What negative and positive effects did Columbus have on other explorers?

Answer 1

Too many to list here but a large positive effect was the the fact that he found land. Navigators at the time had access to writings, Viking and Irish, that recorded trips to lands across the Northern Atlantic but many Navigators were not convinced of their accuracy. They did not know for sure that such a trip was possible.

Once Columbus showed that there were New Worlds to sail to it was not long before hundreds and then thousands of ships were crossing the oceans, unleashing a new era of exploration.

Negative effects would be the same that occurs with all massive human migration. These include conflict, death, and loss of cultures. The clash between advanced cultures and neolithic cultures had devastating results that continue to today.