Symposium Introduction

In cushion lichens we find all the necessary components of the ecosystem. The producers - symbiotic algae conducting photosynthesis. Consuments - small arthropods that feed on living tissues of the lichen, and mushrooms hyphae parasitizing on algae cells. Decomposers - fungal hyphae living not only at the expense of living, but at the expense of the dead cells of algae, and small

Animals - saprophagous, processing dead thalli, in the destruction which they help to many microorganisms. The degree of isolation cycling in this system is very small: it means that part of the decay products is carried out of lichen - washed away by rain water, crumbling down from the trunk. In addition, some animals migrate to other habitats. It at least some of the atoms have time to go through several cycles, including in the body living organisms, and getting rid of them before leaving this ecosystem.

In some types of ecosystems to removal of substances beyond them is so great that their stability is maintained largely due to the inflow of the same amount of substance from the outside, while internal cycle is ineffective. These flow ponds, rivers, streams, land on steep slopes. Other ecosystems are far more cycles of substances and on autonomous (forests, meadows, lakes, etc.).

But no, even the largest, the Earth's ecosystem is not fully vicious cycle. The continents are actively exchanging material with oceans, with a big role in these processes is played by the atmosphere, and all our Planet of the matter gets out of outer space and gives part of space.