The seasonality of biotic and abiotic processes controls the turnover of organic matter in wetlands

Authors Chiara Pasut1,2, Fiona H. M. Tang3,6, Budiman Minasny4, Charles R. Warren4, Feike A. Dijkstra4, William J. Riley5, Federico Maggi1,4 1 Environmental Engineering, School of Civil Engineering, The University of Sydney, Bld. J05, 2006 Sydney, NSW, Australia. 2CSIRO Agriculture &amp; Food, Kaurna Country, Gate 4 Waite Road, Urrbrae, SA 5064, Australia. 3 Department of Crop Production Ecology, Swedish University of Agricultural Sciences (SLU), Ulls väg 16, Box 7043, 750 07 Uppsala, Sweden. 4 Sydney Institute of Agriculture, School of Life and Environmental Sciences, The University of Sydney, New South Wales, Australia. 5 Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. 6 School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia <strong>Contact</strong> Chiara Pasut ([e-mail]), <strong>Background</strong> We described the soil organic carbon cycle SOC using The BAMS4 (Biotic and Abiotic Model for SOM-version 4), which includes five organic C pools: PolyC represents lignin, cellulose, and hemicellulose organic polymers; PolyCN represents peptidoglycan; MonoC, MonoCN, and MonoCS are three low molecular weight organic monomers containing C, C and N, and C and S, respectively, representing monosaccharides, fatty acids, organic acids, phenols, amino acid, amino sugar, and nucleotides resulting from root exudates and depolymerization of PolyC and PolyCN, which contain C, and C and N, respectively. The model included two C pools representing CH4 and CO2. Four microbial functional groups control the SOC cycle: fungi <em>FDEP</em> are responsible for depolymerisation of PolyC; heterotrophs <em>BAER</em> are responsible for aerobic respiration on MonoC, MonoCN, MonoCS, and PolyCN; methanogens <em>BMGB</em> are responsible for anaerobic respiration on MonoC; and methanotrophs <em>BMOB</em> are responsible for CH4 oxidation. The C cycle was coupled with the N and S cycles to account for the feedback introduced by e- donors and acceptors on the biotic response of each elemental cycle (Figure 1). Specific to the N cycle, we accounted for atmospheric N2 fixation, NH4+ nitrification by ammonia oxidizers <em>BAOB</em> and nitrite oxidizers <em>BNOB</em>, and NO2- and NO3- denitrification mediated by denitrifiers <em>BDEN</em>. For S, we accounted for reduction, disproportionation, and oxidation reactions mediated by sulphur S reducers <em>BSrRB</em>, thiosulfate and sulfite (S2O32-, SO32-) reducers <em>BThSRB</em>, sulfate SO42- reducers <em>BSRB</em>, S2O32- and SO32- disproportioning microbes <em>BSDB</em>, and photolithoautotroph oxidizers <em>BSOB</em>. Each of the organic and inorganic C, N, and S pools can be in the aqueous and gaseous phases, or minerally-associated, that is, protected from biological action. All the biochemical reactions and corresponding parameters are presented in Supplementary Information in Pasut et al., 2021. Table 1 summarizes the pool aggregation used in this work, and each flux from and to each pool. <br> <strong>Contents</strong> We distribute the turnover time and carbon fluxes of global freshwater wetlands. The computational domain covers an average wetland surface area of 3.8 Mkm2 (ranging between 1.2 and 11.4 Mkm2 from 2000 to 2017) described by about 45,000 grid cells at a grid resolution of 0.5 degree (about 50 km at the equator). Grid cells covered by wetlands for at least 2% of the total grid cell area were selected from the SWAMPS v3.2 wetlands database (Poulter et al., 2017), which reported the monthly flooded land area from 2000 to 2017 based on active and passive microwave satellite images excluding lakes, reservoirs, rivers, and saline environments. Each selected grid cell is represented by 2 m atmospheric column that includes four atmospheric layers necessary for heat and gas exchanges, and water flooding (30, 30, 40, and 100 cm thick from land surface upward), one layer of the topsoil (0 to 30 cm), two layers of subsoil (30 to 100 cm), and one layer below the root zone (100 cm thick). Each grid cell is characterized by a depth-specific soil bulk density, porosity, and textural soil fractions (Poggio et al., 2021), hydraulic and thermal conductivity, heat capacity, air-entry potential, and pore volume distribution index (Dai et al., 2013). Table 1 summarizes the data released in this version and the corresponding variables. <br> <strong>Resources</strong> BAMS4 was integrated in a general-purpose multiphase and multi-species bioreactive transport simulator, BRTSim-v5.0b solver. The BRTSim-v5.0b solver package can be downloaded at https://sites.google.com/site/thebrtsimproject/home or from the mirror https://www.dropbox.com/sh/wrfspx9f1dvuspr/AAD5iA9PsteX3ygAJxQDxAy9a?dl=0. <strong>Georeferencing system</strong> Resolution: 0.5°×0.5° (approximately 55 km at the equator) Pixel resolution: 360 by 720 Coordinates: standard WGS84 Bounding box: 180°E-180°W; 90°S-90°N

作者：Chiara Pasut¹,², Fiona H. M. Tang³,⁶, Budiman Minasny⁴, Charles R. Warren⁴, Feike A. Dijkstra⁴, William J. Riley⁵, Federico Maggi¹,⁴
¹ 悉尼大学土木工程学院环境工程系，澳大利亚新南威尔士州悉尼2006，J05教学楼
² 澳大利亚联邦科学与工业研究组织农业与食品部（CSIRO Agriculture & Food），卡纳纳地区，韦特路4号入口，乌拉布赖5064，南澳大利亚州
³ 瑞典农业科学大学作物生产生态系，乌尔斯韦格16号，7043信箱，75007乌普萨拉，瑞典
⁴ 悉尼大学生命与环境科学学院悉尼农业研究所，澳大利亚新南威尔士州
⁵ 劳伦斯伯克利国家实验室地球科学部，美国加利福尼亚州伯克利94720
⁶ 新英格兰大学环境与农村科学学院，澳大利亚新南威尔士州阿米代尔2351
**联系方式**：Chiara Pasut ([e-mail])
**研究背景**：本研究采用BAMS4（土壤有机质生物与非生物模型第4版，Biotic and Abiotic Model for SOM-version 4）描述土壤有机碳（SOC, Soil Organic Carbon）循环。该模型包含5个有机碳库：多碳库（PolyC）代表木质素、纤维素与半纤维素有机聚合物；聚碳氮库（PolyCN）代表肽聚糖；单碳库（MonoC）、单碳氮库（MonoCN）与单碳硫库（MonoCS）分别为仅含碳、含碳氮、含碳硫的三种低分子量有机单体，对应根系分泌物以及多碳库、聚碳氮库解聚产生的单糖、脂肪酸、有机酸、酚类、氨基酸、氨基糖与核苷酸。模型另包含2个碳库，分别代表甲烷（CH₄）与二氧化碳（CO₂）。
四个微生物功能群调控土壤有机碳循环：真菌分解者（FDEP）负责多碳库的解聚；异养微生物（BAER）负责对单碳库、单碳氮库、单碳硫库与聚碳氮库进行有氧呼吸；产甲烷菌（BMGB）负责对单碳库进行厌氧呼吸；甲烷氧化菌（BMOB）负责甲烷氧化。
本研究将碳循环与氮、硫循环耦合，以阐明电子供体与受体对各元素循环生物响应的反馈作用（见图1）。针对氮循环，本研究纳入了大气固氮、氨氧化菌（BAOB）介导的铵态氮（NH₄⁺）硝化作用、亚硝酸盐氧化菌（BNOB）介导的亚硝酸盐氧化，以及反硝化菌（BDEN）介导的亚硝态氮（NO₂⁻）与硝态氮（NO₃⁻）反硝化作用。针对硫循环，本研究纳入了硫还原菌（BSrRB）、硫代硫酸盐与亚硫酸盐（S₂O₃²⁻、SO₃²⁻）还原菌（BThSRB）、硫酸盐（SO₄²⁻）还原菌（BSRB）、硫代硫酸盐与亚硫酸盐歧化微生物（BSDB）以及光合自养氧化菌（BSOB）介导的还原、歧化与氧化反应。
所有有机与无机碳、氮、硫库均可处于水相、气相，或与矿物结合（即免受生物作用）。所有生化反应及对应参数详见Pasut等（2021）的补充材料。表1汇总了本研究采用的库聚合方式，以及各库之间的通量。
**数据集内容**：本数据集发布了全球淡水湿地的周转时间与碳通量。计算域覆盖平均湿地表面积3.8百万平方公里（2000-2017年范围为1.2至11.4百万平方公里），采用约45000个网格单元，网格分辨率为0.5度（赤道处约50公里）。本研究从SWAMPS v3.2湿地数据库（Poulter等，2017）中筛选出湿地覆盖面积占网格单元总面积至少2%的网格单元，该数据库基于主动与被动微波卫星影像，报告了2000-2017年的每月淹水陆地面积，排除了湖泊、水库、河流与盐生环境。
每个选定的网格单元由2米高的大气柱组成，包含用于热量与气体交换的4层大气层，以及淹水层（从地表向上依次为30、30、40、100厘米厚）、1层表层土壤（0至30厘米）、2层亚表层土壤（30至100厘米）与1层根区以下土层（100厘米厚）。每个网格单元的特征包括深度特异性的土壤容重、孔隙度、土壤质地组分（Poggio等，2021）、水力与导热系数、热容量、进气势与孔隙体积分布指数（Dai等，2013）。表1汇总了本版本发布的数据与对应变量。
**资源获取**：BAMS4已集成至通用多相多物种生物反应运输模拟器BRTSim-v5.0b求解器中。BRTSim-v5.0b求解器包可从https://sites.google.com/site/thebrtsimproject/home或镜像站点https://www.dropbox.com/sh/wrfspx9f1dvuspr/AAD5iA9PsteX3ygAJxQDxAy9a?dl=0下载。
**地理参考系统**：分辨率：0.5°×0.5°（赤道处约55公里）；像素分辨率：360×720；坐标：标准WGS84；边界框：180°E-180°W；90°S-90°N