Below-surface water mediates the response of African forests to reduced rainfall

Terrestrial ecosystem gross primary productivity (GPP) is the largest land-atmosphere carbon flux and the primary mechanism of photosynthetic fixation of atmospheric CO2 into plant biomass. Anomalous rainfall events have been shown to have a great impact on the global carbon cycle. However, less is...

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Bibliographic Details
Published in:Environmental research letters 2020-03, Vol.15 (3), p.34063
Main Authors: Madani, Nima, Kimball, John S, Parazoo, Nicholas C, Ballantyne, Ashley P, Tagesson, Torbern, Jones, Lucas A, Reichle, Rolf H, Palmer, Paul I, Velicogna, Isabella, Bloom, A Anthony, Saatchi, Sassan, Liu, Zhihua, Geruo, A
Format: Article
Language:English
Subjects:
Annual variations
Aridity
Carbon cycle
Carbon dioxide
Carbon dioxide fixation
Carbon sequestration
Ecosystems
Forest ecosystems
GPP
Groundwater
Groundwater storage
Moisture content
Photosynthesis
Plant biomass
Rainfall
SIF
Soil moisture
Soil surfaces
Soil water
Spatial data
Surface water
Terrestrial environments
Tropical forests
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Summary:Terrestrial ecosystem gross primary productivity (GPP) is the largest land-atmosphere carbon flux and the primary mechanism of photosynthetic fixation of atmospheric CO2 into plant biomass. Anomalous rainfall events have been shown to have a great impact on the global carbon cycle. However, less is known about the impact of these events on GPP, especially in Africa, where in situ observations are sparse. Here, we use a suite of satellite and other geospatial data to examine the responses of major ecosystems in Africa to anomalous rainfall events from 2003 to 2017. Our results reveal that higher-than-average groundwater storage in tropical ecosystems offsets the rainfall deficit during the dry years. While the inter-annual variations in GPP in semi-arid ecosystems are controlled by near surface soil water, deeper soil moisture and groundwater control the inter-annual variability of the GPP in dense tropical forests. Our study highlights the critical role of groundwater in buffering rainfall shortages and continued availability of near-surface water to plants through dry spells.
ISSN:1748-9326
1748-9326
DOI:10.1088/1748-9326/ab724a