UPSC Prelims 2026 Practice Set on Amazon’s Silent Cry — Dolphin Deaths & Climate Emergency
(By Suryavanshi IAS)
Q1.
Which of the following best explains the recent mass deaths of dolphins in Lake Tefé, Brazil (2023)?
A. Plastic ingestion and chemical contamination
B. Algal toxins due to fertilizer runoff
C. Severe drought combined with extreme heat raising water temperature to lethal levels
D. Overfishing and loss of prey species
✅ Answer: C
Explanation:
The Science (2024) study by Mamirauá Institute found 41°C water temperature due to drought + heat wave, causing mass mortality of Amazon pink dolphins and tucuxis.
Q2.
The species “Amazon Pink Dolphin” (Inia geoffrensis) and “Tucuxi Dolphin” (Sotalia fluviatilis) are listed as:
A. Vulnerable in the IUCN Red List
B. Endangered in the IUCN Red List
C. Critically Endangered in the IUCN Red List
D. Near Threatened in the IUCN Red List
✅ Answer: B
Explanation:
Both the Amazon River Dolphin and Tucuxi are Endangered on the IUCN Red List, threatened by climate change, habitat loss, and fishing gear entanglement.
Q3.
In the Lake Tefé incident (Brazil, 2023), what was unusual about the thermal structure of the lake water?
A. Only the surface water reached extreme temperatures.
B. The temperature increased with depth beyond 10 metres.
C. The same high temperature (≈41°C) was recorded from surface to bottom (2 metres).
D. Only the deeper layer was hot due to geothermal heating.
✅ Answer: C
Explanation:
Scientists observed uniform heating throughout the water column, indicating loss of vertical mixing — an effect of drought, turbidity, and low wind speeds.
Q4.
Which of the following combinations contributed to the lethal heating of Amazonian lakes during the 2023 drought?
-
Strong solar radiation
-
Shallow water depth
-
Low wind speed
-
High turbidity (murky water)
Select the correct answer:
A. 1, 2 and 3 only
B. 2 and 4 only
C. 1, 2, 3 and 4
D. 1 and 3 only
✅ Answer: C
Explanation:
All four factors were identified in the Science (2024) paper as reinforcing feedbacks that trapped solar heat and prevented cooling in shallow Amazon lakes.
Q5.
According to the Mamirauá Institute’s study, Amazonian lakes have been warming at what approximate rate since 1990?
A. 0.1°C per decade
B. 0.3°C per decade
C. 0.6°C per decade
D. 1.2°C per decade
✅ Answer: C
Explanation:
Satellite data (NASA, 1990–2023) show +0.6°C/decade warming, which is higher than the global average for freshwater lakes.
Q6.
The Amazon River dolphin is locally known as:
A. Boto
B. Guppy
C. Piranha
D. Arapaima
✅ Answer: A
Explanation:
The Amazon Pink Dolphin (Inia geoffrensis) is called “Boto” in Portuguese and is revered in local folklore as a mystical guardian of rivers.
Q7.
Which of the following best describes the “Turbidity–Heat Feedback Loop” mentioned in the 2024 Science study?
A. Clear water allows sunlight to penetrate deeper, keeping the surface cool.
B. Murky water absorbs and retains more heat, preventing cooling and causing uniform high temperatures.
C. Cold rainwater mixes with sediments, lowering surface temperature.
D. High turbidity reduces evaporation and stabilizes temperature.
✅ Answer: B
Explanation:
High turbidity (murkiness) increases absorption of solar radiation → traps heat → reduces cooling → intensifies water warming — a positive feedback mechanism.
Q8.
In context of climate science, “aquatic heat domes” as observed in the Amazon refer to:
A. Geothermal heat pockets under the Earth’s crust.
B. Water bodies enclosed by volcanic formations.
C. Stagnant shallow lakes that trap solar radiation due to heat, drought, and low wind, leading to extreme surface temperatures.
D. Artificial heat generated from industrial effluents.
✅ Answer: C
Explanation:
An aquatic heat dome is analogous to atmospheric heat domes — stagnant water layers trapping heat under clear skies and calm conditions.
Q9.
Which of the following Sustainable Development Goals (SDGs) are directly impacted by the Amazon dolphin mortality event?
-
SDG 6 – Clean Water and Sanitation
-
SDG 13 – Climate Action
-
SDG 14 – Life Below Water
-
SDG 15 – Life on Land
Select the correct answer:
A. 1 and 2 only
B. 2 and 3 only
C. 1, 2 and 3 only
D. 2, 3 and 4 only
✅ Answer: C
Explanation:
The crisis directly affects freshwater systems (SDG 6), is driven by climate change (SDG 13), and impacts aquatic biodiversity (SDG 14).
Q10.
Which of the following policy lessons can be derived from the Lake Tefé tragedy, relevant to COP30 discussions?
-
Need for long-term monitoring of tropical lakes and river systems.
-
Inclusion of Indigenous and local communities in water governance.
-
Integration of freshwater ecosystems into national climate commitments (NDCs).
-
Promotion of biofuel plantations in Amazon wetlands for carbon offsets.
Select the correct answer:
A. 1, 2 and 3 only
B. 1 and 3 only
C. 2, 3 and 4 only
D. 1, 2, 3 and 4
✅ Answer: A
Explanation:
Points (1–3) were directly proposed by Ayan Fleischmann at COP30. Biofuel plantations (4) are ecologically harmful to wetlands.
🧾 Prelims Revision Table
| Key Theme | Fact / Concept |
|---|
| Event | Dolphin mass mortality, Lake Tefé, Brazil (2023) |
| Temperature Recorded | 41°C (both surface & deep layer) |
| Species Affected | Amazon Pink Dolphin (Inia geoffrensis), Tucuxi (Sotalia fluviatilis) |
| IUCN Status | Endangered |
| Main Causes | Drought + Heat + Turbidity + Low Wind |
| Warming Trend | +0.6°C per decade (since 1990) |
| Scientific Institution | Mamirauá Institute for Sustainable Development |
| Related COP Summit | COP30, Brazil (2025) |
| SDGs Impacted | SDG 6, 13, 14 |
| Broader Message | Climate emergency threatens tropical freshwater ecosystems |
💬 Bonus UPSC Mains Practice Questions
Q1.
The death of Amazon’s river dolphins is a microcosm of the global climate crisis. Discuss how rising heat and droughts are reshaping aquatic ecosystems worldwide.
(GS Paper 3 – Environment)
Q2.
“The Amazon is both a victim and a regulator of global climate.” In light of recent environmental events, examine the need for global cooperation in conserving tropical freshwater ecosystems.
(GS Paper 3 – Environment & International Cooperation)
No comments:
Post a Comment