Elevated-CO2 and nutrient limitation synergistically reduce the growth and photosynthetic performances of a commercial macroalga Gracilariopsis lemaneiformis

In view of the current and expected future rise in atmospheric CO2 concentrations, we examined the effect of elevated CO2 on photoinhibition of photosystem I (PSI) under fluctuating light in Arabidopsis thaliana. At 400 ppm CO2, PSI showed a transient over-reduction within the first 30 s after transition from dark to actinic light. Under the same CO2 conditions, PSI was highly reduced after a transition from low to high light for 20 s. However, such PSI over-reduction greatly decreased when measured in 800 ppm CO2, indicating that elevated atmospheric CO2 facilitates the rapid oxidation of PSI under fluctuating light. Furthermore, after fluctuating light treatment, residual PSI activity was significantly higher in 800 ppm CO2 than in 400 ppm CO2, suggesting that elevated atmospheric CO2 mitigates PSI photoinhibition under fluctuating light. We further demonstrate that elevated CO2 does not affect PSI activity under fluctuating light via changes in non-photochemical quenching or cyclic electron transport, but rather from a rapid electron sink driven by CO2 fixation. Therefore, elevated CO2 mitigates PSI photoinhibition under fluctuating light at the acceptor rather than the donor side. Taken together, these observations indicate that elevated atmospheric CO2 can have large effects on thylakoid reactions under fluctuating light.

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Interaction of nutrient limitation and elevated CO2 concentration on carbon assimilation of a tropical tree seedling (Cedrela odorata)

Tree Physiology ◽

10.1093/treephys/20.14.977 ◽

2000 ◽

Vol 20 (14) ◽

pp. 977-986 ◽

Cited By ~ 12

Author(s):

F. E. Carswell ◽

J. Grace ◽

M. E. Lucas ◽

P. G. Jarvis

Keyword(s):

Nutrient Limitation ◽

Elevated Co2 ◽

Carbon Assimilation ◽

Co2 Concentration ◽

Tropical Tree ◽

Cedrela Odorata ◽

Tree Seedling ◽

Elevated Co2 Concentration

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The role of phosphorus dynamics in tropical forests – a modeling study using CLM-CNP

Biogeosciences Discussions ◽

10.5194/bgd-10-14439-2013 ◽

2013 ◽

Vol 10 (8) ◽

pp. 14439-14473 ◽

Cited By ~ 4

Author(s):

X. Yang ◽

P. E. Thornton ◽

D. M. Ricciuto ◽

W. M. Post

Keyword(s):

Nutrient Limitation ◽

Tropical Forests ◽

Elevated Co2 ◽

Field Experiments ◽

Global Climate ◽

P Availability ◽

Tropical Ecosystems ◽

Model Simulations ◽

P Limitation

Abstract. Tropical forests play a significant role in the global carbon cycle and global climate. However, tropical carbon cycling and the feedbacks from tropical ecosystems to the climate system remain critical uncertainties in current generation carbon-climate models. One of the major uncertainties comes from the lack of representation of phosphorus (P), the most limiting nutrient in tropical regions. Here we introduce P dynamics and C–N–P interactions into the CLM4-CN model and investigate the role of P cycling in controlling the productivity of tropical ecosystems. The newly developed CLM-CNP model includes all major biological and geochemical processes controlling P availability in soils and the interactions between C, N, and P cycles. Model simulations at sites along a Hawaiian soil chronosequence indicate that the introduction of P limitation greatly improved the model performance at the P-limited site. The model is also able to capture the shift in nutrient limitation along this chronosequence (from N limited to P limited), as shown in the comparison of model simulated plant responses to fertilization with the observed data. Model simulations at Amazonian forest sites show that CLM-CNP is capable of capturing the overall trend in NPP along the P availability gradient. This comparison also suggests a significant interaction between nutrient limitation and land use history. Model experiments under elevated atmospheric CO2 ([CO2]) condition suggest that tropical forest responses to increasing [CO2] will interact strongly with changes in the P cycle. We highlight the importance of two feedback pathways (biochemical mineralization and desorption of secondary mineral P) that can significantly affect P availability and determine the extent of P limitation in tropical forests under elevated [CO2]. Field experiments with elevated CO2 are therefore needed to help quantify these important feedbacks. Predictive modeling of C–P interactions will have important implications for the prediction of future carbon uptake and storage in tropical ecosystems and global climate change.

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Marked growth response of communities of two tropical tree species to elevated CO2 when soil nutrient limitation is removed

Flora ◽

10.1016/s0367-2530(17)30011-7 ◽

2001 ◽

Vol 196 (1) ◽

pp. 47-58 ◽

Cited By ~ 21

Author(s):

Klaus Winter ◽

Milton Garcia ◽

Richard Gottsberger ◽

Marianne Popp

Keyword(s):

Nutrient Limitation ◽

Elevated Co2 ◽

Tree Species ◽

Growth Response ◽

Soil Nutrient ◽

Tropical Tree ◽

Tropical Tree Species

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The role of phosphorus dynamics in tropical forests – a modeling study using CLM-CNP

Biogeosciences ◽

10.5194/bg-11-1667-2014 ◽

2014 ◽

Vol 11 (6) ◽

pp. 1667-1681 ◽

Cited By ~ 95

Author(s):

X. Yang ◽

P. E. Thornton ◽

D. M. Ricciuto ◽

W. M. Post

Keyword(s):

Tropical Forest ◽

Nutrient Limitation ◽

Tropical Forests ◽

Elevated Co2 ◽

Global Climate ◽

P Availability ◽

Tropical Ecosystems ◽

Model Simulations ◽

P Limitation

Abstract. Tropical forests play a significant role in the global carbon cycle and global climate. However, tropical carbon cycling and the feedbacks from tropical ecosystems to the climate system remain critical uncertainties in the current generation of carbon–climate models. One of the major uncertainties comes from the lack of representation of phosphorus (P), currently believed to be the most limiting nutrient in tropical regions. Here we introduce P dynamics and C–N–P interactions into the CLM4-CN (Community Land Model version 4 with prognostic Carbon and Nitrogen) model and investigate the role of P cycling in controlling the productivity of tropical ecosystems. The newly developed CLM-CNP model includes all major biological and geochemical processes controlling P availability in soils and the interactions between C, N, and P cycles. Model simulations at sites along a Hawaiian soil chronosequence indicate that the introduction of P limitation greatly improved the model performance at the P-limited site. The model is also able to capture the shift in nutrient limitation along this chronosequence (from N limited to P limited), as shown in the comparison of model-simulated plant responses to fertilization with the observed data. Model simulations at Amazonian forest sites show that CLM-CNP is capable of capturing the overall trend in NPP (net primary production) along the P availability gradient. This comparison also suggests a significant interaction between nutrient limitation and land use history. Model experiments under elevated atmospheric CO2 ([CO2]) conditions suggest that tropical forest responses to increasing [CO2] will interact strongly with changes in the P cycle. We highlight the importance of two feedback pathways (biochemical mineralization and desorption of secondary mineral P) that can significantly affect P availability and determine the extent of P limitation in tropical forests under elevated [CO2]. Field experiments with elevated CO2 are therefore needed to help quantify these important feedbacks. CO2 doubling model experiments show that tropical forest response to elevated [CO2] can only be predicted if the interactions between C cycle and nutrient dynamics are well understood and represented in models. Predictive modeling of C–nutrient interactions will have important implications for the prediction of future carbon uptake and storage in tropical ecosystems and global climate change.

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