Biology 20 Alberta: Ecology; 2 (Biogeochemical Cycles)

How much of the adult human body is water?

70%

How much N2 is in the Earth's atmosphere?

78.1%

What does a hydrogen bond occur between?

A hydrogen atom and an oxygen atom on different water molecules

H2SO4 and H2SO3 deposition =

Acid rain (or snow)

What can excess nutrients in a body of water result in?

Algal blooms, which can create a dead zone in the water

At what temperature is water most dense?

At 4 degrees Celsius

Cohesion

Attraction of water molecules to each other (responsible for surface tension)

Adhesion

Attraction of water molecules to molecules of other substances (responsible for transpiration)

Why does drought decrease plant productivity?

Because plants close their stomata to reduce water loss and can no longer take in CO2

How is metabolic water generated?

By metabolic reactions

How is phosphorus released?

By weathering

If life on Earth did not happen the levels of...

CO2 and O2 would be very different

Wetlands

Can clean polluted water and provide other ecosystem services

CHNOPS

Carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur

What is water a product of?

Cellular respiration (due to the chemical breakdown of glucose)

In respect to matter, Earth is a...

Closed system

Due to the polarity of a water molecule...

Excellent carrier of other materials. Allows one water molecule to form a hydrogen bond with another water molecule. Can dissolve a wide variety of substances

How is carbon returned via natural processes

Forest fires, weathering, combustion

How do consumers obtain phosphorus?

From food

Hydrogen bonds in water are responsible for...

High melting and boiling points (requires lots of energy to break bonds in a volume of water). Liquid water being more dense than frozen water

Gaia Hypothesis

Idea that Earth acts like an organism; needs a constant input of energy and cycling of nutrients to maintain its internal balance

In what state does most of the water in the biosphere exit?

In liquid form

Where are carbon and oxygen found?

In living organisms and in the land, atmosphere, and water

Where is phosphorus found?

In soil and water

Acid rain is part of the natural cycle, but...

Large amounts are damaging —> increased by burning fossil fuels

In the sulfur cycle, bacteria convert sulfur to forms that are...

Layered down as sediments. These become rocks or incorporated into fossil fuels (slow cycling)

Phosphorus is an essential nutrient, but...

Limited quantities in environment keeps producers in balance

Phosphorus is most concentrated in...

Living organisms (like in DNA and ATP)

High heat capacity

Measure of the amount of heat a substance can absorb or release

Is liquid water more or less dense than frozen water?

More dense

What can affect the transfer of energy and the cycling of matter through the biosphere?

Natural processes and human activities

Carbon is released back into the atmosphere as CO2 how?

Naturally (from forest fires = decomposition) and unnaturally ( from deforestation and burning fossil fuels)

Some species of bacteria in soil convert NH4+ into...

Nitrite (NO2-) and then into nitrate (NO3-)

Does phosphorus cycle through the atmosphere?

No

Can most organisms use atmospheric N2?

No (some species of bacteria can convert N2 into ammonium (NH4+) —> nitrogen fixation

Where are carbon, oxygen, sulfur, nitrogen, and phosphorus stored and cycled through?

Nutrient reservoirs (cycle through at different rates)

Rapid cycling

Nutrients transfer through reservoirs relatively quickly

Liquid water

Ocean currents transfer warm water from hotter regions to cooler regions

If disruption occurs in one biogeochemical cycle...

Other cycles may be affected (because biogeochemical cycles are interrelated)

Producers can only use phosphorus as...

Phosphate (PO43-)

What might have caused the increase of atmospheric oxygen?

Photosynthesis

Some bacteria use sulfur-containing compounds in...

Photosynthesis or types of cellular respiration (rapid cycling)

What is nitrate (NO3-) used by?

Plants

Sulphur is an important part of...

Proteins and vitamins

Productivity

Rate at which an ecosystems producers capture and store energy over time

Carbon, oxygen, sulfur, nitrogen, and phosphorus cycle through reserves at different...

Rates

There is a limited amount of water so it must be...

Recycled

Slow cycling

Relatively slow transfer of nutrients (millions of years)

Biogeochemical cycles

Route that water and other chemical nutrients take through the biosphere

Nodules

Some plants have these structures containing nitrogen fixing bacteria

Carbon sinks

Store carbon in different forms (e.g. deep ocean —> methane hydrates and CO2

What form of sulfur do plants and algae use?

Sulfate (SO42)

Volcanoes release trapped sulfur into the atmosphere as...

Sulfur dioxide (SO2)

Sulfur dioxide (SO2) reacts with O2 and H2O(g) to form...

Sulphurous acid (H2SO3) and sulfuric acid (H2SO4)

What influences productivity?

Sunlight, pollution

What is cohesion responsible for?

Surface tension

How is water lost (in the human body)?

Through breathing, sweating, urine, and feces

How is denitrification done?

Through denitrifying bacteria

How is O2 released?

Through plants, animals and decomposers (photosynthesis and cellular respiration)

Other than through nitrogen fixation, what is another way NH4+ is produced

Through the process of ammonification

What is adhesion responsible for?

Transpiration

Water vapour

Traps heat in the atmosphere and transfers it around the planet (I.e. greenhouse gas)

Four major properties of water:

Universal solvent, relatively high boiling point and melting point, cohesive and adhesive properties, high heat capacity

Hydrologic cycle

Water cycle. Can connect ecosystems separated by great distances

Denitrification

When nitrite and nitrate are converted back to nitrogen gas via denitrifying bacteria

When do algal blooms appear?

When phosphorus (and sometimes nitrogen too) is in excess. This is a result of human activities (e.g. agriculture)

Is phosphorus an essential nutrient?

Yes

Is water vapour a greenhouse gas?

Yes

What are biogeochemical cycles?

water cycle, carbon cycle, nitrogen cycle, phosphorus cycle, oxygen cycle, sulfur cycle (CHNOPS)