Aquatic Environments: Freshwater and Marine Systems

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Questions and Answers

What is the approximate percentage of water in all living cells?

90%

95%

50%

75% (correct)

The hydrologic cycle is driven by solar radiation.

True

What occurs when precipitation falls onto surfaces like vegetation and streets?

Interception

The process by which water travels from the air to Earth and back is called the __________.

Hydrologic Cycle Signup and view all the answers

Match the water properties with their descriptions:

Cohesion = Attraction among water molecules Adhesion = Attraction between water and other substances Surface Tension = Result of cohesion exceeding adhesion Viscosity = Measure of the force necessary to separate liquid molecules Signup and view all the answers

What percentage of the planet's surface is covered by water?

75% Signup and view all the answers

Ice is denser than liquid water.

False Signup and view all the answers

What is the term for the evaporation of water from the internal surfaces of plants?

Transpiration Signup and view all the answers

Surface runoff occurs when the soil is __________.

saturated Signup and view all the answers

Which of the following properties of water helps buffer aquatic habitats?

Temperature Stability Signup and view all the answers

What causes buoyancy for aquatic organisms in water?

The density of water being greater than that of air Signup and view all the answers

The absorption of blue wavelengths occurs at a greater depth than red wavelengths in water.

True Signup and view all the answers

What are the three layers of water column identified in lakes?

Epilimnion, Hypolimnion, Thermocline Signup and view all the answers

The maximum salinity concentration of open sea water is _____ ‰.

35 Signup and view all the answers

Match the following terms to their definitions:

Epilimnion = Warm surface layer of water Hypolimnion = Cold deep layer of water Thermocline = Layer where temperature declines rapidly Buoyancy = Upward force of water on less dense objects Signup and view all the answers

Which property of water allows it to dissolve more substances than any other liquid?

Polarity Signup and view all the answers

Freshwater has a higher concentration of solutes than saltwater.

False Signup and view all the answers

What happens to the solubility of Sodium Chloride in water once saturation is reached?

Additional solutes will precipitate. Signup and view all the answers

Aquatic plants and the _____ are sources of oxygen in aquatic environments.

atmosphere Signup and view all the answers

What is the primary factor that affects the depth of the thermocline?

Solar radiation input Signup and view all the answers

Study Notes

Aquatic Environments: Freshwater and Marine Systems

Water is essential for life, comprising 75-95% of living cells and ~70% of organisms.
Water covers 75% of Earth's surface.
Freshwater makes up only 3% of the planet's water.

Hydrologic Cycle

Water continuously circulates from the atmosphere to Earth's surface and back to the atmosphere.
Solar radiation drives evaporation.
Precipitation (rain, snow, etc.) returns water to Earth.

Water Movement and Interception

Interception is when precipitation falls on vegetation, organic matter, or surfaces, then evaporates.
Infiltration is water absorbed into the soil.
Surface runoff occurs when soil is saturated.
Groundwater collects below an impervious layer.
Evaporation and transpiration (plant water loss) return water to the atmosphere.
Evapotranspiration is the combined amount of water evaporating and transpiring.

Physical Properties of Water

Water's temperature stability buffers aquatic habitats and is crucial for thermal regulation in organisms.
Ice (solid water) is less dense than liquid water, allowing it to float. Ice insulates water bodies, preventing them from freezing solid.
Cohesion is the attraction between water molecules due to hydrogen bonding.
Adhesion is the attraction between water molecules and other substances.
Surface tension results from stronger cohesion than adhesion between water and air.
Viscosity is the force needed to separate water molecules, related to cohesion. Water's high viscosity is due to its high density.
Buoyancy is the upward force of water on an object less dense than water.

Light in Aquatic Environments

Light is reflected and absorbed or scattered by water and particles.
Water absorbs longer wavelengths (like red light) more readily, allowing blue light to penetrate deeper.
This absorption pattern influences adaptations in aquatic organisms, like body coloration and eyesight.
Surface water temperatures rise from absorbed sunlight, and this heat is distributed through winds and waves.
Temperature decreases with depth, but not at the same rate as light.

Temperature Stratification in Water Bodies

Epilimnion is the warm, upper layer of water.
Hypolimnion is the cold, deep layer.
Thermocline (metalimnion) is the layer of rapid temperature change between epilimnion and hypolimnion.
Thermocline depth varies depending on solar radiation and mixing.
In tropical waters, the thermocline is permanent. Temperate lakes mix epilimnion and hypolimnion during fall and spring.

Water as a Solvent

Water is a universal solvent; it dissolves more substances than any other liquid.
Solutions have a solvent (dissolving agent) and a solute (dissolved substance). Aqueous solutions have water as the solvent.
Water's ability to dissolve substances is crucial for life.
Fresh water has a lower concentration of solutes (ions) compared to saltwater.
Maximum solubility is the point at which additional solutes precipitate out.

Salinity and Dissolved Oxygen

Salinity, often measured by chlorine concentration, is expressed as parts per thousand (‰).
Freshwater salinity is 0.065-0.30 ‰; open sea salinity is ~35 ‰.
Oxygen diffuses from the atmosphere into surface water and then deeper waters.
Warm water holds less oxygen than cold water.
Winds mix oxygen-rich water with oxygen-poor water.
Oxygen levels are highest in the upper 10-20 meters of the ocean.
Flowing water tends to have higher oxygen content due to greater contact with the atmosphere.

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Description

Explore the essential role of water in freshwater and marine ecosystems. Dive into the hydrologic cycle, understand water movement, and learn about the physical properties of water. This quiz will enhance your knowledge about the significance of water in sustaining life on Earth.