William Martin Hagopian

• Bajard, Manon Juliette Andree; Ballo, Eirik Gottschalk; Høeg, Helge Irgens; Bakke, Jostein; Støren, Eivind Wilhelm Nagel & Loftsgarden, Kjetil [Show all 11 contributors for this article] (2022). Climate adaptation of pre-Viking societies. Quaternary Science Reviews. ISSN 0277-3791. 278. doi: 10.1016/j.quascirev.2022.107374.
• Khezri, Rojyar; Holland, Petter; Schoborg, Todd Andrew; Abramovich, Ifat; Takats, Szabolcs & Dillard, Caroline Marie Claude [Show all 21 contributors for this article] (2021). Host autophagy mediates organ wasting and nutrient mobilization for tumor growth. EMBO Journal. ISSN 0261-4189. 40(18). doi: 10.15252/embj.2020107336. Full text in Research Archive
• Bostic, Joshua Neilson; Hagopian, William Martin & Jahren, Anne Hope (2018). Carbon and nitrogen stable isotopes in U.S. milk: Insight into production process. Rapid Communications in Mass Spectrometry. ISSN 0951-4198. 32(7), p. 561–566. doi: 10.1002/rcm.8069.
• Hagopian, William Martin; Schubert, Brian A; Graper, Robert A & Jahren, Anne Hope (2018). Plant growth chamber design for subambient pCO2 and δ13C C studies. Rapid Communications in Mass Spectrometry. ISSN 0951-4198. 32(15), p. 1296–1302. doi: 10.1002/rcm.8176.

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• Holland, Petter; Hagopian, William Martin; Jahren, Anne Hope Florine & Rusten, Tor Erik (2021). Natural abundance isotope ratios to differentiate sources of carbon used during tumor growth in vivo. BMC Biology. ISSN 1741-7007. 19(1), p. 1–10. doi: 10.1186/s12915-021-01012-5.
• Bajard, Manon Julietto Andree; Ballo, Eirik Magnus Gottschalk; Høeg, Helge I.; Bakke, Jostein; Støren, Eivind N. & Loftsgarden, Kjetil [Show all 11 contributors for this article] (2021). Instability or adaptation of the pre-Viking society to the climate variability of the Late Antiquity?
• Bostic, Joshua Neilson; Hagopian, William Martin; Svensen, Henrik & Jahren, Anne Hope (2019). Predicting seasonal climate using intra-ring stable isotope analysis. Show summary

  By emitting stratospheric sulphur aerosol clouds that dim the light-energy received from the sun, large-scale volcanic eruptions may cause acute changes in global climate that impact both natural ecosystems and human societies. One example is the 536 Event, a prolonged period of darkness and cooling across the northern hemisphere caused by two separate volcanic eruptions in 536 and 540 CE. Recent mean annual temperature (MAT) and mean annual precipitation (MAP) reconstructions suggest that the decade following the 536 event was one of the coldest and wettest of the past two millennia. This cold period likely contributed to the cultural upheavals that occurred in Scandinavia during the 6th century by reducing the geographic range suitable for cereal grain production. However, while annually-resolved MAT and MAP reconstructions are useful for identifying climatic perturbations, they provide limited insight into the effects of such climate anomalies on regional agricultural productivity due to their limited ability to differentiate summer and winter climatic conditions. To accurately estimate the number of days suitable for growing crops, or Growing Degree Days (GDD), seasonal resolution must be achieved by determining the ratio of summer to winter temperature and precipitation. To reconstruct growing season temperature and precipitation across southern Scandinavia in the decade following the 536 event (535-545 CE), we will combine prior reconstructions of annual mean data with novel analyses of summer/winter temperature and precipitation ratios derived from intra-ring carbon and oxygen stable isotope analysis of Picea abies collected from Raknehaugen, a burial mound in southern Norway constructed in 551 CE. These growing season temperature and precipitation estimates will be combined with other geo-climatic data (latitude, altitude etc.) for regional GDD reconstruction to ultimately determine changes in the geographic range suitable for crop production in Southern Norway following the 536/540 double event. Here, we 1.) Provide a conceptual outline of the project’s expected outcomes and 2.) Demonstrate the ability of intra-ring stable isotope analysis to detect short-term seasonal climatic perturbations in Scandinavia by reconstructing the European summer drought of 1959 from estimates of summer/winter temperature and precipitation ratios derived from stable isotope patterns in Picea abies samples from two locations in southern Norway.

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