Hydrogen sulphide-Sulfur-SO4 in the marine aquarium

This information firstly applies to the production of sulfur in the marine eco system and finaly in the reef aquarium.

The largest natural source of sulfur gas on the planet is from the ocean.

Once hydrogen sulfide gas interacts with oxygen rich waters of the ocean or aquarium, it becomes sulfur.

This gas is also the most abundant biogenic gas emitted by the ocean and has that signature smell.

Sulfur gas from the ocean is predominantly from the decomposition DMSP,of dying phytoplankton cells in more shallow areas of the ocean.

Though the ocean produces enormous amounts of this gas, once it leaves the waters either by sea spray or windblown sulfur rich dust from the land, it has at best one day in the atmosphere and the majority is deposited back in to the ocean only passing on small amounts back to the land.

An extremely important action upon our climate from the oceans produced sulfur gas, is in the formation of clouds.

When sulfur gas is assimilated by life forms it becomes organic sulfur making it an essential component of proteins.

Some other ways sulfur can be concentrated in nature is from volcanic activity and the burning of coal and other fossil fuels contributing a great deal of SO2 and is classed as an air pollutant.

It is thought that the production of SO4  and SO2 from extensive volcanic activities at different times helped bring about at least one of the great dying events from the earths very distant past from altering the earths climate adversely.

Sulfur along with oxygen and other substances are major oxidising agents in nature including the marine aquarium.

Now the concern of the chemical compound H2S or hydrogen sulphide for aquarium hobbyists.

H2S is completely colourless, highly poisonous, very flammable and has the pungent smell of rotten eggs if disturbed and converted!

The production of this gas is from sulfate reduction from bacteria classed mainly as anaerobes.
They exist in low oxygen environments, as is the lower depths of a deep sand bed or deep with in live rock utilising sulfates to oxidise organic matter or hydrogen producing as a waste product, hydrogen sulfide!

These anaerobes have been traced back to one of the oldest life forms on the planet and though their out put is quite polluting to the marine aquarium, they have been major contributors to life being able to exist on our planet.