Phosphorus supply controls the long-term functioning of mid-latitude ombrotrophic peatlands

This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint.

Downloads

Download Preprint

Authors

Daniel Schillereff , Richard Chiverrell, Jenny Sjöström, Malin Kylander, John Boyle, Jessica Davies, Hannah Toberman, Edward Tipping

Abstract

Phosphorus (P) supply is pivotal to global ecological functioning and carbon cycling. Ombrotrophic peatlands are waterlogged, nutrient-limited ecosystems where plant litter production exceeds decomposition rates, creating an important soil carbon (C) store (~500 Pg). Published experimental evidence demonstrates that the tight stoichiometric balance between P, nitrogen (N) and C regulates present-day peatland behaviour and carbon sequestration. We know little about the dynamics and importance of P in long-term bog development, limiting understanding of how the global peatland carbon sink may respond to prolonged human-perturbed and elevated P deposition. Here we show that P supply imposes a strong and overlooked control on long-term biogeochemical cycling and carbon storage across a range of individual bogs. Holocene stoichometric (P, N and C) profiles from 23 ombrotrophic, Sphagnum peatlands across Europe, North and South America confirm the importance of P recycling and retention by living vegetation in the acrotelm. Phosphorus accumulation in the catotelm shows a strong, positive correlation with site-specific proxies for decomposition (r2 = 0.91) and the P:N balance appears linked to long-term C burial (r2 = 0.63). More significantly, we find that modern measured P deposition in each study region is associated with greater decomposition and lower carbon accumulation in the catotelm. As ombrotrophic bogs source P solely from the atmosphere, the P supply to a particular bog appears to drive its biogeochemical cascade from surface vegetation to catotelm storage. We propose, supported by published experimental evidence, that P constrains productivity and microbial nutrient turnover over Holocene timescales. In turn, this dictates the intensity of organic matter decomposition, the amount of C export prior to permanent burial and, ultimately, the size of globally significant carbon and nutrient stores. We also calculate the P pool in mid-latitude ombrotrophic peatlands to be 0.23 Gt, representing 1.7% of global soil P. Our findings identify P supply as an overlooked driver of long-term peatland development and raises the prospect that increased post-industrial P deposition may degrade the global peatland carbon sink.

DOI

https://doi.org/10.31223/X5FW3J

Subjects

Earth Sciences, Environmental Sciences

Keywords

Holocene, Peatland ecology, Peatland biogeochemistry

Dates

Published: 2021-03-12 14:49

Last Updated: 2021-03-12 14:49

License

CC BY Attribution 4.0 International

Add a Comment

You must log in to post a comment.


Comments

Comment #24 Daniel Schillereff @ 2021-04-07 12:44

Dear Leszek, Many thanks for your comment and pointers to those papers, they are new to me. Best wishes, Daniel

Comment #18 Leszek A Bledzki @ 2021-03-31 18:37

Hi it is interesting paper, however helpful, would be also another two papers dealing with P and Rotifers - missing in almost all P budget calculations. Błędzki, L. A., et al. (2020). "Nutrient addition increases rotifer abundance and diversity in a temperate bog." Fundamental and Applied Limnology 194(2): 77-83 Błędzki, L. A., et al. (2018). "Ecology of rotifers and their unappreciated source of nitrogen and phosphorus in temperate northeastern American bogs." Fundamental and Applied Limnology 191(4): 277-287. Sincerely Leszek Bledzki