HAL Id: insu-01624744
https://hal-insu.archives-ouvertes.fr/insu-01624744
Submitted on 30 Oct 2017
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Effects of early diagenesis on the isotopic signature of wood (δ13C and δ15N): incubation in aquatic microcosm
Romain Tramoy, Thanh Thuy Nguyen Tu, Veronique Vaury, Mathieu Sebilo, Laurence Millot-Cornette, Céline Roose-Amsaleg, Johann Schnyder
To cite this version:
Romain Tramoy, Thanh Thuy Nguyen Tu, Veronique Vaury, Mathieu Sebilo, Laurence Millot- Cornette, et al.. Effects of early diagenesis on the isotopic signature of wood (δ13C and δ15N):
incubation in aquatic microcosm. Goldschmidt-2017, Aug 2017, Paris, France. 2017. �insu-01624744�
Romain Tramoy
1, Thanh Thuy Nguyen Tu
2, Véronique Vaury
3, Mathieu Sebilo
3, Laurence Millot Cornette
2, Celine Roose-Amsaleg
2, Johann Schnyder
1.
1Sorbonne universités, CNRS, UPMC, UMR 7193, ISTEP, France ; 2 Sorbonne universités, CNRS, UPMC, EPHE, UMR 7619, METIS, France ; 3 Sorbonne universités, CNRS, UPMC, INRA, IRD-Paris Diderot-UPEC, UMR7618, IEES, France
Effects of early diagenesis on the isotopic signature of wood ( δ 13 C and δ 15 N):
incubation in aquatic microcosm
Milieux Environnementaux Transferts et Interactions dans les hydrosystèmes et les sols
DW DW
RW RW
DW
60 cm
Removal Initial branch Removal
Wood
pieces
(Triplicate)
Initial
Variability
Ground
for
analyses
Sampling
(Triplicate)
t
1t
nt
1t
nt
1t
nt
0t
1t
n140 rpm / ambient
T° / Dark SHAKING T
ABLE
DW RW DW RW
RW
80 100
0 20 40 60
90
80
70
60
DW; r2 = 0.83; slope = -0.11(t) RW; r2 = 0.996; slope = -0.36(t)
Time (week)
Remaining organic matter (%)
t
4b
t
0 1 cm DW DWa a
t
4b
t
4t
a a
4e
c
d
t
RW0
t
7t
7e
A C
B D
Morphologies of the wood pieces before (t
0) and
after degradation (t
4to t
7).
A (DW) and B (RW) correspond to wood before (t0) and after 16 weeks (t4) a, braun-reddish areas = soft- or black-rot fungi
b, braun fungi flotting in water and growing in the growth-rings c, flotting particles of wood (brittle and spongy traits)
d, mottled whitish aspect = white-rot fungi e, color uniformisation = white-rot fungi
Mass loss of wood pieces vs time
46 45 -23.5
-24.0
-24.5 47 48 49 50 51
Content (%)
pieces
Isotopic composition (‰)
δ13C
%C %N
δ15N
20 40 60 80
0
Time (week) Time (week)
20 40 60 80
0 0.12
0.14 1.37
35
0.10 0.08 0.06 0.04
-2.0 0.0 2.0 -22.6 4.0
Carbon Nitrogen
Numbers = AWCD*
*AWCD (Average Well Colour Development):
Index showing the development of microorga- nisms on differents tested substrates. It corres- ponds to the bacterial activity and diversity in the study environment (Zak et al., 1994; Zhao et al., 2013).
Picture of a BiologECO plate after incubation
Introduction
Conclusions
*Work published as Tramoy et al. (2017) in Environmental Chemistry
M
E
T
H
O
D
%C, δ
13C
%N, δ
15N
Slice
(Ø = 2 mm)
or powders
powders
46 45 -23.5
-24.0
-24.5 47 48 49 50 51
20 40 60 80
0 0 20 40 60 80
0.11 0.12
0.10 0.09 0.08 0.07
-1.5 -1.0 -0.5 0.0 0.5 1,0
Time (week)
River Water (RW)
Distilled Water (DW) Flotting particles Refill water
Time (week)
δ13C
%C %N
δ15N Content (%)Isotopic composition (‰)
Carbon Nitrogen
Error bars correspond to standard deviation of triplicate 100 % corresponds to the initial state (t0)
W ood
W ater
Fonctional diversity of the bacterial communities
using Method BiologECO (Garland & Mills 1991)
Organic-rich sediments (Kazakhstan-Jurassique)
Pic. from J. Schnyder
Paleoenvironmental reconstruction
Pieces of wood or powders
T° = 22 °C - pH neutral
Permanent Oxygenation
(agitation)Darkness
(avoid photo-organisms development)73 weeks
(t1 to 7 = 2, 4, 8, 16, 32, 52 and 73 weeks)10 cm
Sciadopitys verticillata (Taxodiacae)
INITIAL VARIABILITY (t
0)
1. Observations: Fungi as main decomposers ? 2. Microflora in powders
>
3. Degradation state 4. Effects on the isotopic signature of wood
Soft-rot linked to
Ascomycetes and Deu-
teromycètes activity
White-rot linked to Ba-
sidiomycetes activity
Color uniformisation
Mottled & Spongy traits
Whitish-yellow coloration
Degrading
Lignin/Cellulose
Degrading
Cellulose
Dark color
Growth-rings braun-reddish
Bacteria are NOT the main decomposers
Fungi are the main decomposers
δ
13C values of organic matter has lower variability than δ
15N
values, which confirms its interest as a source and environ-
ment indicator
Without invalidating the use of δ
15N
orgas a paleoenvironmen-
tal marker, this study shows that early diagenesis leads to
the integration of isotopic compositions from multi-
ple environmental origins that should be addressed when
interpreting δ
15N
orgin soils and sediments
In both type of water, mycellium of fungi likely constitute a nitrogen transport network and their activity may proceed toward
isotopic uniformisation of a system (e.g. wood-fungi-water) as long as nitrogen is maintained in the bulk system
- Pieces: Low variability in δ
13C and in %C
Low amount of material affected by degradation when
compared to the bulk carbon pool.
Loss of
13C-depleted compounds (cf. flotting particles;
tannins, lignin, other non-polar compounds; Melillo et al., 1989)
- Powders: complex dynamic
Key-role of respiration leading to
13C-enrichment ?
- Similar between pieces and powders
- Nitrogen gain in pieces in RW +
15N-enrichment
Incorporation of exogenous nitrogen into the wood (nitrates from
water ?) thanks to fungi activity. Higher NO3- δ
15N supports this hypothesis.
N accumulation according to Melillo et al. (1989)
- Nitrogen loss in pieces in DW +
15N-depletion
Amino-acids and proteins (
15N-enriched) consumption by fungi,
which exports nitrogen from the wood through mycellium.
Références
Garland, J.L., Mills, A.L., 1991. Classification and characterization of heterotrophic microbial communities on the basis of patterns of community-le- vel-sole-carbon-source-utilization. Appl. Environ. Microbiol. 57, 2351–2359.
Melillo, J.M., Aber, J.D., Linkins, A.E., Ricca, A., Fry, B., Nadelhoffer, K.J., 1989. Carbon and nitrogen dynamics along the decay continuum: Plant litter to soil organic matter, in: Clarholm, M., Bergström, L. (Eds.), Ecology of Arable Land — Perspectives and Challenges, Developments in Plant and Soil Sciences. Springer Netherlands, pp. 53–62.
Tramoy, R., Sebilo, M., Nguyen Tu, T.T., Schnyder, J., 2017. Carbon and nitrogen dynamics in decaying wood: paleoenvironmental implications. Environ.
Chem. 14, 9–18. doi:10.1071/EN16049
Zak, J.C., Willig, M.R., Moorhead, D.L., Wildman, H.G., 1994. Functional diversity of microbial communities: A quantitative approach. Soil Biol. Biochem.
26, 1101–1108.
Zhao, D., Li, F., Yang, Q., Wang, R., Song, Y., Tao, Y., 2013. The influence of different types of urban land use on soil microbial biomass and functional diver- sity in Beijing, China. Soil Use Manag. 29, 230–239. doi:10.1111/sum.12034
Acknowledgement
We thank Julien Legrand, who collected the wood used. We are grateful to Véronique Vaury (Institute of Ecology and Environmental Sciences of Paris; IEES-UPMC) for analyses.
This study was supported by the EMERGENCE project from UPMC. We also thank Sylvie Derenne for access to experimental facilities and financial support for congress.
Average
