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Mastocarpus stellatus - a red alga

Mastocarpus stellatus - a red alga

A species sometimes confused with Irish Moss. The frond of Mastocarpus is channelled and is often covered in papillae that are actually reproductive structures. Found in the middle and lower shore where light levels are low it is well adapted for the conditions. The red algae have accessory pigments contained in cell organelles called phycobilisomes. These pigments absorb light and pass the energy via a chain reaction to the chlorophyll a for photosynthesis. The red algae are very shade tolerant, living under the kelp, and require a fraction of the light used by land plants. In fact, if the light is too intense it soon becomes bleached. Mastocarpus is not very palatable and few herbivores will graze upon it. This may cause it to dominate the smaller algae in pools. Dioecious.

Mastocarpus is common on exposed shores amongst the barnacles and mussels of the middle shore although it will exist in the lower regions as well. A very common and widespread species around the Atlantic, North Sea and English Channel.

Similar to Irish moss Chondrus crispus.


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