need to overcome a greater fluid resistance. It may be more difficult for them to maintain stability.
Certain species may have special adaptations like shells to protect them from high pressure.
Food may be washed away by the high water current

17. Summary
Clemency favors the growth and development of the species perhaps due to malnutrition and instability
Species with adaptations may have greater possibilities to survive in malevolence per