how many millimetre can sea sponges move

Warming waters and increased eutrophication (excessive richness of nutrients in a body of water) has led to ocean stratification and seafloor deoxygenation in several regions, which means less food and oxygen reaching seafloor animals. Southern polar warming has led to ice-shelf collapse, glacier retreat and loss of sea ice, causing increased iceberg scouring, sedimentation and rising sea levels.

Sea surface temperatures in the Arctic are among the most rapidly rising of anywhere on Earth, leading to greening, melting, and eroding of permafrost and tundra in the Arctic region, as well as sea-ice loss. But the cryosphere is changing rapidly: just within the last 30 years the polar oceans have warmed steadily and climate models predict more rapid changes in the near future. Short-term disturbances from iceberg scouring, and longer-term changes in sea level, temperature, and the waxing and waning of ice sheets and ice shelves are a feature of shallower sectors of polar deep-sea regions. Yet they now face significant threats from climate change and human activity. These areas of ocean were once believed to be protected from human impacts, due to their remoteness, vast depths, and heavily ice-laden land and seas. Polar environments are likely to hold more than 10% of the world’s sponge species, with up to half of them endemic to polar environments. This ‘blue carbon’ ecosystem service performed by polar deep-water sponges is not yet fully recognised, but could be an important negative feedback to rising carbon dioxide levels.

Sponges also filter organic matter, which is fed on by other animals or assimilated into carbon that is locked away for long periods in sponge tissue. They and their microbiomes are recognised as key organisms in ocean nutrient cycling, and this ‘sponge loop’ of nutrient processing can make a substantial contribution to maintaining the resilience and resistance of seafloor communities. Individual polar deep-water sponges can live for hundreds to possibly thousands of years and become important semi-permanent structures supporting tens of thousands of animals on the seafloor.

These mysterious animals are flexible enough to thrive in this changeable environment, but can they survive the extensive changes expected from climate change and human activity? Glass sponge found in the Antarctic (image courtesy of Julian Gutt)ĭeep below the polar ice, centuries-old sponges capture carbon and support an enormous variety of marine life.

How many millimetre can sea sponges move