This fact still isn't widely known by laypeople today - nor was it known by many scientists back in 1940.
I mention this only because the world in 1940 was as consumed with killing off all the germs in general, including those found in sea water, as the Nazis were about killing of all the Jewish 'germs' in particular.
The civilized world in 1940 widely supported the effort to greatly reduce biological diversity by ridding the world of all kinds of "pests", an idea that spilled over into the minds of the ordinary Nazi (and their ordinary/silent tolerators) when thinking about a possible solution for the 'problem' of the Jews.