the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Multi-scale dynamics of carbon dioxide flux and its environmental drivers in the Pantanal wetland
Abstract. Understanding carbon flux dynamics in tropical ecosystems is crucial for evaluating their role in global climate regulation. This study investigates the temporal variability of the net ecosystem exchange (NEE) of CO2 and its interactions with key meteorological variables in a tropical forest ecosystem of the Pantanal, Brazil. Using high-resolution hourly data from a flux tower, we apply Detrended Fluctuation Analysis (DFA) and Detrended Cross-Correlation Analysis (DCCA) to analyze diurnal to seasonal cycles of NEE, latent heat (LE), sensible heat (H), global radiation (Rg), air and soil temperature (Tair and Tsoil), relative humidity (rH), and vapor pressure deficit (VPD). The results reveal a strong diurnal coupling between solar radiation, temperature, and carbon fluxes, with peak CO2 uptake occurring at midday. A key novel finding is a marked shift to strong anti-persistence in NEE at the weekly scale during the dry season, a pattern supported by concurrent reductions in LE and rH and increases in H and VPD. This highlights that water limitation is a critical driver of carbon release and reveals a previously unidentified regulatory mechanism in the ecosystem's carbon cycle. These findings underscore the sensitivity of carbon dynamics to hydrometeorological conditions and underline the necessity of multi-scale analysis. Uncertainties remain regarding the role of extreme droughts and floods, as well as land-use dynamics, which merit further investigation.
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Status: open (until 11 Nov 2025)
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RC1: 'Comment on egusphere-2025-4102', Anonymous Referee #2, 28 Oct 2025
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CC1: 'Reply on RC1', Gilney Zebende, 29 Oct 2025
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We appreciate the reviewer's comments.
We agree with your comments, and yes, we will look at Table 5 and what is written on lines 357 and 356.
In the final version, a map (illustration) of the location will be added to the paper.
Citation: https://doi.org/10.5194/egusphere-2025-4102-CC1
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CC1: 'Reply on RC1', Gilney Zebende, 29 Oct 2025
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Data sets
Climate dataset of Brazilian pantanal wetland Paulo H. Z. de Arruda https://doi.org/10.5281/zenodo.17230250
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This manuscript presents a rigorous analysis of the multi-scale dynamics of net ecosystem exchange (NEE) and its environmental drivers in the Pantanal, a region undergoing significant anthropogenic pressures from deforestation, agriculture, and the broader impacts of climate change. By leveraging high temporal resolution data, the authors quantitatively explore the interactions between carbon fluxes and environmental variables, contributing valuable insights to ongoing efforts in climate–ecosystem modelling.
The methodological framework is sound and well justified. The authors employ Detrended Cross-Correlation Analysis (DCCA) to investigate the scale-dependent relationships between NEE and key climatic drivers. This approach has been widely used and validated in various contexts, and its application here is both appropriate and effective. The paper is clearly structured, with coherent progression from methods to results and a balanced, thoughtful interpretation. The quality of writing is excellent—precise, fluent, and engaging—making this an enjoyable and informative read. The attention to detail throughout is commendable.
Detrended Cross-Correlation Analysis (DCCA) Findings
The DCCA results reveal a nuanced picture of carbon–climate interactions across temporal scales:
Conclusions on Carbon Flux–Climate Interactions
The study compellingly demonstrates that carbon flux–climate relationships in the Pantanal are strongly scale-dependent.
Overall Assessment
This is a well-executed and insightful study that enhances our understanding of carbon–climate coupling in floodplain ecosystems. The analytical approach is robust, the interpretations are well grounded in the data, and the broader implications are clearly articulated. The findings also open avenues for comparative analyses in drier and semi-arid ecosystems, where water-use efficiency and carbon–water coupling dynamics are more pronounced. Such extensions would be valuable for testing the generality of the patterns identified here.
In conclusion, this manuscript makes a substantial and well-argued contribution to ecosystem and climate science. I commend the authors for their meticulous work and recommend the paper for publication with only minor revisions:
Line 370 – revisit this section as these details have already been provided in lines 357 and 356
It would be great to include a map of the site, and a picture of the site set up as an insert – preferably.