water in matter cycles

why is water important in organisms?

sustains organisms and allows us to survive, since the majority of organisms’ bodies are water

• 50% of plant/animal tissue have water

• 74% of human bodies are water, with 3% gained & lost

why is water important in the biosphere?

there is a limited amount of water on our surface, so it has to be naturally recycled to sustain us

how much of water in the biosphere is liquid?

95%

where do we get water vapor?

• cellular respiration

• evapotranspiration

evapotranspiration

total amount of water from evaporation and transpiration combined

metabolic water

water from cellular respiration

where does the majority of water vapor come from?

the ocean

what property does water vapor have?

it is a greenhouse gas that traps and transfers heat

hydrologic cycle

what are the two main sources of heat transfer?

• evaporation

• ocean currents

what causes evaporation of water, and where does it take place?

• large amounts of solar energy heating the ground

• takes place near equator (more direct solar energy)

where does evaporated water go, and how does it transfer heat?

• evaporated water rises and moves away from the equator

• as the water cools, heat releases from the water vapor which distributes heat

how do ocean currents regulate the temperature?

• currents transfer warmer water at the equator to cooler regions away from the equator

• increases the temperature of these areas

why do ocean currents increase the temperature in cooler areas?

• warm water heats air, which is why warmer currents increase temperature in cooler areas

what can water do?

• transfer heat energy

• carry dissolved material

what four characteristics of water make it perfect for transferring energy?

• universal solvent

• high boil/melt point

• adhesion + cohesion

• high heat capacity

how does water being a universal solvent affect its capabilities?

• water moves + changes state, carries substances

  • since water is polar, it can dissolve more substances

why does water have a higher melt/boil point?

amount of hydrogen bonds contained within water

• must break more bonds to boil/melt water, requires more energy

why is ice less dense than water

the hydrogen bonds hold water molecules in open crystals

how does temperature affect the open crystal model?

• when water freezes, it expands and becomes more dense

• when water melts, it collapses and becomes less dense

when is water most dense?

at 4C, and then it decreases from there

why does water decrease in density after it hits 4C?

thermal expansion (change in size due to heating/cooling)

how does density affect oxygen concentration?

temperature increases, solubility decreases

how does temperature affect density within bodies of water during the spring?

• temperature increases, density increases until it reaches 4C

how does water cycle within bodies of water during the spring?

• warm water sinks b/c it is more dense

• cooler water floats since it is less dense,

  • the sun warms it until it is dense enough to sink

how does temperature affect density within bodies of water during the fall?

• increase in temperature, increase in density of water

how does water cycle within bodies of water during the fall?

• cooler water sinks because it’s more dense

  • reaches max density at 4C, so it sinks then

• warmer water floats since it is less dense, and it is cooled until it sinks

why is the rise and fall of water important in bodies of water?

nutrients and oxygen cycle throughout the body of water

how does ice float?

ice that floats on top insulates the water below

• due to the fact that ice is less dense than water, which means that it will float

how are nutrients gained from rock?

1. water seeps in between rock

2. when the water freezes, it expands between the rock

3. causes weathering of rock consisting of sand + soil consisting nutrients

cohesion

attraction of water molecules to each other

how does cohesion affect bodies of water?

creates surface tension

• keeps things afloat

• provides nutrients

adhesion

attraction of water molecules to other molecules

how does adhesion affect water distribution in plants?

1. water sticks to xylem

2. provides upward force pushing water from root → leaf, then leaving the plant

what properties do water have thanks to having a high heat capacity?

• holds heat more readily and for longer

• heats slower

why does water have a high heat capacity?

large amount of H-bonds

• therefore needs more energy to break bonds n increase temps

what does water’s high heat capacity do?

regulates equal distribution of heat

why do organisms have more water in tissue?

to regulate body temperature w heat stored in water

what do bodies of water do to land?

regulate temperature w heat stored in water

what do surface currents do?

distribute heat from equator → poles

what is the main cause of a lack of water?

droughts

what are the main factors that keep our water supply in danger?

• increased temps, increase rate of evaporation

• higher demand for water due to industry and population

• less CO2 intake and photosynthesis

  • less oxygen made w plants