Name:
Ch 3: Section 4 Notes - Cycles in the Biosphere
Nutrients Cycling
 Matter may be transformed from one type to another, but it cannot be
or
 This is called the
.
 Nutrients are matter that organisms require for their life processes.

–nutrients that are required in large amounts. (nitrogen, carbon,
phosphorus)

–nutrients needed in smaller amounts.
What goes in must come out?
 Materials on the planet are constantly being used and re-used. Those materials are moved through different
phases on the planet in
.
 Biogeochemical means “
”.
 Different items and elements require different amounts of time to cycle through the environment.
 The amount of matter cycled by biogeochemical cycles is gigantic! For example, about 90 million metric tons (1
metric ton = 1,000 kg or 2,210 lbs) of nitrogen are cycled per year. 90% of it is done by
 The major biogeochemical cycles are: the
cycle, and the
.
cycle, the
cycle, the
cycle.
The Nitrogen Cycle
 The nitrogen cycle is the process in which nitrogen is cycled between the
,
,
and other living things.
 All living things need nitrogen to
 Nitrogen makes up
, which are used to make new cells.
of the atmosphere.
 BUT…living things cannot use the nitrogen in the atmosphere…so how do we get what we need?
 Nitrogen in the atmosphere must be “fixed” by
before it can be used by plants and animals.
in the ground
 These bacteria live in little nodules on the roots of plants called
(ie: beans, peas, clover) or
in the soil.
 Once the nitrogen is converted into the right form, animals get that nitrogen by eating plants that contain it. Plants
get that nitrogen by absorbing it through their roots in the soil.
 There is a good amount of nitrogen in

and
such as
and
.
break down animal waste,
leaves, dead trees, dead animals, etc.
 During decomposition, nitrogen that was once in living things is returned to the
returned to the
and some is
.
 If decomposers did not exist, nitrogen would build up in waste and dead organisms rather than being returned to
the soil to be used again.
The Phosphorus Cycle
 The phosphorous cycle involves the
and the
. It is a key
component of cell membranes, DNA, and RNA.
 Although phosphorous is found in
,
…tons more of it is found in
, and the
,
.
 It is released naturally when rocks are broken down by water or wind. This makes it difficult for phosphorous to be
released.
 Plants can only take up phosphorous through their roots when it is dissolved in water.
The Carbon Cycle
 The
is the process in which carbon is cycled through the land, water,
and living things.
 On average it takes one carbon atom
to complete the full carbon cycle.
 Carbon is an essential part of
,
, and
 Carbon is found in
.
.
 Carbon dioxide found in the atmosphere is used by plants and trees to carry out
.
During that process, carbohydrates and oxygen are made.
 All living things carry out
, breathing in the oxygen
and using it to create energy. Living things breath out and release carbon dioxide back into the atmosphere.
 All living things eventually die and decay = C returned to the ground.
 C is compacted into
 Those fossil fuels such as
over millions of years.
,
, and
were once living things.
 Fossil fuels are burned to make vehicles move, heat homes, provide electricity, etc. When those fossil fuels are
burned, carbon dioxide is released into the atmosphere.
The Water Cycle
 The water cycle is the
waterways, the ground, and back to the atmosphere.
 Water is continuously in motion on our planet.
 The key phase of the water cycle are:
 1.
 2.
 3.
 4.
from the atmosphere, to