Wildfires offset the increasing but spatially heterogeneous Arctic–boreal CO₂ uptake

The Arctic–Boreal Zone is rapidly warming, impacting its large soil carbon stocks. Here we use a new compilation of terrestrial ecosystem CO2 fluxes, geospatial datasets and random forest models to show that although the Arctic–Boreal Zone was overall an increasing terrestrial CO2 sink from 2001 to 2020 (mean ± standard deviation in net ecosystem exchange, −548 ± 140 Tg C yr−1; trend, −14 Tg C yr−1; P &lt; 0.001), more than 30% of the region was a net CO2 source. Tundra regions may have already started to function on average as CO2 sources, demonstrating a shift in carbon dynamics. When fire emissions are factored in, the increasing Arctic–Boreal Zone sink is no longer statistically significant (budget, −319 ± 140 Tg C yr−1; trend, −9 Tg C yr−1), and the permafrost region becomes CO2 neutral (budget, −24 ± 123 Tg C yr−1; trend, −3 Tg C yr−1), underscoring the importance of fire in this region.</p

Decadal increases in carbon uptake offset by respiratory losses across northern permafrost ecosystems

Tundra and boreal ecosystems encompass the northern circumpolar permafrost region and are experiencing rapid environmental change with important implications for the global carbon (C) budget. We analysed multi-decadal time series containing 302 annual estimates of carbon dioxide (CO2) flux across 70 permafrost and non-permafrost ecosystems, and 672 estimates of summer CO2 flux across 181 ecosystems. We find an increase in the annual CO2 sink across non-permafrost ecosystems but not permafrost ecosystems, despite similar increases in summer uptake. Thus, recent non-growing-season CO2 losses have substantially impacted the CO2 balance of permafrost ecosystems. Furthermore, analysis of interannual variability reveals warmer summers amplify the C cycle (increase productivity and respiration) at putatively nitrogen-limited sites and at sites less reliant on summer precipitation for water use. Our findings suggest that water and nutrient availability will be important predictors of the C-cycle response of these ecosystems to future warming

Practical Guide for Underwater Photogrammetric Reconstruction Version 1.0

Disclaimer: This is a resource for Underwater Photogrammetric 3D Reconstruction using Agisoft Metashape. It contains best practice and problem-solving strategies for photogrammetric reconstruction with Agisoft Metashape (version 1.7.4) for the underwater AUV/ROV use case. This is not a replacement of the user manual (https://www.agisoft.com/downloads/user-manuals/) as it is neither exhaustive nor does it aim to be

Striking the Air: Early Modern Parisian Sound Worlds

The sounds of early modern Paris are first explored through poetic and satirical depictions of urban noise, with emphasis placed on the disruption that they present. The attempt by Louis XIV to assert his absolute power becomes manifest in the means employed to control and contain those sounds deemed to be potentially subversive and seditious, especially in the threat posed by performers of songs on the Pont-Neuf, which was one of the few public spaces where people of all classes rubbed shoulders. The example of the blind singer Philippot le Savoyard shows how the Pont-Neuf became the prime locus of difference and marginality