[Lewis Thomson (OP)]

Donald is curious about finding the answers to this question.

"The Earth has been through many ice ages and even been a 'snowball' with life existing in the oceans. Obviously, the liquid ocean must lose volume as more water is trapped in ice and on land, though exactly the amount is difficult to know exactly. Is there a record of the Earth's ocean's salinity in the geologic record? And can the amount of liquid water be calculated from that record. And at the most extreme, how much of the Earth's water was ice when it was a snowball? And at what time was the living biomass greatest? What is the limiting element that restricts biomass among H, C, K, N, P, O, or is it available liquid water?"

Discuss in the comments below...

[Zer0]

Hmm...are you the same Donald who asked a different question sometime ago?

I'd probably never know...hmm.

Salinity perhaps increases with time.
Rain water washes away salts into rivers, and rivers deposit it into the Ocean.
Hence in the past it must have been lower.

Not all water must have frozen, as layers of ice form & float over the water, they would create an insulating layer of sorts so the bottom of the oceans could still remain in liquid form, even water pressure would add to the warmth of the bottom of oceans, also geothermal vents would have prevented it from freezing completely.

P.S. - Plastic perhaps Exceeds All land and marine animals combined.
A call for measures Drastic,
To cut off usage of Plastic,
& Make the Earth Fantastic!
✌️
(Sorry for the late reply)