Scientists found living glass reefs once thought extinct off Canada’s Pacific coast

For many years, marine biologists would talk about glass sponge reefs in the past tense. These incredible and fragile undersea formations, which were made by creatures that spun their siliceous skeletons, were thought of as ancient structures that belonged to the age of dinosaurs. The textbooks claimed that these ancient communities had become extinct millions of years ago. Nature, however, always likes to surprise us. While exploring the mysterious sonar readings, scientists found a huge living reef of glass sponges far beneath the freezing water of British Columbia’s sea.The finding came as a huge surprise to the scientific community. Turns out, we didn't lose the prehistoric glass towers of the sea into oblivion; we just didn't know where to look. The discovery changes our perception of what the contemporary ocean can hide in terms of secrets – the oldest and most sophisticated ecological design systems have continued to operate in the depths of the ocean.Glass factories are building themselves inside outTo fully appreciate the significance of this discovery, one must realise the unique way in which these reefs come to be. Glass sponge reefs are not merely heaps of ancient remains. They represent a complex multigenerational process during which living organisms constantly die and give way to their skeletons, which act as the foundations for future generations. In the unstable seafloor environment, the glassy skeleton provides a stable basis.This interesting scientific paper in Scientific Reports helps to reveal the mysteries of such a unique phenomenon. The findings describe how free-swimming larvae of glass sponges travel deep underwater and settle directly on the fused remains of their predecessors. Year after year, new generations of sponges grow upwards and sideways, thus transforming a seemingly dead area into a thriving biological structure. If not for these growing layers of living sponges constantly enlarging the framework, the whole structure would collapse. Still, in reality, these frameworks evolve into massive ecosystems capable of lasting for thousands of years.Feeding on a modern deep-sea menuWhat helped this ancient type of reef withstand several extinction events that killed off most of the other creatures? The answer is simple - high efficiency and an excellent adaptation to deep-sea currents. Glass sponges are great filter feeders, allowing huge amounts of water to flow through their bodies and filter tiny particles of nutrients.The mechanisms keeping them well-fed are explored in a comprehensive study published in Scientific Reports titled Trophic ecology of glass sponge reefs in the Strait of Georgia, British Columbia. The researchers found that these reefs are deeply intertwined with modern ocean movements and sediment dynamics. Instead of being isolated from the world above, the sponges survive by intercepting organic matter and plankton flowing down from the upper ocean. The reefs exist today because they found a perfect geographic sanctuary where the local currents consistently deliver the exact food supply they need to thrive.This discovery is a powerful illustration of just how little we know about our very own planet. The waters of the Pacific are notoriously hard to map, and it is all too simple to confuse a thriving ecosystem with a mere piece of rock when looking at a typical sonar display. In demonstrating that the assumed extinct prehistoric environment was still alive, the reefs off Canada's coast offer a valuable lesson for all explorers yet to come. It proves that the deep waters of the sea are far from being a silent relic of the past, but rather a place where history is rewritten every single day.