Rhodophyta, Red Algae
Corallina elongata Ellis and Solander
Rhodophyta, Order: Corallinales; Family: Corallinaceae.
Corallina refers to coral. The high calcium content in the thallus provides this alga with a tough structure and the appearance of a coral. In the sea depths, a colony of Corallina resembles a small coral reef. Elongata, refers to its elongated branches.
The Corallina elongata is an erect, calcified alga. Its thallus is jointed, slightly flattened and wider at the top than at the bottom. Often, one to three additional joints are connected to each joint. The alga as a cluster is often very dense, and sometimes flat.
The alga can grow up to 10 cm, but is usually smaller than 5 cm.
The red colouring in conjunction with its large calcium content provides the alga with a pink colour.
The alga is very common in the subtidal zone, providing the rocks there with a calcified pink colour. It is easy to confuse the Corallina elongata with the Jania rubens, which sports the same colour and is also very common. The telling feature is the algal triangular joints and the feather-like structure formed by the central joint and its two peripheral joints.
The alga is prevalent in the subtidal zone of the Eastern Mediterranean. Some individuals have wandered to the intertidal zone, and may sometimes even be exposed to air for short periods.
Biology and reproduction
The egg-like or vase-like reproductive organs (sporangia) are located at the edges of the points. The male reproductive cells (sporangium) have horn-like protrusions, and the female ones have none. The life cycle has three stages.
The high calcium content prevents fish from eating it, and this is an important factor that greatly affects its wide distribution in the subtidal zone of the Eastern Mediterranean.
Calcification in the alga occurs in the Corallina only in cells containing pigments. Since the area of the joint lacks pigmentation, it breaks when the alga dehydrates and crumbles. Skeletons of red calcified algae form, along with other matter, the coarse sand (zif-zif) of Lebanon and Israel’s northern beaches.
Seasonality and distribution
The Corallina elongata inhabits warm and temperate seas. In the Eastern Mediterranean region, it is very common and found year round. The branches that grow in winter are more cylindrical than those that grow in summer.
The Corallinales incorporates about 25 species, of which the most common in our region is the Corallina elongata Ellis and Solander
= Corallina mediterranea Areschoug.
Other species described in literature about the Eastern Mediterranean include:
Corallina attenuata K.tzing
Corallina gracilis Lamouroux
Corallina granifera Ellis and Solander (Definition doubtful) Corallina officinalis Linnaeus
Corallina pinnatifolia (Manza) Dawson
Corallina rubens Linnaeus
= Jania rubens (Linnaeus) Lamouroux
Corallina squamata Ellis and Solander.
The Corallinales contain a substance called vermifuge, which in the past was used in powdered form to cure intestinal worms