Seasonal and intra-canopy fates of absorbed photons across microclimatic gradients in Central Amazonian forests
Data files
Mar 07, 2025 version files 266.50 KB
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README.md
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Ziccardi_et_al_2025_data_NP.csv
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Abstract
We assessed seasonal and intra-canopy variations in leaf energy partitioning in central Amazonian forests with extensive in-canopy sampling and pulse amplitude modulated (PAM) chlorophyll fluorescence measurements. In order to cover seasonal variation of leaf microenvironments and energy partitioning, we compared measurements between dry (Jul.-Dec.) and wet (Jan.-Mar.) seasons in the TNF K67 site. The dataset includes the pathways of photon utilization for photochemistry (ΦPSII), heat dissipation (ΦNPQ), and fluorescence re-emission (ΦNO). Dry season field campaigns were conducted in 2019, 2021, and 2022, and a wet season campaign was conducted in 2023. We conducted pulse amplitude modulated (PAM) chlorophyll-a fluorescence measurements and sampling of microenvironmental variation at the leaf level with the MultispeQ (V2.0).
https://doi.org/10.5061/dryad.tb2rbp0cr
Description of the data and file structure
PAM ChlF measurements and sampling of microenvironmental variation at the leaf level were conducted with the MultispeQ (V2.0). Leaves fully expanded, mature, free of epiphylls and lacking necrotic and chlorotic patches were measured from the lower, middle, and upper regions of the crown using advanced tree climbing techniques to provide a representative sample. The MultispeQ replicates ambient photosynthetically active radiation (PAR) inside a leaf chamber, enabling quick measurements (approximately 30 seconds) of leaf-level PAR (µmol m-2 s-1), vapor pressure deficit (VPD), ΦNO, ΦPSII, and ΦNPQ while photosynthesis remains active. Height above ground level was measured with a tape extending to the ground to determine the height of each sampled leaf.
Files and variables
File: Ziccardi_et_al_2025_data_NP.csv
Variables Description
- Height: Height above ground level (m)
- scientific: Scientific name
- Season: Studied seasons (wet / dry)
- Light.Intensity..PAR.: Photosynthetically active radiation (µmol m-2 s-1)
- VPD: Vapor pressure deficit (kPa)
- Phi2: Yield of PSII photochemistry (ΦPSII)
- PhiNPQ: Yield for dissipation through downregulation (ΦNPQ)
- PhiNO: Yield of other non-photochemical losses (ΦNO)
- qL_0: Fraction of open PSII centers based on the "lake" model
- NPQt_0: Non-photochemical quenching
Code/software
The data can be freely accessed using python and R.
The research was conducted at the Tapajós National Forest (TNF) site, located near km 67 (K67, 02°51′S, 54°58′W) of the Santarém-Cuiabá highway, south of the city of Santarém (Pará, Brazil). It is an evergreen tropical forest on a well-drained infertile oxisol plateau, with a mean canopy height of approximately 40 to 45 m and a sub-dominant layer ranging from 15 to 30 m (with a mean of 28 m) (Hutyra et al., 2007; Hunter et al., 2015).
Individual leaf-level sampling approach employed advanced tree climbing techniques to access different canopy levels and measure in situ leaf-chlorophyll fluorescence with the MultispeQ.