scholarly journals Tropical forest responses to increasing atmospheric CO2: current knowledge and opportunities for future research

2013 ◽  
Vol 40 (6) ◽  
pp. 531 ◽  
Author(s):  
Lucas A. Cernusak ◽  
Klaus Winter ◽  
James W. Dalling ◽  
Joseph A. M. Holtum ◽  
Carlos Jaramillo ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Tropical Forests ◽  
Current Knowledge ◽  
Co2 Enrichment ◽  
Atmospheric Co2 ◽  
Root Production ◽  
Future Research ◽  
Temperature Threshold ◽  
Stepping Stones ◽  
Elevated Atmospheric Co2

Elevated atmospheric CO2 concentrations (ca) will undoubtedly affect the metabolism of tropical forests worldwide; however, critical aspects of how tropical forests will respond remain largely unknown. Here, we review the current state of knowledge about physiological and ecological responses, with the aim of providing a framework that can help to guide future experimental research. Modelling studies have indicated that elevated ca can potentially stimulate photosynthesis more in the tropics than at higher latitudes, because suppression of photorespiration by elevated ca increases with temperature. However, canopy leaves in tropical forests could also potentially reach a high temperature threshold under elevated ca that will moderate the rise in photosynthesis. Belowground responses, including fine root production, nutrient foraging and soil organic matter processing, will be especially important to the integrated ecosystem response to elevated ca. Water use efficiency will increase as ca rises, potentially impacting upon soil moisture status and nutrient availability. Recruitment may be differentially altered for some functional groups, potentially decreasing ecosystem carbon storage. Whole-forest CO2 enrichment experiments are urgently needed to test predictions of tropical forest functioning under elevated ca. Smaller scale experiments in the understorey and in gaps would also be informative, and could provide stepping stones towards stand-scale manipulations.

Ocean Acidification: Knowns, Unknowns, and Perspectives

2011 ◽  
Author(s):  
Jean-Pierre Gattuso ◽  
Jelle Bijma
Keyword(s):  
Ocean Acidification ◽  
Elevated Co2 ◽  
Acoustic Noise ◽  
Current Knowledge ◽  
Co2 Enrichment ◽  
Marine Organisms ◽  
Societal Implications ◽  
Future Research ◽  
First Results ◽  
Enrichment Experiments

Although the changes in the chemistry of seawater driven by the uptake of CO2 by the oceans have been known for decades, research addressing the effects of elevated CO2 on marine organisms and ecosystems has only started recently (see Chapter 1). The first results of deliberate experiments on organisms were published in the mid 1980s (Agegian 1985) and those on communities in 2000 (Langdon et al. 2000; Leclercq et al. 2000 ). In contrast, studies focusing on the response of terrestrial plant communities began much earlier, with the first results of free-air CO2 enrichment experiments (FACE) being published in the late 1960s (see Allen 1992 ). Not surprisingly, knowledge about the effects of elevated CO2 on the marine realm lags behind that concerning the terrestrial realm. Yet ocean acidification might have significant biological, ecological, biogeochemical, and societal implications and decision-makers need to know the extent and severity of these implications in order to decide whether they should be considered, or not, when designing future policies. The goals of this chapter are to summarize key information provided in the preceding chapters by highlighting what is known and what is unknown, identify and discuss the ecosystems that are most at risk, as well as discuss prospects and recommendation for future research. The chemical, biological, ecological, biogeochemical, and societal implications of ocean acidification have been comprehensively reviewed in the previous chapters with one minor exception. Early work has shown that ocean acidification significantly affects the propagation of sound in seawater and suggested possible consequences for marine organisms sensitive to sound (Hester et al . 2008). However, sub sequent studies have shown that the changes in the upper-ocean sound absorption coefficient at future pH levels will have no or a small impact on ocean acoustic noise (Joseph and Chiu 2010; Udovydchenkov et al . 2010). The goal of this section is to condense the current knowledge about the consequences of ocean acidification in 15 key statements. Each statement is given levels of evidence and, when possible, a level of confidence as recommended by the Intergovernmental Panel on Climate Change (IPCC) for use in its 5th Assessment Report (Mastrandrea et al. 2010).

scholarly journals Fine-root production dominates response of a deciduous forest to atmospheric CO2 enrichment

2004 ◽  
Vol 101 (26) ◽  
pp. 9689-9693 ◽  
Author(s):  
R. J. Norby ◽  
J. Ledford ◽  
C. D. Reilly ◽  
N. E. Miller ◽  
E. G. O'Neill
Keyword(s):  
Fine Root ◽  
Deciduous Forest ◽  
Co2 Enrichment ◽  
Atmospheric Co2 ◽  
Root Production ◽  
Fine Root Production

Climate-induced hysteresis of the tropical forest in the fire-enabled Earth system model CM2Mc-LPJmL

2021 ◽  
Author(s):  
Markus Drüke ◽  
Werner v. Bloh ◽  
Boris Sakschewski ◽  
Nico Wunderling ◽  
Stefan Petri ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Tropical Forests ◽  
Atmospheric Co2 ◽  
Forest Recovery ◽  
Surface Model ◽  
Original State ◽  
Co2 Concentrations ◽  
Impact Phase ◽  
Atmospheric Co2 Concentrations ◽  
The Impact

<p>Tropical rainforests are recognized as one of the terrestrial tipping elements which could have profound impacts on the global climate, once their vegetation has transitioned into savanna or grassland states. While several studies investigated the savannization of, e.g., the Amazon rainforest, few studies considered the influence of fire. Fire is expected to potentially shift the savanna-forest boundary and hence impact the dynamical equilibrium between these two possible vegetation states under changing climate. To investigate the climate-induced hysteresis in pan-tropical forests and the impact of fire under future climate conditions, we coupled the well established and comprehensively validated Dynamic Global Vegetation Model LPJmL5.0-FMS to the coupled climate model CM2Mc, which is based on the atmosphere model AM2 and the ocean model MOM5 (CM2Mc-LPJmL v1.0). In CM2Mc, we replaced the simple land surface model LaD with LPJmL and fully coupled the water and energy cycles. Exchanging LaD by LPJmL, and therefore switching from a static and prescribed vegetation to a dynamic vegetation, allows us to model important biosphere processes, including wildfire, tree mortality, permafrost, hydrological cycling, and the impacts of managed land (crop growth and irrigation).</p><p>With CM2Mc-LPJmL we conducted simulation experiments where atmospheric CO2 concentrations increased from a pre-industrial level up to 1280 ppm (impact phase) followed by a recovery phase where CO2 concentrations reach pre-industrial levels again. This experiment is performed with and without allowing for wildfires. We find a hysteresis of the biomass and vegetation cover in tropical forest systems, with a strong regional heterogeneity. After biomass loss along increasing atmospheric CO2 concentrations and accompanied mean surface temperature increase of about 4°C (impact phase), the system does not recover completely into its original state on its return path, even though atmospheric CO2 concentrations return to their original state. While not detecting large-scale tipping points, our results show a climate-induced hysteresis in tropical forest and lagged responses in forest recovery after the climate has returned to its original state. Wildfires slightly widen the climate-induced hysteresis in tropical forests and lead to a lagged response in forest recovery by ca. 30 years.</p>

Elevated Atmospheric CO2 Increases Root Exudation of Carbon in Wetlands: Results from the First Free-Air CO2 Enrichment Facility (FACE) in a Marshland

Ecosystems ◽  
2017 ◽  
Vol 21 (5) ◽  
pp. 852-867 ◽  
Author(s):  
Salvador Sánchez-Carrillo ◽  
Miguel Álvarez-Cobelas ◽  
David G. Angeler ◽  
Lilia Serrano-Grijalva ◽  
Raquel Sánchez-Andrés ◽  
...  
Keyword(s):  
Root Exudation ◽  
Co2 Enrichment ◽  
Atmospheric Co2 ◽  
Enrichment Facility ◽  
Elevated Atmospheric Co2 ◽  
Free Air Co2 Enrichment ◽  
Free Air

scholarly journals Soybean-BioCro: A semi-mechanistic model of soybean growth

2021 ◽  
Author(s):  
Megan L Matthews ◽  
Amy Marshall-Colón ◽  
Justin M McGrath ◽  
Edward B Lochocki ◽  
Stephen P Long
Keyword(s):  
Elevated Co2 ◽  
Mechanistic Model ◽  
Co2 Enrichment ◽  
Field Measurements ◽  
Atmospheric Co2 ◽  
Growth And Yield ◽  
Elevated Atmospheric Co2 ◽  
Crop Models ◽  
Growing Seasons ◽  
Or Gene

Abstract Soybean is a major global source of protein and oil. Understanding how soybean crops will respond to the changing climate and identifying the responsible molecular machinery, are important for facilitating bioengineering and breeding to meet the growing global food demand. The BioCro family of crop models are semi-mechanistic models scaling from biochemistry to whole crop growth and yield. BioCro was previously parameterized and proved effective for the biomass crops miscanthus, coppice willow, and Brazilian sugarcane. Here, we present Soybean-BioCro, the first food crop to be parameterized for BioCro. Two new module sets were incorporated into the BioCro framework describing the rate of soybean development and carbon partitioning and senescence. The model was parameterized using field measurements collected over the 2002 and 2005 growing seasons at the open air [CO2] enrichment (SoyFACE) facility under ambient atmospheric [CO2]. We demonstrate that Soybean-BioCro successfully predicted how elevated [CO2] impacted field-grown soybean growth without a need for re-parameterization, by predicting soybean growth under elevated atmospheric [CO2] during the 2002 and 2005 growing seasons, and under both ambient and elevated [CO2] for the 2004 and 2006 growing seasons. Soybean-BioCro provides a useful foundational framework for incorporating additional primary and secondary metabolic processes or gene regulatory mechanisms that can further aid our understanding of how future soybean growth will be impacted by climate change.

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