Seasonality of foliar respiration in two dominant plant species from the Arctic tundra: response to long-term warming and short-term temperature variability

2014 ◽  
Vol 41 (3) ◽  
pp. 287 ◽  
Author(s):  
Mary A. Heskel ◽  
Danielle Bitterman ◽  
Owen K. Atkin ◽  
Matthew H. Turnbull ◽  
Kevin L. Griffin
Keyword(s):  
Carbon Cycling ◽  
Leaf Gas Exchange ◽  
Nitrogen Concentration ◽  
Temperature Variability ◽  
The Arctic ◽  
Photosynthetic Parameters ◽  
Carbon Exchange ◽  
Short Term ◽  
Photosynthesis And Respiration

Direct measurements of foliar carbon exchange through the growing season in Arctic species are limited, despite the need for accurate estimates of photosynthesis and respiration to characterise carbon cycling in the tundra. We examined seasonal variation in foliar photosynthesis and respiration (measured at 20°C) in two field-grown tundra species, Betula nana L. and Eriophorum vaginatum L., under ambient and long-term warming (LTW) conditions (+5°C), and the relationship of these fluxes to intraseasonal temperature variability. Species and seasonal timing drove most of the variation in photosynthetic parameters (e.g. gross photosynthesis (Agross)), respiration in the dark (Rdark) and light (Rlight), and foliar nitrogen concentration. LTW did not consistently influence fluxes through the season but reduced respiration in both species. Alongside the flatter respiratory response to measurement temperature in LTW leaves, this provided evidence of thermal acclimation. The inhibition of respiration by light increased by ~40%, with Rlight : Rdark values of ~0.8 at leaf out decreasing to ~0.4 after 8 weeks. Though LTW had no effect on inhibition, the cross-taxa seasonal decline in Rlight : Rdark greatly reduced respiratory carbon loss. Values of Rlight : Agross decreased from ~0.3 in both species to ~0.15 (B. nana) and ~0.05 (E. vaginatum), driven by decreases in respiratory rates, as photosynthetic rates remained stable. The influence of short-term temperature variability did not exhibit predictive trends for leaf gas exchange at a common temperature. These results underscore the influence of temperature on foliar carbon cycling, and the importance of respiration in controlling seasonal carbon exchange.

scholarly journals Contrasting effects of long term versus short-term nitrogen addition on photosynthesis and respiration in the Arctic

Plant Ecology ◽  
2013 ◽  
Vol 214 (10) ◽  
pp. 1273-1286 ◽  
Author(s):  
Martine J. van de Weg ◽  
Gaius R. Shaver ◽  
Verity G. Salmon
Keyword(s):  
Nitrogen Addition ◽  
The Arctic ◽  
Short Term ◽  
Photosynthesis And Respiration

scholarly journals Seasonal temperature variability and emergency hospital admissions for respiratory diseases: a population-based cohort study

Thorax ◽  
2018 ◽  
Vol 73 (10) ◽  
pp. 951-958 ◽  
Author(s):  
Shengzhi Sun ◽  
Francine Laden ◽  
Jaime E Hart ◽  
Hong Qiu ◽  
Yan Wang ◽  
...  
Keyword(s):  
Respiratory Diseases ◽  
Hospital Admissions ◽  
Temperature Variability ◽  
Seasonal Temperature ◽  
Short Term ◽  
Emergency Hospital ◽  
Emergency Hospital Admissions ◽  
Mean Temperature

BackgroundClimate change increases global mean temperature and changes short-term (eg, diurnal) and long-term (eg, intraseasonal) temperature variability. Numerous studies have shown that mean temperature and short-term temperature variability are both associated with increased respiratory morbidity or mortality. However, data on the impact of long-term temperature variability are sparse.ObjectiveWe aimed to assess the association of intraseasonal temperature variability with respiratory disease hospitalisations among elders.MethodsWe ascertained the first occurrence of emergency hospital admissions for respiratory diseases in a prospective Chinese elderly cohort of 66 820 older people (≥65 years) with 10–13 years of follow-up. We used an ordinary kriging method based on 22 weather monitoring stations in Hong Kong to spatially interpolate daily ambient temperature for each participant’s residential address. Seasonal temperature variability was defined as the SD of daily mean summer (June–August) or winter (December–February) temperatures. We applied Cox proportional hazards regression with time-varying exposure of seasonal temperature variability to respiratory admissions.ResultsDuring the follow-up time, we ascertained 12 689 cases of incident respiratory diseases, of which 6672 were pneumonia and 3075 were COPD. The HRs per 1°C increase in wintertime temperature variability were 1.20 (95% CI 1.08 to 1.32), 1.15 (1.01 to 1.31) and 1.41 (1.15 to 1.71) for total respiratory diseases, pneumonia and COPD, respectively. The associations were not statistically significant for summertime temperature variability.ConclusionWintertime temperature variability was associated with higher risk of incident respiratory diseases.

scholarly journals Challenges in modelling isoprene and monoterpene emission dynamics of Arctic plants: a case study from a subarctic tundra heath

2016 ◽  
Vol 13 (24) ◽  
pp. 6651-6667 ◽  
Author(s):  
Jing Tang ◽  
Guy Schurgers ◽  
Hanna Valolahti ◽  
Patrick Faubert ◽  
Päivi Tiiva ◽  
...  
Keyword(s):  
Response Curve ◽  
Large Scale ◽  
Ecosystem Model ◽  
The Arctic ◽  
Short Term ◽  
Response Curves ◽  
Arctic Plants ◽  
Scale Modelling

Abstract. The Arctic is warming at twice the global average speed, and the warming-induced increases in biogenic volatile organic compounds (BVOCs) emissions from Arctic plants are expected to be drastic. The current global models' estimations of minimal BVOC emissions from the Arctic are based on very few observations and have been challenged increasingly by field data. This study applied a dynamic ecosystem model, LPJ-GUESS, as a platform to investigate short-term and long-term BVOC emission responses to Arctic climate warming. Field observations in a subarctic tundra heath with long-term (13-year) warming treatments were extensively used for parameterizing and evaluating BVOC-related processes (photosynthesis, emission responses to temperature and vegetation composition). We propose an adjusted temperature (T) response curve for Arctic plants with much stronger T sensitivity than the commonly used algorithms for large-scale modelling. The simulated emission responses to 2 °C warming between the adjusted and original T response curves were evaluated against the observed warming responses (WRs) at short-term scales. Moreover, the model responses to warming by 4 and 8 °C were also investigated as a sensitivity test. The model showed reasonable agreement to the observed vegetation CO2 fluxes in the main growing season as well as day-to-day variability of isoprene and monoterpene emissions. The observed relatively high WRs were better captured by the adjusted T response curve than by the common one. During 1999–2012, the modelled annual mean isoprene and monoterpene emissions were 20 and 8 mg C m−2 yr−1, with an increase by 55 and 57 % for 2 °C summertime warming, respectively. Warming by 4 and 8 °C for the same period further elevated isoprene emission for all years, but the impacts on monoterpene emissions levelled off during the last few years. At hour-day scale, the WRs seem to be strongly impacted by canopy air T, while at the day–year scale, the WRs are a combined effect of plant functional type (PFT) dynamics and instantaneous BVOC responses to warming. The identified challenges in estimating Arctic BVOC emissions are (1) correct leaf T estimation, (2) PFT parameterization accounting for plant emission features as well as physiological responses to warming, and (3) representation of long-term vegetation changes in the past and the future.

Thermal acclimation of respiration but not photosynthesis in Pinus radiata

2008 ◽  
Vol 35 (6) ◽  
pp. 448 ◽  
Author(s):  
Lai Fern Ow ◽  
David Whitehead ◽  
Adrian S. Walcroft ◽  
Matthew H. Turnbull
Keyword(s):  
Pinus Radiata ◽  
Growth Temperature ◽  
Dark Respiration ◽  
Temperature Acclimation ◽  
Short Term ◽  
Photosynthesis And Respiration ◽  
Term Response ◽  
N Status ◽  
Respiratory Responses

Pinus radiata L. were grown in climate-controlled cabinets under three night/day temperature treatments, and transferred between treatments to mimic changes in growth temperature. The objective was to determine the extent to which dark respiration and photosynthesis in pre-existing and new needles acclimate to changes in growth temperatures. We also assessed whether needle nitrogen influenced the potential for photosynthetic and respiratory acclimation, and further assessed if short-term (instantaneous, measured over a few hours) respiratory responses are accurate predictors of long-term (acclimated, achieved in days–weeks) responses of respiration to changing temperature. Results show that respiration displayed considerable potential for acclimation. Cold and warm transfers resulted in some acclimation of respiration in pre-existing needles, but full acclimation was displayed only in new needles formed at the new growth temperature. Short-term respiratory responses were poor predictors of the long-term response of respiration due to acclimation. There was no evidence that photosynthesis in pre-existing or new needles acclimated to changes in growth temperature. N status of leaves had little impact on the extent of acclimation. Collectively, our results indicate that there is little likelihood that respiration would be significantly stimulated in this species as night temperatures increase over the range of 10–20°C, but that inclusion of temperature acclimation of respiration would in fact lead to a shift in the balance between photosynthesis and respiration in favour of carbon uptake.

scholarly journals Rapid retreat of permafrost coastline observed with aerial drone photogrammetry

2019 ◽  
Vol 13 (5) ◽  
pp. 1513-1528 ◽  
Author(s):  
Andrew M. Cunliffe ◽  
George Tanski ◽  
Boris Radosavljevic ◽  
William F. Palmer ◽  
Torsten Sachs ◽  
...  
Keyword(s):  
Coastal Erosion ◽  
Average Rate ◽  
Temporal Frequency ◽  
Shoreline Change ◽  
Yukon Territory ◽  
Aerial Photographs ◽  
The Arctic ◽  
Storm Events ◽  
Short Term

Abstract. Permafrost landscapes are changing around the Arctic in response to climate warming, with coastal erosion being one of the most prominent and hazardous features. Using drone platforms, satellite images, and historic aerial photographs, we observed the rapid retreat of a permafrost coastline on Qikiqtaruk – Herschel Island, Yukon Territory, in the Canadian Beaufort Sea. This coastline is adjacent to a gravel spit accommodating several culturally significant sites and is the logistical base for the Qikiqtaruk – Herschel Island Territorial Park operations. In this study we sought to (i) assess short-term coastal erosion dynamics over fine temporal resolution, (ii) evaluate short-term shoreline change in the context of long-term observations, and (iii) demonstrate the potential of low-cost lightweight unmanned aerial vehicles (“drones”) to inform coastline studies and management decisions. We resurveyed a 500 m permafrost coastal reach at high temporal frequency (seven surveys over 40 d in 2017). Intra-seasonal shoreline changes were related to meteorological and oceanographic variables to understand controls on intra-seasonal erosion patterns. To put our short-term observations into historical context, we combined our analysis of shoreline positions in 2016 and 2017 with historical observations from 1952, 1970, 2000, and 2011. In just the summer of 2017, we observed coastal retreat of 14.5 m, more than 6 times faster than the long-term average rate of 2.2±0.1 m a−1 (1952–2017). Coastline retreat rates exceeded 1.0±0.1 m d−1 over a single 4 d period. Over 40 d, we estimated removal of ca. 0.96 m3 m−1 d−1. These findings highlight the episodic nature of shoreline change and the important role of storm events, which are poorly understood along permafrost coastlines. We found drone surveys combined with image-based modelling yield fine spatial resolution and accurately geolocated observations that are highly suitable to observe intra-seasonal erosion dynamics in rapidly changing Arctic landscapes.

scholarly journals Physiological framework for adaptation of stomata to CO 2 from glacial to future concentrations

2012 ◽  
Vol 367 (1588) ◽  
pp. 537-546 ◽  
Author(s):  
Peter J. Franks ◽  
Ilia J. Leitch ◽  
Elizabeth M. Ruszala ◽  
Alistair M. Hetherington ◽  
David J. Beerling
Keyword(s):  
Leaf Surface ◽  
Unit Area ◽  
Leaf Gas Exchange ◽  
Feedback Regulation ◽  
Cell Nuclei ◽  
Short Term ◽  
Dna Amount ◽  
Taxonomic Range ◽  
Operational Range

In response to short-term fluctuations in atmospheric CO 2 concentration, c a , plants adjust leaf diffusive conductance to CO 2 , g c , via feedback regulation of stomatal aperture as part of a mechanism for optimizing CO 2 uptake with respect to water loss. The operational range of this elaborate control mechanism is determined by the maximum diffusive conductance to CO 2 , g c(max) , which is set by the size ( S ) and density (number per unit area, D ) of stomata on the leaf surface. Here, we show that, in response to long-term exposure to elevated or subambient c a , plants alter g c(max) in the direction of the short-term feedback response of g c to c a via adjustment of S and D . This adaptive feedback response to c a , consistent with long-term optimization of leaf gas exchange, was observed in four species spanning a diverse taxonomic range (the lycophyte Selaginella uncinata , the fern Osmunda regalis and the angiosperms Commelina communis and Vicia faba ). Furthermore, using direct observation as well as flow cytometry, we observed correlated increases in S , guard cell nucleus size and average apparent 1C DNA amount in epidermal cell nuclei with increasing c a , suggesting that stomatal and leaf adaptation to c a is linked to genome scaling.

Transition to sustainable development of cities and regions Baikal natural territory and the Arctic zone of the Russian Federation

2020 ◽  
pp. 37-46
Author(s):  
S.M. Nikonorov ◽  
S.N. Kirillov ◽  
M.V. Slipenchuk
Keyword(s):  
Sustainable Development ◽  
Russian Federation ◽  
The Arctic ◽  
Arctic Zone ◽  
Short Term ◽  
Complex Concept ◽  
The Russian Federation ◽  
Constituent Elements ◽  
Natural Territory

In our study, a comparative analysis is made between cities and regions of the Baikal natural territory and the Arctic zone of the Russian Federation. The main goals of sustainable development for the Baikal natural territory are outlined. By focusing on sustainable development, we focus on the long-term, not the short-term. Analyzing this complex concept, the article presents several aspects and constituent elements of sustainable development. The paper presents the analytics of sustainable development of cities and regions of the Arctic zone of the Russian Federation and the Baikal natural territory. The article analyzes the socio-economic indicators of the development of the regions of the Arctic zone of the Russian Federation and the Baikal natural territory.

Temporal scale and the accumulation of peat in a Sphagnum bog

1996 ◽  
Vol 74 (3) ◽  
pp. 366-377 ◽  
Author(s):  
Lisa R. Belyea ◽  
Barry G. Warner
Keyword(s):  
Mass Loss ◽  
Decay Rate ◽  
Nitrogen Concentration ◽  
Rate Coefficients ◽  
Short Term ◽  
Concentration Data ◽  
Peat Accumulation ◽  
Litter Bag ◽  
Sphagnum Bog

We examined short-term (decadal) and long-term (millenial) processes of peat accumulation, and the links between them, in a Sphagnum bog in continental Canada. A previously published model of bog growth was fitted to age profiles of the oxic acrotelm (surface, < 60 cm thick) and the underlying, anoxic catotelm (210 cm thick). Approximately 5300 years of accumulation were represented in a radiocarbon-dated core that extended to the base of the deepest part of the peat deposit. The model estimated that the overall rate at which material entered long-term storage in the catotelm was 60–66 g∙m−2∙a−1. Although the decay rate coefficient was near zero, the bog stopped accumulating peat within the past 1500 years, resulting from either a decrease in the rate of transfer of material from the acrotelm or an increase in the rate of decay of material at the top of the catotelm. The model of bog growth estimated recent inputs to the acrotelm (90–930 g∙m−2∙a−1) that were twofold higher than published field measurements of aboveground productivity, and decay rate coefficients (0.005–0.040 a−1) that were 10-fold lower than published litter-bag measurements of mass loss. The pattern of mass loss over time, approximated from nitrogen concentration data, deviated from the pattern predicted by exponential models of decay. Calculations of the balance between additions to and losses from the acrotelm suggest that the amount of material transferred to the underlying catotelm differs among microhabitats. Such spatial variability in short-term processes is incompatible with long-term processes determining the position of the acrotelm–catotelm boundary. We discuss the applicability of the model to continental peatlands and suggest ways to improve modelling of short-term autogenic processes. Keywords: peatland, peat accumulation, organic matter, decomposition, age profiles, mathematical models.

scholarly journals What are the challenges for modelling isoprene and monoterpene emission dynamics of subarctic plants?

2016 ◽  
Author(s):  
Jing Tang ◽  
Guy Schurgers ◽  
Hanna Valolahti ◽  
Patrick Faubert ◽  
Päivi Tiiva ◽  
...  
Keyword(s):  
Response Curve ◽  
Large Scale ◽  
Ecosystem Model ◽  
The Arctic ◽  
Emission Rates ◽  
Short Term ◽  
Response Curves ◽  
Arctic Plants ◽  
Scale Modelling

Abstract. The Arctic is warming at twice the global average speed, and the warming-induced increases in biogenic volatile organic compounds (BVOC) emissions from arctic plants are expected to be drastic. The current global models' estimations of minimal BVOC emissions from the Arctic are based on very few observations and have been challenged by increasing field data. This study applied a dynamic ecosystem model, LPJ-GUESS, as a platform to investigate short-term and long-term BVOC emission responses to climate warming. Field observations in a subarctic heath tundra with long-term (13 years) warming treatments were extensively used for parameterizing and evaluating BVOC related processes. We proposed an adjusted temperature (T) response curve for arctic plants with much stronger T sensitivity than the commonly-used algorithms for large-scale modelling. The simulated emission responses to 2 °C warming between the adjusted and original T response curves in the model were evaluated against the observed warming responses (WR) at short-term scales. Moreover, the model's responses to higher levels' warming (4 °C and 8 °C) were also investigated as a sensitivity test. The model was able to reproduce vegetation CO2 fluxes as well as day-to-day variability of isoprene and monoterpene emissions. The modelled BVOC WR, especially for isoprene, were better captured by using the adjusted T response curve, comparing with using the original one. A few days' underestimation of leaf T led to the underestimated emission rates as well as WR. During 1999–2012, the modelled annual mean isoprene and monoterpene emissions were 20 and 8 mg C m−2 yr−1, with an increase in emission by 55 % and 57 % for 2 °C summertime warming, respectively. Warming by 4 °C and 8 °C further elevated isoprene emission for all years compared with 2 °C warming, but the impacts on monoterpene emissions levelled off because of a decreased coverage of monoterpene-emitters among the evergreen prostrate dwarf shrubs. The high WR captured by the adjusted T response curve highlight the strong T sensitivity of arctic plants. At short-term scale, the WR seem to be strongly impacted by leaf T; while at long-term scale, the WR are a combined effect of plant functional type (PFT) dynamics as well as instantaneous BVOC responses to warming. The identified essential issues associated with estimating arctic BVOC emissions are: (1) leaf T estimation/extrapolation based on air T; (2) PFT parameterization accounting for BVOC emission features as well as PFT's responses to warming; and (3) representation of vegetation dynamics in the past and the future.

Soil water availability influences the temperature response of photosynthesis and respiration in a grass and a woody shrub

2014 ◽  
Vol 41 (5) ◽  
pp. 468 ◽  
Author(s):  
Tony Joseph ◽  
David Whitehead ◽  
Matthew H. Turnbull
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Temperature Sensitivity ◽  
Photosynthetic Capacity ◽  
Temperature Response ◽  
Photosynthetic Parameters ◽  
Short Term ◽  
Respiratory Capacity ◽  
Photosynthesis And Respiration

Seedlings of the shrub kānuka (Kunzea ericoides var. ericoides (A. Rich) J. Thompson) and the pasture grass brown top (Agrostis capillarus L.) were grown in intact soil cores in climate-controlled cabinets to analyse the thermal response of leaf-level carbon exchange at four levels of volumetric soil water content (θ). The objective was to resolve the combined effects of relatively rapid and short-term changes in θ and temperature on the thermal responses of both photosynthesis and respiration in these two contrasting plant types. Results showed that θ had a greater effect on the short-term temperature response of photosynthesis than the temperature response of respiration. The optimum value of θ for net photosynthesis was around 30% for both plants. The photosynthetic capacity of kānuka and the grass declined significantly when θ fell below 20%. The temperature sensitivity of photosynthesis was low at low soil water content and increased at moderate to high soil water content in both plant types. Statistical analysis showed that the temperature sensitivity of photosynthetic parameters was similar for both plant types, but the sensitivity of respiratory parameters differed. Respiratory capacity increased with increasing soil water content in kānuka but declined significantly when θ fell below 15%. There was no significant influence of soil water content on respiratory capacity in the grass. Collectively, our results indicate that θ influenced the temperature sensitivity of photosynthesis and respiration, and altered the balance between foliar respiration and photosynthetic capacity in both plant types.

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