BIOGEOCHEMICAL CYCLES:

The RECYCLING of MATERIALS through living

organisms and the physical environment.

BIOCHEMIST:

Scientists who study how LIFE WORKS at

a CHEMICAL level.

The work of biochemists has led to the

understanding that LIVING ORGANISMS are

composed of some of the SAME elements

that are found in air, water, and soil.

Although there are 92 elements known to

occur naturally on Earth, fewer than 20

elements are presently known to occur in the

tissues of living things.

For example, only 6 elements make up 99.2

% of human tissue

CONCLUSIONS:

THE FOUR ELEMENTS that make up the

MAJORITY of LIVING TISSUES are:

•OXYGEN

•CARBON

•HYDROGEN

•NITROGEN

THE CYCLING PROCESS

The 4 elements --O, C, N, and H –are cycled

constantly between 2 parts of nature:

LIVING ORGANISMS

PHYSICAL ENVIRONMENT

The cycling of these elements is

dependent on two types of processes in

order to work:

•BIOLOGICAL PROCESSES

•GEOLOGICAL PROCESSES

BIOLOGICAL PROCESSES

The cycling of these elements requires

LIVING ORGANISMS, which make up the

BIOSPHERE of Earth.

What are some examples of BIOLOGICAL

PROCESSES?

•Respiration

•Photosynthesis

•Decomposition

•Assimilation

•Excretion

GEOLOGICAL PROCESSES

The cycling of these elements require the

PHYSICAL ENVIRONMENT, which INCLUDES:

AIR –ATMOSPHERE

LAND –GEOSPHERE

WATER -HYDROSPHERE

What are some examples of GEOLOGICAL

PROCESSES? •FOSSILIZATION

•EROSION

•COMBUSTION/BURNING

•WEATHERING

•SEDIMENTATION

3 TYPES OF CYCLES

CARBON CYCLE

NITROGEN CYCLE

OXYGEN CYCLE

THE CARBON CYCLE P. 62-65

DEFINITION: The cycling of carbon through the

atmosphere, the physical environment, and

ecosystems.

CARBON AND THE BIOSPHERE

HOW IMPORTANT IS CARBON for LIFE?

Carbon is the ELEMENT that is the

BACKBONE for ALL LIFE on Earth. In other

words, we are CARBON-BASED life forms.

HOW DOES CARBON MOVE THROUGH LIVING

ORGANISMS?

The two main PROCESSES that help

cycle CARBON through the BIOSPHERE

are:

•PHOTOSYNTHESIS

•CELLULAR RESPIRATION

WHERE IS CARBON STORED IN THE NON

LIVING PHYSICAL ENVIRONMENT?

2 TYPES OF CARBON STORAGE:

1) Organic Reservoirs: Carbon that has been

stored as the result of decomposition of

living organisms. PEAT, COAL, OIL and

NATURAL GAS2) INORGANIC RESERVOIRS:

•AIR –0.03 % of air is carbon

•OCEANS –both dissolved (CO2 gas) and in

shells (CaCO3 –calcium carbonate)

•LAND –in sedimentary rocks, which can be

released during volcanic eruptions

NITROGEN CYCLE P. 66-67

DEFINITION: The movement of nitrogen through the atmosphere, physical environment and ecosystems.

SIMPLIFIED NITROGEN CYCLE

WHAT IS NITROGEN USED FOR IN LIVING

ORGANISMS?

Nitrogen is used to make DNA and PROTEINS.

DNA is the GENETIC MATERIAL found in every

living cell.

Most nitrogen on Earth is found in the air.

•The air is 79% NITROGEN.

•This atmospheric nitrogen is in the form N2, a

gas.

Although nitrogen is plentiful in the air, it is

UNUSABLE to most living organisms (we cannot

simply “breathe in” nitrogen).

HOW DO LIVING ORGANISMS GET NITROGEN?

Plants and animals cannot use N2 gas.

We can use nitrogen in TWO FORMS:

•AMMONIA, NH3

•NITRATES, NO3

WHAT ARE THE KEY NITROGEN CYCLE PROCESSES?

NITROGEN FIXATION

DENITRIFICATION

NITROGEN FIXATION

Also known as NITRIFICATION

Gaseous nitrogen, N2, is converted to

usable forms in TWO WAYS:

•By LIGHTNING

•By NITROGEN-FIXINGBACTERIA

These bacteria are found in the

ROOT NODULES of LEGUMES

such as ALFALFA and CLOVER.

DENITRIFICATION

DENITRIFYING BACTERIA convert usable forms

of nitrogen back into gaseous nitrogen, N2.

These bacteria are found in the soil.

HUMAN IMPACTS ON THE......

CARBON CYCLE

GLOBAL WARMING and the GREENHOUSE

EFFECT

NITROGEN CYCLE

AQUATIC EUTROPHICATION

GLOBAL WARMING AND THE GREENHOUSE

EFFECT

Humans have DISRUPTED the CARBON CYCLE

in TWO MAIN WAYS:

Burning FOSSIL FUELS –

Increased CO2

DEFORESTATION –

Decreased O2 production by plants

Increased CO2

These INCREASES in CO2 Levels

have led to an ENHANCED

GREENHOUSE EFFECT.

WHAT ARE GREENHOUSE GASES?

Gases that have the ability to HOLD HEAT IN the atmosphere.

These gases are important to keep the Earth warm enough to sustain life.

3 MAIN GREENHOUSE GASES

1) CARBON DIOXIDE CO2

Sources:

•Cellular Respiration

•Combustion (burning)

2) METHANE CH4

Sources:

•Fossil fuel production and transportation

•Decomposition

•Livestock

3) NITROUS OXIDES NOx

Sources:

•Combustion

•Agricultural Fertilizers

•Industrial Emissions

GLOBAL WARMING 101

Humans have DRAMATICALLY INCREASED the

amount of greenhouse gases in the

atmosphere, leading to the ENHANCED

GREENHOUSE EFFECT, or GLOBAL WARMING.

POSSIBLE EFFECTS

Increased spread of disease

Rising sea levels and loss of polar ice caps

Figure below is 1979 versus 2005

Loss of freshwater sources

More extreme weather

Accelerated species extinction

AQUATIC EUTROPICATION

Humans have impacted the nitrogen cycle by

releasing 2 substances into AQUATIC

ECOSYSTEMS:

•FERTILIZERS

•UNTREATED HUMAN SEWAGE

Fertilizers, and untreated human sewage,

contain NITRATES and PHOSPHATES.

These chemicals LEACH into water ways

through groundwater, road runoff, etc.

Lakes that have HIGH LEVELS of phosphates

and nitrates can undergo EUTROPHICATION

A transformation from an OLIGOTROPHIC LAKE

to a EUTROPHIC LAKE.

THINK ABOUT IT!!!!!!!!!!!!!