[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?"

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