Within a century, much of the Western economy was founded on slave labor, both indigenous (the often overlooked source of slave labor, especially in North America) and African. Indirectly, you might argue that the commercial revolution that accompanied the establishment of the Atlantic system had the effect of proletarianizing labor, especially on European farms, but the most direct effect was the use of enormous quantities of slave labor.
I bet your textbook says something specific about this. All I can think of is that this "discovery" led to the widespread use of Africans as slaves. Africans had been enslaved previously, but on a much smaller scale. I suppose this move towards mass slavery can be seen as a change in global labor structures.