A tithe barn was a type of barn used in the Middle Ages for storing the tithes - a tenth of the farm's produce which had to be given freely to the church.
There are many surviving examples of medieval tithe barns in England:
There are still many examples of tithe barns around England.
... release oxygen. One significant group of such organism are bacteria which use hydrogen sulfide instead of water in their photosynthetic pathway:
CO2 + 2 H2S → CH2O ...