2024 Cambridge IGCSE Environmental Management (0680) 模拟试题及答案详解

(a) Condensation. (b) Forests intercept rainfall, which reduces surface run-off, and absorb groundwater through their roots to release it back into the atmosphere via transpiration. (c) Urbanisation introduces impermeable surfaces like concrete which prevent infiltration, increasing surface run-off and reducing groundwater recharge.

(a) Condensation [1 mark] (b) Award 1 mark for each valid point up to 2 marks: Interception (leaves trap rain/reduces run-off) [1]; Transpiration (absorbs water/releases vapor) [1]; Infiltration (roots open soil channels) [1]. (c) Award 1 mark for each valid point up to 2 marks: Impermeable surfaces/concrete prevent infiltration [1]; Increased surface run-off/flooding risk [1]; Reduced groundwater recharge/lowering of water table [1]; Deforestation reduces transpiration [1].

(a) (i) The focus is the underground point where the earthquake rupture starts and seismic waves originate. (ii) The epicentre is the point on the Earth's surface directly above the focus. (b) At destructive boundaries, tectonic plates move towards each other, causing one plate to subduct beneath the other. Friction causes the plates to lock, building up immense pressure and tension over time. When this friction is overcome, a sudden release of stored energy occurs, sending shockwaves through the crust.

(a) (i) Focus: point underground where earthquake/rupture starts [1 mark] (ii) Epicentre: point on Earth's surface directly above the focus [1 mark] (b) Award 1 mark for each valid point up to 3 marks: Plates move towards each other / subduction occurs [1]; Plates get stuck/locked due to friction [1]; Tension/pressure/stress builds up over time [1]; Sudden release of stored energy causes shockwaves/vibrations [1].

(a) Bycatch refers to non-target marine species that are caught accidentally while fishing for a specific target species. (b) Overfishing has risen due to increased global demand for seafood from a growing human population, and advancements in fishing technology, such as sonar, GPS tracking, and massive factory trawlers. (c) A closed season bans fishing during breeding times, protecting spawning adults and allowing young fish to reach reproductive age to replenish the population.

(a) Bycatch: non-target species caught accidentally/unintentionally [1 mark] (b) Award 1 mark for each valid point up to 2 marks: Growing global human population/increased demand [1]; Advancements in technology (sonar/GPS/larger nets) [1]; Lack of international regulation/enforcement in open oceans [1]; Fishing industry subsidies [1]. (c) Award 1 mark for each valid point up to 2 marks: Prevents fishing during critical breeding/spawning seasons [1]; Allows juvenile fish to grow to maturity/reproduce [1]; Reduces overall annual catch rates [1].

(a) 3. Air, 4. Water. (b) Humus acts as a binding agent that aggregates mineral particles, improving soil crumb structure. It also significantly increases the soil's capacity to retain water, preventing drought stress. Furthermore, as humus decomposes, it slowly releases essential mineral nutrients such as nitrogen and phosphorus into the soil, which are absorbed by plants.

(a) Award 1 mark for each component: Air [1 mark]; Water [1 mark] (either order). (b) Award 1 mark for each valid point up to 3 marks: Binds soil particles together / improves crumb structure/stability [1]; Increases water retention capacity/prevents drying out [1]; Releases essential nutrients (nitrogen/phosphorus) as it decomposes [1]; Promotes aeration / improves drainage [1]; Provides food for beneficial soil organisms/microbes [1].

(a) Under normal conditions, strong trade winds push warm surface water westward, allowing cold, nutrient-rich deep water to rise (upwelling). During an El Niño event, the trade winds weaken or reverse, causing warm water to flow eastwards. This suppresses the upwelling of nutrients like nitrates and phosphates, reducing phytoplankton growth and starving the anchovy population.

(b) Decrease in catch: \(8.2 \text{ million tonnes} - 1.2 \text{ million tonnes} = 7.0 \text{ million tonnes}\). Percentage decrease: \(\frac{7.0}{8.2} \times 100 \approx 85.4\%\) (accept 85% or 85.37%).

(c) Closed seasons to protect breeding adults; quotas or catch limits to restrict the total weight caught; marine protected areas (no-take zones) to provide safe habitats; gear restrictions such as larger mesh sizes to allow juvenile fish to escape.

(d) Setting Exclusive Economic Zones (EEZs) up to 200 nautical miles so nations can police their own waters; setting legally-binding regional catch quotas through international fishing commissions; enforcing compliance via satellite tracking and coordinated naval patrols.

(e) Farmed carnivorous fish are fed fishmeal and fish oil derived from wild-caught species, continuing pressure on wild stocks; high-density cages release concentrated waste causing eutrophication; escaped farmed fish can compete with or spread diseases to wild populations.

(a) Max 4 marks:
- Suppressing/weakening of upwelling [1]
- Warm surface water flows eastwards [1]
- Reduction in nutrients (nitrates/phosphates) [1]
- Reduction in phytoplankton/algae growth [1]
- Lack of food causes fish to starve or migrate [1]

(b) Max 2 marks:
- Correct subtraction of catches: 7.0 million tonnes [1]
- Correct calculation to 85.4% (accept 85% or 85.37%) [1]

(c) Max 3 marks:
- Closed seasons [1]
- Catch quotas/limits [1]
- No-take zones/MPAs [1]
- Mesh size regulations [1]
- Vessel licensing [1]

(d) Max 3 marks:
- Establishment of EEZs (Exclusive Economic Zones) [1]
- Collaborative international treaties/agreements [1]
- Joint monitoring/patrolling of high seas [1]
- Imposition of trade sanctions or fines [1]

(e) Max 3 marks:
- Feeding requires wild-caught fish/fishmeal [1]
- High concentration of waste leads to eutrophication [1]
- High risk of disease transmission to wild stocks [1]
- Escapes cause genetic pollution or resource competition [1]

(a) An oceanic plate meets a continental plate. The denser oceanic plate subducts (sinks) beneath the less dense continental plate into the asthenosphere. High friction and intense geothermal heat melt the subducting plate, forming magma. This magma rises under pressure through fissures and vents in the overlying crust, leading to an eruption.

(b) Sulfur dioxide (\(\text{SO}_2\)) and carbon dioxide (\(\text{CO}_2\)).

(c) Seismometers detect harmonic tremors and small volcanic earthquakes caused by the upward movement of magma fracturing rock. Gas monitoring detects increases in sulfur dioxide or carbon dioxide emission rates, indicating that magma is rising close to the surface.

(d) Fertile volcanic soils: volcanic ash contains rich minerals that make the land highly productive for agriculture. Geothermal energy: volcanic heat can be tapped to provide clean, cheap electricity. Tourism: unique landscapes generate local jobs and income.

(e) Magma is molten rock located beneath the Earth's crust, while lava is molten rock that has erupted onto the Earth's surface.

(a) Max 4 marks:
- Oceanic plate subducts beneath continental plate [1]
- Due to density differences (oceanic plate is denser) [1]
- Friction and heat melt the subducting plate [1]
- Magma is formed and builds pressure [1]
- Magma rises through cracks/vents to the surface [1]

(b) Max 2 marks:
- Sulfur dioxide / \(\text{SO}_2\) [1]
- Carbon dioxide / \(\text{CO}_2\) [1]
- Accept water vapor or hydrogen sulfide [1]

(c) Max 3 marks:
- Seismometers record seismic tremors/harmonic tremors [1]
- Tremors indicate magma movement/fracturing rock [1]
- Gas monitoring measures output changes of key volcanic gases [1]
- Increasing emissions suggest magma is nearing the surface [1]

(d) Max 4 marks (1 mark for identifying, 1 mark for explanation, up to two reasons):
- Fertile soil [1]; volcanic minerals increase crop yield [1]
- Geothermal power [1]; provides affordable renewable energy [1]
- Tourism [1]; generates service sector jobs [1]
- Mining [1]; source of valuable minerals/sulfur [1]

(e) Max 2 marks:
- Magma: molten rock below the surface [1]
- Lava: molten rock above/on the surface [1]

(a) Plant species richness increases as the distance from the highway increases. The lowest richness is found closest to the highway (4 species per \(100\text{ m}^2\) at 10 m), while the highest is found deep in the forest (28 species per \(100\text{ m}^2\) at 200 m).

(b) The highway divides the continuous forest, leading to habitat fragmentation. This isolates plant and animal populations, reducing genetic diversity. The 'edge effect' creates a drier, windier microclimate at the forest boundaries. Sun-loving invasive species outcompete specialized deep-forest plants along these edges.

(c) Use a grid system with random coordinates to place the quadrat without bias. Within the quadrat, identify and count the number of different plant species present. Repeat this process multiple times at random locations to calculate a reliable average for the area.

(d) Seed banks store seeds under cold, dry conditions to preserve their viability over long periods. This acts as an insurance policy against extinction in the wild, providing genetic material for future habitat restoration or reintroduction projects.

(e) Entrance fees provide direct funding for forest patrols and management. Ecotourism creates sustainable employment for local communities, reducing the financial incentive for logging or poaching. It educates visitors, raising global and local awareness of biodiversity conservation.

(a) Max 2 marks:
- Species richness increases with distance [1]
- Supporting data point citation (e.g., 4 at 10m vs 28 at 200m) [1]

(b) Max 4 marks:
- Habitat fragmentation isolates populations [1]
- Limits gene flow/reduces genetic diversity [1]
- Edge effect alters microclimate (more wind/sunlight/drier) [1]
- Invasive species outcompete native shade-tolerant forest plants [1]
- Noise/disturbance from highway deters seed-dispersing animals [1]

(c) Max 3 marks:
- Random placement/use of random coordinates [1]
- Identification/counting of species within the frame [1]
- Replicate sampling (repeating) to calculate average [1]

(d) Max 3 marks:
- Collection of seeds from endangered species [1]
- Low temperature and moisture-controlled storage prevents decay/germination [1]
- Preserves genetic diversity for future reintroduction/restoration [1]

(e) Max 3 marks:
- Direct funding from tourism revenue (fees/tickets) [1]
- Job creation (guides, hospitality) reduces pressure on resource extraction [1]
- Raises educational awareness [1]
- Encourages government protection of areas to maintain tourism appeal [1]

(a) Intensive monoculture depletes specific soil nutrients over time, requiring high inputs of chemical fertilisers. It also creates a large, uniform food source that allows specialized pests and diseases to multiply rapidly, forcing heavy pesticide use.

(b) Legumes have nitrogen-fixing bacteria (Rhizobium) inside their root nodules. These bacteria convert atmospheric nitrogen gas into nitrates. When the legume crop is harvested or ploughed back into the soil, this accumulated nitrogen remains, enriching the soil for the next crop.

(c) Windbreaks are lines of trees or shrubs planted perpendicular to the prevailing wind; they reduce wind velocity and prevent topsoil from being blown away. Contour ploughing involves tilling the land across a slope rather than up and down. This creates horizontal ridges that slow surface water runoff, preventing water from washing away topsoil.

(d) Trickle/drip irrigation and scheduling irrigation to take place during the night or early morning to minimize evaporation.

(e) Rainwater washes excess nitrogen fertilisers from fields into nearby lakes (leaching/runoff). This sudden influx of nutrients triggers rapid growth of algae (algal bloom), which blocks sunlight from reaching deeper aquatic plants.

(a) Max 4 marks (1 mark for identifying problem, 1 mark for explanation, up to two problems):
- Depletion of specific soil nutrients [1]; leads to heavy dependency on chemical fertilisers [1]
- Pest population explosion [1]; requires intensive pesticide use which harms non-target species [1]
- Loss of biodiversity [1]; uniform crop canopy supports very few species [1]

(b) Max 3 marks:
- Legumes contain nitrogen-fixing bacteria in root nodules [1]
- Convert atmospheric nitrogen to soil nitrates [1]
- Decaying plant matter releases nutrients to enrich the soil for subsequent crops [1]

(c) Max 4 marks:
- Windbreaks lower wind speeds at ground level [1]
- Reduces wind-driven topsoil loss [1]
- Contour ploughing creates ridges across slopes [1]
- Slows down surface water runoff and increases water infiltration [1]

(d) Max 2 marks:
- Trickle/drip irrigation [1]
- Night/early morning watering [1]
- Rainwater harvesting [1]

(e) Max 2 marks:
- Nutrients leach/run off into water bodies [1]
- Algal bloom blocks sunlight, causing death of submerged plants [1]
- Decomposers use up oxygen, causing anoxia and death of aquatic animals [1]

Detailed answers and marking criteria provided in the marking scheme.

**(a)** [Total: 4 marks]
- Calculation of difference: 12.0 - 6.8 = 5.2 million [1]
- Percentage calculation: (5.2 / 12.0) * 100 [1]
- Correct numerical answer: 43.3 (accept 43 or 43.3) [1]
- Unit included: % [1]

**(b)** [Total: 3 marks]
Any three from:
- Quotas / Total Allowable Commercial Catch (TACC) limits [1]
- Closed seasons (e.g., stopping harvest during spawning periods) [1]
- Restricting dredge size / limiting the number of fishing licenses [1]
- Marine protected areas / no-take zones where dredging is banned [1]
- Size limits (only harvesting oysters above a minimum size) [1]

**(c)** [Total: 4 marks]
- Advantages (any two): Renewable energy resource / no CO2 emissions during operation [1]; reduces reliance on fossil fuels [1]; artificial reefs can form around underwater structures, boosting marine life [1]
- Disadvantages (any two): Visual pollution [1]; noise / vibration disturbs marine mammals during construction [1]; risk of bird collisions with turbine blades [1]; disruption of the seabed / local habitats [1]

**(d)** [Total: 4 marks]
Any four from:
- Warmer waters hold less dissolved oxygen, causing physiological stress to species [1]
- Increased risk of marine diseases / pathogens thriving in warmer temperatures [1]
- Shifts in geographic distribution of key species / migration of warmer-water species into the strait [1]
- Disruption of spawning triggers / breeding cycles of oysters or fish [1]
- Reduction in phytoplankton/algae production, which forms the base of the food web [1]

**(e)** [Total: 5 marks]
Any five from:
- Baseline surveys of seabird populations (species richness, abundance) [1]
- Satellite tracking / radar monitoring of migration pathways and flight altitudes [1]
- Expert consultation with ornithologists / conservationists [1]
- Comparison with existing offshore wind farms globally to assess bird mortality rates [1]
- Noise and visual disturbance assessments during construction and operation phases [1]
- Mitigations suggested (e.g., temporary shutdown during peak migration seasons) [1]

**(f)** [Total: 6.6 marks]
Level 3 [5-6.6 marks]: A balanced and well-developed response that evaluates both sides of the debate. Clearly states the extent of agreement. Uses precise scientific vocabulary. Discusses the trade-offs between local ecosystem preservation (marine life, birds, fishing livelihoods) and global atmospheric/climate benefits (reducing greenhouse gases via renewable transition).

Level 2 [3-4 marks]: Some balanced discussion but lacks depth or specific examples. States agreement/disagreement but arguments may be one-sided or lack detail.

Level 1 [1-2 marks]: Basic points made, potentially as a list. Minimal or no evaluation.

Indicative content:
- Agree: Local ecosystems are unique and irreversible damage to species (like oysters/seabirds) cannot be undone; renewable energy can be built elsewhere (e.g., onshore solar/wind) without harming fragile marine straits.
- Disagree: Climate change is a global threat to all biodiversity, including marine life; generating clean energy is crucial to prevent ocean acidification and extreme warming; sustainable planning/EIAs can mitigate local impacts while securing green energy.

Detailed answers and marking criteria provided in the marking scheme.

**(a)** [Total: 3 marks]
Any three from:
- Mineral particles (sand, silt, clay) [1]
- Organic matter / humus [1]
- Soil air [1]
- Soil water [1]
- Microorganisms / soil biota (bacteria, fungi, earthworms) [1]

**(b)** [Total: 4 marks]
- Prevailing warm, moist air is pushed up over the Southern Alps [1]
- As air rises, it cools, condenses, and releases precipitation on the western slopes [1]
- Air descending on the eastern side (Canterbury) becomes warmer and drier [1]
- This creates a dry zone / rain-shadow area with low humidity and minimal rainfall [1]

**(c)** [Total: 4 marks]
- Total Rainfall calculation: 45 + 38 + 42 = 125 mm [1]
- Total PET calculation: 135 + 150 + 120 = 405 mm [1]
- Total Deficit: 405 - 125 = 280 mm [1]
- Correct units (mm) stated in final answer [1]

**(d)** [Total: 4 marks]
Two practices (each with explanation, 2 marks per practice):
- Practice 1: Conservation tillage / zero-tillage [1]; keeps crop residue on the soil surface to reduce evaporation and wind erosion [1]
- Practice 2: Planting windbreaks / shelterbelts [1]; reduces wind speed across flat plains, minimizing moisture loss and topsoil blowout [1]
- Practice 3: Organic mulching / cover cropping [1]; keeps soil covered, retaining moisture and building soil structure [1]

**(e)** [Total: 5 marks]
- Mineral ions: Nitrate (or nitrogen) [1] and Phosphate (or phosphorus) [1]
- Explanation (any three): Run-off carries ions into lakes, causing rapid algae growth / algal blooms [1]; algae blocks sunlight, preventing photosynthesis of submerged plants [1]; dead algae/plants are decomposed by bacteria [1]; bacteria consume dissolved oxygen, leading to anoxic conditions / fish kills [1]

**(f)** [Total: 6.6 marks]
Level 3 [5-6.6 marks]: A balanced, deep evaluation of groundwater restrictions. Discusses both ecological benefits (aquifer recharge, protecting wetland flows) and economic/food security downsides (loss of crop yields, dairy farm viability). Offers alternative or complementary strategies (e.g., smart drip irrigation, changing to drought-tolerant crops/livestock, rainwater harvesting).

Level 2 [3-4 marks]: Discusses some pros and cons of restricting water but lacks a comprehensive system-wide view. Reasonable but limited depth.

Level 1 [1-2 marks]: Simple opinion with little justification or only lists basic facts.

Indicative content:
- Agree: Unchecked extraction depletes aquifers permanently; water tables drop, drying out streams; limits force transition to sustainable agriculture.
- Disagree: Sudden restrictions cause economic ruin for farmers; doesn't solve the soil moisture issue directly; must be combined with better soil management, drought-tolerant species, and efficient water-use technology rather than just outright bans.

Detailed answers and marking criteria provided in the marking scheme.

**(a)** [Total: 4 marks]
Any four from:
- The denser Pacific plate subducts/descends under the lighter Indo-Australian plate [1]
- The sinking plate is subjected to extreme heat and pressure in the mantle [1]
- Water released from the subducting plate lowers the melting point of mantle rocks, forming magma [1]
- Magma is less dense than the surrounding solid rock and rises [1]
- Magma reaches the surface through volcanic vents/fissures, causing eruptions [1]

**(b)** [Total: 4 marks]
- Benefits (any two): Low greenhouse gas emissions / reduces carbon footprint [1]; reliable 24/7 baseload power / not weather-dependent [1]; small land footprint compared to solar or wind [1]
- Disadvantages (any two): Release of dissolved toxic gases (e.g., hydrogen sulfide, carbon dioxide) [1]; risk of land subsidence as fluids are extracted [1]; high water usage for cooling [1]; potential contamination of local groundwater with heavy metals/arsenic [1]

**(c)** [Total: 3 marks]
- High-pressure hot water/steam is drawn up from deep underground wells [1]
- The steam turns/rotates a turbine [1]
- The rotating turbine drives/powers a generator to generate electricity [1]

**(d)** [Total: 4 marks]
Two techniques with explanations (2 marks per technique):
- Seismic monitoring / seismometers [1]; detects small earthquakes/tremors caused by moving magma underground [1]
- Ground deformation / GPS tiltmeters [1]; measures swelling or bulging of the volcano slope as magma rises [1]
- Gas emission analysis / spectrometers [1]; monitors changes in the ratio/volume of gases like sulfur dioxide escaping from vents [1]

**(e)** [Total: 5 marks]
- Endemic species explanation (any two): High adaptation to acidic/sulfur-rich soils [1]; ability to tolerate high soil temperatures where other competing plants cannot survive [1]; isolation of thermal patches creates unique evolutionary niches [1]
- Ecotourism management (any three): Constructing elevated boardwalks to prevent soil compaction and trampling [1]; putting up educational signage explaining the fragility of the habitat [1]; limiting visitor numbers / requiring guides [1]; strict penalties/fines for leaving designated paths [1]

**(f)** [Total: 6.6 marks]
Level 3 [5-6.6 marks]: A highly structured, balanced evaluation of geothermal expansion vs volcanic hazards. Integrates geographical safety (exclusion zones, catastrophic eruption risks, infrastructure loss) with long-term climate targets (reliable renewable baseload energy, economic independence). Clearly articulates a nuanced personal stance supported by logical reasoning.

Level 2 [3-4 marks]: Discusses some pros and cons but lacks a complete integration of hazard mitigation and energy strategy. The argument is somewhat unbalanced or missing clear depth.

Level 1 [1-2 marks]: Simple list of benefits and hazards with minimal or no attempt to evaluate the trade-off.

Indicative content:
- Agree: Geothermal energy is essential for decarbonising the grid; it provides stable baseload power; modern power stations can be engineered to be modular or monitored; the likelihood of major eruptions is rare compared to the constant threat of climate change.
- Disagree: Building expensive energy infrastructure in high-risk zones is economically reckless; eruptions can destroy plants and grids instantly; local ecosystems are already heavily modified by drilling; safety of workers and continuous supply cannot be guaranteed in active hazard zones.