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.
Western lowland gorillas are native to several areas of Africa including Angola, Congo, and Cameroon. This is the type of gorilla that is frequently seen in zoos. The western lowland is the smallest of the great apes. Adults are about 5 feet 7 inches (1.7 meters) tall and weigh 400 pounds (180 kg). As of 2008, there were an estimated 125,000 western lowland gorillas living in Africa.