A 13-year-old girl died after being found unconscious in a pool at the marine-themed park. The girl was rushed to a hospital, where she was later pronounced dead. Source
Accidents
Theme parks and roller coasters are statistically very, very, very safe. Out of the millions of people who ride the thousands of rides every year, there are only a small handful of incidents. You are statistically more likely to be involved in an accident driving to an amusement park than having one at a park. The rarity of accidents is one reason why the media report them, similar to plane crashes.
Every important element of a ride is inspected on a regular basis and every ride is tested every day without passengers before it opens. A ride might not open, or a safety system might activate, if there is an imperfection. For theme parks to operate, they must obtain insurance and one stipulation is their rides are frequently inspected and signed off by a strict Health & Safety governing body. Every theme park does what they can to prevent accidents because the negative press would be bad for business.
Having said all that, theme park accidents still happen…
TRP Game Zone, Rajkot, Gujarat, India
At least 33 people, including seven children, died in a fire that consumed the four-year-old amusement park that was built in temporary tin roof structures. The vast majority of bodies recovered at the site were charred beyond recognition and DNA samples were taken to identify the victims. The blaze was reportedly caused when welding work was being carried out. Source

Roller Coaster, Dream Park, 6th of October City, Egypt
Tram, Universal Studios Hollywood, Los Angeles, California
Fifteen guests were taken to hospital after receiving minor injuries in a tram collision. Officials said the last car of the four-car tram struck a guard rail in the studio’s backlot. Source
Airplane ride, Jesus Maria fair, Jalisco, Mexico
A 2-year-old boy died when he stood up on the cycling kiddie ride, lost his balance and fell to the ground, sustaining a fractured skull. Source (in Spanish)
Waterpark, Six Flags Great Escape, Queensbury, New York
A 5-year-old child nearly drowned and was taken to a hospital after being found unconscious in the water. Source
Roller Bowl, Funfair, Blois, Loir-et-Cher, France
A 27-year-old woman died after being ejected from one of the free-spinning gondolas on the rotating fairground ride, which is believed to be manufactured in Spain. Source (in French)
Jumping Frog, Huasteca National Fair, San Luis Potosi, Mexico
Nine children sustained injuries at a fair in Ciudad Valles when the “Jumping Frog” drop tower abruptly faltered. Source (in Spanish)
Aquatic Center, Plainfield, Indiana
A two-year-old girl died after being pulled unconscious from the water at the Richard Carlucci Recreation & Aquatic Center. The drowning took place in the center’s indoor pool, not the Splash Island outdoor water park. Source