Rhodophyta, Red Algae

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Schottera nicaeensis (Duby) Guiry and Hollenberg

 Order: Rhodophyta, Gigartinales; Family: Phyllophoraceae.

Etymology

The generic name is dedicated to the French algae researcher G. Schotter. The name of the species refers to the city Nice in Southern France.

Description

The Schottera nicaeensis is an elongated, flat alga with irregular dichotomous branching. The thallus is elongated but also irregular. The alga clings to a substrate using a number of holdfasts. The sporangia are located at the edges of branches, and when underwater have a luminous, phosphorus colour. The unique colour disappears when extracted from the water.

Size

The alga grows up to 2-3 cm in length. Its width is 0.5 cm and it is 1 mm thick.

Colour

Schottera nicaeensis is a shiny red that ranges from bright-red to reddish-orange. As mentioned, underwater luminous stripes can be seen at the edges of the branches that fade upon exposure to air.

Special features

The alga somewhat resembles the Rhodymenia pseudopalmata in size, texture and colour, but is distinguished from it by its irregular shape. The Schottera nicaeensis is usually thicker, cartilaginous and softer.

Habitat

The alga has been found in shaded habitats, especially in

 

 

 the upper, hidden parts of potholes. It often grows amidst Botryocladia botryoides.

Biology and reproduction

The Phyllophoraceae family is distinguished by its variety of reproductive sequences. The difference between the Petroglossum genus and the Schottera genus was determined according to the different ways in which female reproductive cells are generated (Abbott, 1969; Guiry and Hollenberg, 1975), following which the Schottera was pronounced a separate genus. Several investigations have been carried out upon the species in Italy, where it grows. In one (Chillemi et al., 1990), a unique nitrogenous compound was isolated from the alga that has not been reported anywhere else, and named after the algal alternative name - Nicaeensin. In another experiment dealing with the effects of environmental conditions upon growth, two ways of growing were discerned entailing either a flat thallus or a cylindrical, slightly bloated thallus. The flat thallus mainly

develops in summer and generates sexual reproductive cells; the cylindrical thallus appears in winter and generates asexual reproductive cells. Research shows a transformation in shape from cylindrical to flat and adaptation to reproduction in summer, with the heating of the sea, but regulated by the length of daylight and not by temperature. The process is also affected by the thallus’ age and hormonal condition.

Seasonality and distribution

The alga can be found during nearly all seasons. It is common in the Mediterranean, the Atlantic Ocean and in the vicinity of the British Isles.

Additional species

Schottera nicaeensis is the only species so far reported in our region. Petroglossum nicaeense (Duby) Schotter is a synonym.

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