Nature-based solutions are gaining momentum as approaches to address major environmental challenges, including markets for soil carbon (C) sequestration for mitigating climate change. This special collection of papers, stemming from a symposium of the 2021 Fall Meeting of the American Geophysical Union, poses several tough questions about the practical potential for significant C sequestration resulting

Countries and companies with net-zero emissions targets are considering carbon removal strategies to compensate for remaining greenhouse gas emissions. Soil carbon sequestration is one such carbon removal strategy, and policy and corporate interest is growing in figuring out how to motivate farmers to sequester more carbon. But how do farmers in various cultural and geographic contexts view soil carbon

This review suggests that most of the management practices associated with regenerative agriculture are not likely to lead to a large net sequestration of organic carbon in soils. Some improved management practices, such as increased fertilizer use, manuring, and applications of biochar, are constrained by biogeochemical stoichiometry and the availability of organic inputs. Other management practices

Calcitic valves of non-marine ostracodes are important geochemical archives. Investigations of the relationship between the ranges of oxygen and carbon isotope values of modern ostracode populations and their host water provide important information on local or regional conditions and influences. Here we present the first δ18Oostracode and δ13C of the freshwater ostracode species Cytheridella ilosvayi

With climate change, streams and rivers are at increased risk of droughts and flow intermittency. The full implications of these conditions for fluvial carbon (C) processing and stream-atmosphere CO2 emissions are not well understood. We performed a controlled drought experiment in outdoor hyporheic flumes. We simulated small rain events that increase sediment moisture content, but do not cause streamflow

The structure of the phytoplankton community is strongly influenced by environmental variables linked with variations in sea–air CO2 net fluxes (FCO2). However, compared to physical parameters, the relationship between phytoplankton and CO2 dynamics has been largely unexplored. The complex interplay between CO2 uptake by the coastal ocean and the dominance of different phytoplankton groups was investigated

Lakes and ponds play a disproportionate role in retaining sediment, carbon, nitrogen, and phosphorus, potentially mitigating negative environmental effects. However, how sequestration rates change over a pond’s lifetime, and how rates are affected by watershed land use practices remains poorly characterized. In this study, we quantified sediment, carbon, nitrogen, and phosphorus burial rates, and the

Dissolved organic matter (DOM) plays a fundamental role in nutrient cycling dynamics in riverine systems. Recent research has confirmed that the concentration of riverine DOM is not the only factor regulating its functional significance; the need to define the chemical composition of DOM is a priority. Past studies of riverine DOM rested on bulk quantification, however technological advancements have

Thermokarst (thaw) lakes of the Western Siberian Lowland (WSL), the World´s largest permafrost peatland, contain important but poorly constrained stocks of organic carbon (OC) and nitrogen. These lakes are highly vulnerable to climate warming and permafrost thaw. The present work aims to quantify the OC and total nitrogen (TN) stocks and accumulation rates in sediments of 11 thermokarst lakes in the

Soil nitrous oxide (N2O) is an important greenhouse gas contributing to climate change. Many processes produce N2O in soil and the production rate of each process is affected by climatic-edaphic factors, making the soil-to-atmosphere N2O flux extremely dynamic. Experimental approaches, including natural and enriched isotopic methods, have been developed to separate and quantify the N2O production from

To investigate how source and processing control the composition of “terrestrial” dissolved organic matter (DOM), we combine soil and tree leachates, tree DOM, laboratory bioincubations, and ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry in three common landscape types (upland forest, forested wetland, and poor fen) of Southeast Alaska’s temperate rainforest. Tree