Estimates of GPP in a Wet Tropical Forest and Effects of Temporal Scale on the Drivers of LUE

SSRN Electronic Journal · 2026-01-01

Scaling from Flux Towers to Ecosystem Models: Regional Constraints on Carbon Cycle Processes from Atmospheric Carbonyl Sulfide (Final Report)

2023-05-24

DOE supported research suggests that gross primary productivity (GPP) is largely underestimated by global earth system models [Welp et al., 2011], reflecting the persistent challenge in extrapolating from local-scale GPP observations to global-scale earth system models. This poor understanding of GPP at large spatial scales is of particular concern in tropical forests. In tropical forests, some earth systems models forecast a powerful feedback between a warming climate and a decline in GPP resulting in forest dieback. While this simulated feedback is intensely debated, we lack robust large-scale constraints on GPP that are needed to resolve this debate. In particular, carbon dioxide measurements provide valuable information on net carbon flux, but not on the gross flux associated with GPP. Here we conducted a study of regional-to-global scale GPP using atmospheric carbonyl sulfide to provide a new constraint on GPP mechanisms in earth system models. Our project activities integrated modeling, in situ measurement, and remote sensing techniques to resolve GPP for the Amazon as well as global scale trends. The results of this work included initiating airborne carbonyl sulfide monitoring in the Amazon, training for postdocs and graduate students at a Hispanic Serving Institution, fundamental advances in carbonyl sulfide budgets [e.g. Hilton et al., Nature Climate Change, 2017], and high-profile publications that focused on GPP trends for the Amazon [Stinecipher et al., GRL, 2022] and global historical GPP trends [Campbell, et al., Nature, 2017]. Based on the suggestion of our DOE program manager, we published a state-of-the-science commentary to the scientific community on GPP monitoring with COS [Campbell et al., EOS, 2017] which was selected as the cover story. DOE support was acknowledged in all reports. The importance of this research to understanding climate change was communicated to the general public through community seminars (Rotary, Public Libraries, State Parks), an op-ed (SF Chronicle), and interviews in the mass media including two stories in the New York Times (4/5/17; 7/30/18), one of which was especially widely read after it was featured in the New York Time’s Quote of the Day.

Physical and ecophysiological controls on the relationship between solar-induced chlorophyll fluorescence and gross primary productivity across diurnal and seasonal scales in the boreal forest

2021

• Computer Science
• World Wide Web
• Computer Science

Earth and Space Science Open Archive Presented WorkOpen AccessYou are viewing the latest version by default [v1]Physical and ecophysiological controls on the relationship between solar-induced chlorophyll fluorescence and gross primary productivity across diurnal and seasonal scales in the boreal forestAuthorsZoePierratiDTroyMagneyNicholasParazooiDKatjaGrossmanniDBruceJohnsoniDAlanBarrJacobBortnikiDAlexanderNortoniDAndrewMaguireDavidBowlingUlrikeSeibtChristianFrankenbergJochenStutziDSee all authors Zoe PierratiDCorresponding Author• Submitting AuthorUniversity of California Los AngelesiDhttps://orcid.org/0000-0002-6726-2406view email addressThe email was not providedcopy email addressTroy MagneyUniversity of California Davisview email addressThe email was not providedcopy email addressNicholas ParazooiDJet Propulsion Laboratory (JPL)iDhttps://orcid.org/0000-0002-4424-7780view email addressThe email was not providedcopy email addressKatja GrossmanniDHeidelberg UniversityiDhttps://orcid.org/0000-0002-5154-197Xview email addressThe email was not providedcopy email addressBruce JohnsoniDUniversity of SaskatchewaniDhttps://orcid.org/0000-0001-9013-5774view email addressThe email was not providedcopy email addressAlan BarrUniversity of Saskatchewanview email addressThe email was not providedcopy email addressJacob BortnikiDUniversity of California Los AngelesiDhttps://orcid.org/0000-0001-8811-8836view email addressThe email was not providedcopy email addressAlexander NortoniDJet Propulsion Laboratory, California Institute of TechnologyiDhttps://orcid.org/0000-0001-7708-3914view email addressThe email was not providedcopy email addressAndrew MaguireNASA Jet Propulsion Laboratoryview email addressThe email was not providedcopy email addressDavid BowlingUniversity of Utahview email addressThe email was not providedcopy email addressUlrike SeibtUniversity of California Los Angelesview email addressThe email was not providedcopy email addressChristian FrankenbergNASA Jet Propulsion Laboratoryview email addressThe email was not providedcopy email addressJochen StutziDUniversity of California Los AngelesiDhttps://orcid.org/0000-0001-6368-7629view email addressThe email was not providedcopy email address

Plant Functional Traits Predict the Drought Response of Native California Plant Species

International Journal of Plant Sciences · 2019-10-23 · 8 citations

Premise of research. As extreme climate events, such as California’s 2012–2016 drought, become more frequent with climate change, it is imperative to understand how different native plant communities respond to drought-induced dehydration stress. Chaparral and California sage scrub (CSS), two widespread plant communities in California, face threats from droughts of increased frequency and severity. Despite chaparral and CSS plants being adapted to seasonal drought conditions, it is not known how the strategies of recovery from extreme multiyear droughts associated with changing climate differ between them.Methodology. We measured chlorophyll fluorescence and water potentials for two evergreen chaparral shrubs (Heteromeles arbutifolia and Quercus berberidifolia) and two drought deciduous CSS shrubs (Salvia leucophylla and Salvia mellifera) in the Santa Monica Mountains both during and after the extreme drought in California (between 2015 and 2017).Pivotal results. We found that the maximum electron transport rate (Jmax) varied seasonally for all species, decreasing in the dry season and recovering in the wet season. However, Jmax and the seasonal change in Jmax (ΔJmax) were larger for the CSS species than for the chaparral species, and recovery of Jmax began earlier in the year for CSS species than for chaparral species. Dark-adapted maximum photochemical efficiency of photosystem II (Fv/Fm) and both midday (ΨMD) and predawn (ΨPD) water potential for all species also followed similar seasonal patterns—higher in the wet season than in the dry season, with CSS species exhibiting the largest seasonal changes in Ψ. A strong linear relationship was found between Jmax and ΨMD for all species except Q. berberidifolia.Conclusions. Our results show that recovery from drought-induced dehydration differs between representatives of two major plant communities in California and is linked to life-history strategy: the higher sensitivity to and quicker recovery from seasonal drought for the CSS species compared with the chaparral species could be attributed to the shallower rooting depths and dehydration tolerance of the CSS species. In addition, water relations and chlorophyll fluorescence can serve as useful metrics to compare species-specific dehydration stress tolerance or avoidance strategies in the field.

Influences of light and humidity on carbonyl sulfide-based estimates of photosynthesis

Proceedings of the National Academy of Sciences · 2019-01-25 · 117 citations

Understanding climate controls on gross primary productivity (GPP) is crucial for accurate projections of the future land carbon cycle. Major uncertainties exist due to the challenge in separating GPP and respiration from observations of the carbon dioxide (CO 2 ) flux. Carbonyl sulfide (COS) has a dominant vegetative sink, and plant COS uptake is used to infer GPP through the leaf relative uptake (LRU) ratio of COS to CO 2 fluxes. However, little is known about variations of LRU under changing environmental conditions and in different phenological stages. We present COS and CO 2 fluxes and LRU of Scots pine branches measured in a boreal forest in Finland during the spring recovery and summer. We find that the diurnal dynamics of COS uptake is mainly controlled by stomatal conductance, but the leaf internal conductance could significantly limit the COS uptake during the daytime and early in the season. LRU varies with light due to the differential light responses of COS and CO 2 uptake, and with vapor pressure deficit (VPD) in the peak growing season, indicating a humidity-induced stomatal control. Our COS-based GPP estimates show that it is essential to incorporate the variability of LRU with environmental variables for accurate estimation of GPP on ecosystem, regional, and global scales.

Variations in spatiotemporal averaging and canopy illumination and its impact on the interpretation of SIF and vegetation index observations

EGU General Assembly Conference Abstracts · 2019-04-01

PhotoSpec - A New Instrument to Measure Spatially Distributed Red and Far-Red Solar-Induced Chlorophyll Fluorescence: An Overview of First-Year Experience

AGUFM · 2018-12-01

Effectiveness of vegetation and sound wall-vegetation combination barriers on pollution dispersion from freeways under early morning conditions

The Science of The Total Environment · 2018-12-11 · 63 citations

Spatial inhomogeneity of SIF in natural and agricultural canopies and its impact on the interpretation of spatially averaged ground observations

AGU Fall Meeting Abstracts · 2018-12-01

PhotoSpec: A new instrument to measure spatially distributed red and far-red Solar-Induced Chlorophyll Fluorescence

Remote Sensing of Environment · 2018-07-13 · 156 citations