EMERGING CONCERNS - Marine Pollution: What Everyone Needs to Know - page 140

have adverse health effects. The most well-known marine
effect of nighttime lighting is the disorientation of hatching
sea turtles, which emerge from nests on beaches at night and
need to orient to the ocean. They wait just beneath the sand
surface until conditions become cool. This temperature cue
prompts them to emerge primarily at night, although some
emerge in the late-afternoon or early-morning. They find the
ocean by moving away from the dark silhouette of dunes and
their vegetation. Sea turtle hatchlings have an inborn ten-
dency to move in the brightest direction. On a natural beach,
the brightest direction is the open view of the night sky over
the ocean. Hatchlings also tend to move away from darkly sil-
houetted objects associated with the dune. This behavior can
take place during any phase and position of the moon, which
indicates that they do not depend on lunar light to lead them
to the sea. They become disoriented by the brightness and
glare of artificial lights from hotels, condominiums, and other
buildings near the beach. To a hatchling, an artificial light
appears bright because it is relatively close by, but not intense
enough to brighten the sky. The glare makes the direction of
the source appear much brighter than the other directions, so
they will move toward the artificial light no matter where it
is relative to the sea. While crawling the wrong way on the
beach, hatchlings exhaust their limited energy stores, which
they need once they reach the ocean where they must swim
out as far as 60 miles offshore toward the floating Sargassum
seaweed. Disoriented hatchlings may wander inland, where
they can die of dehydration or predation, or may be run over
or drown in swimming pools. Artificial lighting causes thou-
sands of hatchling deaths each year in Florida alone, and is a
significant marine turtle conservation problem.
What can be done about light pollution?
Reducing the amount of artificial light that is visible from nest-
ing beaches is the first step to reducing light pollution. Coastal