Water distribution
About what percentage of Earth's water is freshwater that is readily available for human use (found in lakes, rivers, and accessible groundwater)?
What is less than 1%?
What two physical properties of seawater primarily drive deep ocean currents?
What are temperature and salinity?
Which water quality factor measures how acidic or basic water is?
What is pH?
Give one example of a human activity that can reduce water quality.
What are agricultural runoff, sewage discharge, industrial pollution, excessive groundwater withdrawal?
Define "estuary" in one short sentence.
Name the three main reservoirs of Earth's hydrosphere (major categories where water is stored).
What are oceans, ice, and freshwater?
Name the surface current that brings warm water from the Gulf of Mexico across the Atlantic toward Europe.
What is the gulf stream?
Name two nutrients that in excess can lead to algal blooms in freshwater systems.
What are nitrates and phosphates?
Name one common method used to treat drinking water to remove pathogens.
What are filtration and disinfection (chlorination, UV)?
Name one bio-indicator organism commonly used to assess stream health (example: a type of insect group or organism).
What are macroinvertebrates such as mayflies, stoneflies, caddisfly larvae?
Explain what a watershed (or river basin) is in one sentence.
What is the land area that drains rainfall and streams to a common outlet?
Explain in one sentence how ocean currents influence climate for coastal regions.
What is currents bring warm or cold water to coasts, moderating temperatures to be warmer or cooler based on the water temperature?
What does dissolved oxygen (DO) tell us about a water body's ability to support aquatic life?
What is the amount of Oxygen available for respiration - low DO can stress or kill aquatic organisms?
State one reason why regular monitoring of local water bodies is important for public health.
What is monitoring detects contamination early, preventing illness and guiding remediation?
Describe how land use changes (like urban development) in a river basin can affect runoff and water availability.
What is increasing runoff, erosion, pollutant loads, and reducing groundwater recharge?
Identify two processes in the water cycle that move water from the surface into the atmosphere.
What are evaporation and transpiration?
Describe how a change in ocean circulation could affect the distribution of nutrients and marine life.
What is a change could affect upwelling zones, reducing nutrient supply to surface waters and decreasing productivity for fisheries?
Explain how turbidity can affect temperature and photosynthesis in a stream or lake.
What is turbidity reduces light penetration, which can decrease photosynthesis and raise water temperature, stressing aquatic organisms?
Describe a best-practice stewardship action communities can take to protect local rivers and estuaries.
What are reducing fertilizer use, proper stormwater management, community clean-ups?
Identify two physical or chemical measurements you would collect to assess a local stream's potability and why each is important.
What are DO (shows ability to support life), pH (affects toxicity), nitrates/phosphates (nutrient pollution), and turbidity (sediment load)?
Describe how glaciers and ice caps affect local and global water availability.
What is glaciers store freshwater, but losing glaciers reduces long-term water availability and can raise sea levels?
Using the concept of density-driven circulation, explain why polar waters tend to sink and how that contributes to global conveyor-belt circulation.
What is cold, salty polar waters are dense and sink, driving deep cirulation that transports heat and nutrients globally?
Given a sample with low DO, high nitrates, and cloudy water, predict two likely causes and one ecological consequence.
What is are causes: agricultural runoff, high turbidity and what is an effect: death of aquatic organisms and reduced biodiversity?
Explain how water quality standards help protect both human health and ecosystems (one to two sentences).
What are setting standards for safe thresholds (for DO, nitrates, pH) and guide treatment and enforcement to protect people and ecosystems?
You measure a local river and find: pH 6.0, DO 4 mg/L, nitrate 8 mg/L, turbidity high. Interpret whether this water is likely safe for drinking without treatment and justify your answer with at least two reasons.
What is not safe without treatment; DO is too low, nitrates are too high, and turbidity indicates contamination?