Halimeda tuna

Below and between these utricles, there are gaps and it is here that the fluid is saturated with calcium carbonate and crystalline needles of aragonite form.

Members of this genus are likely to be one of the most important agents of calcification in the marine environment, considerably more productive in tropical seas than stony corals.

[citation needed] This species is found in the tropical and subtropical Indo-Pacific region, the Mediterranean Sea and the western Atlantic Ocean.

The segments are sometimes damaged by storms, but are replaced by new growth which occurs with rising temperatures and increasing amounts of irradiation and dissolved nutrients.

[3] In the deepwater habitats in the Mediterranean, it is the dominant species and is often found in association with the encrusting red alga Mesophyllum lichenoides.