Free the Ocean Blog

Rediscovering Ancient Marvels: The Glass Sponge Reefs

The ocean, always full of surprises, recently revealed a secret that left scientists in awe. Imagine the delight of uncovering something believed to be lost forever, much like finding an unexpected treasure in a winter coat pocket. This was the experience of researchers who stumbled upon living glass-sponge reefs, previously thought extinct for 40 million years.

A Glimpse into Glass Sponge History

Glass sponges, intriguing residents of the deep sea, boast a fascinating history. They rank among the ocean’s oldest creatures, having no mouths or eyes yet pulsating with life. Their unique skeletal structures, resembling glass, are formed from silica-based particles called spicules. These spicules, in some species, fuse together to create what look like underwater glass houses.

Thriving in the ocean’s depths, glass sponges anchor themselves to the seafloor or other solid structures. Their bodies are dotted with thousands of tiny holes, facilitating constant water flow. Through this process, they filter and feed on plankton and bacteria, playing a subtle yet vital role in the ocean’s ecosystem.

The Formation of Reefs

The glass sponges are not just solitary figures; they are community builders. As they grow, they interconnect, forming robust structures known as reefs. These reefs, even after the sponges’ demise, stand tall, some reaching the height of six-story buildings. They become habitats for various other marine life, showcasing the interconnectedness of oceanic ecosystems.

Glass sponges reproduce by releasing tiny larvae into the water. Carried by currents, these larvae eventually settle on hard surfaces, growing into replicas of their adult forms. This life cycle contributes to the continual growth and expansion of the glass sponge communities.

A Living Fossil

Glass sponges have a lineage stretching back over 570 million years, predating even the dinosaurs. The first glass sponge reefs formed about 220 million years ago. Believed to have vanished 40 million years ago, their discovery in 1987 in Canada’s Hecate Strait was nothing short of miraculous. This finding, akin to encountering a living herd of dinosaurs, opened a new chapter in our understanding of these ancient creatures. Previously, knowledge of glass sponge reefs was limited to fossil cliffs in Europe. The discovery of these living reefs, estimated to be 9,000 years old, underscores the vastness and mystery of our oceans, revealing secrets that challenge our understanding of marine history.

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