UGC NET — Environmental Sciences (subject code 89) · India · National Testing Agency for the University Grants Commission
Original practice questions written to the published syllabus · not past papersWetlands, mangroves, seagrasses and estuaries: their ecology, the services they give agriculture and fisheries, their carbon stores, and the Ramsar and coastal-zone rules that protect them.
In the exams: ICAR AICE subject 71 Unit 2 (wetlands, mangroves, Ramsar); ICAR AICE Aquatic Environmental Management; UPSC CSE environment
GATE ES and UGC NET Environmental Sciences
Wetland biogeochemistry and methane, constructed wetland design (first-order areal model, loading and retention time), blue carbon arithmetic, IPCC rice emission calculations.
How our questions for UGC NET spread across the units of Wetlands, Coastal Ecosystems & Blue Carbon. Difficulty: 6 easy, 18 medium, 19 hard.
| Wetland hydrology, soils and vegetation | 9 | |
| Wetland definitions and classification | 5 | |
| Wetland functions and services | 5 | |
| Blue carbon: stocks, fluxes and accounting | 5 | |
| Constructed wetlands for treating farm and village wastewater | 4 | |
| Peatlands: drainage, fire and rewetting | 4 | |
| Integrated Coastal Zone Management | 4 | |
| Mangroves, seagrasses, salt marshes and estuaries | 3 | |
| Rice paddies as managed wetlands | 3 | |
| Ramsar Convention and wetland inventories | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
Water hyacinth and duckweed belong to which wetland plant growth form?
A. Free-floating
Free-floating plants are not rooted in the sediment. Submerged plants live underwater; emergent plants are rooted with shoots above water; floating-leaved rooted plants include water lilies.
Further reading: Mitsch and Gosselink, Wetlands
Grey (gleyed) soil colours with orange mottles in a wetland soil indicate what?
B. Iron reduction and re-oxidation
Reduced iron gives grey colours; where oxygen returns along roots and pores, iron re-oxidises into orange mottles — classic redox features of hydric soils. Carbonate, ash and phosphorus do not produce this pattern.
Further reading: Mitsch and Gosselink, Wetlands
What is a wetland's 'hydroperiod'?
C. The seasonal pattern of water level
Hydroperiod describes depth, duration, frequency and timing of flooding over the year — a wetland's hydrological signature.
Further reading: Mitsch and Gosselink, Wetlands
Why can a wetland that once retained phosphorus begin to release it?
B. Sorption sites saturate and sediment conditions change
Phosphorus is retained by sedimentation and sorption; when capacity is exceeded or conditions become reducing, it can be released. Phosphorus has no significant gaseous phase.
Further reading: Mitsch and Gosselink, Wetlands
Why are many wetland services undervalued in land-use decisions?
A. They are public goods that benefit people other than the landowner
Flood control, water purification and biodiversity benefit downstream and wider society, so owners gain little from conserving them, leading to conversion. The other statements are false.
Further reading: Ecosystem services literature
In southern India, what was the main function of traditional village irrigation tanks?
C. Storing monsoon runoff for dry-season irrigation and recharge
Tanks capture monsoon runoff for crops and recharge groundwater; many have degraded with weakening community institutions. They are not hydropower, salt pans or drains.
Further reading: Tank irrigation literature
In which type of estuary does dense seawater intrude along the bottom beneath a fresher outflowing layer, with weak tidal mixing?
A. Salt-wedge estuary
Salt-wedge estuaries occur where river flow dominates over tides; well-mixed estuaries have strong tides; partially mixed are intermediate.
Further reading: Estuarine oceanography
Above roughly what salinity does methane emission from coastal wetlands become low?
B. About 18 parts per thousand
Wetlands with salinity above about 18 ppt generally have low methane emissions because sulphate suppresses methanogenesis; fresh and brackish systems emit more.
Further reading: IPCC 2013 Wetlands Supplement
Why can blue carbon soils keep accumulating carbon for millennia, unlike many forest soils?
D. Sediments build upward with sea-level rise
Vertical accretion of anoxic sediments as sea level rises creates new space for carbon burial; forest soils tend to reach equilibrium. The other statements are wrong.
Further reading: Mcleod et al. 2011
What is peat made of?
C. Partly decayed plant material
Peat accumulates from partly decomposed plant remains under waterlogged conditions.
Further reading: Mitsch and Gosselink, Wetlands
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