Cycles of Matter

MATTER CYCLING IN ECOSYSTEMS

Nutrient Cycles: Global Recycling Global Cycles recycle nutrients through the

earth’s air, land, water, and living organisms. Nutrients are the elements and compounds that

organisms need to live, grow, and reproduce. Biogeochemical cycles move these substances

through air, water, soil, rock and living organisms.

Hydrogen Cycle

We alter the water cycle by:

Withdrawing large amounts of freshwater. Clearing vegetation and eroding soils. Polluting surface and underground water. Contributing to climate change.

Effects of Human Activities

on Water Cycle

Answer the handout water cycle

Oxygen-Carbon Cycle

We alter the carbon cycle by adding excess CO2 to the atmosphere through:

Burning fossil fuels. Clearing vegetation faster

than it is replaced.

Effects of Human Activities on Carbon Cycle

Nitrogen Cycle

Nitrogen can exists either solid, liquid, or gas.

In the atmosphere nitrogen gas makes up 78% of the atmosphere. However, nitrogen must be converted or FIXED by bacteria before it can be used by others.

Where can you find Nitrogen?

Nitrogen fixation occurs when bacteria

(rhizobium) converts Nitrogen gas into organic compounds that living things can take up.

Step 1: Nitrogen Fixation

In this process, bacteria (rhizobium) in soil or

fungi will convert Nitrogen into AMMONIUM IONS

Step 2: Ammonification

A 2- step process:

Soil bacteria (Rhizobium) converts ammonium ions into NITRITE ions

Soil bacteria (rhizobium) then convert Nitrite ions into NITRATE

Step 3: Nitrification

In this process, NITRATES are converted to

Nitrogen gas, which are then released to the atmosphere.

Step 4: Denitrification

When living things/ organisms take up

NITROGEN

Step 5: Assimilation

We alter the nitrogen cycle by:

Adding gases that contribute to acid rain. Adding nitrous oxide to the atmosphere through

farming practices which can warm the atmosphere and deplete ozone.

Contaminating ground water from nitrate ions in inorganic fertilizers.

Releasing nitrogen into the troposphere through deforestation.

Effects of Human Activities on the Nitrogen Cycle

Human activities such as

production of fertilizers now fix more nitrogen than all natural sources combined.

Effects of Human Activities on the Nitrogen Cycle