Aquatic Ecosystems and Freshwater Resources

These flashcards cover key concepts, terms, and processes related to aquatic ecosystems and freshwater resources.

What percentage of all water on Earth is freshwater?

2.5%.

What is the hydrologic cycle?

The continuous movement of water on, above, and below the surface of the Earth.

What are lotic systems?

Rivers and streams that are dynamic with flowing water.

What is a watershed?

An area of land drained by a river system and all its tributaries.

What does the term 'floodplain' refer to?

Low lying land along the sides of a river.

What do you call lakes that are low in nutrients and high in oxygen?

Oligotrophic lakes.

What distinguishes eutrophic lakes from oligotrophic lakes?

Eutrophic lakes are high in nutrients and relatively low in oxygen.

What is a vernal pool?

A seasonal body of water that only holds water temporarily.

What is the purpose of irrigation in agriculture?

It is the largest single use of water.

What happens to groundwater withdrawn excessively from an aquifer?

It can lead to ground subsidence and water table decline.

What impact can excessive water use have on rivers?

Rivers may run dry before reaching their natural outlets, such as the Ocean.

What are non-point sources of water pollution?

Pollution from diffuse sources, often carried by runoff.

How does primary treatment of municipal sewage work?

It allows solids to settle out of wastewater in settling tanks.

What happens during secondary treatment of wastewater?

Circulation occurs between high and low oxygen zones to break down pollutants.

What is the role of treatment wetlands?

They absorb remaining nutrients from wastewater before discharge.

What is the benthic zone in a lake?

The bottom of a lake that may be exposed during drought.

What are dikes and levees used for?

To hold back rivers and prevent flooding.