Skip header and navigation

3 records – page 1 of 1.

Fast Responses of Root Dynamics to Increased Snow Deposition and Summer Air Temperature in an Arctic Wetland.

https://arctichealth.org/en/permalink/ahliterature294864
Source
Front Plant Sci. 2018; 9:1258
Publication Type
Journal Article
Date
2018
Author
Ludovica D'Imperio
Marie F Arndal
Cecilie S Nielsen
Bo Elberling
Inger K Schmidt
Author Affiliation
Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark.
Source
Front Plant Sci. 2018; 9:1258
Date
2018
Language
English
Publication Type
Journal Article
Abstract
In wet tundra ecosystems, covering vast areas of the Arctic, the belowground plant biomass exceeds the aboveground, making root dynamics a crucial component of the nutrient cycling and the carbon (C) budget of the Arctic. In response to the projected climatic scenarios for the Arctic, namely increased temperature and changes in precipitation patterns, root dynamics may be altered leading to significant changes in the net ecosystem C budget. Here, we quantify the single and combined effects of 1 year of increased winter snow deposition by snow fences and summer warming by open-top chambers (OTCs) on root dynamics in a wetland at Disko Island (West Greenland). Based on ingrowth bags, snow accumulation decreased root productivity by 42% in the 0-15 cm soil depth compared to ambient conditions. Over the growing season 2014, minirhizotron observations showed that root growth continued until mid-September in all treatments, and it peaked between the end of July and mid-August. During the season, plots exposed to experimental warming showed a significant increase in root number during September (between 39 and 53%) and a 39% increase in root length by the beginning of September. In addition, a significant reduction of root diameter (14%) was observed in plots with increased snow accumulation. Along the soil profile (0-40 cm) summer warming by OTCs significantly increased the total root length (54%), root number (41%) and the root growth in the 20-30 cm soil depth (71%). These results indicate a fast response of this ecosystem to changes in air temperature and precipitation. Hence, on a short-term, summer warming may lead to increased root depth and belowground C allocation, whereas increased winter snow precipitation may reduce root production or favor specific plant species by means of reduced growing season length or increased nutrient cycling. Knowledge on belowground root dynamics is therefore critical to improve the estimation of the C balance of the Arctic.
Notes
Cites: Plant Sci. 2011 Jan;180(1):157-67 PMID 21421357
Cites: New Phytol. 2016 Feb;209(3):978-86 PMID 26390239
Cites: Sci Rep. 2015 Dec 09;5:17951 PMID 26647837
Cites: Sci Rep. 2018 Jan 25;8(1):1586 PMID 29371633
Cites: Oecologia. 1999 Sep;120(4):575-581 PMID 28308308
Cites: Sci Total Environ. 2016 May 15;553:297-304 PMID 26933965
Cites: Ecol Appl. 2015 Jan;25(1):99-115 PMID 26255360
Cites: Glob Chang Biol. 2015 Jun;21(6):2410-23 PMID 25788025
Cites: New Phytol. 2008;179(3):837-47 PMID 18537885
Cites: Oecologia. 2005 Feb;142(4):616-26 PMID 15688218
Cites: New Phytol. 2015 Jan;205(1):34-58 PMID 25209220
Cites: Glob Chang Biol. 2014 Oct;20(10):3256-69 PMID 24599697
Cites: Glob Chang Biol. 2015 Dec;21(12):4520-32 PMID 26183112
Cites: Nature. 2004 Sep 23;431(7007):440-3 PMID 15386009
Cites: J Exp Bot. 2016 Jun;67(12):3617-28 PMID 26931171
Cites: New Phytol. 2007;176(4):862-73 PMID 17937761
Cites: New Phytol. 2015 Feb;205(3):1054-61 PMID 25729805
Cites: Oecologia. 1977 Mar;28(1):57-65 PMID 28309688
Cites: Oecologia. 2007 Sep;153(3):643-52 PMID 17497180
PubMed ID
30214452 View in PubMed
Less detail

Methane oxidation in contrasting soil types: responses to experimental warming with implication for landscape-integrated CH4 budget.

https://arctichealth.org/en/permalink/ahliterature274556
Source
Glob Chang Biol. 2016 Jul 15;
Publication Type
Article
Date
Jul-15-2016
Author
Ludovica D'Imperio
Cecilie Skov Nielsen
Andreas Westergaard-Nielsen
Anders Michelsen
Bo Elberling
Source
Glob Chang Biol. 2016 Jul 15;
Date
Jul-15-2016
Language
English
Publication Type
Article
Abstract
Arctic ecosystems are characterized by a wide range of soil moisture conditions and thermal regimes and contribute differently to the net methane (CH4 ) budget. Yet, it is unclear how climate change will affect the capacity of those systems to act as a net source or sink of CH4 . Here, we present results of in situ CH4 flux measurements made during the growing season 2014 on Disko Island (west Greenland) and quantify the contribution of contrasting soil and landscape types to the net CH4 budget and responses to summer warming. We compared gas flux measurements from a bare soil and a dry heath, at ambient conditions and increased air temperature, using open-top chambers (OTCs). Throughout the growing season, bare soil consumed 0.22 ± 0.03 g CH4 -C m(-2) (8.1 ± 1.2 g CO2 -eq m(-2) ) at ambient conditions, while the dry heath consumed 0.10 ± 0.02 g CH4 -C m(-2) (3.9 ± 0.6 g CO2 -eq m(-2) ). These uptake rates were subsequently scaled to the entire study area of 0.15 km(2) , a landscape also consisting of wetlands with a seasonally integrated methane release of 0.10 ± 0.01 g CH4 -C m(-2) (3.7 ± 1.2 g CO2 -eq m(-2) ). The result was a net landscape sink of 12.71 kg CH4 -C (0.48 tonne CO2 -eq) during the growing season. A nonsignificant trend was noticed in seasonal CH4 uptake rates with experimental warming, corresponding to a 2% reduction at the bare soil, and 33% increase at the dry heath. This was due to the indirect effect of OTCs on soil moisture, which exerted the main control on CH4 fluxes. Overall, the net landscape sink of CH4 tended to increase by 20% with OTCs. Bare and dry tundra ecosystems should be considered in the net CH4 budget of the Arctic due to their potential role in counterbalancing CH4 emissions from wetlands - not the least when taking the future climatic scenarios of the Arctic into account.
PubMed ID
27416869 View in PubMed
Less detail

Survival of rapidly fluctuating natural low winter temperatures by High Arctic soil invertebrates.

https://arctichealth.org/en/permalink/ahliterature268082
Source
J Therm Biol. 2015 Dec;54:111-7
Publication Type
Article
Date
Dec-2015
Author
Peter Convey
Holly Abbandonato
Frode Bergan
Larissa Teresa Beumer
Elisabeth Machteld Biersma
Vegard Sandøy Bråthen
Ludovica D'Imperio
Christina Kjellerup Jensen
Solveig Nilsen
Karolina Paquin
Ute Stenkewitz
Mildrid Elvik Svoen
Judith Winkler
Eike Müller
Stephen James Coulson
Source
J Therm Biol. 2015 Dec;54:111-7
Date
Dec-2015
Language
English
Publication Type
Article
Abstract
The extreme polar environment creates challenges for its resident invertebrate communities and the stress tolerance of some of these animals has been examined over many years. However, although it is well appreciated that standard air temperature records often fail to describe accurately conditions experienced at microhabitat level, few studies have explicitly set out to link field conditions experienced by natural multispecies communities with the more detailed laboratory ecophysiological studies of a small number of 'representative' species. This is particularly the case during winter, when snow cover may insulate terrestrial habitats from extreme air temperature fluctuations. Further, climate projections suggest large changes in precipitation will occur in the polar regions, with the greatest changes expected during the winter period and, hence, implications for the insulation of overwintering microhabitats. To assess survival of natural High Arctic soil invertebrate communities contained in soil and vegetation cores to natural winter temperature variations, the overwintering temperatures they experienced were manipulated by deploying cores in locations with varying snow accumulation: No Snow, Shallow Snow (30cm) and Deep Snow (120cm). Air temperatures during the winter period fluctuated frequently between +3 and -24°C, and the No Snow soil temperatures reflected this variation closely, with the extreme minimum being slightly lower. Under 30cm of snow, soil temperatures varied less and did not decrease below -12°C. Those under deep snow were even more stable and did not decline below -2°C. Despite these striking differences in winter thermal regimes, there were no clear differences in survival of the invertebrate fauna between treatments, including oribatid, prostigmatid and mesostigmatid mites, Araneae, Collembola, Nematocera larvae or Coleoptera. This indicates widespread tolerance, previously undocumented for the Araneae, Nematocera or Coleoptera, of both direct exposure to at least -24°C and the rapid and large temperature fluctuations. These results suggest that the studied polar soil invertebrate community may be robust to at least one important predicted consequence of projected climate change.
PubMed ID
26615733 View in PubMed
Less detail