Could the ocean ever become too salty for life to exist?

It may taste good on crisps, but too much sea salt can be harmful to fish and plants.

Asked by: Martin Simpson, Huddersfield

In the open ocean, whatever water evaporates must eventually return. Rivers continually wash more salt in from the land, but the sea has reached equilibrium now, and extra salt just precipitates out of solution onto the ocean floor.

The concentration of salt in the Dead Sea is almost 10 times higher than the average for the rest of the oceans. This is far too salty for fish and plants, but even here there are some bacteria and fungi that can survive. The Dead Sea’s high salinity is because the water is evaporating much faster than fresh water flows in.

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