NSFDEB-NERC:Tropical deadwood carbon fluxes: Improving carbon models by incorporating termites and microbes

GSTDTAP

项目编号	NE/R012342/1
	NSFDEB-NERC:Tropical deadwood carbon fluxes: Improving carbon models by incorporating termites and microbes
	Paul Eggleton
主持机构	The Natural History Museum
项目开始年	2017
	2017-10-09
项目结束日期	2022-10-08
资助机构	UK-NERC
项目类别	Research Grant
国家	英国
语种	英语
英文摘要	Objectives of this project are to measure rates of tropical deadwood (coarse woody debris; CWD) turnover and identify mechanisms that determine fates of CWD carbon (C) under current and future climates. Woody plants are the largest aboveground terrestrial biotic C store, and CWD biomass is likely substantial but poorly estimated. Much of our knowledge of turnover comes from temperate systems, where CWD is thought to be slow cycling. Less is known about tropical CWD pools and turnover, despite large living tree biomass. Due to differences in climate (warmer temperatures and sometimes greater precipitation), wood construction, and loss pathways (increasing role of termites), it is likely that CWD is dynamic in tropical systems. This project combines field, molecular, and modeling approaches in tropical Australia, where termites and fungi are key agents of wood turnover. A continuous belt of forest from rainforest to savanna with existing long-term data and infrastructure makes it an ideal location. Three questions will be addressed: Q1. What controls rates of CWD C turnover? Turnover rates will be determined by termite and fungal activity, which are dependent on climate and wood construction. Warmer and wetter conditions should increase turnover, but termites should increase turnover relatively more in dry conditions as they have water conservation strategies. Dense highly lignified wood should decay more slowly. Q2. What controls fates of C from CWD? C fates (CO2, CH4, organic residues) will depend on stage of decay and functional composition of termite and microbial communities. Later stages of decay, increased methanogens, decreased methanotrophs and changes in termite species should result in greater CH4:CO2. Greater organic residue formation will occur when C loss is via termites. Q3. How do mechanisms of wood turnover scale up to affect ecosystem-level C fluxes under climate change? Climate warming in Northern Australia will increase turnover rates and alter C fates of wood. To date, CWD is poorly parameterized in Earth system models (e.g., CWD decays only via physical fragmentation). Field data from Q1 and Q2 will be used to drive new predictive models of wood turnover and greenhouse gas (GHG) production under climate change. To test Q1 and determine relative saprobic microbe and termite decay rates in response to precipitation variation, blocks of a novel substrate (Pinus radiata) known to attract termites will be placed at 6 sites (Rainfall gradient experiment). Blocks will be enclosed in fine-mesh with or without holes manipulating termite access; blocks will be harvested at end of wet and dry seasons for 4 years. To determine influence of wood construction on decay, replicate logs of 10 species/site similarly enclosed will be placed at rainforest and savannah sites (Common garden experiment). Logs will be harvested at end of 2 wet and 2 dry seasons. For logs/blocks, initial and final mass, density and chemistry will be measured. Local weather stations will provide climate data. To test Q2, wood subsamples and termites in wood will be collected to determine termite community, microbial community and functional gene composition, and organic residue formation. CO2 and CH4 will be measured for harvested logs/blocks. As some termites live in mounds, experimental mounds (Termite mesocosm experiment) will be established and mound diel CO2 and CH4 fluxes will be measured monthly for 1 yr. To test Q3, field data will be incorporated into woodCLM, an ecosystem model derived from the Community Land Model. Results from the modified and original models will be compared. Using woodCLM, wood dynamics and GHG emissions will be simulated under future climate scenarios
来源学科分类	Natural Environment Research
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/86840
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Paul Eggleton.NSFDEB-NERC:Tropical deadwood carbon fluxes: Improving carbon models by incorporating termites and microbes.2017.