BIOGEOCHEMICAL CYCLES and HUMAN IMPACTS
NAME:_______________________
OUTLINE
BIOGEOCHEMICAL CYCLES
 INTRODUCTION
 THE CYCLING PROCESS
 TWO CYCLES:
 CARBON CYCLE
 NITROGEN CYCLE
HUMAN IMPACTS
 GLOBAL WARMING
 AQUATIC
EUTROPHICATION
BIOGEOCHEMICAL CYCLES:
_______________________________________________________________________________________
_______________________________________________________________________________________
BIOCHEMIST:
_______________________________________________________________________________________
The work of biochemists has led to the understanding that _________________________ are
composed of some of the ___________________ elements that are found in air, water, and soil.
BIOGEOCHEMICAL CYCLES . . .
Although there are _______________elements known to occur naturally on Earth, fewer than
_____________ elements are presently known to occur in the tissues of living things.
For example, only ________________ elements make up 99.2 % of human tissue . . . And pumpkin
tissue!!!
How do we HUMANS compare to the EARTH'S CRUST and a PUMPKIN???
THE FOUR ELEMENTS that make up the MAJORITY of LIVING TISSUES are:
 ______________________
 ______________________
 ______________________
 ______________________
-------------------------------------------------------------------------------------------------------------------------------THE CYCLING PROCESS
The 4 elements -- O, C, N, and H – are cycled constantly between 2 parts of nature:
 ___________________________________________
 ___________________________________________
The cycling of these elements is dependent on two types of processes in order to work:
 ___________________________________________
 ___________________________________________
BIOLOGICAL PROCESSES
The cycling of these elements requires ______________________________, which make up the
_________________________ of Earth.
What are some examples of BIOLOGICAL PROCESSES?
 ___________________________________________
 ___________________________________________
 ___________________________________________
 ___________________________________________
 ___________________________________________
GEOLOGICAL PROCESSES
The cycling of these elements requires the ___________________________________, which
INCLUDES:
AIR –
___________________________
LAND – ___________________________
WATER - ___________________________
What are some examples of GEOLOGICAL PROCESSES?
 ___________________________________________
 ___________________________________________
 ___________________________________________
 ___________________________________________
 ___________________________________________
2 TYPES OF CYCLES discussed in SCIENCE 1206:
 CARBON CYCLE
 NITROGEN CYCLE
THE CARBON CYCLE
 See also Figure 3, p. 63
 DEFINITION
 ____________________________________________________________________________________
 CARBON AND THE BIOSPHERE
 HOW IMPORTANT IS CARBON for LIFE?
 Carbon is the ELEMENT that is the _______________________________ on Earth. In other
words, we are _________________________ life forms.
 HOW DOES CARBON MOVE THROUGH LIVING ORGANISMS?
 The two main PROCESSES that help cycle CARBON through the BIOSPHERE are:
_____________________________________
_____________________________________
 CARBON AND NONLIVING SYSTEMS
 WHERE IS CARBON STORED IN THE NON LIVING PHYSICAL ENVIRONMENT?
 2 TYPES OF CARBON STORAGE:

ORGANIC RESERVOIRS
Carbon that has been stored as the result of decomposition of living organisms. These
processes are VERY SPECIFIC and take MILLIONS OF YEARS to complete.
When DETRITUS gets TRAPPED UNDER:
_________________________________________________________________________
_________________________________________________________________________

INORGANIC RESERVOIRS
3 MAIN AREAS:
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
THE NITROGEN CYCLE
 DEFINITION:
 ____________________________________________________________________________________
 NITROGEN AND THE BIOSPHERE
 WHAT IS NITROGEN USED FOR IN LIVING ORGANISMS?
 Nitrogen is used to make ___________________________________________.
 DNA is the __________________________________ found in every living cell.
 WHERE IS MOST NITROGEN FOUND ON EARTH?
 Most nitrogen on Earth is found in the ____________.
The air is ______________ NITROGEN.
This atmospheric nitrogen is in the form __________________, a gas.
Although nitrogen is plentiful in the air, it is ___________________________ 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:
_________________________________
_________________________________
 WHAT ARE THE KEY NITROGEN CYCLE PROCESSES?
 ___________________________________
 ___________________________________
 NITROGEN FIXATION
 Also known as _______________________________________
 Gaseous nitrogen, N2, is converted to usable forms in TWO WAYS:
 ______________________________________
 ______________________________________
 These bacteria are found in the ________________________________________ such as ALFALFA
and CLOVER.
 DENITRIFICATION
 ____________________________ convert usable forms of nitrogen back into gaseous nitrogen, N2.
 These bacteria are found in the _________________.
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 –
 _______________________________________
 DEFORESTATION –
 _______________________________________
 _______________________________________
 These INCREASES in CO2 Levels have led to an _________________________________________.
 GREENHOUSE GASES
 WHAT ARE GREENHOUSE GASES?
 Gases that have the ability of ____________________________ the atmosphere.
 These gases are important to keep the Earth warm enough to sustain life.
 3 MAIN GREENHOUSE GASES . . .
 _____________________________________
 Sources:
_________________________________
_________________________________
 _____________________________________
 Sources:
_________________________________
_________________________________
_________________________________
 _____________________________________
 Sources:
_________________________________
_________________________________
________________________________
 GLOBAL WARMING 101
 Humans have DRAMATICALLY INCREASED the amount of greenhouse gases in the atmosphere,
leading to the ______________________________________________________________________.
 POSSIBLE EFFECTS OF GLOBAL WARMING
 ___________________________________________________
 ___________________________________________________
 ___________________________________________________
 ___________________________________________________
 ___________________________________________________
 ___________________________________________________
--------------------------------------------------------------------------------------------------------------------------------
AQUATIC EUTROPHICATION
 Humans have impacted the nitrogen cycle by releasing 2 substances into AQUATIC
ECOSYSTEMS:
 ____________________________________________
 ____________________________________________
 WHAT ARE FERTILIZERS?
 ____________________________________________________________________________________
____________________________________________________________________________________
 Fertilizers, and untreated human sewage, contain _______________________________________.
 These chemicals ______________________ into water ways through groundwater, road runoff, etc.
 Lakes that have HIGH LEVELS of phosphates and nitrates can undergo EUTROPHICATION
 AQUATIC EUTROPHICATION:
 ____________________________________________________________________________________
OLIGOTROPHIC LAKE
EUTROPHIC LAKE