Abiotic and biotic factors controlling the dynamics of soil respiration in a coastal dune ecosystem in western Japan.

In this study, we examined the abiotic and biotic factors controlling the dynamics of soil respiration (R) while considering the zonal distribution of plant species in a coastal dune ecosystem in western Japan, based on periodic R data and continuous environmental data. We set four measurement plots with different vegetation compositions: plot 1 on bare sand; plot 2 on a cluster of young Vitex rotundifolia seedlings; plot 3 on a mixture of Artemisia capillaris and V. rotundifolia; and plot 4 on the inland boundary between the coastal vegetation zone and a Pinus thunbergii forest.

Historically inconsistent productivity and respiration fluxes in the global terrestrial carbon cycle.

The terrestrial carbon cycle is a major source of uncertainty in climate projections. Its dominant fluxes, gross primary productivity (GPP), and respiration (in particular soil respiration, R), are typically estimated from independent satellite-driven models and upscaled in situ measurements, respectively. We combine carbon-cycle flux estimates and partitioning coefficients to show that historical estimates of global GPP and R are irreconcilable.

COSORE: A community database for continuous soil respiration and other soil-atmosphere greenhouse gas flux data.

Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil-to-atmosphere CO flux, commonly though imprecisely termed soil respiration (R ), is one of the largest carbon fluxes in the Earth system. An increasing number of high-frequency R measurements (typically, from an automated system with hourly sampling) have been made over the last two decades; an increasing number of methane measurements are being made with such systems as well.

Temperature sensitivity of soil respiration across multiple time scales in a temperate plantation forest.

Soil respiration (Rs) is the largest carbon (C) flux from terrestrial ecosystems to the atmosphere. Predictions of Rs and associated feedback to climate change remain largely uncertain, in part due to the high temporal heterogeneity of temperature sensitivity (apparent Q) of Rs under a changing climate. Therefore, it is of critical importance to provide better insight into how Q varies across multiple temporal scales.

High-resolution data on the impact of warming on soil CO efflux from an Asian monsoon forest.

This paper describes a project for evaluation of global warming's impacts on soil carbon dynamics in Japanese forest ecosystems. We started a soil warming experiment in late 2008 in a 55-year-old evergreen broad-leaved forest at the boundary between the subtropical and warm-temperate biomes in southern Japan. We used infrared carbon-filament heat lamps to increase soil temperature by about 2.

Sustained acceleration of soil carbon decomposition observed in a 6-year warming experiment in a warm-temperate forest in southern Japan.

To examine global warming's effect on soil organic carbon (SOC) decomposition in Asian monsoon forests, we conducted a soil warming experiment with a multichannel automated chamber system in a 55-year-old warm-temperate evergreen broadleaved forest in southern Japan. We established three treatments: control chambers for total soil respiration, trenched chambers for heterotrophic respiration (R), and warmed trenched chambers to examine warming effect on R. The soil was warmed with an infrared heater above each chamber to increase soil temperature at 5 cm depth by about 2.

Pathway and sink activity for photosynthate translocation in Pisolithus extraradical mycelium of ectomycorrhizal Pinus thunbergii seedlings.

The purpose of this study was to identify the pathway and sink activity of photosynthate translocation in the extraradical mycelium (ERM) of a Pisolithus isolate. We labelled ectomycorrhizal (ECM) Pinus thunbergii seedlings with (14)CO2 and followed (14)C distribution within the ERM by autoradiography. (14)C photosynthate translocation in the ERM resulted in (14)C distribution in rhizomorphs throughout the ERM, with (14)C accumulation at the front.

Structural and functional interactions between extraradical mycelia of ectomycorrhizal Pisolithus isolates.

Extraradical mycelia from different ectomycorrhizal (ECM) roots coexist and interact under the forest floor. We investigated structural connections of conspecific mycelia and translocation of carbon and phosphorus between the same or different genets. Paired ECM Pinus thunbergii seedlings colonized by the same or different Pisolithus isolates were grown side by side in a rhizobox as their mycelia contacted each other.

Transfer of 14C-photosynthate to the sporocarp of an ectomycorrhizal fungus Laccaria amethystina.

Sporocarps of ectomycorrhizal fungi are strong carbon sinks for the source in host trees, but the details of carbon transfer from the host to the sporocarp are unknown. In this study, single seedlings of Japanese red pine (Pinus densiflora) colonised by Laccaria amethystina were grown on floral foam plates fitted in rhizoboxes, resulting in fruiting on the substrate. The seedlings were photosynthetically labelled with (14)CO(2); (14)C-labelled photosynthate transfer from leaves to sporocarps was then chased using a time-course autoradiography technique.