scholarly journals Thermal Acclimation of Foliar Carbon Metabolism in Pinus taiwanensis Along an Elevational Gradient

2022 ◽  
Vol 12 ◽  
Author(s):  
Min Lyu ◽  
Mengke Sun ◽  
Josep Peñuelas ◽  
Jordi Sardans ◽  
Jun Sun ◽  
...  
Keyword(s):  
Climate Change ◽  
Temperature Response ◽  
Elevational Gradient ◽  
Thermal Acclimation ◽  
Optimal Conditions ◽  
Climatic Warming ◽  
Response Curves ◽  
Respiration Rates ◽  
Time Substitution ◽  
Photosynthesis And Respiration

Climate change could negatively alter plant ecosystems if rising temperatures exceed optimal conditions for obtaining carbon. The acclimation of plants to higher temperatures could mitigate this effect, but the potential of subtropical forests to acclimate still requires elucidation. We used space-for-time substitution to determine the photosynthetic and respiratory-temperature response curves, optimal temperature of photosynthesis (Topt), photosynthetic rate at Topt, temperature sensitivity (Q10), and the rate of respiration at a standard temperature of 25°C (R25) for Pinus taiwanensis at five elevations (1200, 1400, 1600, 1800, and 2000 m) in two seasons (summer and winter) in the Wuyi Mountains in China. The response of photosynthesis in P. taiwanensis leaves to temperature at the five elevations followed parabolic curves, and the response of respiration to temperature increased with temperature. Topt was higher in summer than winter at each elevation and decreased significantly with increasing elevation. Q10 decreased significantly with increasing elevation in summer but not winter. These results showed a strong thermal acclimation of foliar photosynthesis and respiration to current temperatures across elevations and seasons, and that R25 increased significantly with elevation and were higher in winter than summer at each elevation indicating that the global warming can decrease R25. These results strongly suggest that this thermal acclimation will likely occur in the coming decades under climate change, so the increase in respiration rates of P. taiwanensis in response to climatic warming may be smaller than predicted and thus may not increase atmospheric CO2 concentrations.

scholarly journals Effects of climate warming and declining species richness in grassland model ecosystems: acclimation of CO<sub>2</sub> fluxes

2007 ◽  
Vol 4 (1) ◽  
pp. 27-36 ◽  
Author(s):  
S. Vicca ◽  
P. Serrano-Ortiz ◽  
H. J. De Boeck ◽  
C. M. H. M. Lemmens ◽  
I. Nijs ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Cover ◽  
Temperature Response ◽  
Thermal Acclimation ◽  
Continuous Heating ◽  
Co2 Fluxes ◽  
Response Curves ◽  
Model Ecosystems ◽  
Declining Species ◽  
Photosynthesis And Respiration

Abstract. To study the effects of warming and declining species richness on the carbon balance of grassland communities, model ecosystems containing one, three or nine species were exposed to ambient and elevated (ambient +3°C) air temperature. In this paper, we analyze measured ecosystem CO2 fluxes to test whether ecosystem photosynthesis and respiration had acclimated to warming after 28 months of continuous heating, and whether the degree of acclimation depended on species richness. In order to test whether acclimation occurred, short term temperature response curves were established for all communities in both treatments. At similar temperatures, lower flux rates in the heated communities as compared to the unheated communities would indicate thermal acclimation. Because plant cover was significantly higher in the heated treatment, we normalized the data for plant cover. Subsequently, down-regulation of both photosynthesis and respiration was observed. Although CO2 fluxes were larger in communities with higher species richness, species richness did not affect the degree of acclimation to warming. These results imply that models need to take thermal acclimation into account to simulate photosynthesis and respiration in a warmer world.

scholarly journals Differences in Leaf Temperature between Lianas and Trees in the Neotropical Canopy

2018 ◽  
Author(s):  
J. Antonio Guzmán Q. ◽  
G. Arturo Sánchez-Azofeifa ◽  
Benoit Rivard
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Temperature Response ◽  
Life Forms ◽  
Leaf Temperature ◽  
Response Curves ◽  
Tropical Environments ◽  
Host Trees ◽  
Temperature Responses ◽  
Photosynthesis And Respiration

Leaf temperature (Tleaf) influences photosynthesis and respiration. Currently, there is a growing interest on including lianas in productivity models due to their increasing abundance, and their detrimental effects on net primary productivity in tropical environments. Therefore, understanding the differences of Tleaf between lianas and trees is important for future of forest on whole ecosystem productivity. Here we determined the displayed leaf temperature (Td= Tleaf &ndash; ambient temperature) of several species of lianas and their host trees during ENSO and non-ENSO years to evaluate if the presence of lianas affects the Td of their host trees, and if leaves of lianas and their host trees exhibit differences in Td. Our results suggest that close to midday, the presence of lianas does not affect the Td of their host trees; however, lianas tend to have higher values of Td than their hosts across seasons, in both ENSO and non-ENSO years. Although lianas and trees tend to have similar physiological-temperature responses, differences in Td could lead to significant differences in rates of photosynthesis and respiration based temperature response curves. Future models should thus consider differences in leaf temperature between these life forms to achieve robust predictions of productivity.

Acclimation of leaf dark respiration to nocturnal and diurnal warming in a semiarid temperate steppe

2013 ◽  
Vol 40 (11) ◽  
pp. 1159 ◽  
Author(s):  
Yonggang Chi ◽  
Ming Xu ◽  
Ruichang Shen ◽  
Shiqiang Wan
Keyword(s):  
Dark Respiration ◽  
Temperature Response ◽  
Terrestrial Ecosystems ◽  
Northern China ◽  
Thermal Acclimation ◽  
Nonstructural Carbohydrates ◽  
Temperate Steppe ◽  
Response Curves ◽  
Diurnal Warming ◽  
Leaf Dark Respiration

A better understanding of thermal acclimation of leaf dark respiration in response to nocturnal and diurnal warming could help accurately predict the changes in carbon exchange of terrestrial ecosystems under global warming, especially under the asymmetric warming. A field manipulative experiment was established with control, nocturnal warming (1800–0600 hours), diurnal warming (0600–1800 hours), and diel warming (24 h) under naturally fluctuating conditions in a semiarid temperate steppe in northern China in April 2006. Temperature response curves of in situ leaf dark respiration for Stipa krylovii Roshev. were measured at night (Rn) and after 30 min of darkness imposed in the daytime (Rd). Leaf nonstructural carbohydrates were determined before sunrise and at sunset. Results showed that Rn could acclimate to nocturnal warming and diurnal warming, but Rd could not. The decreases in Q10 (temperature sensitivity) of Rn under nocturnal-warming and diurnal warming regimes might be attributed to greater depletion of total nonstructural carbohydrates (TNC). The real-time and intertwined metabolic interactions between chloroplastic and mitochondrial metabolism in the daytime could affect the impacts of warming on metabolite pools and the distinct response of Rn and Rd to warming. Projection on climate change–carbon feedback under climate warming must account for thermal acclimation of leaf dark respiration separately by Rn and Rd.

scholarly journals Response of Northern Populations of Black Spruce and Jack Pine to Southward Seed Transfers: Implications for Climate Change

Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1363
Author(s):  
John H. Pedlar ◽  
Daniel W. McKenney ◽  
Pengxin Lu ◽  
Ashley Thomson
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
Black Spruce ◽  
Jack Pine ◽  
Seed Source ◽  
Response Curves ◽  
Climate Change Responses ◽  
Provenance Data ◽  
Time Substitution ◽  
Potential Climate Change

A variety of responses to climate change have been reported for northern tree populations, primarily from tree-ring and satellite-based studies. Here we employ provenance data to examine growth and survival responses of northern populations (defined here as those occurring north of 52° N) of black spruce (Picea mariana) and jack pine (Pinus banksiana) to southward seed transfers. This space for time substitution affords insights into potential climate change responses by these important northern tree species. Based on previous work, we anticipated relatively flat response curves that peak at much warmer temperatures than those found at seed source origin. These expectations were generally met for growth-related responses, with peak growth associated with seed transfers to environments with mean annual temperatures 2.2 and 3.6 °C warmer than seed source origin for black spruce and jack pine, respectively. These findings imply that northern tree populations harbor a significant amount of resilience to climate warming. However, survival responses told a different story, with both species exhibiting reduced survival rates when moved to warmer and drier environments. Together with the growth-based results, these findings suggest that the warmer and drier conditions expected across much of northern Canada under climate change may reduce survival, but surviving trees may grow at a faster rate up until a certain magnitude of climate warming has been reached. We note that all relationships had high levels of unexplained variation, underlining the many factors that may influence provenance study outcomes and the challenges in predicting tree responses to climate change. Despite certain limitations, we feel that the provenance data employed here provide valuable insights into potential climate change outcomes for northern tree populations.

scholarly journals Temperature response of soil respiration largely unaltered with experimental warming

2016 ◽  
Vol 113 (48) ◽  
pp. 13797-13802 ◽  
Author(s):  
Joanna C. Carey ◽  
Jianwu Tang ◽  
Pamela H. Templer ◽  
Kevin D. Kroeger ◽  
Thomas W. Crowther ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Temperature Sensitivity ◽  
Boreal Forests ◽  
Temperature Response ◽  
Experimental Warming ◽  
Climatic Warming ◽  
Ambient Temperatures ◽  
Respiration Rates ◽  
Temperature Manipulation ◽  
Scientific Attention

The respiratory release of carbon dioxide (CO2) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold of ∼25 °C, above which respiration rates decrease with further increases in temperature. This consistent decrease in temperature sensitivity at higher temperatures demonstrates that rising global temperatures may result in regionally variable responses in soil respiration, with colder climates being considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic warming.

Modelling the Environmental Niche of Plants: Implications for Plant Community Response to Elevated CO2 Levels.

1992 ◽  
Vol 40 (5) ◽  
pp. 615 ◽  
Author(s):  
MP Austin
Keyword(s):  
Climate Change ◽  
Elevated Co2 ◽  
Temperature Response ◽  
Nutrient Status ◽  
Community Response ◽  
Process Models ◽  
Annual Rainfall ◽  
Mean Annual Temperature ◽  
Environmental Niche ◽  
Response Curves

No simple natural gradients in CO2 concentration exist for testing predictions about changes in plant communities in response to elevated CO2. However indirect effects of CO2 via temperature increases can be tested by reference to natural analogues. Physiologists, vegetation modellers of climate change and community ecologists assume very different temperature responses for plants. Physiologists often assume a skewed non-monotonic curve with a tail towards low temperatures, forest modellers using FORET type models, a symmetric curve, and community ecologists a skewed response with a tail towards high temperatures. These assumptions are reviewed in relation to niche theory, and recent propositions concerning the continuum concept. Confusion exists between the different approaches over the shape of response curves to temperature. Distinctions need to be made between responses due to growth (physiological response), potential fitness (fundamental niche) and observed performance (realized niche). These types of response should be quantified and related to each other if process-models are to be tested for predictive success by reference to naturally occurring communities and temperature gradients. An example of a statistical method for quantifying the realized environmental niche response of a species to temperature is provided. It is based on generalised linear modelling (GLM) of presence/absence data on Eucalyptus fastigata for 8377 sites in southern New South Wales, Australia. Seven environmental variables or factors are considered: mean annual temperature, mean annual rainfall, mean monthly solar radiation, topographic position, rainfall seasonality, lithology, and soil nutrient status. The temperature response is modelled with a β-function, logy = a + α log ( t - a ) + δ log ( b - t), where t is temperature and letters are parameters. The probability of occurrence is shown to be a skewed function of mean annual temperature. Any process-models of climate change for vegetation incorporating temperature changes due to elevated CO2 must be capable of generating such realised environmental niche responses for species.

scholarly journals Continental vs. Global Niche-Based Modelling of Freshwater Species’ Distributions: How Big Are the Differences in the Estimated Climate Change Effects?

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 816
Author(s):  
Danijela Markovic ◽  
Jörg Freyhof ◽  
Oskar Kärcher
Keyword(s):  
Climate Change ◽  
Thermal Properties ◽  
Safety Margin ◽  
Thermal Response ◽  
Future Climate Change ◽  
Freshwater Species ◽  
Response Curves ◽  
Preferred Temperature ◽  
Continental Scale ◽  
Management Actions

Thermal response curves that depict the probability of occurrence along a thermal gradient are used to derive various species’ thermal properties and abilities to cope with warming. However, different thermal responses can be expected for different portions of a species range. We focus on differences in thermal response curves (TRCs) and thermal niche requirements for four freshwater fishes (Coregonus sardinella, Pungitius pungitius, Rutilus rutilus, Salvelinus alpinus) native to Europe at (1) the global and (2) European continental scale. European ranges captured only a portion of the global thermal range with major differences in the minimum (Tmin), maximum (Tmax) and average temperature (Tav) of the respective distributions. Further investigations of the model-derived preferred temperature (Tpref), warming tolerance (WT = Tmax − Tpref), safety margin (SM = Tpref − Tav) and the future climatic impact showed substantially differing results. All considered thermal properties either were under- or overestimated at the European level. Our results highlight that, although continental analyses have an impressive spatial extent, they might deliver misleading estimates of species thermal niches and future climate change impacts, if they do not cover the full species ranges. Studies and management actions should therefore favor whole global range distribution data for analyzing species responses to environmental gradients.

Equilibrium Spin-up of Cold and Warm Permafrost Models

2021 ◽  
Author(s):  
Cameron Ross ◽  
Ryley Beddoe ◽  
Greg Siemens
Keyword(s):  
Climate Change ◽  
Temperature Response ◽  
Ground Temperature ◽  
Future Climate Change ◽  
Climate Projections ◽  
Multiple Model ◽  
Climate Data ◽  
Ground Temperatures ◽  
C Cycle ◽  
Warm Permafrost

&lt;p&gt;Initialization (spin-up) of a numerical ground temperature model is a critical but often neglected step for solving heat transfer problems in permafrost. Improper initialization can lead to significant underlying model drift in subsequent transient simulations, distorting the effects on ground temperature from future climate change or applied infrastructure. &amp;#160;In a typical spin-up simulation, a year or more of climate data are applied at the surface and cycled repeatedly until ground temperatures are declared to be at equilibrium with the imposed boundary conditions, and independent of the starting conditions.&lt;/p&gt;&lt;p&gt;Spin-up equilibrium is often simply declared after a specified number of spin-up cycles. In few studies, equilibrium is visually confirmed by plotting ground temperatures vs spin-up cycles until temperatures stabilize; or is declared when a certain inter-cycle-temperature-change threshold is met simultaneously at all depths, such as &amp;#8710;T &amp;#8804; 0.01&lt;sup&gt;o&lt;/sup&gt;C per cycle. In this study, we investigate the effectiveness of these methods for determining an equilibrium state in a variety of permafrost models, including shallow and deep (10 &amp;#8211; 200 m), high and low saturation soils (S = 100 and S = 20), and cold and warm permafrost (MAGT = ~-10 &lt;sup&gt;o&lt;/sup&gt;C and &gt;-1 &lt;sup&gt;o&lt;/sup&gt;C). The efficacy of equilibrium criteria 0.01&lt;sup&gt;o&lt;/sup&gt;C/cycle and 0.0001&lt;sup&gt;o&lt;/sup&gt;C/cycle are compared. Both methods are shown to prematurely indicate equilibrium in multiple model scenarios. &amp;#160;Results show that no single criterion can programmatically detect equilibrium in all tested models, and in some scenarios can result in up to 10&lt;sup&gt;o&lt;/sup&gt;C temperature error or 80% less permafrost than at true equilibrium. &amp;#160;A combination of equilibrium criteria and visual confirmation plots is recommended for evaluating and declaring equilibrium in a spin-up simulation.&lt;/p&gt;&lt;p&gt;Long-duration spin-up is particularly important for deep (10+&amp;#160;m) ground models where thermal inertia of underlying permafrost slows the ground temperature response to surface forcing, often requiring hundreds or even thousands of spin-up cycles to establish equilibrium. Subsequent transient analyses also show that use of a properly initialized 100 m permafrost model can reduce the effect of climate change on mean annual ground temperature of cold permafrost by more than 1 &lt;sup&gt;o&lt;/sup&gt;C and 3 &lt;sup&gt;o&lt;/sup&gt;C under RCP2.6 and RCP8.5 climate projections, respectively, when compared to an identical 25 m model. These results have important implications for scientists, engineers and policy makers that rely on model projections of long-term permafrost conditions.&lt;/p&gt;

Aquatic community metabolism response to municipal effluent inputs in rivers quantified using diel δ18O values of dissolved oxygen

2010 ◽  
Vol 67 (8) ◽  
pp. 1232-1246 ◽  
Author(s):  
L. I. Wassenaar ◽  
J. J. Venkiteswaran ◽  
S. L. Schiff ◽  
G. Koehler
Keyword(s):  
Municipal Wastewater ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Response Curves ◽  
Aquatic Community ◽  
Nutrient Additions ◽  
Four Seasons ◽  
Upstream Control ◽  
Photosynthesis And Respiration

The spatial footprint over which municipal wastewater effluents cause changes to aquatic community structure and metabolism is key information required for the management of discharges into rivers. Longitudinal studies were undertaken on the Bow and South Saskatchewan rivers, Canada, to assess a new isotopic and modelling approach that combined O2 and δ18O-O2 diel (24 h) response curves to quantify changes in integrated community aquatic metabolism as a result of point-source wastewater inputs. Diel samplings were conducted over four seasons along 50 km transects at Calgary (Bow River) and Saskatoon (South Saskatchewan River). Diel O2 and δ18O-O2 cycles grew in magnitude downstream of effluent inputs in all seasons compared with upstream control sites. δ18O-O2 depletions clearly revealed the stimulating effect of effluent on aquatic photosynthesis. Diel isotopic mass balance modelling showed community metabolic responses to effluent inputs were most pronounced in the spring and summer when photosynthesis and respiration rates were about two- to three-fold higher than at upstream control sites. Our findings revealed that sewage treatment plant nutrient additions resulted in an enhanced metabolic footprint that extended beyond 50 km downstream.

Plant population differentiation and climate change: responses of grassland species along an elevational gradient

2013 ◽  
Vol 20 (2) ◽  
pp. 441-455 ◽  
Author(s):  
Esther R. Frei ◽  
Jaboury Ghazoul ◽  
Philippe Matter ◽  
Martin Heggli ◽  
Andrea R. Pluess
Keyword(s):  
Climate Change ◽  
Population Differentiation ◽  
Elevational Gradient ◽  
Plant Population ◽  
Grassland Species ◽  
Climate Change Responses
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