What Do Lichens Eat?

What Lichens Eat

• The fungus portion of lichen is dominant in the relationship, called the mycobiont. It's composed of a tightly packed string-like fibers called hyphae which looks like a sheet of tissue. The hyphae absorb nutrients deposited on surroundings and feed on the algae. Algae is submissive in the relationship, completely controlled by the fungus, called the photobiont. It makes its own food through photosynthesis which is process of converting light energy into chemical energy and storing it as a sugar bond.

Types

• The type of lichen corresponds to the type of thallus that the fungus produces to house the algae. Foliose lichen has a leaf like thallus that's loosely attached to the surface on which it's growing. Crustose lichen are tightly packed and forcefully attached to the surface on which they grow. Furthermore crustose lichen make up 75 percent of all lichen on the planet. Fruticose lichen grow upright and look like puffy shrubs or long, hair-like strands that hang from tree branches.

Growth

• Lichens grow incredibly slow; the fastest lichen adds only 30mm to its length in a year. However, the symbiosis allows lichen to survive for extremely long periods of time. In fact a species of lichen found in western Greenland has been estimated as 4, 500 years old. During a dry period lichen survives because the fungus is capable of storing two to three times its weight in water within the hyphae. The hyphae can also store extra sugars and nutrients absorbed from the algae for times of drought.

Reproduction

• While they survive together, the algae and fungus reproduce separately. The algae reproduces asexually through mitosis which is the splitting of a single cell into two identical cells. The fungus reproduces sexual. The hyphae contain two mating strains called the plus and minus. The stains fuse to produce a nuclei that divides multiple times to form spores. When ready the spores are carried away by the wind to germinate in a new place.