The floodwater in New York influences the lives of everyone in the story. The flood was the result of global warming, which was itself the result of humanity’s failure to change the effect its habits were having on the planet. The flood has parallels to the biblical flood in the Old Testament, during which God punished the planet for its sins. In the Biblical version, humanity gets a fresh start, having learned from its mistakes. In New York 2140, however, the flood does not recede, but it does give people a chance to reflect on their mistakes. The flood is a symbol of both humanity’s forgetfulness and adaptability, and of history’s cyclical repetitions. 

The Hussar is a gold-laden English warship that sank in the 18th century on a spot that was later paved over. Roberto, Stefan, and Mr. Hexter are obsessed with finding it. The ship is initially a symbol of curiosity and adventure: The mystery of its location gives purpose to the lives of the boys and Mr. Hexter. Once they find the ship, its treasure hoard becomes a symbol of hope. The gold provides for their futures and bodes well for the lives of the marine animals in New York, since the boys open a marine life institute.