This set of Marine Biotechnology Multiple Choice Questions & Answers (MCQs) focuses on “Sustainable Marine Food Production Systems – Set 5”.
1. Attached growth biofilters do not produce significant solids in the outflow.
a) True
b) False
View Answer
Explanation: There are two types of nitrifying biofilters namely suspended growth (Biofloc system) and attached growth. The advantage of attached growth biofilters is that these do not result in significant solids in the outflow.
2. Choose the correct option.
| 1. Settleable solids | a. Sieving |
| 2. Suspended solids | b. Gravity separation |
| 3. Fine solids | c. Ozonation |
a) 1-b 2-a 3-c
b) 1-a 2-b 3-c
c) 1-c 2-a 3-b
d) 1-c 2-b 3-a
View Answer
Explanation: The suspended solids in aquaculture are broadly categorized into three namely suspended solids, settleable solids, and fine solids. Depending upon their respective sizes different mechanical filters are used for the removal.
3. Which is not a technique for removing fine solids from recirculating aquaculture system?
a) Swirl separator
b) Bioclarification
c) Radial flow separator
d) Sieving
View Answer
Explanation: Fine solids are less than 30 micrometers in size and can be removed from RAS by techniques such as swirl separators, radial flow separator, and dual drain tanks among others. Sieving is however used for the removal of suspended solids.
4. Biosolids are the most difficult to control in aquaculture.
a) True
b) False
View Answer
Explanation: Biosolids are one of the most difficult parameters to control especially in recirculating aquaculture where the velocity of water is high. Biosolids originate from uneaten feed, fecal matter, and bacterial biofilms.
5. Select the incorrect option.
a) CO2 increase results in pH drop
b) CO2can originate by bacterial metabolism
c) CO2 is highly soluble
d) In water CO2 reaches equilibrium fast
View Answer
Explanation: Carbon dioxide is a highly soluble gas and unlike oxygen and nitrogen, does not reach equilibrium fast. To ensure transfer of CO2 out of water large volumes of water must be added.
6. Which of the following cannot be used for CO2 stripping?
a) Low-head oxygenator
b) Cascade aerator
c) Trickling biofilter
d) Packed column aerator
View Answer
Explanation: Low-head oxygenators are devices used for aeration, cannot be used for stripping carbon dioxide out of the RAS culture water. CO2 stripping devices include cascade aerators and other cascade-type devices.
7. ________________ causes chalky deposits in organs of cultured salmonids.
a) Heterotrophic bacteria
b) Elevated pH
c) Carbon dioxide
d) Ammonia
View Answer
Explanation: Carbon dioxide, a highly soluble gas in water is linked to a variety of ailments in cultured fish. Examples include chalky deposits in organs of cultured salmonids, nephrocalcinosis, and systemic granulomas.
8. Total gas pressure (TSP) is sum of _______________
a) total pressure of gases
b) partial pressure of O2 and CO2
c) partial pressure of all gases
d) partial pressure of N2 and CO2
View Answer
Explanation: Total gas pressure (TGP) is the sum of partial pressures of all the gases dissolved in an aqueous solution. Nitrogen gas contributes most to the total gas pressure of water in RAS.
9. Which is the least soluble gas?
a) Hydrogen sulfide
b) Oxygen
c) Carbon dioxide
d) Nitrogen
View Answer
Explanation: Nitrogen is the least soluble gas hence exerts more pressure thereby contributing most to the total gas pressure (TGP). Nitrogen is not consumed by fish or heterotrophic bacteria; therefore to preclude accumulation it must be stripped.
10. For optimal growth of fish TGP should be _____________
a) equal to atmospheric pressure
b) greater than 1
c) between 0 and 1
d) greater than 10
View Answer
Explanation: For optimal growth of fish in aquaculture, the total gas pressure (TGP) must be equal to atmospheric pressure. TGP greater than atmospheric pressure causes gas bubble disease in fish.
11. Which is the end product of nitrification?
a) Ammonia
b) Nitrogen
c) Nitrite
d) Nitrate
View Answer
Explanation: Nitrification is the process by which nitrifying bacteria convert ammonia into nitrite and further into nitrate. Nitrate has extremely low toxicity and has low permeability through fish gills.
12. Which is an acid forming process?
a) Nitrification
b) Sulfide oxidation
c) Humification
d) Dewatering
View Answer
Explanation: Nitrification, the process by which ammonia is converted to nitrate, is an acid forming process. Nitrifying bacteria need a constant supply of alkalinity that is determined by feed addition, alkalinity content of make-up water and presence of denitrifying bacteria.
Sanfoundry Global Education & Learning Series – Marine Biotechnology.
To practice all areas of Marine Biotechnology, here is complete set of 1000+ Multiple Choice Questions and Answers.
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