CARBON AND NITROGEN CYCLES: SCAVENGER HUNT
is critically important to the formation of
,
which are monomers of proteins. The basic structure of the amino acid
includes two
. The one which contains nitrogen is known
as the
, and at the other end, a
(which is a
carbon linked with oxygen and hydrogen). There are
known
amino acids, which in turn form all of the proteins in your body, and all
other organisms’ bodies for that matter.
carry out almost all of the
chemical reactions in your body, and are proteins too. The chief
reservoir of nitrogen on Earth is the
, which is about 78%
nitrogen. This form of nitrogen is not assimilated by organisms besides
one special group, which
nitrogen in such a way as to make it
useable by other life. Nitrogen can also be
by the action of
, which actually “burns” it out of the atmosphere, creating
(NO3) which is nitrogen bound to three oxygen atoms. Nitrogen
fixing bacteria called rhizobium are found in the roots of
, and fix
nitrogen either in the form of
(NO3), or
(NH3). Since NH3
is rather toxic, we are fortunate that there are
bacteria in the soil
and in the water which take up ammonia and convert it to
, (NO2).
Ammonia is also somewhat toxic, but
bacteria, take it and convert
it to nitrate, which can be taken up by plants to continue the cycle.
is the process whereby plants absorb (NH3) ,
ions (NH4),
and nitrate ions (NO3 ) through their roots. Most plants can take up
and convert it to amino acids, which are, of course, the building
blocks of proteins.
acquire all of their amino acids when they eat
plants (or other animals that consume plants). When organisms die and
, or release
the nitrogen is returned to the soil, usually in
the form of
. This NH3 or NH4 is a product of decomposing
bacteria, and in this state, may be reused by plants. If this is indeed a
cycle…how is N2 returned to the atmosphere? It turns out that there are
bacteria (usually anaerobic) which take the nitrites and nitrates
and combine the nitrogen back into
gas, and nitrous oxide. This,
of course, sends it back into the atmosphere to begin the cycle all over
again.
CARBON AND NITROGEN CYCLES: SCAVENGER HUNT
is a molecule that has a huge capacity to absorb great
amounts of thermal energy. It is this molecule that is most often
attributed to global warming. The
moves and stores
carbon in the
(living subsystem), lithosphere,
(watery subsystem) and atmosphere. Carbon is stored in
the biosphere as
, and in the atmosphere as
gas. In
the lithosphere, which includes the solid part of Earth’s crust,
both continental and oceanic…as well as soil organic matter,
you will also find Earth’s fossil fuel deposits, and sedimentary
rock deposits, which are generally composed of substances like
or calcium carbonate (CaCO3). In the oceans, rivers and
streams, carbon is stored as dissolved carbon dioxide gas and as
calcium carbonate shells in marine organisms (although parts of
the hydrosphere overlap with the atmosphere, because
remember,
can exist in three states on Earth, and when it
is a gas, it is in the atmosphere).
Humans have altered the
through fossil fuel burning,
deforestation, and land-use change. The net result of these
processes is an increasing concentration of carbon dioxide in the
atmosphere. Remember, a carbon
is an area that “stores”
carbon. The largest storage place for carbon on Earth is the
and marine
.