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1. A life cycle and product type based estimator for quantifying the carbon stored in wood products

   https://doi.org/10.1186/s13021-022-00220-y  

   Wei, Xinyuan; Zhao, Jianheng; Hayes, Daniel J; Daigneault, Adam; Zhu, He (December 2023, Carbon Balance and Management)

   Abstract BackgroundTimber harvesting and industrial wood processing laterally transfer the carbon stored in forest sectors to wood products creating a wood products carbon pool. The carbon stored in wood products is allocated to end-use wood products (e.g., paper, furniture), landfill, and charcoal. Wood products can store substantial amounts of carbon and contribute to the mitigation of greenhouse effects. Therefore, accurate accounts for the size of wood products carbon pools for different regions are essential to estimating the land-atmosphere carbon exchange by using the bottom-up approach of carbon stock change. ResultsTo quantify the carbon stored in wood products, we developed a state-of-the-art estimator (Wood Products Carbon Storage Estimator, WPsCS Estimator) that includes the wood products disposal, recycling, and waste wood decomposition processes. The wood products carbon pool in this estimator has three subpools: (1) end-use wood products, (2) landfill, and (3) charcoal carbon. In addition, it has a user-friendly interface, which can be used to easily parameterize and calibrate an estimation. To evaluate its performance, we applied this estimator to account for the carbon stored in wood products made from the timber harvested in Maine, USA, and the carbon storage of wood products consumed in the United States. ConclusionThe WPsCS Estimator can efficiently and easily quantify the carbon stored in harvested wood products for a given region over a specific period, which was demonstrated with two illustrative examples. In addition, WPsCS Estimator has a user-friendly interface, and all parameters can be easily modified. 

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2. Recent Advances and Challenges in Monitoring and Modeling Non-Growing Season Carbon Dioxide Fluxes from the Arctic Boreal Zone

   https://doi.org/10.1007/s40641-023-00190-4  

   Arndt, Kyle A.; Hashemi, Josh; Natali, Susan M.; Schiferl, Luke D.; Virkkala, Anna-Maria (October 2023, Current Climate Change Reports)

   Abstract Purpose of ReviewWhile previously thought to be negligible, carbon emissions during the non-growing season (NGS) can be a substantial part of the annual carbon budget in the Arctic boreal zone (ABZ), which can shift the carbon balance of these ecosystems from a long-held annual carbon sink towards a net annual carbon source. The purpose of this review is to summarize NGS carbon dioxide (CO₂) flux research in the ABZ that has been published within the past 5 years. Recent FindingsWe explore the processes and magnitudes of CO₂fluxes, and the status of modeling efforts, and evaluate future directions. With technological advances, direct measurements of NGS fluxes are increasing at sites across the ABZ over the past decade, showing ecosystems in the ABZ are a large source of CO₂in the shoulder seasons, with low, consistent, winter emissions. SummaryEcosystem carbon cycling models are being improved with some challenges, such as modeling below ground and snow processes, which are critical to understanding NGS CO₂fluxes. A lack of representative in situ carbon flux data and gridded environmental data are leading limiting factors preventing more accurate predictions of NGS carbon fluxes. 

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3. Inorganic Carbon-Limited Freshwater Algal Growth at High pH: Revisited with Focus on Alkalinity

   https://doi.org/10.13031/ja.15411  

   Watson, Mary Katherine; Flanagan, Elizabeth; Drapcho, Caye M. (January 2023, Journal of the ASABE)

   Highlights Non-carbonate components of BG11 media impact TIC calculation on average 4.00 mg/L at high pH. BG11 media non-carbonate alkalinity (NCA) varies with pH: NCA (meq/L) = 0.0393×e^0.2075×pH+ (2.086×10^-9)e^1.860×pH.Monod kinetic constants with CO₂, HCO₃^-, and CO₃^2-as inorganic carbon sources are improved from a previous report.Kinetic constants continue to be the only known reports considering multiple inorganic carbon sources.Algal stoichiometric reactions are developed that account for variation in cell content and carbon source. Abstract.Due to increasing atmospheric CO2, algal growth systems at high pH are of interest to support enhanced diffusion and carbon capture. Given the interactions between algal growth, pH, and alkalinity, data from Watson and Drapcho (2016) were re-examined to determine the impact of the non-carbonate constituents in BG11 media on estimates of Monod kinetic parameters, biomass yield, and cell stoichiometry. Based on a computational method, non-carbonate alkalinity (NCA) in BG11 media varies with pH according to: NCA (meq/L) = 0.0393×e0.2075×pH + (2.086×10-9)e1.860×pH (R2 = 0.999) over the pH range of 10.3 – 11.5. Updated maximum specific growth rates were determined to be 0.060, 0.057, and 0.051 hr-1 for CO2, HCO3, and CO3, respectively. Generalizable stoichiometric algal growth equations that consider variable nutrient ratios and multiple inorganic carbon species were developed. Improved kinetic and stoichiometric parameters will serve as the foundation for a dynamic mathematical model to support the design of high pH algal carbon capture systems. Keywords: Algae, Alkalinity, Carbon Abatement, Carbon Capture, Kinetics, Stoichiometry, Total Inorganic Carbon. 

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4. Soil nutrients cause threefold increase in pathogen and herbivore impacts on grassland plant biomass

   https://doi.org/10.1111/1365-2745.14111  

   Zaret, Max; Kinkel, Linda; Borer, Elizabeth T.; Seabloom, Eric W. (August 2023, Journal of Ecology)

   Abstract A combination of theory and experiments predicts that increasing soil nutrients will modify herbivore and microbial impacts on ecosystem carbon cycling.However, few studies of herbivores and soil nutrients have measured both ecosystem carbon fluxes and carbon pools. Even more rare are studies manipulating microbes and nutrients that look at ecosystem carbon cycling responses.We added nutrients to a long‐term, experiment manipulating foliar fungi, soil fungi, mammalian herbivores and arthropods in a low fertility grassland. We measured gross primary production (GPP), ecosystem respiration (ER), net ecosystem exchange (NEE) and plant biomass throughout the growing season to determine how nutrients modify consumer impacts on ecosystem carbon cycling.Nutrient addition increased above‐ground biomass and GPP, but not ER, resulting in an increase in ecosystem carbon uptake rate. Reducing foliar fungi and arthropods increased plant biomass. Nutrients amplified consumer effects on plant biomass, such that arthropods and foliar fungi had a threefold larger impact on above‐ground biomass in fertilized plots.Synthesis. Our work demonstrates that throughout the growing season soil resources modify carbon uptake rates as well as animal and fungal impacts on plant biomass production. Taken together, ongoing nutrient pollution may increase ecosystem carbon uptake and drive fungi and herbivores to have larger impacts on plant biomass production. 

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5. Experimental warming and drying increase older carbon contributions to soil respiration in lowland tropical forests

   https://doi.org/10.1038/s41467-024-51422-6  

   McFarlane, Karis J; Cusack, Daniela F; Dietterich, Lee H; Hedgpeth, Alexandra L; Finstad, Kari M; Nottingham, Andrew T (December 2024, Nature Communications)

   Abstract Tropical forests account for over 50% of the global terrestrial carbon sink, but climate change threatens to alter the carbon balance of these ecosystems. We show that warming and drying of tropical forest soils may increase soil carbon vulnerability, by increasing degradation of older carbon. In situ whole-profile heating by 4 °C and 50% throughfall exclusion each increased the average radiocarbon age of soil CO₂efflux by ~2–3 years, but the mechanisms underlying this shift differed. Warming accelerated decomposition of older carbon as increased CO₂emissions depleted newer carbon. Drying suppressed decomposition of newer carbon inputs and decreased soil CO₂emissions, thereby increasing contributions of older carbon to CO₂efflux. These findings imply that both warming and drying, by accelerating the loss of older soil carbon or reducing the incorporation of fresh carbon inputs, will exacerbate soil carbon losses and negatively impact carbon storage in tropical forests under climate change. 

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