Biology 20: Unit A- Energy & Matter in the Biosphere: Topic 2

Cycles of Matter

Hydrologic Cycle

involves all phases of water. It is the
cycling of water that connects ecosystems across the globe.

Hydrologic Cycle States

Solids, liquids, gasses

Hydrologic Cycle Stage 1

Liquid water in lakes/ponds/oceans
is turned into a gas through
evaporation (or transpiration
from the leaves of plants).

Hydrologic Cycle Stage 2

Water vapour in the atmosphere
condenses in clouds.

Hydrologic Cycle Stage 3

Liquid water returns to the ground
through precipitation.

Hydrologic Cycle Stage 4

Water re

What is the universal solvent?

Water, due to its ability to dissolve many substances.

Polar

different charges at each end of the molecule

Water molecules are polar which results in:

in a weak
attraction between
molecules known as a
hydrogen bond, this enables water to
make weak bonds with
other substances
which causes them to
dissolve

Biogeochemical Cycling

The process of transporting dissolved materials
between organisms and their environment

Hydrogen bonding allows water to remain in a
______ state across a large ___________ range

liquid, temperature

_____ amounts of energy are required to make
water change _____ (high specific heat capacity)

large, state.

Water boiling point

100 degrees Celsius

Ice melting point

0°C

When water _____ , hydrogen bonds ______ , causing cold or
frozen water to have a _____ density.

cools, loosen, lower

When water _____ up, these bonds _______ , causing warm water
to have a _______ density.

warms, tighten, higher

Cohesion

responsible for surface
tension, the binding force or tendency of like molecules or particles to stick together

Adhesion

Water molecules are also
attracted to molecules of
other substances, produces an
upward force on water that
counteracts the pull of
gravity

The adult human body is composed of ___% water;
many plants near __% water

70, 95

Evaporation

The physical process where a liquid, such as water, absorbs heat energy and transforms into a gas (water vapour)

Transpiration

The process where plants absorb liquid water through their roots and release it as vapor into the atmosphere, primarily through small pores on leaves called stomata

Condensation

The transition of a substance from a gaseous state (vapour) to a liquid state, occurring when vapour cools or encounters a surface below its dew point

Precipitation

Any form of water (snow, sleet, ice, rain, etc) that falls from clouds and reaches Earth's surface.

Runoff

Water that flows over the ground surface rather than soaking into the ground

Where is inorganic carbon found?

Carbon plays a key role in metabolic processes such as:

Photosynthesis and Cellular Respiration

Carbon moves from ________ to ________ and decomposers, and back to the atmosphere through _____ _______.

producer, consumer, rapid cyclings

Carbon Sinks

A carbon sink is any natural or artificial reservoir—such as forests, soils, and oceans—that absorbs Carbon Dioxide

Slow Cycling of Carbon

Long

Rapid Cycling of Carbon

The carbon is going through the cycle on a daily basis. An example of this is excrements and respiration. It is considered the biological cycling of carbon.

Human impact on Carbon cycle

Increased atmospheric carbon =

Increase in greenhouse effect & climate change

What is made of nitrogen

DNA, Amino acids

Can organisms use atmospheric nitrogen? (N2)

No, it is too stable for metabolic processes

Nitrogen is made usable for organisms when its converted to:

Nitrates (NO3) (which is created in small amounts by lightning)

Nitrogen Fixation

Bacteria converting nitrogen gas into ammonia (NH3)

Nitrification

Ammonia is converted to nitrate (NO3) (which now be used by plants)

How do animals obtain nitrogen?

By eating plants or other animals

Denitrification

Excess nitrates in the soil are converted back into atmospheric nitrogen (N2) by a different set of bacteria

Symbiotic Relationship

Bacteria get sugar from the plant, the plant gets nitrates (both benefit)

How can we maintain nitrate levels in soil?

Nitrogen fixing bacteria

bacteria that can use nitrogen in soil to make nitrogen compounds (legumes; alfalfa, clover)

Aerating lawns

Sulfur Cycle Stage 1

Volcanic activity, geologic uplifting, mining and/or burning fossil fuels releases sulfur dioxide in the air (SO2)

Geologic Uplifiting

the vertical rise of the Earth's crust to higher elevations

Sulfur Cycle Stage 2

Sulfates return to the earth through acid precipitation

Sulfur Cycle Stage 3

Bacteria in the soil then allow the sulfates to be used for protein synthesis. Sulfur compounds are then returned to the soil once the plants die and decompose

Sulfur Cycle Stage 4

Some of the sulfur returned to the ground is also redeposited in rocks

What is the "rotten egg" smell?

H2S gas; produced by decomposers

Phosphorus

Where is phosphorus found?

soil, water, and rocks (released by weathering)

Long phosphorus cycle

Phosphate ions combine w/ other elements and are deposited in rocks

Short phosphorus cycle

Phosphates dissolved in water and taken up by living organism

Large amounts of phosphates and nitrates are harmful because:

it can influence the overgrowth of algae; algal bloom which causes eutrophication

Eutrophication

excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land