Let’s like Lichens!
Being bedazzled by the larger, more obvious forms of life out there, we often overlook, or worse still, forget to acknowledge the lesser forms. Whether it is the back-breaking hardworking ant or the not-so-colourful corals of the sea world, it is important to know that each of these has an important role to play in the overall ecosystem. One such long-lost wildlife specimen is the lichen- found often in the world down under or in crevices, where we hardly care to look! But these humble beings have much up their sleeves- something that we must give them credit for! Read on to know more about these lesser-known species, and let’s liken up to the lichens!
Not one, but two organisms!
Lichens appear to be the green mossy mass often seen on barks or rocks. Surely, they are plants, and that too lowly ones with hardly a presence, right? Wrong! Lichens are astoundingly not just single organisms, but two organisms functioning together to form a stable unit. On one hand there is the fungus, and on the other hand, there is the alga (mostly green alga) or cyanobacterium (blue-green algae). The fungal component is called the mycobiont, while the algal or cyanobacterial component is known as the photobiont.
And hey, despite such a close association, these beings seldom fight (unlike common human nature!), but mutually coexist in a beautiful bond of symbiosis. Why would anyone get so much up, close and personal, common sense would say? Well, this is Mother Nature at her brilliant best. Fungi do not have chlorophyll, the food-making pigment, and cannot make their own food. Alga benefit because they get an anchor in the form of the fungal filaments- a means to gather moisture and nutrients from the atmosphere.
Lichen Closeup
Co-dependency with a good cause
Sometimes, such is the level of dependency that one cannot exist without the other. That one is usually the fungus i.e. the fungus is associated as an obligate with the lichen, and hence it is the one who mostly controls the association. The real beauty lies in the fact that this dependency is not random, but highly organized and selective. Which means that any fungus cannot associate with any alga to produce a lichen. The following concepts help both the parties make the right selection for a sustainable, successful life*.
- Recognition: A complex series of chemical reactions occur when a potential fungus and alga come together to coexist.
- Acceptance: If the two find mutual benefit in the association, and no threat then acceptance goes through. For example, if a fungus is parasitic towards a particular alga, and the alga perceives this, there is no way they can associate symbiotically because one stands to lose, which is the very antithesis of symbiosis.
- Fitness: Fitness is a function of how the two components work together to create a healthy growing and reproductively successful dyad. Fitness is also influenced by environmental factors such as the amount of moisture, food substrate etc. If conditions are unfavourable, the two may decide to part ways and switch to a different partner. Not quite unlike human beings, are they; with a mind of their own!
Dull denizens of bright beings?
We often think of lichens as the dusty brown and dirty things lining walls or tree barks. But surprisingly, lichens can don a rich garb- it all depends on the richness of resources and favourable growth conditions being available. Especially in dry season, it is the dull colours of the fungi which are dominantly visible, whereas, in monsoons, the green alga may bloom profusely, giving a rich green plumage to the lichen colony.
Selfless beings to take a liking to!
For all their dullness or brightness, lichens are often less liked, or even less noticed. They are non-glamorous and even creepy to some, with their interlinked structures in despicable places. Why then should we bother to like lichens? This is because of the phenomenal ecosystem services that lichens render in the overall scheme of the earth. Lichens are responsible for:
- Nitrogen fixation is done by the cyanobacteria, making the soil rich and arable.
- Biological weathering such as breaking down of rocks, thereby releasing useful minerals.
- Serve as life-saving fodder in the high arctic regions especially for reindeer and elk.
- Pollution indicator: Lichens are able to absorb pollutants such as heavy metals, sulphur and other harmful components. Such lichen can be analysed to understand the pollution levels.
So, what’s there to not really like about lichens? It’s best for us humans to not discredit the less obvious life forms on this earth, and instead treat them with due worth. After all, the very fact that these two beings reside so closely and peacefully, in all kindness helping each other is an act seldom found in our human colonies. Maybe a lesson to learn from?
Cover pic: Lichen in Dry Habitat | By Rhucha Kulkarni
Read also: Serenity in silence of the valley
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