Biological transfer on a non-contact Rocheworld

I've been pondering for some time an alternate-history story where the Earth as we know it is replaced by a Rocheworld, of the canonical variety introduced in the eponymous Robert Forward novel where the two lobes share a common atmosphere but the solid and liquid surfaces do not touch, and in which the "New World" (i.e., the Americas) is literally a different world--the other lobe of the Rocheworld, inaccessible by land or sea from Eurasia, Africa, and Australia.

The two lobes are separated by approximately 150 miles. While that's well above the conventional edge of space, the lower gravity and correspondingly larger scale height of the atmosphere at the interior poles should result in an atmosphere that remains dense enough to breathe all the way through the gap.

So, I figure the occasional bird every few hundred, or maybe thousand, years will manage to fly or get swept from one lobe to the other, along with plenty of airborne microbes, flying insects, and whatever seeds or other small animals the birds might carry with them... but just how much viable biological material, of what maximum complexity, should I expect to be regularly exchanged? And as a result, just how weird should the flora and fauna of the New World be expected to be?

posted about 7 years ago

Logan R. Kearsley‭

-1 reputation 32 0 -2 0