good morning John last week I joined an
extremely unexcusable of people who said
that the Amazon rainforest produces 20%
of the world's oxygen I've since deleted
it from the video because it's a fake
fact no one even knows where it came
from all of the land plants on the earth
combined produce around 25% of the
world's oxygen the rest comes from the
oceans mostly phytoplankton which are
like teeny tiny plants except it turns
out that we are imagining all of this
incorrect the frame were in here
indicates that if a phytoplankton and
the plants stopped producing oxygen
within a year we would run out we would
not we would all die immediately if
there was no o2 being produced that
means there would be no photosynthesis
and photosynthesis is where all food
originates so we would stop everything
would die but there would still be
plenty of oxygen in the atmosphere so
let's do this on introduction to the
carbon cycle I guess cuz I of all people
should know this plants use energy to
turn carbon dioxide into carbohydrates
and oxygen in a process called
photosynthesis and then those
carbohydrates get turned back into co2
and energy and that consumes a molecule
of o2 if this happens inside an organism
that's called respiration
if it happens outside an organism it's
called combustion I'm gonna lump those
two together and call them both burning
because I'm frustrated that there is no
collective word that includes both of
these things except for I guess
oxidation which is just too broad this
is just one of my science communicator
beef we're sticking with burning fine
carbohydrates are as Olive Garden has
effectively capitalized on delicious
they are unstable reservoirs of energy
so on a geological time scale all carbs
get burned when a carb gets burned that
molecule of o2 that the plant produced
gets sucked back up every single time
it's a one to one cycle so now you're
like okay Hank yes but like I can
breathe so you're wrong you're right I
was lying to you
not every carb gets burnt here on land
almost always there's oxygen around to
do the burn in the oceans there's a
fairly common exception sometimes
phytoplankton can bloom so successfully
that the organisms that consume them
after they die eat up all the oxygen in
an area and no oxygen is left for more
burning the carbohydrate just falls to
the bottom of the
where it can never get burned this
process upsets the balance between co2
and oxygen it's the reason I'm breathing
right now the photosynthesis produces
that oxygen but that oxygen doesn't get
evenly distributed throughout the earth
so there are some areas where the
burning can't happen over time that
results in a giant reservoir of o2 in
the atmosphere so if the Amazon
rainforest disappeared there would be
less oxygen produced but over time they
would also be less oxygen consumed
because oxygen consumption and there's
an asterisk here but like basically
oxygen consumption only happens when
plant material is burned either in a
fire or in an organism since oxygen is
abundant to the atmosphere carbon
dioxide is the limiting agent in this
carbon cycle which is why there's such a
tiny amount of co2 in the atmosphere
that carbon dioxide is what gets trapped
and brought to the bottom of the ocean
when these blooms happen they're over
geologic time they're compressed from
carbohydrates into hydrocarbons fossil
fuels and when we burn those fossil
fuels yes that consumes oxygen and we
can see the oxygen concentration of the
earth going down but it's not a big
percentage of the total amount of oxygen
in the atmosphere because there's a lot
but the carbon dioxide concentration is
extremely low and we are well on our way
to doubling it and that's one of the
very real reasons why it's a bad idea to
burn rainforests the Amazon rainforest
is a sink for something like 90 billion
tons of carbon dioxide and that is a
huge service that we need so we're not
gonna suffocate
very happy about that sounds miserable
but I kind of wish we could see the
threats to the other services that the
earth provides to us as similarly
significant because they are John I'll
see you on Tuesday we're gonna be okay
all right
we're gonna make it through this