Neptune's Necklace - Hormosira banksii

"Hormosira banksii" is a species of seaweed found in Australia and New Zealand. It is commonly found in rock pools at mid-tide levels and is characterised by strings of olive-brown hollow beads. The beads have a slimy layer which conserves moisture. They also contain gas, allowing them to rise to the surface of the water, obtaining more sunlight and moving with the flow of the current. Each bead is filled with water that prevents desiccation between tides.