Sanderman
Jonathan
Sanderman
Jonathan
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ArticleSoil organic carbon development and turnover in natural and disturbed salt marsh environments(American Geophysical Union, 2020-12-11) Luk, Sheron Y. ; Todd‐Brown, Katherine ; Eagle, Meagan ; McNichol, Ann P. ; Sanderman, Jonathan ; Gosselin, Kelsey M. ; Spivak, Amanda C.Salt marsh survival with sea‐level rise (SLR) increasingly relies on soil organic carbon (SOC) accumulation and preservation. Using a novel combination of geochemical approaches, we characterized fine SOC (≤1 mm) supporting marsh elevation maintenance. Overlaying thermal reactivity, source (δ13C), and age (F14C) information demonstrates several processes contributing to soil development: marsh grass production, redeposition of eroded material, and microbial reworking. Redeposition of old carbon, likely from creekbanks, represented ∼9%–17% of shallow SOC (≤26 cm). Soils stored marsh grass‐derived compounds with a range of reactivities that were reworked over centuries‐to‐millennia. Decomposition decreases SOC thermal reactivity throughout the soil column while the decades‐long disturbance of ponding accelerated this shift in surface horizons. Empirically derived estimates of SOC turnover based on geochemical composition spanned a wide range (640–9,951 years) and have the potential to inform predictions of marsh ecosystem evolution.
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ArticleNatural climate solutions for the United States(American Association for the Advancement of Science, 2018-11-14) Fargione, Joseph E. ; Bassett, Steven ; Boucher, Timothy ; Bridgham, Scott D. ; Conant, Richard T. ; Cook-Patton, Susan C. ; Ellis, Peter W. ; Falcucci, Alessandra ; Fourqurean, James W. ; Gopalakrishna, Trisha ; Gu, Huan ; Henderson, Benjamin ; Hurteau, Matthew D. ; Kroeger, Kevin D. ; Kroeger, Timm ; Lark, Tyler J. ; Leavitt, Sara M. ; Lomax, Guy ; McDonald, Robert I. ; Megonigal, J. Patrick ; Miteva, Daniela A. ; Richardson, Curtis J. ; Sanderman, Jonathan ; Shoch, David ; Spawn, Seth A. ; Veldman, Joseph W. ; Williams, Christopher A. ; Woodbury, Peter B. ; Zganjar, Chris ; Baranski, Marci ; Elias, Patricia ; Houghton, Richard A. ; Landis, Emily ; McGlynn, Emily ; Schlesinger, William H. ; Siikamaki, Juha V. ; Sutton-Grier, Ariana E. ; Griscom, Bronson W.Limiting climate warming to <2°C requires increased mitigation efforts, including land stewardship, whose potential in the United States is poorly understood. We quantified the potential of natural climate solutions (NCS)—21 conservation, restoration, and improved land management interventions on natural and agricultural lands—to increase carbon storage and avoid greenhouse gas emissions in the United States. We found a maximum potential of 1.2 (0.9 to 1.6) Pg CO2e year−1, the equivalent of 21% of current net annual emissions of the United States. At current carbon market prices (USD 10 per Mg CO2e), 299 Tg CO2e year−1 could be achieved. NCS would also provide air and water filtration, flood control, soil health, wildlife habitat, and climate resilience benefits.
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ArticleDecreased soil organic matter in a long-term soil warming experiment lowers soil water holding capacity and affects soil thermal and hydrological buffering(American Geophysical Union, 2020-04-04) Werner, William J. ; Sanderman, Jonathan ; Melillo, Jerry M.Long‐term soil warming can decrease soil organic matter (SOM), resulting in self‐reinforcing feedback to the global climate system. We investigated additional consequences of SOM reduction for soil water holding capacity (WHC) and soil thermal and hydrological buffering. At a long‐term soil warming experiment in a temperate forest in the northeastern United States, we suspended the warming treatment for 104 days during the summer of 2017. The formerly heated plot remained warmer (+0.39 °C) and drier (−0.024 cm3 H2O cm−3 soil) than the control plot throughout the suspension. We measured decreased SOM content (−0.184 g SOM g−1 for O horizon soil, −0.010 g SOM g−1 for A horizon soil) and WHC (−0.82 g H2O g−1 for O horizon soil, −0.18 g H2O g−1 for A horizon soil) in the formerly heated plot relative to the control plot. Reduced SOM content accounted for 62% of the WHC reduction in the O horizon and 22% in the A horizon. We investigated differences in SOM composition as a possible explanation for the remaining reductions with Fourier transform infrared (FTIR) spectra. We found FTIR spectra that correlated more strongly with WHC than SOM, but those particular spectra did not differ between the heated and control plots, suggesting that SOM composition affects WHC but does not explain treatment differences in this study. We conclude that SOM reductions due to soil warming can reduce WHC and hydrological and thermal buffering, further warming soil and decreasing SOM. This feedback may operate in parallel, and perhaps synergistically, with carbon cycle feedbacks to climate change.
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ArticlePeat decomposition and erosion contribute to pond deepening in a temperate salt marsh(American Geophysical Union, 2023-01-30) Luk, Sheron ; Eagle, Meagan J. ; Mariotti, Giulio ; Gosselin, Kelsey ; Sanderman, Jonathan ; Spivak, Amanda C.Salt marsh ponds expand and deepen over time, potentially reducing ecosystem carbon storage and resilience. The water filled volumes of ponds represent missing carbon due to prevented soil accumulation and removal by erosion and decomposition. Removal mechanisms have different implications as eroded carbon can be redistributed while decomposition results in loss. We constrained ponding effects on carbon dynamics in a New England marsh and determined whether expansion and deepening impact nearby soils by conducting geochemical characterizations of cores from three ponds and surrounding high marshes and models of wind‐driven erosion. Radioisotope profiles demonstrate that ponds are not depositional environments and that contemporaneous marsh accretion represents prevented accumulation accounting for 32%–42% of the missing carbon. Erosion accounted for 0%–38% and was bracketed using radioisotope inventories and wind‐driven resuspension models. Decomposition, calculated by difference, removes 22%–68%, and when normalized over pond lifespans, produces rates that agree with previous metabolism measurements. Pond surface soils contain new contributions from submerged primary producers and evidence of microbial alteration of underlying peat, as higher levels of detrital biomarkers and thermal stability indices, compared to the marsh. Below pond surface horizons, soil properties and organic matter composition were similar to the marsh, indicating that ponding effects are shallow. Soil bulk density, elemental content, and accretion rates were similar between marsh sites but different from ponds, suggesting that lateral effects are spatially confined. Consequently, ponds negatively impact ecosystem carbon storage but at current densities are not causing pervasive degradation of marshes in this system.
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Working PaperRobust carbon monitoring, reporting, and verification for grassland management in the Great Plains(Woods Hole Oceanographic Institution, 2025-02-10) Xia, Yushu ; Sanderman, Jonathan ; Watts, Jennifer D. ; Carr, Craig ; Ewing, Stephanie A. ; Parisien, Alexandra ; Burdett, Christopher ; Hogrefe, Todd ; Lamoreux, John ; Bamford, HollyIn recent years, the National Fish and Wildlife Foundation (NFWF) has invested heavily in improving grazing management across the United States, with particular emphasis on the Great Plains (Figure EX1). This work advances the goals of many partners (government, business and nonprofit) who share interests in the conservation of grasslands through management and restoration actions that sequester carbon (C) and reduce atmospheric greenhouse gases (GHG). Alongside wildlife benefits, NFWF and many other organizations currently estimate the GHG benefits of improved grazing management using simplistic emission factor-based methods; however, our collective confidence in those estimates has been constrained by the short duration and limited sampling (number of samples, spatial extent, controls) of previous studies.