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What do you mean - they measured rising sea levels, and wanted to find the missing ice it came from?
by fdggdfsvscvsd 8y ago
What do you mean - they measured rising sea levels, and wanted to find the missing ice it came from?
- kaybe 8y agoNo, basically the isotope composition of the sea changes when a lot of water evaporates and doesn't come back over the rivers (because it fell as snow and just stayed on land). The heavier isotopes need a little bit more energy to evaporate, so the remaining sea water has more and more heavy isotopes left. The most commonly used tracer is oxygen 16 vs oxygen 18 [0]. The isotopes are also used by sea organisms when they grow [1]. When they die and their shells become part of the sea floor (this is optional, there are also old corals that can be used), the signal can remain for a very long time (essentially as long as the sea floor remains, a few 100,000 years). So we know quite well how much water was missing from the ocean at these points in time. The method can also be used to deduce temperatures from back then. [0] https://en.wikipedia.org/wiki/%CE%9418O https://en.wikipedia.org/wiki/%CE%9418O [1] https://en.wikipedia.org/wiki/Foraminifera https://en.wikipedia.org/wiki/Foraminifera
- fdggdfsvscvsd 8y agoThanks for the explanation.