Sea turtles use beaches and the lower dunes to nest and lay their eggs. Sea turtles lay around 100 eggs in a nest and lay between 3 and 7 nests during the summer nesting season. Along a 20 mile stretch of beach on the east coast of Florida sea turtles lay over 150,000 lbs of eggs in the sand. Not every nest will hatch, not every egg in a nest will hatch, and not all of the hatchlings in a nest will make it out of the nest. All the unhatched nests, eggs and trapped hatchlings are very good sources of nutrients for the dune vegetation, even the left over egg shells from hatched eggs provide some nutrients.
Dune vegetation is able to grow and become stronger with the presence of nutrients from turtle eggs.
Stronger vegetation and root systems helps to hold the sand in the dunes and helps protect the beach from erosion. As the number of turtles declines, fewer eggs are laid in the beaches, providing less nutrients. If sea turtles went extinct, dune vegetation would lose a major source of nutrients and would not be as healthy and would not be strong enough to maintain the dunes, resulting in increased erosion. Once again, all parts of an ecosystem are important, if you lose one, the rest will eventually follow. Hope this helps answer your questions.