Chapter 3 – The Aquatic Environment
Water is the essential substance of life
Water Cycles Between Earth + the Atmosphere
Water cycle (hydrologic cycle) – process by which water travels in a sequence from the
air to the Earth + returns to the atmosphere
oSolar radiation is the driving force behind the water cycle because it provides the
energy for the evaporation of water
Water vapor eventually falls in some sort of precipitation
Interception – occurs when precipitation falls onto vegetation, dead organic matter, +
urban structures or streets. This water evaporates directly back to the atmosphere
Infiltration – precipitation that reaches the soil + moves into the ground
oSurface runoff – occurs when soils is saturated
oWater that seeps down to an impervious layer of rock collects as ground water\
Evapotranspiration – total amount of evaporating water
oSuperficial water in terrestrial + aquatic environments returns to the atmosphere
by evaporation
oTranspiration – evaporation of water from the internal surfaces of plants
Stomata open to in take CO2, lose water from opening up
Ecological Issues: Groundwater Resources
Irrigation of agricultural fields provides a steady supply of water
oGenerally supplied by groundwater
