problem 1. Given that the density of a water sample is 1.023 g/cm3 at 25?C, what is its salinity?

problem 2. In what way does the presence of dissolved salts affect the density of seawater?

problem 3. Comment on the pros and cons of each of the three different methods of measuring salinity:
a) Chemical method:
b) Hydrometer:
c) Refractometer:
Which method do you prefer in measuring salinity in seawater? Please describe.

problem 4. Is there any alternative method of measuring dissolved oxygen in seawater?
Briefly describe the methodology and underlying principles. Attach additional sheets of paper if needed. Give the source of reference from which you obtain the information.

problem 5. How are the nutrients introduced to aquatic environment? What are the biological consequence of high nutrients input into aquatic ecosystem?

problem 6. How does BOD5 tell us the importance of water quality at a particular location? Why the temperature has to be constant (e.g. 20 °C) in darkness throughout the incubation period? How would you adjust the measurement if the BOD5 of your sample is too low or too high within 5 days?