Rhodophyta, Red Algae

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Dasya C. Agardh, 1824

Rhodophyta, Order: Ceramiales; Family: Dasyaceae.

Etymology

Dasya is ‘hairy’, and refers to the abundance of soft hair on the thallus.

Description

The Dasya is an erect alga, soft and very delicate. It resembles a collection of small pompons arranged in clumps. The branches are cylindrical and interleaved. They are bare at the base, and have a lump at the edge that looks like a soft ball of filaments; in fact, each contains thin crimson branches that are dichotomously branched. Microscopic examination reveals that the thallus usually comprises four to five rows of cells, each leading to a separate branch.

Size

The branches measure up to 1 mm each. Each pompon is several millimeters in diameter. The entire alga may reach 12 cm in diameter, and sometimes even more.

Colour

The alga is red, in shades ranging from burgundy to reddish- brown. It may sometimes be slightly faded.

Special features

The algal softness is its major characteristic, along with the instability of the thallus: when extracted from the water, it loses its erect form.

Habitat

The alga is found in the intertidal zone upon the rims of abrasion platforms and sometimes in potholes.

Biology and reproduction

During the reproduction season, transparent cystocarps that carry long carpospores in dense clumps may be seen on the Dasya. The reproductive tetraspores are arranged along special branches that are also arranged in clumps.

The structural complexity and its beauty have attracted researchers to this alga. Amongst these, research into the spatial development has resulted in a model that exhibits a three-dimensional loop shape of development.

Seasonality and distribution

The alga may be found along the coastline year round. The genus is prevalent in temperate seas around the world. Some species, such as Dasya hutchinsiae, are common around the world. Others, like Dasya baillouviana, are common in the Mediterranean, and there are other species that are distributed only locally.

Additional species

The definition of species is in accordance with the branch arrangement, pigmentation and other characteristics. As with many other genus, additional research is needed to assess the species in this region. Some species that have been reported in this area are:

Dasya arbuscula (Dillwyn) C. Agardh Dasya baillouviana (S. G. Gmelin) Montagne

Dasya corymbifera J. Agardh

Dasya elegans (Martens) C. Agardh Dasya flocculosa Zanardini

Dasya hutchinsiae Harvey

Dasya ocellata (Grateloup) Harvey

Dasya punicea Meneghini and Zanardini

Dasya rigidula (K.tzing) Ardissone.

Dasya ocellata

Dasya elegans -general view of the thallus.

In some species of Dasya, laboratory experiments show the presence of antibiotic material, a fact that indicates economic potential for the Dasya.

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