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López-Blanco E, Langen PL, Williams M, Christensen JH, Boberg F, Langley K, Christensen TR. The future of tundra carbon storage in Greenland - Sensitivity to climate and plant trait changes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 846:157385. [PMID: 35870583 DOI: 10.1016/j.scitotenv.2022.157385] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/02/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
The continuous change in observed key indicators such as increasing nitrogen deposition, temperatures and precipitation will have marked but uncertain consequences for the ecosystem carbon (C) sink-source functioning of the Arctic. Here, we use multiple in-situ data streams measured by the Greenland Ecosystem Monitoring programme in tight connection with the Soil-Plant-Atmosphere model and climate projections from the high-resolution HIRHAM5 regional model. We apply this modelling framework with focus on two climatically different tundra sites in Greenland (Zackenberg and Kobbefjord) to assess how sensitive the net C uptake will expectedly be under warmer and wetter conditions across the 21st century and pin down the relative contribution to the overall C sink strength from climate versus plant trait variability. Our results suggest that temperatures (5-7.7 °C), total precipitation (19-110 %) and vapour pressure deficit will increase (32-36 %), while shortwave radiation will decline (6-9 %) at both sites by 2100 under the RCP8.5 scenario. Such a combined effect will, on average, intensify the net C uptake by 9-10 g C m-2 year-1 at both sites towards the end of 2100, but Zackenberg is expected to have more than twice the C sink strength capacity of Kobbefjord. Our sensitivity analysis not only reveals that plant traits are the most sensitive parameters controlling the net C exchange in both sites at the beginning and end of the century, but also that the projected increase in the net C uptake will likely be similarly influenced by future changes in climate and existing local nutrient conditions. A series of experiments forcing realistic changes in plant nitrogen status at both sites corroborates this hypothesis. This work proves the unique synergy between monitoring data and numerical models to assist robust model calibration/validation and narrow uncertainty ranges and ultimately produce more reliable C cycle projections in understudied regions such as Greenland.
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Affiliation(s)
- Efrén López-Blanco
- Department of Environment and Minerals, Greenland Institute of Natural Resources, Kivioq 2, PO Box 570, 3900 Nuuk, Greenland; Department of Ecoscience, Arctic Research Center, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark.
| | - Peter L Langen
- Department of Environmental Sciences, iClimate, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Mathew Williams
- School of GeoSciences and NCEO, University of Edinburgh, Alexander Crum Brown Road, EH9 3FF Edinburgh, UK
| | - Jens Hesselbjerg Christensen
- Niels Bohr Institute, Copenhagen University, Tagensvej 16, 2200 Copenhagen, Denmark; Danish Meteorological Institute, Lyngbyvej 100, 2100 Copenhagen, Denmark; NORCE, Norwegian Research Centre AS, Bjerknes Centre for Climate Research, P.O.B 22 Nygårdstangen, 5838 Bergen, Norway
| | - Fredrik Boberg
- Danish Meteorological Institute, Lyngbyvej 100, 2100 Copenhagen, Denmark
| | - Kirsty Langley
- Asiaq, Greenland Survey, Qatserisut 8, 3900 Nuuk, Greenland
| | - Torben Røjle Christensen
- Department of Ecoscience, Arctic Research Center, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark; Oulanka Research Station, Oulu University, PO Box 8000, 90014, Finland
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Abstract
Agriculture in subarctic regions is limited by a short and cold growing season. With warming in the region, the number of growing days and, consequently, the potential for agricultural intensification and expansion may increase. However, subarctic soils are typically acidic, low in plant-available nutrients, and coarsely textured, so they require soil amendment prior to intensification. This is the case in South Greenland, where we tested the use of glacial rock flour (GRF) produced by glaciers as a soil amendment. An experiment was made on a farm in South Greenland during the 2019 summer to quantify the short-term effect of applying GRF to a field dominated by perennial timothy grass. Three treatments were compared to control sites (n = 5): 20 t GRF ha−1 without conventional NPK-fertilizer, as well as 20 and 40 t GRF ha−1 in combination with 25% NPK-fertilizer. The experiment showed no significant response in biomass production (aboveground and belowground) for the plots treated with GRF only. The low rate of GRF combined with 25% NKP showed a marked and significant increase in yield in contrast to a high GRF rate with NPK, which resulted in a significant reduction in yields. The chemical composition of the plants versus soil and GRF showed that the plant uptake of nutrients was significantly higher for NPK-fertilized plots, as expected, but no differences were found between GRF-treated plots and the control plots with respect to nutrient availability or pH in the soil. We conclude that adding water and fertilizer has the potential to increase yields in South Greenland, but applying glacial rock flour as a short-term agricultural supplement needs to be further investigated before it can be recommended.
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Bequest of the Norseman—The Potential for Agricultural Intensification and Expansion in Southern Greenland under Climate Change. LAND 2017. [DOI: 10.3390/land6040087] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Lund M, Raundrup K, Westergaard-Nielsen A, López-Blanco E, Nymand J, Aastrup P. Larval outbreaks in West Greenland: Instant and subsequent effects on tundra ecosystem productivity and CO 2 exchange. AMBIO 2017; 46:26-38. [PMID: 28116687 PMCID: PMC5258657 DOI: 10.1007/s13280-016-0863-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Insect outbreaks can have important consequences for tundra ecosystems. In this study, we synthesise available information on outbreaks of larvae of the noctuid moth Eurois occulta in Greenland. Based on an extensive dataset from a monitoring programme in Kobbefjord, West Greenland, we demonstrate effects of a larval outbreak in 2011 on vegetation productivity and CO2 exchange. We estimate a decreased carbon (C) sink strength in the order of 118-143 g C m-2, corresponding to 1210-1470 tonnes C at the Kobbefjord catchment scale. The decreased C sink was, however, counteracted the following years by increased primary production, probably facilitated by the larval outbreak increasing nutrient turnover rates. Furthermore, we demonstrate for the first time in tundra ecosystems, the potential for using remote sensing to detect and map insect outbreak events.
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Affiliation(s)
- Magnus Lund
- Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Katrine Raundrup
- Greenland Institute of Natural Resources, Kivioq 2, P.O. Box 570, 3900 Nuuk, Greenland
| | - Andreas Westergaard-Nielsen
- Department of Geosciences and Natural Resource Management, Center for Permafrost (CENPERM), University of Copenhagen, Oestervoldgade 10, 1350 Copenhagen, Denmark
| | - Efrén López-Blanco
- Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Josephine Nymand
- Greenland Institute of Natural Resources, Kivioq 2, P.O. Box 570, 3900 Nuuk, Greenland
| | - Peter Aastrup
- Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
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