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 mountain gorilla is estimated to have several small protected family groups living around the Virunga volcanoes (about 380 individuals) and the Bwindi area (about 320 individuals). Even though many mountain gorillas live in protected parks, disease outbreaks, environmental catastrophic events, and genetic isolation could significantly reduce their population.