Ecology Live with Franciska de Vries - Machiavellian microbes - drought-induced changes

The British Ecological Society is broadcasting free online talks on the latest ecological research during the coronavirus lockdown period. In this talk, Franciska de Vries of the University of Amsterdam talks about machiavellian microbes: how drought-induced changes in belowground communities can have aboveground consequences.

"Climate change is increasing the occurrence of drought in many regions of the world, which is illustrated by the hot and dry summers that we have experienced in Europe three years in a row. The aboveground effects of drought are obvious: plants stop growing, turn brown, and might die, which can lead to changes in plant community composition. But belowground, hidden from our eyes, the consequences of drought are at least as drastic: during drought and especially after rewetting strong changes in microbial communities occur, and these changes can have long-lasting consequences for their functioning. In this talk, I will elucidate some of the mechanisms through which drought affects soil microbial communities, and the consequences for ecosystem functioning and plant community composition."

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Franciska has answered a number of the questions that we didn't have time for during the live talk. We've posted them here in the comments.

[BritishEcolSoc]

Kevin Watts: In general terms is 'soil respiration' a useful measure of the resilience/recovery of a system to disturbance such as droughts

Franciska: Probably as it's an indicator of microbial activity, stress, or efficiency, and of the loss of C from soils.

[Csasil]

Great session thanks. I was referred here from the futurelearn soils course

[BritishEcolSoc]

Kevin Mganga:
How was drought simulated? How would drought tolerant C4 species adapted in dryland environments compare with the selected species?

Franciska: In the field experiments, rainfall was intercepted using roofs. In the pot greenshouse/ controlled growth chamber experiments, watering was stopped until a certain WHC was reached (either 10 or 12%), and kept at that moisture content for the remainder of the drought period.

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Sophie Lane: Hello, thanks for the fantastic talk. Do you plan to find out what the biochemical composition of the root exudates are in different plants? If so, how?

Franciska: Yes, this is what we are working on now in follow-up experiments!

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Monique Weemstra: Hi! Excellent talk! I was wondering, do the exudated chemical compounds differ between plants or species? Are some species better at shaping their microbial communities than others, and if so, what are the 'costs' of this to the plant?

Franciska: This is what we are working on now in follow-up experiments!

[BritishEcolSoc]

Nickson:
Was the nutrient input to the experimental plants always kept constant(controlled)?

Franciska: Yes, most of our (short-term) experiments don't receive nutrient inputs, but when they do, we use a slow-release fertiliser and that is kept constant across treatments.

[BritishEcolSoc]

Lucas: Do you have any idea of exudate chemical composition that could induced soil respiration? (de Vries et al 2019, New Phyt.)

Franciska: This is what we are working on now in follow-up experiments!

[kailashpatibhandari]

It was great informative session.Thank you

[BritishEcolSoc]

Natasja van Gestel: Given that you have fungal ITS, do you have info on how AM fungi responded to the different treatments?

Franciska: Yes, in the field-based mesocosms their relative abundance increased under drought.

[BritishEcolSoc]

Anonymous: How does soil mineralogical composition affects these results?

Franciska: That is a good question, which needs its own experiment!

[BritishEcolSoc]

Vivek Babu: Is there any interaction between soil structure and exudates?

Franciska: That's very likely but as far as I know that question hasn't been addressed in experiments yet.

[BritishEcolSoc]

Irish Emmanuel Agpoon: Hi. Will drought or heat wave increase microbial pathogens that could damage the plant roots?

Franciska: That is a possibility and we are looking into the identities of the bacteria and fungi that increased!

[BritishEcolSoc]

Jordan Chetcuti
: I was just wondering why the diversity of the bacteria declined in the control? Or is it a non-significant decline?

Franciska: This might be an artefact of the experimental set up, and for example the result of sieving or the lack of plant inputs
.