If you hit $0 Avail. funds for trading, your account will go into a margin call and Ameritrade will force you to sell positions or deposit money. I'm going to assume your Account Balance isn't -8.1k because you would have hit a margin call long before your account went negative unless this all happened overnight.
Sadly, these peaceful animals may not survive into the next century. Ape conservationists say time is running out, as there are only about 720 mountain gorillas left in the world, and the majority of gorilla populations are plummeting.
According to the IUCN, the Gorilla gorilla species (Western lowland gorillas and Cross River gorillas) is critically endangered, with a population reduction of more than 80 percent over three generations (a generation is about 22 years). It is unknown exactly how many of these gorillas are left.