if you can fully grasp the nitrogen cycle you will never deal with high nitrates again
well why is that because you'll understand the biochemical
process that converts nitrate into nitrogen gas no more buying random nitrate reducing products
and then having them not work and wondering why rather you'll be able to cultivate
all of the bacterias you need to complete the nitrogen cycle in your salt water tank
hey everybody matthew here from my first fish tank in collaboration with marine depot bringing you
week 18 in the beginner how-to guide for saltwater aquariums and reef tanks the nitrogen cycle we are
going to be dropping a lot of scientific jargon so we have made a glossary of all the terms
and we're going to put them in the description below and at the my first fish tank blog
i need to give you a disclaimer before we start though i was a jesuit seminarian for three years
after that i was a catholic high school theology teacher retreat director and campus minister i
am not a scientist nor do i pretend to even have any scientific training at all but i have been a
teacher and as a teacher i have done tons of research to bring this video to you today if
you're a scientist and you see a mistake that i make in today's video please drop a comment below
letting us know what the correction is that way we can all learn all right everybody get out that pad
and pencil because i'm about to drop on you some serious scientific brain bombs
let's start out with the absolute basic what is the nitrogen cycle the nitrogen cycle is the bio
geochemical cycle by which nitrogen gas is converted into different chemical forms
as it circulates between the atmosphere the earth and the oceans however even though the atmosphere
is made up of 78 nitrogen atmospheric nitrogen is basically useless to humans and thus needs to be
converted into other chemical forms why is the nitrogen cycle important for plants and animals
nitrogen is crucially important for all life as we know it on this planet it is a crucial
part of our cell structure from amino acids for proteins and even for our dna it is also essential
for making chlorophyll implants which is used in photosynthesis to provide them with food so what
would happen without the nitrogen cycle basically life as we know it would cease to exist period
so how does nitrogen even get into our oceans remember that our atmosphere is made up of 78
nitrogen so how does that get into the water the first is through diffusion between the air and
the water also runoff from the land and the last is actually through lightning which converts that
nitrogen gas into ammonia and nitrate and then precipitation whether that's rain sleet or snow
drags that down and deposits it into the ocean okay so here we are how does the nitrogen cycle
work please note that the nitrogen cycle is slightly different when we're talking
about terrestrial land based versus the marine environment they're almost completely identical
they just have different players that help move the cycle along n2 or nitrogen gas comprises 78 of
our earth's atmosphere but is completely unusable by humans we breathe it in with every breath but
we can't use it as we already mentioned nitrogen enters the marine environment through diffusion
through runoff from the land or through lightning and precipitation let's just put up over here the
nitrogen cycle you start with n2 nitrogen gas then we get ammonium which is nh4 plus from ammonium to
nitrite which is no2 minus from nitrite to nitrate which is no3 negative and from nitrate back to n2
which is nitrogen gas those are the basics of the cycle but how do we work our way through it
the first step in the nitrogen cycle is nitrogen fixation nitrogen fixation is the chemical process
by which nitrogen gas n2 is assimilated into organic compounds which is usable by life as we
know it basically it's the conversion of nitrogen gas n2 into nh4 plus ammonium which is an organic
carbon-based compound this first process of converting nitrogen gas into ammonium is known as
ammonification by the way i should have mentioned this n stands for nitrogen h stands for hydrogen
and the o stands for oxygen just in case there are any non-science people like myself out there
in terrestrial earth environments nitrogen fixation happens in one of two ways the first is
via nitrogen fixing bacteria that lives in legume roots and the second is through nitrogen fixing
bacteria that lives in the soil in the marine environment nitrogen fixation happens primarily
via cyanobacteria which converts nitrogen into ammonium nh4 plus or ammonium is a building block
for all other nitrogen-based compounds it's also toxic to fish nh4 plus forms the amino portion of
amino acids and amino acids make proteins and proteins are responsible for cell structure
enzyme reactions and a lot more nh4 plus can be taken in by plants by fungi and by bacteria
and incorporated into amino acids thus building cell structure so whereas most biological life
as we know it can't use the nitrogen gases in the atmosphere we can consume other plants and animals
that have taken in that nitrogen and absorb that into our systems all organisms have nitrogen-based
waste and in human beings that nitrogen-based waste comes out in our urine and like i said
we get our nitrogen from consuming other plants and animals and absorbing that into our bodies for
fish the nitrogen-based waste is actually nh4 plus or ammonium and most of this is secreted through
their gills and fish get this nitrogen through eating other plants and animals just like we do
as all of us in this hobby already know ammonia is highly toxic to fish and destroys gill tissues
which means that if you have too much ammonia in your tank your fish will suffocate to death all
right so we started with n2 or atmospheric nitrogen gas and through a modification we
converted that into nh4 plus or ammonium the next step in the nitrogen cycle is to convert
that ammonium into no2 negative or nitrite this is through a process called nitrification which
is the biological oxidation or breakdown of nh4 plus ammonium into no2 negative and no3 negative
or nitrite and nitrate this is accomplished through a genus of bacteria called nitrous simonas
rather than eating proteins and carbohydrates like we do nitrosamonas consume ammonium or nh4
plus as their food source so these bacteria nitrous simonas consume as their food source
ammonium or nh4 positive and they secrete as their waste nitrite which is no2 negative no2 negative
or nitrite is also toxic to fish although not as toxic as ammonium okay so just to recap we started
with nitrogen gas and then through a process called a monofication we arrived at ammonium
or nh4 positive then through nitrification we went from ammonium to nitrite which is no2 negative now
comes the next step in the nitrogen cycle which is going from nitrite to nitrate through another
process of nitrification a different genus of bacteria known as microbacter oxidizes or breaks
down no2 negative to no3 negative nitrate okay at this point we're almost done with the cycle we
started with nitrogen gas we went to ammonium we went to nitrite and now we're at nitrate but how
do we go from nitrate back to nitrogen gas first let's talk about how to get rid of nitrates from
your saltwater aquarium you can do this in one of two ways the first is through water changes
if you remove 50 of your water in your saltwater aquarium you're also going to be removing 50 of
the nitrates or no3 the second way is by adding live plants macro algaes which use the nitrate
the no3 negative as a fertilizer and a food source thus consuming it and then when you remove that
growth at a future time you're actually pulling nitrate out of your system but while both of these
two methods remove nitrate from your system you're not actually completing the cycle by converting
nitrate back into nitrogen gas so we finally arrive at the last stage of the nitrogen cycle
and the stage that most hobbyists seem to forget about denitrification whereas
nitrification converted ammonium to nitrite to nitrate denitrification converts nitrate back
into nitrogen gas denitrification is the exact opposite chemical process from nitrification
denitrification or nitrate reduction is the chemical process that reduces nitrate no3 negative
back to nitrogen gas whereas all the previous parts of this cycle relied on aerobic bacteria
this final portion of the cycle needs anaerobic bacteria in an ideal world for your saltwater
aquarium your tank would become heavily populated with this anaerobic bacteria that way you wouldn't
need to rely on water changes or on macro algae to remove nitrate rather you would actually complete
the nitrogen cycle and that anaerobic bacteria would convert that nitrate back into nitrogen gas
and it would re-enter the atmosphere but as the name suggests denitrification or nitrate reduction
requires anaerobic bacteria which means very very little amounts of oxygen and where would you find
those in your tank they're really found in one of two places the first is at the bottom of a
deep sand bed and the second is deep inside the core of thick large pieces of reef rock that's
it everybody that's it we actually did it now remember all of these terms are in the glossary
below and at the my first fish tank blog if you liked this video please consider liking this video
giving it a thumbs up and subscribing to my first fish tank and marine depot and be sure to tune
in next week for week 19 the beginner how-to guide for saltwater aquariums and reef tanks
filtration it's part one of four we're gonna spend four entire weeks talking about filtration in your
saltwater aquarium and as always everybody take care be well happy reefing we'll see you next time
do