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5. Practical Guide to Measuring Wetland Carbon Pools and Fluxes.

Author

Banerjee, Kakoli, Bastviken, David, Berg, Peter, Bogard, Matthew, Chow, Alex, Conner, William, Craft, Christopher, Creamer, Courtney, DelSontro, Tonya, Duberstein, Jamie, Eagle, Meagan, Fennessy, M, Finkelstein, Sarah, Göckede, Mathias, Grunwald, Sabine, Halabisky, Meghan, Herbert, Ellen, Jahangir, Mohammad, Johnson, Olivia, Jones, Miriam, Kelleway, Jeffrey, Knox, Sara, Kroeger, Kevin, Kuehn, Kevin, Lobb, David, Loder, Amanda, Ma, Shizhou, Maher, Damien, McNicol, Gavin, Meier, Jacob, Middleton, Beth, Mills, Christopher, Mistry, Purbasha, Mitra, Abhijit, Mobilian, Courtney, Nahlik, Amanda, Newman, Sue, OConnell, Jessica, Oikawa, Patty, van der Burg, Max, Schutte, Charles, Song, Changchun, Stagg, Camille, Turner, Jessica, Vargas, Rodrigo, Waldrop, Mark, Wallin, Marcus, Wang, Zhaohui, Ward, Eric, Willard, Debra, Yarwood, Stephanie, Zhu, Xiaoyan, Bansal, Sheel, Creed, Irena, Tangen, Brian, Bridgham, Scott, Desai, Ankur, Krauss, Ken, Neubauer, Scott, Noe, Gregory, Rosenberry, Donald, Trettin, Carl, Wickland, Kimberly, Allen, Scott, Arias-Ortiz, Ariane, Armitage, Anna, and Baldocchi, Dennis

Subjects
Accretion, Accumulation, Biomass, Bulk density, Carbon cycling, Chambers, Core, Decomposition, Dissolved gas, Dissolved organic carbon, Eddy covariance, Greenhouse gas, Groundwater, Hydrology, Incubation, Lateral transport, Litter, Methane, Methods, Microbes, Models, Net primary productivity, Plants, Porewater, Radiometric dating, Remote sensing, Sediment, Soil organic carbon, Vegetation, Water
Abstract

UNLABELLED: Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fluxes. However, the underlying biogeochemical processes that affect wetland C pools and fluxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational, experimental, and analytical approaches have been developed to understand and quantify pools and fluxes of wetland C. Sampling approaches range in their representation of wetland C from short to long timeframes and local to landscape spatial scales. This review summarizes common and cutting-edge methodological approaches for quantifying wetland C pools and fluxes. We first define each of the major C pools and fluxes and provide rationale for their importance to wetland C dynamics. For each approach, we clarify what component of wetland C is measured and its spatial and temporal representativeness and constraints. We describe practical considerations for each approach, such as where and when an approach is typically used, who can conduct the measurements (expertise, training requirements), and how approaches are conducted, including considerations on equipment complexity and costs. Finally, we review key covariates and ancillary measurements that enhance the interpretation of findings and facilitate model development. The protocols that we describe to measure soil, water, vegetation, and gases are also relevant for related disciplines such as ecology. Improved quality and consistency of data collection and reporting across studies will help reduce global uncertainties and develop management strategies to use wetlands as nature-based climate solutions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13157-023-01722-2.

Published
2023

13. Practical Guide to Measuring Wetland Carbon Pools and Fluxes

Author

Bansal, Sheel, Creed, Irena F., Tangen, Brian A., Bridgham, Scott D., Desai, Ankur R., Krauss, Ken W., Neubauer, Scott C., Noe, Gregory B., Rosenberry, Donald O., Trettin, Carl, Wickland, Kimberly P., Allen, Scott T., Arias-Ortiz, Ariane, Armitage, Anna R., Baldocchi, Dennis, Banerjee, Kakoli, Bastviken, David, Berg, Peter, Bogard, Matthew J., Chow, Alex T., Conner, William H., Craft, Christopher, Creamer, Courtney, DelSontro, Tonya, Duberstein, Jamie A., Eagle, Meagan, Fennessy, M. Siobhan, Finkelstein, Sarah A., Göckede, Mathias, Grunwald, Sabine, Halabisky, Meghan, Herbert, Ellen, Jahangir, Mohammad M. R., Johnson, Olivia F., Jones, Miriam C., Kelleway, Jeffrey J., Knox, Sara, Kroeger, Kevin D., Kuehn, Kevin A., Lobb, David, Loder, Amanda L., Ma, Shizhou, Maher, Damien T., McNicol, Gavin, Meier, Jacob, Middleton, Beth A., Mills, Christopher, Mistry, Purbasha, Mitra, Abhijit, Mobilian, Courtney, Nahlik, Amanda M., Newman, Sue, O’Connell, Jessica L., Oikawa, Patty, van der Burg, Max Post, Schutte, Charles A., Song, Changchun, Stagg, Camille L., Turner, Jessica, Vargas, Rodrigo, Waldrop, Mark P., Wallin, Marcus B., Wang, Zhaohui Aleck, Ward, Eric J., Willard, Debra A., Yarwood, Stephanie, and Zhu, Xiaoyan

Published
2023
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25. Global biogeography of fungal and bacterial biomass carbon in topsoil

Author

He, Liyuan, Rodrigues, Jorge L Mazza, Soudzilovskaia, Nadejda A, Barceló, Milagros, Olsson, Pål Axel, Song, Changchun, Tedersoo, Leho, Yuan, Fenghui, Yuan, Fengming, Lipson, David A, and Xu, Xiaofeng

Subjects
Environmental Sciences, Soil Sciences, Infection, Fungi, Bacteria, F:B ratio, Biogeography, Pattern, Biological Sciences, Agricultural and Veterinary Sciences, Agronomy & Agriculture, Soil sciences
Abstract

Bacteria and fungi, representing two major soil microorganism groups, play an important role in global nutrient biogeochemistry. Biogeographic patterns of bacterial and fungal biomass are of fundamental importance for mechanistically understanding nutrient cycling. We synthesized 1323 data points of phospholipid fatty acid-derived fungal biomass C (FBC), bacterial biomass C (BBC), and fungi:bacteria (F:B) ratio in topsoil, spanning 11 major biomes. The FBC, BBC, and F:B ratio display clear biogeographic patterns along latitude and environmental gradients including mean annual temperature, mean annual precipitation, net primary productivity, root C density, soil temperature, soil moisture, and edaphic factors. At the biome level, tundra has the highest FBC and BBC densities at 3684 (95% confidence interval: 1678–8084) mg kg−1 and 428 (237–774) mg kg−1, respectively; desert has the lowest FBC and BBC densities at 16.92 (14.4–19.89) mg kg−1 and 6.83 (6.1–7.65) mg kg−1, respectively. The F:B ratio varies dramatically, ranging from 1.8 (1.6–2.1) in savanna to 8.6 (6.7–11.0) in tundra. An empirical model was developed for the F:B ratio and it is combined with a global dataset of soil microbial biomass C to produce global maps for FBC and BBC in 0–30 cm topsoil. Across the globe, the highest FBC is found in boreal forest and tundra while the highest BBC is in boreal forest and tropical/subtropical forest, the lowest FBC and BBC are in shrub and desert. Global stocks of living microbial biomass C were estimated to be 12.6 (6.6–16.4) Pg C for FBC and 4.3 (0.5–10.3) Pg C for BBC in topsoil. These findings advance our understanding of the global distribution of fungal and bacterial biomass, which facilitates the incorporation of fungi and bacteria into Earth system models. The global maps of bacterial and fungal biomass serve as a benchmark for validating microbial models in simulating the global C cycle under a changing climate.

Published
2020

47. Alder expansion stimulates nitrogen oxide (NOx) emissions from southern Eurasian permafrost peatlands.

Author

Liu, Chunyan, Yue, Hongyu, Zhang, Wei, Yao, Zhisheng, Pan, Yuepeng, Wang, Xianwei, Song, Changchun, Butterbach‐Bahl, Klaus, and Dannenmann, Michael

Subjects
SOIL mineralogy, PERMAFROST, NITROGEN oxides, ALDER, RADIATIVE forcing
Abstract

Nitrogen oxides (NOx) play an important role for atmospheric chemistry and radiative forcing. However, NOx emissions from the vast northern circumpolar permafrost regions have not been studied in situ due to limitations of measurement techniques. Our goals were to validate the offline analytical technique, and based on this, to widely quantify in situ NOx emissions from peatlands in the southern Eurasian permafrost region. To this end, we conducted a comparison of online and offline flux measurements in 2018 and 2019 using the synthetic air flushing, steady‐state opaque chamber method. With differences in annual average and cumulative fluxes less than 0.1 μg N m−2 h−1 and 0.01 kg N ha−1 year−1, the online and offline fluxes were in good agreement, demonstrating the feasibility of conducting offline measurements in remote regions without power supply. The flux measurements over 2 years showed obvious NOx emissions of 0.05–0.14 and 0.13–0.30 kg N ha−1 year−1 in the hollow and hummock microtopography of permafrost peatlands, respectively. The rapid expansion of alder (Alnus sibirica) in the peatlands induced by permafrost degradation significantly increased soil mineral N contents and NOx emissions depending on the age of alder (0.64–1.74 and 1.44–2.20 kg N ha−1 year−1 from the alder forests with tree ages of 1–10 years and 11–20 years, respectively). Alder expansion also intensively altered the thermal state of permafrost including the sharp increases of soil temperatures during the non‐growing season from October to April and active layer thickness. This study provides the first in situ evidences of NOx emissions from the northern circumpolar permafrost regions and uncovers the well‐documented expansion of alders can substantially stimulate NOx emissions and thus, significantly affect air quality, radiative forcing, and ecosystem productivity in the pristine regions. [ABSTRACT FROM AUTHOR]

Published
2024
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49. Reviews and syntheses: Four decades of modeling methane cycling in terrestrial ecosystems

Author

Xu, Xiaofeng, Yuan, Fengming, Hanson, Paul J, Wullschleger, Stan D, Thornton, Peter E, Riley, William J, Song, Xia, Graham, David E, Song, Changchun, and Tian, Hanqin

Subjects
Earth Sciences, Physical Geography and Environmental Geoscience, Climate Action, Environmental Sciences, Biological Sciences, Meteorology & Atmospheric Sciences, Ecology, Physical geography and environmental geoscience, Environmental management
Abstract

Over the past 4 decades, a number of numerical models have been developed to quantify the magnitude, investigate the spatial and temporal variations, and understand the underlying mechanisms and environmental controls of methane (CH4) fluxes within terrestrial ecosystems. These CH4 models are also used for integrating multi-scale CH4 data, such as laboratory-based incubation and molecular analysis, field observational experiments, remote sensing, and aircraft-based measurements across a variety of terrestrial ecosystems. Here we summarize 40 terrestrial CH4 models to characterize their strengths and weaknesses and to suggest a roadmap for future model improvement and application. Our key findings are that (1) the focus of CH4 models has shifted from theoretical to site- and regional-level applications over the past 4 decades, (2) large discrepancies exist among models in terms of representing CH4 processes and their environmental controls, and (3) significant data-model and model-model mismatches are partially attributed to different representations of landscape characterization and inundation dynamics. Three areas for future improvements and applications of terrestrial CH4 models are that (1) CH4 models should more explicitly represent the mechanisms underlying land-atmosphere CH4 exchange, with an emphasis on improving and validating individual CH4 processes over depth and horizontal space, (2) models should be developed that are capable of simulating CH4 emissions across highly heterogeneous spatial and temporal scales, particularly hot moments and hotspots, and (3) efforts should be invested to develop model benchmarking frameworks that can easily be used for model improvement, evaluation, and integration with data from molecular to global scales. These improvements in CH4 models would be beneficial for the Earth system models and further simulation of climate-carbon cycle feedbacks.

Published
2016

50. Faster cycling but lower efficiency: A microbial metabolic perspective on carbon loss after wetland conversion to cropland

Author

Wang, Nannan, primary, Li, Kexin, additional, Yuan, Fenghui, additional, Zuo, Yunjiang, additional, Liu, Jianzhao, additional, Zhu, Xinhao, additional, Sun, Ying, additional, Guo, Ziyu, additional, Zhang, Lihua, additional, Gong, Chao, additional, Song, Yanyu, additional, Song, Changchun, additional, and Xu, Xiaofeng, additional

Published
2023
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