Anglers say the sudden drop in water levels mean that there is not enough oxygen in the water for the fish.

BBC: dead fish

There are also different oxygen isotopes in this meteorite than in younger Martian meteorites.

FORBES: Meteorite Shows Evidence Of Water On Ancient Mars

Air tests overnight suggested there may be oxygen levels of about 20 percent in the area where the miners are thought to be, Stickler said.

CNN: Camera lowered into mine cavity shows 'survivable space'

There had been concern that low levels of oxygen in the water caused by the spell of hot and dry weather during the month would damage their welfare.

BBC: Highest ever numbers of salmon recorded in River Tyne

Creating gigantic algal blooms risks using up all the oxygen in large parts of the ocean, killing anything else that lives there.

ECONOMIST: Geo-engineering

If anything, the soil seemed inimical to life: there was so much iron in it that any whiff of oxygen was quickly bound into rust.

NEWYORKER: The Martian Chroniclers

"The idea is that the oxygen will help Josh improve further and we'll take toys and a CD player in there to entertain him, " said Mrs Clark.

BBC: Stem cell appeal reaches target