This subtidal view shows the alga's terminal blade located at the end of a long stipe. The alga can form an understory canopy beneath that of giant kelp.
This alga has a high concentration of sulphuric acid and malic acid; the acids may deter grazers. Also, they discolor the pigments in other algae if they are placed in the same container.. Photographed at 12 m depth.
Neptune's necklace (Hormosira banksii), also known as sea grapes or bubbleweed, is a species of seaweed (brown algae, Fucales) 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.
This is a female reproductive frond of the kelp floating on the surface and phot.ographed in August. It shows the meiotically produced developing eggs. When these are released and fuse with sperm from a male plant another diploid thallus results. The alga's holdfast is anchored to the sea floor. This life cycle contrasts with that of most kelps in which the diploid thallus alternates with a microscopic haploid sexual phase.
At the tip of each giant kelp frond is found the apical scimitar blade, the site of the meristem or persistent growth zone. Here the kelp's floats and blades differentiate and split apart as the kelp grows toward the surface of the sea. Depth 3 m.