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Tree4flux Forecasting future forest dynamics by exploring climate-growth relationships in the Biosphere Reserve of Yangambi in the Democratic Republic of the Congo
Get PDFTropical forests hold a crucial role in the global carbon cycle. Despite their potential role in mitigating the evolution of the Earth system, they are threatened by climate change. In this context, assessing the carbon balance and the underlying phenomena is a key element in understanding and optimizing the management of tropical forests. At the forest scale, the carbon balance is commonly defined by fluxes, i.e., net primary productivity and respiration, exchanged between three main reservoirs: canopy, stems, and roots. The TREE4FLUX project aims to fill the gapsleft on these subjects for the first time in the forests of Congo Basin forests, by focusing research around the CongoFlux tower in the Yangambi Biosphere Reserve (DRC). The flux tower provides continuous measurements of greenhouse gas fluxes, such as CO2, using the Eddy Covariance approach. On-the-ground approaches through a network of multiple permanent inventory plots help define the processes underlying these fluxes. The combination of these strategies is promising to refine CO2 exchanges between vegetation and the atmosphere. This is essential because expected rising dry periods and temperatures are likely to alter forest dynamics by modifying growth patterns, and mortality risks. More specifically, wood formation, which is actively controlled by different climatic drivers, plays a significant role in carbon uptake by tree growth. But climate-growth relations remain elusive. Pursuing the characterization of forest dynamic components is therefore mandatory to better understand the ongoing changes
Questioning the Reliability of Methane Detections on Mars by the Curiosity Rover
Get PDFOver the past decade, the Tunable Laser Spectrometer (TLS) on NASA's Curiosity rover has reported several detections of methane on Mars, attracting attention due to the potential astrobiological implications of its presence. Here, we re-analyze published TLS data, identifying issues in data robustness and reduction. We find that the TLS foreoptics chamber typically contained methane abundances that were 3–4 orders of magnitude greater than those reported in the sample cell, alongside unexpected and rapidly varying pressure changes inside the instrument. Using information from unreported experiments where methane diffusion into the cell was observed, we estimate a gas transport coefficient and develop a model to simulate gas exchanges between the two compartments in typical experiments, investigating the implications for methane measurements. We find that tiny leaks (<0.1\% of foreoptics methane) would suffice to explain the reported atmospheric methane measurements—leaks that are otherwise undetectable from housekeeping data. Furthermore, in an analysis of five experiments where more complete data are available, we find that the TLS retrieval method—which averages discrepant methane levels from the three lines of the R3 triplet as if the three lines were independent, rather than fitting the spectrum to the distinctive pattern of the triplet itself—likely underestimates uncertainties. The probability that three methane levels from individual triplet lines are disparate in all five experiments is typically ∼10−3, suggesting the presence of systematic errors that are unaccounted for in previously reported methane levels. Finally, we propose a constructive two-step experiment to further investigate our findings
Technical Expertise Report ref. exp-135, 11/2015 - Applicant: Marc Leo Felix, [email protected], 9/10/2015
No full textDecades of ground-based climate monitoring reveal evidence of climate change in the Congo Basin
Get PDFThis multi-decadal study published in Climatic Change in October 2023 (https://link.springer.com/article/10.1007/ s10584-023-03606-0) presents the results of analyses of a unique set of digitised daily temperature and precipitation data from the Yangambi Biosphere Reserve, part of the UNESCO MAB network, covering the period 1960- 2020 (61 years) and located in the heart of the Congo Basin, where ground-based data are not available for the last two decades (with a decline rate of ± 40%). To extend our results to the Congo Basin, we compared ground-based climate observations at Yangambi with monthly temperature and precipitation data generated by satellites. Our results indicate a marked shift in rainfall patterns towards a more seasonal climate, with longer dry seasons and shorter but more intense rainy seasons. The change in precipitation patterns is accompanied by a strong warming trend, with a rapid increase in the frequency of hot days and nights and a decrease in the frequency of cool days and nights. This shift towards a warmer, more seasonal climate could have major consequences for life in general (agriculture, agroforestry, water resources, health, etc.) and for the composition and functioning of Congo Basin forests in particular. Our results corroborate the long-term increase in temperature and temperature extremes (since at least 1960) recently reported across Central Africa, and confirm a significant trend towards a drier dry season and an intensification of the rainy season since the early 2000s. Our results have scientific and policy implications. Climate monitoring networks in Congo Basin countries are becoming increasingly weak as they lack stable long-term funding. There is also a need for a broader policy on access to reliable climate data to monitor, among other things, the evolution of climate variability and climate change, and probably their local and regional societal impacts. In particular, there is an urgent need for effective and coherent funding of climate research in Congo Basin countries to improve real-time monitoring of climate change at national and regional levels, with a view to improving policies and strategies for the sustainable management of forests and other strategic natural resources at national and regional levels. The results of climate science will enable policy makers and all actors in multi-sectoral development to better address questions related to adaptation and mitigation strategies for each sector of life in the face of climate change impacts. We therefore argue that this article provides important new information in the Congo Basin on (i) the importance of digitising archives and continuing to monitor ground-based climate observations, (ii) the modelling of drought and humidity based on meteorological indices, (iii) confirmation of the ongoing shift towards a warmer and more seasonal climate, (iv) the dynamics of climate change and climate variability and their impact on populations and natural resources at local, regional and continental levels, and (v) strengthening and improving international, regional and national negotiation strategies on climate economics. This information is likely to be of interest to a wide audience in the field of climate change and sustainable development
Global invasion history with climate-related allele frequency shifts in the invasive Mediterranean fruit fly (Diptera, Tephritidae: <i>Ceratitis capitata</i>)
No full textA first predictive characterization of the microbial metabolic functions of <i>Dacus vertebratus </i>(Diptera, Tephritidae)
No full textMag je dat zomaar tentoonstellen?
No full textPresentation on the enclosed garden at KMSKA (Royal Museum of Fine Arts Antwerp), seen through the eyes of the museum guide and visitors
