Deep-sea sponges have an extraordinary way of gathering and using the scarce light available in the deep ocean through specialized structures called spicules. These tiny, needle-like structures are made of silica and have the remarkable ability to capture and guide light deep into the sponge’s tissues, functioning like optical fibers. The spicules focus and channel even the faintest traces of sunlight, which allows photosynthetic symbiotic organisms living within the sponge to produce food, even in the seemingly dark depths. This adaptation enables these sponges to efficiently utilize every bit of available light for their survival.