# Acidification of headwater streams: structural and functional assessment of microbial communities associated with decaying leaves

Hugues Clivot, Michael Danger, Christophe Pagnout, Philippe Rousselle, Philippe Wagner, Pascal Poupin, François Guérold

<figure><img src="image_1.png" /></figure>

## ► To cite this version:

Hugues Clivot, Michael Danger, Christophe Pagnout, Philippe Rousselle, Philippe Wagner, et al. Acidification of headwater streams: structural and functional assessment of microbial communities associated with decaying leaves. ASLO/NABS Summer Meeting, Jun 2010, Santa Fe, United States. hal-03518695

HAL Id: hal-03518695

https://hal.inrae.fr/hal-03518695

Submitted on 10 Jan 2022

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Distributed under a Creative Commons Attribution 4.0 International License
# Acidification of headwater streams: structural and functional assessment of microbial communities associated with decaying leaves.

<u>Hugues Clivot</u>, Michael Danger, Christophe Pagnout, Philippe Rousselle, Philippe Wagner, Pascal Poupin and François Guérold

Laboratoire des Interactions Ecotoxicologie, Biodiversité, Ecosystèmes
CNRS UMR 7146, Université Paul Verlaine, Rue du Général Delestraint, 57070 Metz, France
hugues.clivot@umail.univ-metz.fr
Introduction

- Acid depositions → forested headwater streams
  in the Vosges Mountains (North-eastern France)

• Heterotrophic ecosystem ← leaf-litter

* Leaf-litter breakdown = key ecosystem process
  → assess functional alterations

• Acidification → impairs leaf breakdown

- Micro-organisms = pivotal role in organic matter processing
Acidification of headwater streams

-> Microbial communities associated with decaying leaves

-> Microbial activities (organic C and nutrients acquisition)

-> Explain reduced leaf-litter breakdown
Maple leaf disks (18 mm)
*(Acer platanoides)*

<figure><img src="image_3.png" /></figure>

Fine mesh bags

6 headwater streams (3 neutral / 3 acidified)

<figure><img src="image_4.png" /></figure>

Nov 2009

<figure><img src="image_5.png" /></figure>

Jan 2010

7

13

21

28

49

70d

Water
sample

<figure><img src="image_6.png" /></figure>

Water chemistry

<figure><img src="image_7.png" /></figure>

Mass loss

4
replicate
bags

<figure><img src="image_8.png" /></figure>

Microbial community structure (DGGE 16S and 18S)

<figure><img src="image_9.png" /></figure>

Potential Extracellular Enzyme Activities

<figure><img src="image_10.png" /></figure>

N and P content
Water chemistry

<figure><img src="image_11.png" /><figcaption>pH</figcaption></figure>

<figure><img src="image_12.png" /><figcaption>Total Al</figcaption></figure>

Sites
# Maple leaf breakdown

<figure><img src="image_13.png" /><figcaption>Relationship between
breakdown rates
(exponential model) and
mean total aluminium</figcaption></figure>

<figure><img src="image_14.png" /><figcaption>AFDM remaining (%)</figcaption></figure>

Mean total Al (µg.L⁻¹)
Microbial community structure
# Bacterial community structure

<figure><img src="image_15.png" /><figcaption>nMDS plot based on 16S rDNA DGGE profiles</figcaption></figure>
# Fungal community structure

<figure><img src="image_16.png" /><figcaption>nMDS plot based on 18S rDNA DGGE profiles</figcaption></figure>
# Lignocellulolytic Enzyme Activities
Phenol oxidase

<figure><img src="image_17.png" /><figcaption>Enzyme activity (ABTS)
10⁻² µmol.min⁻¹.g⁻¹ AFDM</figcaption></figure>
Exocellulase

Enzyme activity
µmol·h⁻¹·g⁻¹ AFDM

<figure><img src="image_18.png" /></figure>

Enzyme activity
µmol·h⁻¹·g⁻¹ AFDM

<figure><img src="image_19.png" /></figure>

Time (day)
Hemicellulase

<figure><img src="image_20.png" /><figcaption>Enzyme activity
µmol·h⁻¹·g⁻¹ AFDM</figcaption></figure>

Time (day)

Important potential activities in acidified streams
→ enzyme production not reduced
Microbial nutrient acquisition
Nitrogen uptake

<figure><img src="image_21.png" /><figcaption>Nitrogen content
% DM</figcaption></figure>

<figure><img src="image_22.png" /><figcaption>Time (day)</figcaption></figure>
Phosphorus uptake

Phosphorus content
% DM

<figure><img src="image_23.png" /></figure>

Enzyme activity
µmol·h⁻¹·g⁻¹ AFDM

<figure><img src="image_24.png" /></figure>
Conclusion

* Relationship Al concentration / Leaf processing

* Environmental factors controlling :

* Microbial succession and diversity

* Patterns of potential Extracellular Enzyme Activity

* Nutrients acquisition:

* N uptake non limiting

* Acidic streams : Increasing enzymatic effort for P acquisition + uptake reduced with increasing Al concentration
Discussion

* Microbial diversity → Enzyme Activities

* Leaf breakdown not related to Enzymatic effort in acidic streams

* Enzyme production controlled by abiotic and biotic factors

* Microbial activity constrained by nutrients availability

* P limitation (Sequestration of P with high Al concentration)

* Direct and indirect microbial interactions with Al

* Repercussions in the stream food webs
* Ergosterol contents → confirm fungal growth in acidic streams

* Identify differences in microbial community composition
# Acidification of headwater streams: structural and functional assessment of microbial communities associated with decaying leaves.

Hugues Clivot, Michael Danger, Christophe Pagnout, Philippe Rousselle, Philippe Wagner, Pascal Poupin and François Guérold

Laboratoire des Interactions Ecotoxicologie, Biodiversité, Ecosystèmes
CNRS UMR 7146, Université Paul Verlaine, Rue du Général Delestraint, 57070 Metz, France
hugues.clivot@umail.univ-metz.fr