This set of Tough Marine Biotechnology Questions and Answers focuses on “Soil-water Interactions in Aquatic Systems”.
1. Which of the following cannot limit benthic production?
a) Sedimentation
b) Soil texture
c) pH
d) Humus
View Answer
Explanation: Humus increases the benthic productivity thereby acting as a fertilizer. Inappropriate soil texture, unsuitable pH and high rates of sedimentation can adversely affect the benthic invertebrates.
2. Wastewater-fed ponds have high chances of developing anaerobic zones.
a) True
b) False
View Answer
Explanation: Due to high accumulation of organic matter at the bottom of wastewater-fed ponds, there is a high chance of microbial activity. Elevated microbial activity increases the biological oxygen demands, failing to keep up with the BOD through external aerators might lead to anaerobic zones.
3. Bacterial growth efficiency decreases with __________________________
a) decreasing C/N ratio
b) decreasing C/P ratio
c) increasing C/N, C/P ratio
d) increasing N/P ratio
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Explanation: Bacterial growth efficiency in aquaculture ponds decreases with increasing C/N and C/P ratios. Therefore dissolved organic matter (DOM) plays a significant role in the linkage of aquatic and terrestrial systems.
4. Which of the following enhances the aeration of upper layer of pond bottom soil?
a) Burrowing
b) Phytoplankton growth
c) Algal bloom
d) Liming
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Explanation: Burrowing activities by such benthic organisms as annelids and molluscs (bottom dwellers) loosen the bottom soil ensuring aeration and adequate mixing. This also results in removal of noxious gases trapped in the soil bed.
5. Which is not a part of wastewater stabilization ponds?
a) Anaerobic pond
b) Facultative pond
c) Maturation pond
d) Aerobic pond
View Answer
Explanation: Since wastewater stabilization pond relies on functioning of natural ecosystem and self-purification processes, it is low-cost and efficient. Wastewater stabilization ponds consist of anaerobic, facultative, and maturation ponds.
6. In an aquaculture pond, bottom sediment is more productive than overlying water column.
a) True
b) False
View Answer
Explanation: According to several research reports a comparison of sediment microflora and overlying water microflora suggest that more number of active microbes are present in the former. This indicates that the pond bottom is more productive than overlying water.
7. In aquatic (and other ecosystems) elemental nitrogen is converted to _______________
a) inorganic form
b) organic form
c) oxidized form
d) unusable form
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Explanation: In the ecosystem elemental nitrogen (N2) is converted to inorganic form of NH4+ and NO3– before getting incorporated in biological tissues. The process of fixation is mostly undertaken by microbes in the pond systems.
8. Nitrogen fixation does not occur if _______________ is present in the environment.
a) nitrite
b) sulfide
c) nitrate
d) ammonia
View Answer
Explanation: Nitrogen fixation is a process undertaken by autotrophic microorganism in aquaculture ponds. The process is adversely affected by the presence of ammonia and does not usually proceed when NH4+ is present in high enough concentration.
Sanfoundry Global Education & Learning Series – Marine Biotechnology.
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