Gross Primary Productivity in a Small Kansas Lake, Based on Continuous in-situ Recordings, 24 March-31 June 1977

<p>This study utilises in-situ and reanalysis soil moisture data inputs from various sources to evaluate the effect of soil water stress on Gross Primary Productivity (GPP) of different Plant Functional Types (PFTs) using Terrestrial Ecosystem Model in R (TEMIR), which is under development by Tai Group of Atmosphere-Biosphere Interactions (Tai et al. in prep.). An empirical soil water stress function with reference to Community Land Model (CLM) Version 4.5 is employed to quantify water stress experienced by vegetation which hinders stomatal conductance and thus carboxylation rate. The model results are compared against observations at FLUXNET sites in semi-arid regions across the globe at daily timescale where in-situ GPP data is available and water stress inhibits plant functions to some extent. By dividing the soil into two layers (topsoil and root zone), GPP simulation improves significantly comparing with using single layer bulk soil (Modified Nash-Sutcliffe Model Efficiency Coefficient N increases from -0.686 to -0.586). Such upgrade is particularly substantial for vegetation with shallow roots such as grass PFTs. Despite this improvement, the model is characterised by an overall overestimation of GPP when water stress occurs, and inconsistency of accuracy subject to PFTs and degree of water stress experienced. This study informs responses of various PFTs to soil water stress, capacity of TEMIR in simulating the responses, and possible drawbacks of empirical soil water stress functions, and highlights the importance of topsoil moisture data input for vegetation drought monitoring.</p><p>Keywords: Soil water stress, Terrestrial model representation, Photosynthesis, In-situ data, Reanalysis data, FLUXNET</p>

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In Situ Observation of Whole Lake Gross Primary Productivity: Response to and Recovery from Copper Algaecide Application

Environmental Engineering Science ◽

10.1089/ees.2008.0037 ◽

2009 ◽

Vol 26 (3) ◽

pp. 521-529

Author(s):

Thomas Torgersen

Keyword(s):

Primary Productivity ◽

Gross Primary Productivity ◽

In Situ Observation

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No impact of tropospheric ozone on the gross primary productivity of a Belgian pine forest

Biogeosciences ◽

10.5194/bg-14-1839-2017 ◽

2017 ◽

Vol 14 (7) ◽

pp. 1839-1855 ◽

Cited By ~ 6

Author(s):

Lore T. Verryckt ◽

Maarten Op de Beeck ◽

Johan Neirynck ◽

Bert Gielen ◽

Marilyn Roland ◽

...

Keyword(s):

Scots Pine ◽

Primary Productivity ◽

Crop Yields ◽

Gross Primary Productivity ◽

Carbon Uptake ◽

Tree Seedlings ◽

Mixing Ratio ◽

Negative Effects ◽

Uptake Rates

Abstract. High stomatal ozone (O3) uptake has been shown to negatively affect crop yields and the growth of tree seedlings. However, little is known about the effect of O3 on the carbon uptake by mature forest trees. This study investigated the effect of high O3 events on gross primary productivity (GPP) for a Scots pine stand near Antwerp, Belgium over the period 1998–2013. Stomatal O3 fluxes were modelled using in situ O3 mixing ratio measurements and a multiplicative stomatal model, which was parameterised and validated for this Scots pine stand. Ozone-induced GPP reduction is most likely to occur during or shortly after days with high stomatal O3 uptake. Therefore, a GPP model within an artificial neural network was parameterised for days with low stomatal O3 uptake rates and used to simulate GPP during periods of high stomatal O3 uptake. Possible negative effects of high stomatal O3 uptake on GPP would then result in an overestimation of GPP by the model during or after high stomatal O3 uptake events. The O3 effects on GPP were linked to AOT40 and POD1. Although the critical levels for both indices were exceeded in every single year, no significant negative effects of O3 on GPP were found, and no correlations between GPP residuals and AOT40 and POD1 were found. Overall, we conclude that no O3 effects were detected on the carbon uptake by this Scots pine stand.

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Ozone-induced gross primary productivity reductions over European forests inferred from satellite observations

10.5194/bg-2021-125 ◽

2021 ◽

Author(s):

Jasdeep Singh Anand ◽

Alessandro Anav ◽

Marcello Vitale ◽

Daniele Peano ◽

Nadine Unger ◽

...

Keyword(s):

Soil Moisture ◽

Primary Productivity ◽

Land Surface ◽

Gross Primary Productivity ◽

Significant Variable ◽

Terrestrial Carbon ◽

European Forests ◽

The Mediterranean ◽

The Impact

Abstract. Tropospheric O3 damages leaves and directly inhibits photosynthesis, posing a threat to terrestrial carbon sinks. Previous investigations have mostly relied on sparse in-situ data or simulations using land surface models. This work is the first to use satellite data to quantify the effect of O3 exposure on gross primary productivity (GPP). O3-induced GPP reductions were estimated to vary between 0.36–9.55% across European forests along a North-South transect between 2003–2015, in line with prior estimates. No significant temporal trend could be determined over most of Europe, while Random Forest analysis (RFA) shows that soil moisture is a significant variable governing GPP reductions over the Mediterranean. Comparisons between this work and GPP reductions simulated by the Yale Interactive Biosphere (YIBs) model suggest that satellite-based estimates over the Mediterranean region may be biased by +12%, potentially because of differences in modelling stomatal sensitivity to soil moisture and prior O3 exposure. This work has demonstrated for the first time that satellite-based datasets can be leveraged to assess the impact of O3 on the terrestrial carbon sink, which are comparable with in-situ or model-based analyses.

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Spatial, Phenological, and Inter-Annual Variations of Gross Primary Productivity in the Arctic from 2001 to 2019

Remote Sensing ◽

10.3390/rs13152875 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2875

Author(s):

Dujuan Ma ◽

Xiaodan Wu ◽

Xuanlong Ma ◽

Jingping Wang ◽

Xingwen Lin ◽

...

Keyword(s):

Land Cover ◽

Carbon Cycle ◽

Primary Productivity ◽

Gross Primary Productivity ◽

The Arctic ◽

Spatiotemporal Variations ◽

Land Cover Types ◽

Annual Variations ◽

Terrestrial Carbon Cycle

Quantifying the spatial, seasonal (phenological), and inter-annual variations of gross primary productivity (GPP) in the Arctic is critical for comprehending the terrestrial carbon cycle and its feedback to climate warming in this region. Here, we evaluated the accuracy of the MOD17A2H GPP product using the FLUXNET 2015 dataset in the Arctic, then explored the spatial patterns, seasonal variations, and interannual trends of GPP, and investigated the dependence of the spatiotemporal variations in GPP on land cover types, latitude, and elevation from 2001 to 2019. The results showed that MOD17A2H was consistent with in situ measurements (R = 0.8, RMSE = 1.26 g C m−2 d−1). The functional phenology was also captured by the MOD17A2H product (R = 0.62, RMSE = 9 days) in the Arctic. The spatial variation of the seasonal magnitude of GPP and its interannual trends is partly related to land cover types, peaking in forests and lowest in grasslands. The interannual trend of GPP decreased as the latitude and elevation increased, except for the latitude between 62°~66° N and elevation below 700 m. Our study not only revealed the variation of GPP in the Arctic but also helped to understand the carbon cycle over this region.

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