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.
The lowland subspecies are more numerous and widespread than the upland and mountain subspecies. Mountain gorillas are the only gorillas to show an increase in numbers, but the overall population size is still very low. The western lowland gorilla is the most widespread, possibly numbering 100,000.