Flashcards · 0680 · Topic 3

Water flashcards

25 cards on Topic 3, subtopics 3.1 to 3.6. Pick a subtopic or study them all.

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Water cycle: name four stores and four transfers: Stores: oceans, ice sheets and glaciers, ground water, the atmosphere, lakes and rivers. Transfers: precipitation, interception, infiltration, surface run-off, through-flow, transpiration, evaporation, condensation.
What are the stages of treating water to make it potable?: Screening (removes large objects) → sedimentation (particles settle) → filtration (sand and gravel remove fine particles) → chlorination (kills microorganisms).
Distillation vs reverse osmosis for desalination: Distillation: seawater is boiled and the vapour condensed; reliable but energy-intensive. Reverse osmosis: pressure forces water through a membrane; usually uses less energy but membranes need maintenance and can foul.
What are the uses of a multipurpose dam?: Flood control, hydro-electric power, irrigation, water storage, transport, recreation, tourism and fish farming.
Give limitations of multipurpose dams: High cost, people and habitats displaced by the reservoir, silt trapped behind the dam, and disrupted river ecosystems and communities downstream.

Match water pollution sources to their impacts: Sewage and domestic waste: infectious disease such as cholera. Industry: toxic substances. Farming: eutrophication from fertiliser. Air pollution: acid rain harming aquatic life.
What are the stages of eutrophication?: Nutrient enrichment from fertiliser or sewage → algal bloom → light is blocked and plants die → bacteria decompose them, using up oxygen → fish and other aquatic life die.
Bioaccumulation vs biomagnification: Bioaccumulation: a toxin builds up within a single organism over time. Biomagnification: the concentration increases at each step up a food chain, from prey to predator.
How can water pollution be reduced?: Treating sewage and industrial waste before discharge, controlling fertiliser use and leaving buffer strips beside rivers, and passing and enforcing pollution laws.

How is malaria transmitted?: It is vector-borne: the Plasmodium parasite is passed to people in the bite of an infected female Anopheles mosquito.
How is cholera transmitted?: It is waterborne: people swallow water or food contaminated with the cholera bacterium from the faeces of infected people.
How can malaria be controlled?: Personal protection (insecticide-treated bed nets, repellents, covering skin) and vector control (draining standing water, spraying insecticide). Insecticide resistance limits spraying.
How can cholera be controlled?: Safe potable water, proper sanitation and sewage treatment, handwashing, and vaccination. Access to vaccines and clean water can be limited in poorer or disaster-hit areas.

What is marine aquaculture?: The farming of marine species, such as fish, crustaceans and seaweeds, in captivity.
Target species vs bycatch: Target species: the species a fishery intends to catch. Bycatch: other species caught unintentionally. Overfishing harms both and wider food chains.
What are the impacts of marine aquaculture?: Benefits: less pressure on wild fisheries and more food. Problems: escapes and disease spreading to wild stocks, effects on local food webs, nutrient enrichment, energy use, and catching wild fish to feed farmed species.
How can fisheries be managed sustainably?: Limits on boat and net size, larger mesh sizes, sustainable methods such as pole and line, quotas, closed seasons, limited fishing days, marine protected areas, conservation laws and international agreements.

What are the causes of oil pollution?: Off-shore and on-shore extraction, pipelines, shipping accidents, tank cleaning at sea and refineries.
What are the impacts of oil pollution?: Oil coats birds and marine mammals, poisons fish and crustaceans, smothers seaweeds and coral reefs, and pollutes beaches.
How can oil pollution be prevented?: MARPOL (the International Convention for the Prevention of Pollution from Ships), double-hulled tankers, risk assessments and regular maintenance.
How can the impact of an oil spill be minimised?: Improved navigation to avoid collisions, booms and sorbents to contain and soak up oil, skimmers, detergent sprays and controlled burning.

Conventional plastic vs bioplastic: Conventional plastics are made from fossil fuels and are generally non-biodegradable. Bioplastics are made fully or partly from biological material and may or may not be biodegradable.
What are microplastics?: Pieces of plastic less than 5 mm in size, formed when larger plastics break down.
How does plastic pollution affect marine ecosystems?: Visual pollution, entanglement of animals, plastic mistaken for food, and bioaccumulation and biomagnification of plastics and the chemicals in them.
How can plastic pollution be managed?: Alternative packaging, avoiding single-use plastics, safe disposal, recycling, and legislation with enforcement.