As children, we thought it was an alien invasion. The „things“ could somehow move around. We often found it on the patio. After a heavy rain, suddenly dark, very soft and wobbly Jelly babies gathered. Some wandered along the paths …
I now found some of these mysterious hikers again:
Here they marched from the fields onto the path. 😉
Let’s have a look at their structure! What can it be? It has no roots, appears out of nowhere, and disappears again as if someone were beaming it away. (Click the photos to enlarge them).
Indeed, people in former times thought, this stuff came from the cosmos. Nostoc (mostly Nostoc commune) has amazing fantasy names in English: star jelly, spit of moon, troll’s butter, fallen star, or witch’s jelly. Our „alien“ is a fascinating colony-building cyanobacteria capable of photosynthesis. In former times cyanobacteria were called green-blue algae but the scientific classification as bacteria is more correct.
Cyanobacteria are one of the oldest living beings on earth. Its first appearance cannot be dated exactly, but it is estimated to have been 2,1 – 2,7 (or more) Ga years ago. Attention: 1 Ga is one billion or 109 years! For example, the formation of the Earth occurred approximately 4.54 Ga (4.54 billion years) ago and the age of the universe is approximately 13.8 Ga.
Nostoc is a master of survival, symbiotic with plants, fungi, and other bacteria. It can be found in the most inhospitable areas, even under radioactive radiation. It can help moss to survive on bare rocks. You see it on the third photo: moss is groing on the Nostoc colony on a path which is normally too dry for it. This gives us an indication that we should not destroy it, as some cleaning-obsessed patio owners often try to do.
First of all: you can’t destroy it. These colonies dry up into such teeny tiny layers that they are nearly invisible to our eyes. They survive attacks by gardeners better than their garden plants. But more importantly, Nostoc makes a helpful garden fertiliser! Nostoc commune can fix nitrogen from the atmosphere which is not bioavailible to most of the plants. Cyanobacteria fix the nitrogen gas into ammonia, and it’s this so-called Nitrogen cycle which provides plants with fertiliser. If you don’t like Nostoc in your patio, collect it while it is still wobbly Jelly babies: Plants with nitrogen requirements will be delighted with this biofertiliser!