Dry Season Transpiration and Soil Water Dynamics in the Central Amazon.

Autor:	Spanner GC; National Institute of Amazonian Research (INPA), Manaus, Brazil., Gimenez BO; National Institute of Amazonian Research (INPA), Manaus, Brazil.; Smithsonian Tropical Research Institute (STRI), Panama City, Panama., Wright CL; Oak Ridge National Laboratory, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge, TN, United States., Menezes VS; National Institute of Amazonian Research (INPA), Manaus, Brazil., Newman BD; Los Alamos National Laboratory, Los Alamos, NM, United States., Collins AD; Los Alamos National Laboratory, Los Alamos, NM, United States., Jardine KJ; National Institute of Amazonian Research (INPA), Manaus, Brazil.; Lawrence Berkeley National Laboratory, Berkeley, CA, United States., Negrón-Juárez RI; Lawrence Berkeley National Laboratory, Berkeley, CA, United States., Lima AJN; National Institute of Amazonian Research (INPA), Manaus, Brazil., Rodrigues JR; National Institute of Amazonian Research (INPA), Manaus, Brazil., Chambers JQ; National Institute of Amazonian Research (INPA), Manaus, Brazil.; Lawrence Berkeley National Laboratory, Berkeley, CA, United States.; Department of Geography, University of California, Berkeley, Berkeley, CA, United States., Higuchi N; National Institute of Amazonian Research (INPA), Manaus, Brazil., Warren JM; Oak Ridge National Laboratory, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge, TN, United States.
Jazyk:	angličtina
Zdroj:	Frontiers in plant science [Front Plant Sci] 2022 Mar 24; Vol. 13, pp. 825097. Date of Electronic Publication: 2022 Mar 24 (Print Publication: 2022).
DOI:	10.3389/fpls.2022.825097
Abstrakt:	With current observations and future projections of more intense and frequent droughts in the tropics, understanding the impact that extensive dry periods may have on tree and ecosystem-level transpiration and concurrent carbon uptake has become increasingly important. Here, we investigate paired soil and tree water extraction dynamics in an old-growth upland forest in central Amazonia during the 2018 dry season. Tree water use was assessed via radial patterns of sap flow in eight dominant canopy trees, each a different species with a range in diameter, height, and wood density. Paired multi-sensor soil moisture probes used to quantify volumetric water content dynamics and soil water extraction within the upper 100 cm were installed adjacent to six of those trees. To link depth-specific water extraction patterns to root distribution, fine root biomass was assessed through the soil profile to 235 cm. To scale tree water use to the plot level (stand transpiration), basal area was measured for all trees within a 5 m radius around each soil moisture probe. The sensitivity of tree transpiration to reduced precipitation varied by tree, with some increasing and some decreasing in water use during the dry period. Tree-level water use scaled with sapwood area, from 11 to 190 L per day. Stand level water use, based on multiple plots encompassing sap flow and adjacent trees, varied from ∼1.7 to 3.3 mm per day, increasing linearly with plot basal area. Soil water extraction was dependent on root biomass, which was dense at the surface (i.e., 45% in the upper 5 cm) and declined dramatically with depth. As the dry season progressed and the upper soil dried, soil water extraction shifted to deeper levels and model projections suggest that much of the water used during the month-long dry-down could be extracted from the upper 2-3 m. Results indicate variation in rates of soil water extraction across the research area and, temporally, through the soil profile. These results provide key information on whole-tree contributions to transpiration by canopy trees as water availability changes. In addition, information on simultaneous stand level dynamics of soil water extraction that can inform mechanistic models that project tropical forest response to drought. Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (Copyright © 2022 Spanner, Gimenez, Wright, Menezes, Newman, Collins, Jardine, Negrón-Juárez, Lima, Rodrigues, Chambers, Higuchi and Warren.)
Databáze:	MEDLINE
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