Deep in the Sierra Nevada critical zone: saprock represents a large terrestrial organic carbon stock
Large uncertainty remains in the spatial distribution of deep soil organic carbon (OC) storage and how climate controls belowground OC. This research aims to quantify OC stocks, characterize soil OC age and chemical composition, and evaluate climatic impacts on OC storage from the soil surface throu...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2021-01-01
|
| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ac3bfe |
| _version_ | 1797747143725809664 |
|---|---|
| author | Kimber Moreland Zhiyuan Tian Asmeret Asefaw Berhe Karis J McFarlane Peter Hartsough Stephen C Hart Roger Bales Anthony T O’Geen |
| author_facet | Kimber Moreland Zhiyuan Tian Asmeret Asefaw Berhe Karis J McFarlane Peter Hartsough Stephen C Hart Roger Bales Anthony T O’Geen |
| author_sort | Kimber Moreland |
| collection | DOAJ |
| description | Large uncertainty remains in the spatial distribution of deep soil organic carbon (OC) storage and how climate controls belowground OC. This research aims to quantify OC stocks, characterize soil OC age and chemical composition, and evaluate climatic impacts on OC storage from the soil surface through the deep critical zone to bedrock. These objectives were carried out at four sites along a bio-climosequence in the Sierra Nevada, California. On average, 74% of OC was stored below the A horizon, and up to 30% of OC was stored in saprock (friable weakly weathered bedrock). Radiocarbon, spectroscopic, and isotopic analyses revealed the coexistence of very old organic matter (OM) (mean radiocarbon age = 20 300 years) with relatively recent OM (mean radiocarbon age = 4800 years) and highly decomposed organic compounds with relatively less decomposed material in deep soil and saprock. This co-mingling of OM suggests OC is prone to both active cycling and long-term protection from degradation. In addition to having direct effects on OC cycling, climate indirectly controls deep OC storage through its impact on the degree of regolith weathering (e.g. thickening). Although deep OC concentrations are low relative to soil, thick saprock represents a large, previously unrealized OC pool. |
| first_indexed | 2024-03-12T15:46:57Z |
| format | Article |
| id | doaj.art-5f51804b8f0d4ac2965d9465c1cce466 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:46:57Z |
| publishDate | 2021-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-5f51804b8f0d4ac2965d9465c1cce4662023-08-09T15:23:11ZengIOP PublishingEnvironmental Research Letters1748-93262021-01-01161212405910.1088/1748-9326/ac3bfeDeep in the Sierra Nevada critical zone: saprock represents a large terrestrial organic carbon stockKimber Moreland0https://orcid.org/0000-0002-5155-3348Zhiyuan Tian1https://orcid.org/0000-0003-1740-117XAsmeret Asefaw Berhe2https://orcid.org/0000-0002-6986-7943Karis J McFarlane3https://orcid.org/0000-0001-6390-7863Peter Hartsough4Stephen C Hart5https://orcid.org/0000-0002-9023-6943Roger Bales6Anthony T O’Geen7Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory , Livermore, CA, United States of America; Department of Life and Environmental Sciences and Sierra Nevada Research Institute, University of California , Merced, CA, United States of AmericaDepartment of Land, Air, and Water Resources, University of California , Davis, CA, United States of AmericaDepartment of Civil and Environmental Engineering and Sierra Nevada Research Institute, University of California , Merced, CA, United States of AmericaCenter for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory , Livermore, CA, United States of AmericaDepartment of Land, Air, and Water Resources, University of California , Davis, CA, United States of AmericaDepartment of Life and Environmental Sciences and Sierra Nevada Research Institute, University of California , Merced, CA, United States of AmericaDepartment of Civil and Environmental Engineering and Sierra Nevada Research Institute, University of California , Merced, CA, United States of AmericaDepartment of Land, Air, and Water Resources, University of California , Davis, CA, United States of AmericaLarge uncertainty remains in the spatial distribution of deep soil organic carbon (OC) storage and how climate controls belowground OC. This research aims to quantify OC stocks, characterize soil OC age and chemical composition, and evaluate climatic impacts on OC storage from the soil surface through the deep critical zone to bedrock. These objectives were carried out at four sites along a bio-climosequence in the Sierra Nevada, California. On average, 74% of OC was stored below the A horizon, and up to 30% of OC was stored in saprock (friable weakly weathered bedrock). Radiocarbon, spectroscopic, and isotopic analyses revealed the coexistence of very old organic matter (OM) (mean radiocarbon age = 20 300 years) with relatively recent OM (mean radiocarbon age = 4800 years) and highly decomposed organic compounds with relatively less decomposed material in deep soil and saprock. This co-mingling of OM suggests OC is prone to both active cycling and long-term protection from degradation. In addition to having direct effects on OC cycling, climate indirectly controls deep OC storage through its impact on the degree of regolith weathering (e.g. thickening). Although deep OC concentrations are low relative to soil, thick saprock represents a large, previously unrealized OC pool.https://doi.org/10.1088/1748-9326/ac3bfesoil carbonweathered bedrockcarbon biogeochemistrysaprockdeep soil carboncarbon storage |
| spellingShingle | Kimber Moreland Zhiyuan Tian Asmeret Asefaw Berhe Karis J McFarlane Peter Hartsough Stephen C Hart Roger Bales Anthony T O’Geen Deep in the Sierra Nevada critical zone: saprock represents a large terrestrial organic carbon stock Environmental Research Letters soil carbon weathered bedrock carbon biogeochemistry saprock deep soil carbon carbon storage |
| title | Deep in the Sierra Nevada critical zone: saprock represents a large terrestrial organic carbon stock |
| title_full | Deep in the Sierra Nevada critical zone: saprock represents a large terrestrial organic carbon stock |
| title_fullStr | Deep in the Sierra Nevada critical zone: saprock represents a large terrestrial organic carbon stock |
| title_full_unstemmed | Deep in the Sierra Nevada critical zone: saprock represents a large terrestrial organic carbon stock |
| title_short | Deep in the Sierra Nevada critical zone: saprock represents a large terrestrial organic carbon stock |
| title_sort | deep in the sierra nevada critical zone saprock represents a large terrestrial organic carbon stock |
| topic | soil carbon weathered bedrock carbon biogeochemistry saprock deep soil carbon carbon storage |
| url | https://doi.org/10.1088/1748-9326/ac3bfe |
| work_keys_str_mv | AT kimbermoreland deepinthesierranevadacriticalzonesaprockrepresentsalargeterrestrialorganiccarbonstock AT zhiyuantian deepinthesierranevadacriticalzonesaprockrepresentsalargeterrestrialorganiccarbonstock AT asmeretasefawberhe deepinthesierranevadacriticalzonesaprockrepresentsalargeterrestrialorganiccarbonstock AT karisjmcfarlane deepinthesierranevadacriticalzonesaprockrepresentsalargeterrestrialorganiccarbonstock AT peterhartsough deepinthesierranevadacriticalzonesaprockrepresentsalargeterrestrialorganiccarbonstock AT stephenchart deepinthesierranevadacriticalzonesaprockrepresentsalargeterrestrialorganiccarbonstock AT rogerbales deepinthesierranevadacriticalzonesaprockrepresentsalargeterrestrialorganiccarbonstock AT anthonytogeen deepinthesierranevadacriticalzonesaprockrepresentsalargeterrestrialorganiccarbonstock |