Do degree and rate of silicate weathering depend on plant productivity?
<p>Plants and their associated below-ground microbiota possess the tools for rock weathering. Yet the quantitative evaluation of the impact of these biogenic weathering drivers relative to abiogenic parameters, such as the supply of primary minerals, water, and acids, is an open question in Cr...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-10-01
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| Series: | Biogeosciences |
| Online Access: | https://bg.copernicus.org/articles/17/4883/2020/bg-17-4883-2020.pdf |
| _version_ | 1818131060893941760 |
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| author | R. A. Oeser F. von Blanckenburg F. von Blanckenburg |
| author_facet | R. A. Oeser F. von Blanckenburg F. von Blanckenburg |
| author_sort | R. A. Oeser |
| collection | DOAJ |
| description | <p>Plants and their associated below-ground microbiota
possess the tools for rock weathering. Yet the quantitative evaluation of
the impact of these biogenic weathering drivers relative to abiogenic
parameters, such as the supply of primary minerals, water, and acids,
is an open question in Critical Zone research. Here we present a novel
strategy to decipher the relative impact of these drivers. We quantified the
degree and rate of weathering and compared these to nutrient uptake along
the “EarthShape” transect in the Chilean Coastal Cordillera. These sites
define a major north–south gradient in precipitation and primary
productivity but overlie granitoid rock throughout. We present a dataset of
the chemistry of Critical Zone compartments (bedrock, regolith, soil, and
vegetation) to quantify the relative loss of soluble elements (the “degree
of weathering”) and the inventory of bioavailable elements. We use
<span class="inline-formula"><sup>87</sup>Sr∕<sup>86</sup>Sr</span> isotope ratios to identify the sources of mineral
nutrients to plants. With rates from cosmogenic nuclides and biomass growth
we determined fluxes (“weathering rates”), meaning the rate of loss of
elements out of the ecosystems, averaged over weathering timescales
(millennia), and quantified mineral nutrient recycling between the bulk
weathering zone and the bulk vegetation cover. We found that neither the
degree of weathering nor the weathering rates increase systematically with
precipitation from north to south along the climate and vegetation gradient.
Instead, the increase in biomass nutrient demand is accommodated by faster
nutrient recycling. In the absence of an increase in weathering rate despite
a five-fold increase in precipitation and net primary
productivity (NPP), we hypothesize that plant
growth might in fact dampen weathering rates. Because plants are thought to
be key players in the global silicate weathering–carbon feedback, this
hypothesis merits further evaluation.</p> |
| first_indexed | 2024-12-11T08:14:56Z |
| format | Article |
| id | doaj.art-a86aaf61f2a54dcba53da1a0f0c94049 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-11T08:14:56Z |
| publishDate | 2020-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-a86aaf61f2a54dcba53da1a0f0c940492022-12-22T01:14:47ZengCopernicus PublicationsBiogeosciences1726-41701726-41892020-10-01174883491710.5194/bg-17-4883-2020Do degree and rate of silicate weathering depend on plant productivity?R. A. Oeser0F. von Blanckenburg1F. von Blanckenburg2Earth Surface Geochemistry, GFZ German Research Centre for Geosciences, 14473 Potsdam, GermanyEarth Surface Geochemistry, GFZ German Research Centre for Geosciences, 14473 Potsdam, GermanyInstitute of Geological Science, Freie Universität Berlin, 12249 Berlin, Germany<p>Plants and their associated below-ground microbiota possess the tools for rock weathering. Yet the quantitative evaluation of the impact of these biogenic weathering drivers relative to abiogenic parameters, such as the supply of primary minerals, water, and acids, is an open question in Critical Zone research. Here we present a novel strategy to decipher the relative impact of these drivers. We quantified the degree and rate of weathering and compared these to nutrient uptake along the “EarthShape” transect in the Chilean Coastal Cordillera. These sites define a major north–south gradient in precipitation and primary productivity but overlie granitoid rock throughout. We present a dataset of the chemistry of Critical Zone compartments (bedrock, regolith, soil, and vegetation) to quantify the relative loss of soluble elements (the “degree of weathering”) and the inventory of bioavailable elements. We use <span class="inline-formula"><sup>87</sup>Sr∕<sup>86</sup>Sr</span> isotope ratios to identify the sources of mineral nutrients to plants. With rates from cosmogenic nuclides and biomass growth we determined fluxes (“weathering rates”), meaning the rate of loss of elements out of the ecosystems, averaged over weathering timescales (millennia), and quantified mineral nutrient recycling between the bulk weathering zone and the bulk vegetation cover. We found that neither the degree of weathering nor the weathering rates increase systematically with precipitation from north to south along the climate and vegetation gradient. Instead, the increase in biomass nutrient demand is accommodated by faster nutrient recycling. In the absence of an increase in weathering rate despite a five-fold increase in precipitation and net primary productivity (NPP), we hypothesize that plant growth might in fact dampen weathering rates. Because plants are thought to be key players in the global silicate weathering–carbon feedback, this hypothesis merits further evaluation.</p>https://bg.copernicus.org/articles/17/4883/2020/bg-17-4883-2020.pdf |
| spellingShingle | R. A. Oeser F. von Blanckenburg F. von Blanckenburg Do degree and rate of silicate weathering depend on plant productivity? Biogeosciences |
| title | Do degree and rate of silicate weathering depend on plant productivity? |
| title_full | Do degree and rate of silicate weathering depend on plant productivity? |
| title_fullStr | Do degree and rate of silicate weathering depend on plant productivity? |
| title_full_unstemmed | Do degree and rate of silicate weathering depend on plant productivity? |
| title_short | Do degree and rate of silicate weathering depend on plant productivity? |
| title_sort | do degree and rate of silicate weathering depend on plant productivity |
| url | https://bg.copernicus.org/articles/17/4883/2020/bg-17-4883-2020.pdf |
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