Thunder Beach functions as a symbol for the global problem of environmental pollution. Such an immense topic only carries emotional resonance when it can be reduced to a personal level. This particular beach holds special significance for the Underwood clan. It has been the scene for many fishing expeditions that resulted in storied catches. A number of father and son bonding sessions took place on the beach while Bobby and Paine fished there as well. Shelly gravitates to the beach as her favorite sunbathing spot. Both Noah and Abbey use it to swim on a regular basis.

Having established this location as a special spot that has created many positive memories for the characters, to see human waste floating in the waters offshore removes the topic of environmental pollution from the realm of theoretical discussion and allows the reader to feel a personal stake in solving the problem at a local level. 

Because the novel is set in the Florida Keys, one might expect that boats of all kinds would factor into the story. For a population that depends largely on the sea for food and the tourist trade, boats mean survival. They appear in a staggering variety of forms that are designed to fit specific purposes, and their loss carries emotional as well as financial significance for the characters.