GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Seasonal patterns of soil CO2 efflux and soil air CO2 concentration in a Scots pine forest: comparison of two chamber techniques (2003)
    Oxford, UK : Blackwell Science Ltd
    Global change biology 9 (2003), S. 0 
    Details
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: A non-vented non-steady state flow-through chamber and a non-vented non-steady state non-flow-through chamber technique were used to measure CO2 efflux of a young Scots pine forest on a fertile till soil in southern Finland. Soil temperature, soil moisture and soil CO2 concentration were measured concurrently with CO2 efflux for two and a half successive years. The CO2 efflux showed a seasonal pattern, effluxes ranging from low 0.0–0.1 g CO2 m−2 h−1 in winter to peak values of 2.3 g CO2 m−2 h−1 occurring in late June and in July. The daily average effluxes in July measured by flow through chambers were 1.23 and 0.98 g CO2 m−2 h−1 in 1998 and 1999, respectively. The annual accumulated CO2 efflux was 3117 and 3326 g CO2 m−2 in 1998 and 1999, respectively. The spatial variation in CO2 efflux was high (CV 0.18–0.45) and increased with increasing efflux. Soil air CO2 concentration showed similar seasonal pattern the peak concentrations occurring in July–August. The CO2 concentrations ranged from 580 to 780 µmol mol−1 in the humus layer to 13 620–14 470 µmol mol−1 in the C-horizon. In winter the soil air CO2 concentrations were lower, especially in deeper soil layers. Drought decreased CO2 efflux and soil air CO2 concentration. The in situ comparison on forest soil between the chamber methods showed the non-flow-through chamber to give ∼∼50% lower efflux values than that of the flow-through chamber. When calibrated against known CO2 efflux ranging from 0.4 to 0.8 g CO2 m−2 h−1 generated with a diffusion box method developed by Widén and Lindroth [Acta Universitatis Agriculturae Suecia Silvestria, 2001], the flow-through chamber gave equal effluxes at the lower end of the calibration range, but overestimated high effluxes by 20%. Non-flow-through chamber underestimated the CO2 efflux by 30%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2486.2003.00588.x
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    On the separation of net ecosystem exchange into assimilation and ecosystem respiration: review and improved algorithm (2005)
    Oxford, UK : Blackwell Science Ltd
    Global change biology 11 (2005), S. 0 
    Details
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: This paper discusses the advantages and disadvantages of the different methods that separate net ecosystem exchange (NEE) into its major components, gross ecosystem carbon uptake (GEP) and ecosystem respiration (Reco). In particular, we analyse the effect of the extrapolation of night-time values of ecosystem respiration into the daytime; this is usually done with a temperature response function that is derived from long-term data sets. For this analysis, we used 16 one-year-long data sets of carbon dioxide exchange measurements from European and US-American eddy covariance networks. These sites span from the boreal to Mediterranean climates, and include deciduous and evergreen forest, scrubland and crop ecosystems.We show that the temperature sensitivity of Reco, derived from long-term (annual) data sets, does not reflect the short-term temperature sensitivity that is effective when extrapolating from night- to daytime. Specifically, in summer active ecosystems the long-term temperature sensitivity exceeds the short-term sensitivity. Thus, in those ecosystems, the application of a long-term temperature sensitivity to the extrapolation of respiration from night to day leads to a systematic overestimation of ecosystem respiration from half-hourly to annual time-scales, which can reach 〉25% for an annual budget and which consequently affects estimates of GEP. Conversely, in summer passive (Mediterranean) ecosystems, the long-term temperature sensitivity is lower than the short-term temperature sensitivity resulting in underestimation of annual sums of respiration.We introduce a new generic algorithm that derives a short-term temperature sensitivity of Reco from eddy covariance data that applies this to the extrapolation from night- to daytime, and that further performs a filling of data gaps that exploits both, the covariance between fluxes and meteorological drivers and the temporal structure of the fluxes. While this algorithm should give less biased estimates of GEP and Reco, we discuss the remaining biases and recommend that eddy covariance measurements are still backed by ancillary flux measurements that can reduce the uncertainties inherent in the eddy covariance data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2486.2005.001002.x
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Carbon balance of different aged Scots pine forests in Southern Finland (2004)
    Oxford, UK : Blackwell Science Ltd
    Global change biology 10 (2004), S. 0 
    Details
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: We estimated annual net ecosystem exchange (NEE) of a chronosequence of four Scots pine stands in southern Finland during years 2000–2002 using eddy covariance (EC). Net ecosystem productivity (NEP) was estimated using growth measurements and modelled mass losses of woody debris. The stands were 4, 12, 40 and 75 years old. The 4-year-old clearcut was a source of carbon throughout the year combining a low gross primary productivity (GPP) with a total ecosystem respiration (TER) similar to the forest stands. The annual NEE of the clearcut, measured by EC, was 386 g C m−2. Tree growth was negligible and the estimated NEP was −262 g C m−2 a−1. The annual GPPs at the other sites were close to each other (928−1072 g C m−2 a−1), but TER differed markedly, being greatest at the 12-year-old site (905 g C m−2 a−1) and smallest in the 75-year-old stand (616 g C m−2 a−1). Measurements of soil CO2 efflux showed that different rates of soil respiration largely explained the differences in TER. The NEE and NEP of the 12-year-old stand were close to zero. The forested stands were sinks of carbon. They had similar annual patterns of carbon exchange and half-hourly eddy fluxes were highly correlated, indicating similar responses to the environment. The NEE in the 40-year-old stand varied between −179 and –192 g C m−2 a−1, while NEP was between 214 and 242 g C m−2 a−1. The annual NEE of the 75-year-old stand was 323 g C m−2 and NEP was 252 g C m−2. This indicates that there was no reduction in carbon sink strength with stand age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1529-8817.2003.00797.x
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    facet.materialart.
    Unknown
    Looking deeper into the soil : biophysical controls and seasonal lags of soil CO2 production and efflux (2011)
    Ecological Society of America
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Ecological Society of America, 2010. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 20 (2010): 1569–1582, doi:10.1890/09-0693.1.
    Description: We seek to understand how biophysical factors such as soil temperature (Ts), soil moisture (θ), and gross primary production (GPP) influence CO2 fluxes across terrestrial ecosystems. Recent advancements in automated measurements and remote-sensing approaches have provided time series in which lags and relationships among variables can be explored. The purpose of this study is to present new applications of continuous measurements of soil CO2 efflux (F0) and soil CO2 concentrations measurements. Here we explore how variation in Ts, θ, and GPP (derived from NASA's moderate-resolution imaging spectroradiometer [MODIS]) influence F0 and soil CO2 production (Ps). We focused on seasonal variation and used continuous measurements at a daily timescale across four vegetation types at 13 study sites to quantify: (1) differences in seasonal lags between soil CO2 fluxes and Ts, θ, and GPP and (2) interactions and relationships between CO2 fluxes with Ts, θ, and GPP. Mean annual Ts did not explain annual F0 and Ps among vegetation types, but GPP explained 73% and 30% of the variation, respectively. We found evidence that lags between soil CO2 fluxes and Ts or GPP provide insights into the role of plant phenology and information relevant about possible timing of controls of autotrophic and heterotrophic processes. The influences of biophysical factors that regulate daily F0 and Ps are different among vegetation types, but GPP is a dominant variable for explaining soil CO2 fluxes. The emergence of long-term automated soil CO2 flux measurement networks provides a unique opportunity for extended investigations into F0 and Ps processes in the near future.
    Description: Data collection was possible thanks to NASA, the NSF Center for Embedded Networked Sensing (CCR-0120778), DOE (DE-FG02-03ER63638), CONACyT, UCMEXUS, NSF (EF-0410408), NSF-LTER, KAKENHI (12878089 and 13480150), the Academy of Finland (213093), the Austrian Science Fund (FWF, P18756-B16), the Kearney Foundation, the Canadian Foundation for Climate and Atmospheric Sciences (CFCAS), and the Natural Science and Engineering Research Council of Canada (NSERC). R. Vargas was supported by grant DEB-0639235 during the preparation of this manuscript.
    Keywords: Lags ; Moderate-resolution imaging spectroradiometer (MODIS) ; Photosynthesis ; Soil CO2 efflux ; Soil CO2 production ; Soil CO2 sensors ; Soil respiration
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...