Bandome Sporal
Field notes
Local relatives
The bandome is a more distant relative of the nearby teal and pebbled sporals. The bandome is a reefbuilding sponge, producing a botryoidal (grapelike) shell from dissolved carbon dioxide and calcium. This process helps draw carbon out of the atmosphere, eventually carrying it into the deep ocean to be recycled into the planetary crust.
Living tombstone
Most of the bandome's mass is dead rock, leaving only the surface biologically active. Coral polyps hosted in the bandome do not take prey or feed on sunlight. Instead, they use endolithic bacteria to scavenge materials from the bandome's dead lower layers. This recycling process lets the surface of the bandome recapture some of its used building material.
Evolutionary history
The bandome may represent an earlier stage of the coral-sponge partnership seen in the teal and pebbled sporal, or it may simply be a different strategy adopted by both sponge and coral in response to environmental conditions.
Assessment
a curiosity. Reefbuilding sponges of this type dominated Earth's oceans during the Mesozoic period.