| 1. |
- Krause-Jensen, D, et al.
(author)
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Nordic Blue Carbon Ecosystems: Status and Outlook
- 2022
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In: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 9
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Research review (peer-reviewed)abstract
- Vegetated coastal and marine habitats in the Nordic region include salt marshes, eelgrass meadows and, in particular, brown macroalgae (kelp forests and rockweed beds). Such habitats contribute to storage of organic carbon (Blue Carbon – BC) and support coastal protection, biodiversity and water quality. Protection and restoration of these habitats therefore have the potential to deliver climate change mitigation and co-benefits. Here we present the existing knowledge on Nordic BC habitats in terms of habitat area, C-stocks and sequestration rates, co-benefits, policies and management status to inspire a coherent Nordic BC roadmap. The area extent of BC habitats in the region is incompletely assessed, but available information sums up to 1,440 km2 salt marshes, 1,861 (potentially 2,735) km2 seagrass meadows, and 16,532 km2 (potentially 130,735 km2, including coarse Greenland estimates) brown macroalgae, yielding a total of 19,833 (potentially 134,910) km2. Saltmarshes and seagrass meadows have experienced major declines over the past century, while macroalgal trends are more diverse. Based on limited salt marsh data, sediment C-stocks average 3,311 g Corg m-2 (top 40-100 cm) and sequestration rates average 142 g Corg m-2 yr-1. Eelgrass C-stocks average 2,414 g Corg m-2 (top 25 cm) and initial data for sequestration rates range 5-33 g Corg m-2, quantified for one Greenland site and one short term restoration. For Nordic brown macroalgae, peer-reviewed estimates of sediment C-stock and sequestration are lacking. Overall, the review reveals substantial Nordic BC-stocks, but highlights that evidence is still insufficient to provide a robust estimate of all Nordic BC-stocks and sequestration rates. Needed are better quantification of habitat area, C-stocks and fluxes, particularly for macroalgae, as well as identification of target areas for BC management. The review also points to directives and regulations protecting Nordic marine vegetation, and local restoration initiatives with potential to increase C-sequestration but underlines that increased coordination at national and Nordic scales and across sectors is needed. We propose a Nordic BC roadmap for science and management to maximize the potential of BC habitats to mitigate climate change and support coastal protection, biodiversity and additional ecosystem functions.
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| 3. |
- Merle, Renaud E., 1976-, et al.
(author)
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High resolution U-Pb ages of Ca-phosphates in Apollo 14 breccias : Implications for the age of the Imbrium impact
- 2014
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In: Meteoritics and Planetary Science. - : John Wiley & Sons, Ltd (10.1111). - 1086-9379 .- 1945-5100. ; 49:12, s. 2241-2251
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Journal article (peer-reviewed)abstract
- Abstract Previous age estimates of the Imbrium impact range from 3770 to 3920 Ma, with the latter being the most commonly accepted age of this basin-forming event. The occurrence of Ca-phosphates in Apollo 14 breccias, interpreted to represent ejecta formed by this impact, provides a new opportunity to date the Imbrium event as well as refining the impact history of the Moon. We present new precise U-Pb analyses of Ca-phosphates from impact breccia sample 14311 that are concordant and give a reliable weighted average age of 3938 ± 4 Ma (2σ). Comparison with previously published U-Pb data on phosphate from Apollo 14 samples indicate that all ages are statistically similar and suggest phosphates could have been formed by the same impact at 3934 Ma ± 3 Ma (2σ). However, this age is older than the 3770 to 3920 Ma range determined for other samples and also interpreted as formed during the Imbrium impact. This suggests that several impacts occurred during a 20?30 Ma period around 3900 Ma and formed breccias sampled by the Apollo missions.
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| 5. |
- Pidgeon, R. T., et al.
(author)
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Annealing of radiation damage in zircons from Apollo 14 impact breccia 14311 : Implications for the thermal history of the breccia
- 2016
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In: Meteoritics and Planetary Science. - : John Wiley & Sons, Ltd (10.1111). - 1086-9379 .- 1945-5100. ; 51:1, s. 155-166
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Journal article (peer-reviewed)abstract
- Abstract Impact breccia 14311, was collected from the Apollo 14 landing site as a potential sample of the underlying Fra Mauro Formation. Published zircon U-Pb ages of >4000 Ma date the source material of the breccia and the apatite U-Pb age of ~3940 Ma is interpreted as dating thermal resetting of the apatite U-Pb systems. In this contribution we present new age information on the late stage thermal history of the breccia based on the annealing of radiation damage in the zircons. From Raman spectroscopic determination of the radiation damage within SIMS analytical spots on the zircons and the U and Th concentrations determined on these spots, we demonstrate that the radiation damage in the zircons has been annealed and we estimate the age of annealing at 3410 ± 80 Ma. This age is interpreted as a cooling age following heating of the breccia to above the annealing temperature of ~230 °C for stage 1 radiation damage in zircon, but below the temperature needed to reset the U-Pb system of apatite (~500 °C). It is proposed that this thermal event was associated with the prolonged period of Mare volcanism, from 3150 to 3750 Ma, that generated massive basalt flows in the vicinity of the sample location.
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