Posts Climate, Environment, Forestry

Digging deeper – Conference of Ecology of Soil Microorganisms gathers the leading scientists in Helsinki this summer. International community motivates us to stick to science and push further, Luke soil experts say.

A tree needs is a good root to survive in the forest soil and to grow big and strong. Drawing: Tiina Sileoni

– We got the best Finnish scientists to plan the conference and the best ones of the world will come to Helsinki. They would not, if we did not have a strong foothold in the field, says docent Taina Pennanen, expert on forest soil microbes.

Pennanen’s colleague, research professor Hannu Fritze agrees.

– All the research groups working with soil microbes in Finland cooperate in this conference.

Controlling methane emissions with mire moss?

One proof of the active work in the research groups of Fritze and Pennanen is a new dissertation, very fresh and worth noticing. Anuliina Putkinen showed in her doctoral thesis that after a disturbed mire ecosystem is restored, it takes about 60 years for the microbial community to recover.

– Methane cycle, which is essential to the mire ecosystem, recovers faster, but the diversity of the microbes requires more time, Fritze says.

Different mires cover about one third of Finland’s land area and about half of them have been drained. Fritze has dug deep into these peatlands, the world of bacteria and archaea, their role in the carbon cycle and global warming. Recently, his mind has been occupied with Sphagnums, a family of common peat mosses.

– At times when Sphagnums are under water, they attract methane oxidizing bacteria close by. They do it in a very efficient way, which is currently unknown to science, Fritze describes.

Moreover, while the mosses are under water and cannot use the carbon dioxide from air to grow, bacteria feed them with carbon dioxide, which originates from methane produced by archae.

Sphagnums can bind even 10 to 30% of the methane coal. Could they be used as methane filters in landfills and big cattle sheds? Fritze envisions.

Junk food generation needs useful fungi

– Why do some trees grow faster than the others? What is the role of soil microbes in their growth? That is what I am asking, Taina Pennanen describes her career.

After finishing her dissertation, Pennanen left Finland to work in the leading groups of the field and to learn the latest methods abroad.

– I bit my teeth together and left. I had to. Many times.

While Fritze dug into mires, Pennanen grew her expertise in forest microbes, forest nutrient cycles and finally, concentrated on the symbiotic fungi living in roots.

In the Finnish nurseries, trees are mainly grown in peat pots, with added nutrients. The method makes disease control easier, but does not prepare the plant to a life in forest soil.

– Our forest trees are dependent on symbiotic mycorrhizal fungi in their nutrient uptake. If they are given handfuls of nutrients in the nursery, they do not grow good roots or form fungal symbiosis. They are like a junk food generation of trees, Pennanen describes.

It is all about the root

Pennanen spreads her knowledge. First, she recalls, nurseries were not interested, but now the situation is improving. She emphasises that it is important to prepare a sapling for the harsh competition it faces in the forest soil. She is also developing a commercial product for nurseries, a fungi inoculant of useful microbes.

– In our basic research, we mapped a few species especially useful to our trees. Corticoids are fungi, which live under the ground throughout their lives and are very useful for saplings.

However, to survive in the forest soil and to grow big and strong, what a tree needs is a good root.

– A bad root cannot form mycorrhizal symbiosis, Pennanen concludes.

– And in the future, roots will be on the focus of genotype selection, Fritze adds.

– We must continue the work and increase our understanding about the belowground mechanisms. Here aboveground, it is all about co-operation, and luckily we have an excellent group of scientists and technicians here at Luke.