Evidence for a non-linear carbon accumulation pattern along an Alpine glacier retreat chronosequence in Northern Italy
- Published
- Accepted
- Subject Areas
- Climate Change Biology, Biogeochemistry
- Keywords
- Glacier retreat, Carbon accumulation, Plant colonization, Gas exchange, Soil analysis, Ecosystem respiration, Net ecosystem exchange, Gross ecosystem exchange, Life form
- Copyright
- © 2019 Montagnani et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2019. Evidence for a non-linear carbon accumulation pattern along an Alpine glacier retreat chronosequence in Northern Italy. PeerJ Preprints 7:e27703v1 https://doi.org/10.7287/peerj.preprints.27703v1
Abstract
Background. The glaciers in the Alps, as in other high mountain ranges and boreal zones, are generally retreating and leaving a wide surface of bare ground free from ice cover. This early stage soil is then colonized by microbes and vegetation in a process of primary succession. It is rarely experimentally examined whether this colonization process is linear or not at the ecosystem scale. Thus, to improve our understanding of the variables involved in the carbon accumulation in the different stages of primary succession, we conducted this research in three transects on the Matsch glacier forefield (Alps, N Italy) at an altitude between 2350 and 2800 m a.s.l.
Methods. In three field campaigns (July, August and September 2014) a closed transparent chamber was used to quantify the net ecosystem exchange (NEE) between the natural vegetation and the atmosphere. On the five plots established in each of the three transects, shading nets were used to determine ecosystem response function to variable light conditions. Ecosystem respiration (Reco) and gross ecosystem exchange (GEE) was partitioned from NEE. Following the final flux measurements, biometric sampling was conducted to establish soil carbon (C) and nitrogen (N) content and the biomass components for each transect.
Results. A clear difference was found between the earlier and the later successional stage. The older successional stages in the lower altitudes acted as a stronger C sink, where NEE, GEE, and Reco were significantly higher than in the earlier successional stage. Of the two lower transects, the sink capacity of intermediate-succession plots exceeded that of the plots of older formation, in spite of the more developed soil. Total biomass (above- and belowground) approached its maximum value in the intermediate ecosystem. Whilst, the later stage of succession predominated in the corresponding belowground organic mass (biomass, N and C).
Outlook. We found that the process of carbon accumulation along a glacier retreat chronosequence is not linear, and after a quite rapid increase in carbon accumulation capacity in the first 150 years, in average 9 g C m-2 y-1, it slows down, taking place mainly in the belowground biomass components. Concurrently, the photosynthetic capacity peaks in the intermediate stage of ecosystem development. If confirmed by further studies on a larger scale, this study would provide evidence for a predominant effect of plant physiology over soil physical characteristics in the green-up phase after glacier retreat, which has to be taken into account in the creation of scenarios related to climate change and future land use.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Map of the study area
T1, T2, and T3 indicate the experimental transects.
Images of the collars and of the sampled ecosystem portions
The letter T indicates the transect (T1-T3) and the letter C indicates the collar (C1-C5).
Light response curves original data
In this file are reported the environmental variables data and those obtained by the CO2 analyser Li-8100.
Results of the soil and vegetation analyses
In the table are reported the raw results of the analysis performed in the different samples.