22 results on '"Arppe, L."'
Search Results
2. Solar superstorm of AD 774 recorded subannually by Arctic tree rings
- Author
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Uusitalo, J., Arppe, L., Hackman, T., Helama, S., Kovaltsov, G., Mielikäinen, K., Mäkinen, H., Nöjd, P., Palonen, V., Usoskin, I., and Oinonen, M.
- Published
- 2018
- Full Text
- View/download PDF
3. Isotopic insights into the early Medieval (600–1100 CE) diet in the Luistari cemetery at Eura, Finland
- Author
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Etu-Sihvola, H., Salo, K., Naito, Y. I., Kytokari, M., Ohkouchi, N., Oinonen, M., Heyd, V., Arppe, L., Finnish Museum of Natural History, Natural Sciences Unit, Department of Agricultural Sciences, and Department of Cultures
- Subjects
Archeology ,Viking ,AQUATIC RESOURCE CONSUMPTION ,INDIVIDUAL AMINO-ACIDS ,BONE-COLLAGEN ,STABLE-ISOTOPE ,Merovingian ,VIKING AGE ,615 History and Archaeology ,Diet ,Early medieval ,CLIMATE VARIABILITY ,FOOD-WEB STRUCTURE ,Anthropology ,IRON-AGE ,ICE-AGE ,NITROGEN ISOTOPES ,Finland ,Stable isotopes - Abstract
In this article, we present the results of an isotopic study of diet for the early medieval (Merovingian, Viking, Early Christian) humans buried in the unique Luistari cemetery at Eura (ca. 600–1400 CE), southwestern Finland, the largest cemetery of the region. Isotope analysis was conducted on 37 humans for dentine and bone collagen (δ13C, δ15N, and δ34S), and five of them were also studied using compound-specific nitrogen isotope analysis. Dental enamel and/or bone carbonate δ13C values were studied from altogether 65 humans, five cattle, and five sheep/goats. The bone and dentine collagen and carbonate data show that throughout the centuries, freshwater fish was a stable part of the diet for the population. Our results do not show systematic dietary differences between estimated males and females, but differences can be large on the individual level. We also discovered a possible temporal change in the enamel carbonate ẟ13C values that could be related to the increasing role of carbohydrates (e.g., crops) in the diet. Luistari burials are well comparable to contemporary Swedish Viking trading communities like Birka in their higher protein intake. But contrary to the wider Viking network, they do not show the same marine signal.
- Published
- 2022
4. The dIANA database - Resource for isotopic paleodietary research in the Baltic Sea area
- Author
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Etu-Sihvola, H., Bocherens, H., Drucker, D. G., Junno, Aripekka, Mannermaa, K., Oinonen, M., Uusitalo, J., Arppe, L., Etu-Sihvola, H., Bocherens, H., Drucker, D. G., Junno, Aripekka, Mannermaa, K., Oinonen, M., Uusitalo, J., and Arppe, L.
- Abstract
Paleodietary research is a complex field, which requires large sets of background information. Owing to increasing interest and activity in the field, a substantial amount of archaeological isotope baseline data exist for Northern Europe, consisting mainly of animal bone collagen delta C-13, delta N-15, and delta S-34 values. However, the data are scattered into dozens of publications written in multiple languages and less-accessible formats, making the data laborious to use. This article presents the first compilation work of this data, the open access dIANA database (Dietary Isotopic baseline for the Ancient North; https://www.oasisnorth.org/diana.html), aimed to support (paleo)dietary research in the Baltic Sea area. The database work is complemented with new analyses of archaeological and (pre-)modern domestic and wild fauna from Finland and Russia broadening the selection of analysed species in the database. We present and discuss data examples, which on one hand show existing spatiotemporal isotope patterns related to diet and differences in the environmental carbon sources and on the other, also visualize the current status of baseline research and the need for further analyses in the circum-Baltic area.
- Published
- 2019
- Full Text
- View/download PDF
5. Solar superstorm of AD 774 recorded subannually by Arctic tree rings
- Author
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Uusitalo, J. (J.), Arppe, L. (L.), Hackman, T. (T.), Helama, S. (S.), Kovaltsov, G. (G.), Mielikäinen, K. (K.), Mäkinen, H. (H.), Nöjd, P. (P.), Palonen, V. (V.), Usoskin, I. (I.), Oinonen, M. (M.), Uusitalo, J. (J.), Arppe, L. (L.), Hackman, T. (T.), Helama, S. (S.), Kovaltsov, G. (G.), Mielikäinen, K. (K.), Mäkinen, H. (H.), Nöjd, P. (P.), Palonen, V. (V.), Usoskin, I. (I.), and Oinonen, M. (M.)
- Abstract
Recently, a rapid increase in radiocarbon (¹⁴C) was observed in Japanese tree rings at AD 774/775. Various explanations for the anomaly have been offered, such as a supernova, a γ-ray burst, a cometary impact, or an exceptionally large Solar Particle Event (SPE). However, evidence of the origin and exact timing of the event remains incomplete. In particular, a key issue of latitudinal dependence of the ¹⁴C intensity has not been addressed yet. Here, we show that the event was most likely caused by the Sun and occurred during the spring of AD 774. Particularly, the event intensities from various locations show a strong correlation with the latitude, demonstrating a particle-induced ¹⁴C poleward increase, in accord with the solar origin of the event. Furthermore, both annual ¹⁴C data and carbon cycle modelling, and separate earlywood and latewood ¹⁴C measurements, confine the photosynthetic carbon fixation to around the midsummer.
- Published
- 2018
6. Tree height strongly affects estimates of water-use efficiency responses to climate and CO2 using isotopes
- Author
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Brienen, RJW, Gloor, E, Clerici, S, Newton, R, Arppe, L, Boom, A, Bottrell, S, Callaghan, M, Heaton, T, Helama, S, Helle, G, Leng, MJ, Mielikäinen, K, Oinonen, M, Timonen, M, Finnish Museum of Natural History, and Natural Sciences Unit
- Subjects
1171 Geosciences ,EUROPEAN FORESTS ,Science ,PINUS-SYLVESTRIS ,GROWTH DECLINE ,RAIN-FOREST ,PAST CENTURY ,RING DELTA-C-13 ,FAGUS-SYLVATICA ,C-3 PLANTS ,ATMOSPHERIC CO2 ,1172 Environmental sciences ,CARBON-DIOXIDE CONCENTRATIONS - Abstract
Various studies report substantial increases in intrinsic water-use efficiency (Wi), estimated using carbon isotopes in tree rings, suggesting trees are gaining increasingly more carbon per unit water lost due to increases in atmospheric CO2. Usually, reconstructions do not, however, correct for the effect of intrinsic developmental changes in Wi as trees grow larger. Here we show, by comparingWi across varying tree sizes at one CO2 level, that ignoring such developmental effects can severely affect inferences of trees' Wi. Wi doubled or even tripled over a trees' lifespan in three broadleaf species due to changes in tree height and light availability alone, and there are also weak trends for Pine trees. Developmental trends in broadleaf species are as large as the trends previously assigned to CO2 and climate. Credible future tree ring isotope studies require explicit accounting for species-specific developmental effects before CO2 and climate effects are inferred.
- Published
- 2017
7. Tree height strongly affects estimates of water-use efficiency responses to climate and CO2 using isotopes
- Author
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Brienen, R.J.W., Gloor, E., Clerici, S., Newton, R., Arppe, L., Boom, A., Bottrell, S., Callaghan, M., Heaton, T., Helama, S., Helle, G., Leng, M.J., Mielikäinen, K., Oinonen, M., Timonen, M., Brienen, R.J.W., Gloor, E., Clerici, S., Newton, R., Arppe, L., Boom, A., Bottrell, S., Callaghan, M., Heaton, T., Helama, S., Helle, G., Leng, M.J., Mielikäinen, K., Oinonen, M., and Timonen, M.
- Abstract
Various studies report substantial increases in intrinsic water-use efficiency (W i ), estimated using carbon isotopes in tree rings, suggesting trees are gaining increasingly more carbon per unit water lost due to increases in atmospheric CO2. Usually, reconstructions do not, however, correct for the effect of intrinsic developmental changes in W i as trees grow larger. Here we show, by comparing W i across varying tree sizes at one CO2 level, that ignoring such developmental effects can severely affect inferences of trees’ W i . W i doubled or even tripled over a trees’ lifespan in three broadleaf species due to changes in tree height and light availability alone, and there are also weak trends for Pine trees. Developmental trends in broadleaf species are as large as the trends previously assigned to CO2 and climate. Credible future tree ring isotope studies require explicit accounting for species-specific developmental effects before CO2 and climate effects are inferred
- Published
- 2017
8. An arctic seal in temperate waters:History of the tinges seal (Pusa hispida) in the Baltic Sea and its adaptation to the changing environment
- Author
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Ukkonen, P, Aaris-Sørensen, Kim, Arppe, L, Daugnora, L., Halkka, A., Lougas, L., Oinonen, M.J., Pilot, M., Storå, J., Ukkonen, P, Aaris-Sørensen, Kim, Arppe, L, Daugnora, L., Halkka, A., Lougas, L., Oinonen, M.J., Pilot, M., and Storå, J.
- Published
- 2014
9. Tree height strongly affects estimates of water-use efficiency responses to climate and CO2 using isotopes.
- Author
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Brienen, R. J. W., Gloor, E., Clerici, S., Newton, R., Arppe, L., Boom, A., Bottrell, S., Callaghan, M., Heaton, T., Helama, S., Helle, G., Leng, M. J., Mielikäinen, K., Oinonen, M., and Timonen, M.
- Subjects
TREE height ,ISOTOPES ,CARBON isotopes ,TREE-rings ,CLIMATOLOGY ,TREE size - Abstract
Various studies report substantial increases in intrinsic water-use efficiency (Wi), estimated using carbon isotopes in tree rings, suggesting trees are gaining increasingly more carbon per unit water lost due to increases in atmospheric CO
2 . Usually, reconstructions do not, however, correct for the effect of intrinsic developmental changes in Wi as trees grow larger. Here we show, by comparing Wi across varying tree sizes at one CO2 level, that ignoring such developmental effects can severely affect inferences of trees' Wi. Wi doubled or even tripled over a trees' lifespan in three broadleaf species due to changes in tree height and light availability alone, and there are also weak trends for Pine trees. Developmental trends in broadleaf species are as large as the trends previously assigned to CO2 and climate. Credible future tree ring isotope studies require explicit accounting for species-specific developmental effects before CO2 and climate effects are inferred. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
10. The palaeoenvironmental δ13C record in European woolly mammoth tooth enamel
- Author
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Arppe, L., Aaris-Sørensen, Kim, Daugnora, L., Lõugas, L., Wojtal, P., Zupiņš, I., Arppe, L., Aaris-Sørensen, Kim, Daugnora, L., Lõugas, L., Wojtal, P., and Zupiņš, I.
- Published
- 2011
11. Woolly mammoth (Mammuthus primigenius Blum.) and its environment in northern Europe during the last glaciation
- Author
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Ukkonen, P., Aaris-Sørensen, Kim, Arppe, L., Clark, P. U., Daugnora, L., Lister, A. M., Lõugas, L., Seppä, H., Sommer, R. S., Stuart, A. J., Wojtal, P., Zupiņš, I., Ukkonen, P., Aaris-Sørensen, Kim, Arppe, L., Clark, P. U., Daugnora, L., Lister, A. M., Lõugas, L., Seppä, H., Sommer, R. S., Stuart, A. J., Wojtal, P., and Zupiņš, I.
- Published
- 2011
12. BRONZE AGE CATTLE TEETH AND CREMATIONS FROM A MONUMENTAL BURIAL CAIRN IN SELKÄKANGAS, FINLAND: NEW RADIOCARBON DATES AND ISOTOPIC ANALYSIS
- Author
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Bläuer, A, primary, Korkeakoski-Väisänen, K, primary, Arppe, L, primary, and Kantanen, J, primary
- Published
- 2013
- Full Text
- View/download PDF
13. MIS 3 mammoth remains from Sweden:implications for faunal history, paleoclimate and glaciation chronology
- Author
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Ukkonen, P., Arppe, L., Houmark-Nielsen, Michael, Kjær, Kurt H., Karhu, J.A., Ukkonen, P., Arppe, L., Houmark-Nielsen, Michael, Kjær, Kurt H., and Karhu, J.A.
- Published
- 2007
14. MIS 3 mammoth remains from Sweden-implications for faunal history, palaeoclimate and glaciation chronology
- Author
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Ukkonen, P, Arppe, L, Houmark-Nielsen, Michael, Kjær, Kurt H., Karhu, J.P, Ukkonen, P, Arppe, L, Houmark-Nielsen, Michael, Kjær, Kurt H., and Karhu, J.P
- Abstract
Udgivelsesdato: 2007
- Published
- 2007
15. You eat what you find - Local patterns in vegetation structure control diets of African fungus-growing termites.
- Author
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Vesala R, Rikkinen A, Pellikka P, Rikkinen J, and Arppe L
- Abstract
Fungus-growing termites and their symbiotic Termitomyces fungi are critically important carbon and nutrient recyclers in arid and semiarid environments of sub-Saharan Africa. A major proportion of plant litter produced in these ecosystems is decomposed within nest chambers of termite mounds, where temperature and humidity are kept optimal for the fungal symbionts. While fungus-growing termites are generally believed to exploit a wide range of different plant substrates, the actual diets of most species remain elusive. We studied dietary niches of two Macrotermes species across the semiarid savanna landscape in the Tsavo Ecosystem, southern Kenya, based on carbon (C) and nitrogen (N) stable isotopes in Termitomyces fungus combs. We applied Bayesian mixing models to determine the proportion of grass and woody plant matter in the combs, these being the two major food sources available for Macrotermes species in the region. Our results showed that both termite species, and colonies cultivating different Termitomyces fungi, occupied broad and largely overlapping isotopic niches, indicating no dietary specialization. Including laser scanning derived vegetation cover estimates to the dietary mixing model revealed that the proportion of woody plant matter in fungus combs increased with increasing woody plant cover in the nest surroundings. Nitrogen content of fungus combs was positively correlated with woody plant cover around the mounds and negatively correlated with the proportion of grass matter in the comb. Considering the high N demand of large Macrotermes colonies, woody plant matter seems to thus represent a more profitable food source than grass. As grass is also utilized by grazing mammals, and the availability of grass matter typically fluctuates over the year, mixed woodland-grasslands and bushlands seem to represent more favorable habitats for large Macrotermes colonies than open grasslands., Competing Interests: None of the authors have any competing interests., (© 2022 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)
- Published
- 2022
- Full Text
- View/download PDF
16. Buried in water, burdened by nature-Resilience carried the Iron Age people through Fimbulvinter.
- Author
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Oinonen M, Alenius T, Arppe L, Bocherens H, Etu-Sihvola H, Helama S, Huhtamaa H, Lahtinen M, Mannermaa K, Onkamo P, Palo J, Sajantila A, Salo K, Sundell T, Vanhanen S, and Wessman A
- Subjects
- Archaeology, Bone and Bones chemistry, Finland, History, Ancient, Humans, Radiometric Dating, Agriculture history, Climate Change history, Feeding Behavior, Resilience, Psychological
- Abstract
Levänluhta is a unique archaeological site with the remains of nearly a hundred Iron Age individuals found from a water burial in Ostrobothnia, Finland. The strongest climatic downturn of the Common Era, resembling the great Fimbulvinter in Norse mythology, hit these people during the 6th century AD. This study establishes chronological, dietary, and livelihood synthesis on this population based on stable carbon and nitrogen isotopic and radiocarbon analyses on human remains, supported by multidisciplinary evidence. Extraordinarily broad stable isotopic distribution is observed, indicating three subgroups with distinct dietary habits spanning four centuries. This emphasizes the versatile livelihoods practiced at this boundary of marine, freshwater, and terrestrial ecosystems. While the impact of the prolonged cold darkness of the 6th century was devastating for European communities relying on cultivation, the broad range of livelihoods provided resilience for the Levänluhta people to overcome the abrupt climatic decline., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2020
- Full Text
- View/download PDF
17. Human mitochondrial DNA lineages in Iron-Age Fennoscandia suggest incipient admixture and eastern introduction of farming-related maternal ancestry.
- Author
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Översti S, Majander K, Salmela E, Salo K, Arppe L, Belskiy S, Etu-Sihvola H, Laakso V, Mikkola E, Pfrengle S, Putkonen M, Taavitsainen JP, Vuoristo K, Wessman A, Sajantila A, Oinonen M, Haak W, Schuenemann VJ, Krause J, Palo JU, and Onkamo P
- Subjects
- Agriculture, DNA, Mitochondrial genetics, Europe, Farmers statistics & numerical data, Farms, Finland, Genome, Mitochondrial genetics, History, Ancient, Humans, Iron, Oceans and Seas, Crosses, Genetic, DNA, Ancient analysis, DNA, Mitochondrial analysis, Human Migration history, Maternal Inheritance genetics, White People genetics
- Abstract
Human ancient DNA studies have revealed high mobility in Europe's past, and have helped to decode the human history on the Eurasian continent. Northeastern Europe, especially north of the Baltic Sea, however, remains less well understood largely due to the lack of preserved human remains. Finland, with a divergent population history from most of Europe, offers a unique perspective to hunter-gatherer way of life, but thus far genetic information on prehistoric human groups in Finland is nearly absent. Here we report 103 complete ancient mitochondrial genomes from human remains dated to AD 300-1800, and explore mtDNA diversity associated with hunter-gatherers and Neolithic farmers. The results indicate largely unadmixed mtDNA pools of differing ancestries from Iron-Age on, suggesting a rather late genetic shift from hunter-gatherers towards farmers in North-East Europe. Furthermore, the data suggest eastern introduction of farmer-related haplogroups into Finland, contradicting contemporary genetic patterns in Finns.
- Published
- 2019
- Full Text
- View/download PDF
18. Caste-specific nutritional differences define carbon and nitrogen fluxes within symbiotic food webs in African termite mounds.
- Author
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Vesala R, Arppe L, and Rikkinen J
- Subjects
- Animals, Isoptera classification, Isoptera microbiology, Kenya, Nitrogen Fixation, Plants, Carbon Radioisotopes analysis, Food Chain, Fungi physiology, Gastrointestinal Microbiome physiology, Isoptera physiology, Nitrogen Radioisotopes analysis, Symbiosis
- Abstract
Fungus-growing termites of the genus Macrotermes cultivate symbiotic fungi (Termitomyces) in their underground nest chambers to degrade plant matter collected from the environment. Although the general mechanism of food processing is relatively well-known, it has remained unclear whether the termites get their nutrition primarily from the fungal mycelium or from plant tissues partly decomposed by the fungus. To elucidate the flows of carbon and nitrogen in the complicated food-chains within the nests of fungus-growing termites, we determined the stable isotope signatures of different materials sampled from four Macrotermes colonies in southern Kenya. Stable isotopes of carbon revealed that the termite queen and the young larvae are largely sustained by the fungal mycelium. Conversely, all adult workers and soldiers seem to feed predominantly on plant and/or fungus comb material, demonstrating that the fungal symbiont plays a different nutritional role for different termite castes. Nitrogen stable isotopes indicated additional differences between castes and revealed intriguing patterns in colony nitrogen cycling. Nitrogen is effectively recycled within the colonies, but also a presently unspecified nitrogen source, most likely symbiotic nitrogen-fixing bacteria, seems to contribute to nitrogen supply. Our results indicate that the gut microbiota of the termite queen might be largely responsible for the proposed nitrogen fixation.
- Published
- 2019
- Full Text
- View/download PDF
19. The population history of northeastern Siberia since the Pleistocene.
- Author
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Sikora M, Pitulko VV, Sousa VC, Allentoft ME, Vinner L, Rasmussen S, Margaryan A, de Barros Damgaard P, de la Fuente C, Renaud G, Yang MA, Fu Q, Dupanloup I, Giampoudakis K, Nogués-Bravo D, Rahbek C, Kroonen G, Peyrot M, McColl H, Vasilyev SV, Veselovskaya E, Gerasimova M, Pavlova EY, Chasnyk VG, Nikolskiy PA, Gromov AV, Khartanovich VI, Moiseyev V, Grebenyuk PS, Fedorchenko AY, Lebedintsev AI, Slobodin SB, Malyarchuk BA, Martiniano R, Meldgaard M, Arppe L, Palo JU, Sundell T, Mannermaa K, Putkonen M, Alexandersen V, Primeau C, Baimukhanov N, Malhi RS, Sjögren KG, Kristiansen K, Wessman A, Sajantila A, Lahr MM, Durbin R, Nielsen R, Meltzer DJ, Excoffier L, and Willerslev E
- Subjects
- Asia ethnology, DNA, Ancient analysis, Europe ethnology, Gene Pool, Haplotypes, History, 15th Century, History, Ancient, History, Medieval, Humans, Indians, North American, Male, Siberia ethnology, Genome, Human genetics, Human Migration history
- Abstract
Northeastern Siberia has been inhabited by humans for more than 40,000 years but its deep population history remains poorly understood. Here we investigate the late Pleistocene population history of northeastern Siberia through analyses of 34 newly recovered ancient genomes that date to between 31,000 and 600 years ago. We document complex population dynamics during this period, including at least three major migration events: an initial peopling by a previously unknown Palaeolithic population of 'Ancient North Siberians' who are distantly related to early West Eurasian hunter-gatherers; the arrival of East Asian-related peoples, which gave rise to 'Ancient Palaeo-Siberians' who are closely related to contemporary communities from far-northeastern Siberia (such as the Koryaks), as well as Native Americans; and a Holocene migration of other East Asian-related peoples, who we name 'Neo-Siberians', and from whom many contemporary Siberians are descended. Each of these population expansions largely replaced the earlier inhabitants, and ultimately generated the mosaic genetic make-up of contemporary peoples who inhabit a vast area across northern Eurasia and the Americas.
- Published
- 2019
- Full Text
- View/download PDF
20. Volcanic dust veils from sixth century tree-ring isotopes linked to reduced irradiance, primary production and human health.
- Author
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Helama S, Arppe L, Uusitalo J, Holopainen J, Mäkelä HM, Mäkinen H, Mielikäinen K, Nöjd P, Sutinen R, Taavitsainen JP, Timonen M, and Oinonen M
- Subjects
- Dust, Environmental Monitoring, Food Supply, Fossils, History, Medieval, Humans, Carbon Isotopes analysis, Trees chemistry, Volcanic Eruptions history
- Abstract
The large volcanic eruptions of AD 536 and 540 led to climate cooling and contributed to hardships of Late Antiquity societies throughout Eurasia, and triggered a major environmental event in the historical Roman Empire. Our set of stable carbon isotope records from subfossil tree rings demonstrates a strong negative excursion in AD 536 and 541-544. Modern data from these sites show that carbon isotope variations are driven by solar radiation. A model based on sixth century isotopes reconstruct an irradiance anomaly for AD 536 and 541-544 of nearly three standard deviations below the mean value based on modern data. This anomaly can be explained by a volcanic dust veil reducing solar radiation and thus primary production threatening food security over a multitude of years. We offer a hypothesis that persistently low irradiance contributed to remarkably simultaneous outbreaks of famine and Justinianic plague in the eastern Roman Empire with adverse effects on crop production and photosynthesis of the vitamin D in human skin and thus, collectively, human health. Our results provide a hitherto unstudied proxy for exploring the mechanisms of 'volcanic summers' to demonstrate the post-eruption deficiencies in sunlight and to explain the human consequences during such calamity years.
- Published
- 2018
- Full Text
- View/download PDF
21. Tree height strongly affects estimates of water-use efficiency responses to climate and CO 2 using isotopes.
- Author
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Brienen RJW, Gloor E, Clerici S, Newton R, Arppe L, Boom A, Bottrell S, Callaghan M, Heaton T, Helama S, Helle G, Leng MJ, Mielikäinen K, Oinonen M, and Timonen M
- Subjects
- Algorithms, Carbon Isotopes metabolism, Cedrela growth & development, Cedrela metabolism, Fagus growth & development, Fagus metabolism, Models, Theoretical, Pinus growth & development, Pinus metabolism, Quercus growth & development, Quercus metabolism, Species Specificity, Temperature, Time Factors, Trees growth & development, Carbon Dioxide metabolism, Climate, Trees metabolism, Water metabolism
- Abstract
Various studies report substantial increases in intrinsic water-use efficiency (W
i ), estimated using carbon isotopes in tree rings, suggesting trees are gaining increasingly more carbon per unit water lost due to increases in atmospheric CO2 . Usually, reconstructions do not, however, correct for the effect of intrinsic developmental changes in Wi as trees grow larger. Here we show, by comparing Wi across varying tree sizes at one CO2 level, that ignoring such developmental effects can severely affect inferences of trees' Wi . Wi doubled or even tripled over a trees' lifespan in three broadleaf species due to changes in tree height and light availability alone, and there are also weak trends for Pine trees. Developmental trends in broadleaf species are as large as the trends previously assigned to CO2 and climate. Credible future tree ring isotope studies require explicit accounting for species-specific developmental effects before CO2 and climate effects are inferred.Intrinsic water-use efficiency (Wi ) reconstructions using tree rings often disregard developmental changes in Wi as trees age. Here, the authors compare Wi across varying tree sizes at a fixed CO2 level and show that ignoring developmental changes impacts conclusions on trees' Wi responses to CO2 or climate.- Published
- 2017
- Full Text
- View/download PDF
22. Echoes from the past: a healthy Baltic Sea requires more effort.
- Author
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Kotilainen AT, Arppe L, Dobosz S, Jansen E, Kabel K, Karhu J, Kotilainen MM, Kuijpers A, Lougheed BC, Meier HE, Moros M, Neumann T, Porsche C, Poulsen N, Rasmussen P, Ribeiro S, Risebrobakken B, Ryabchuk D, Schimanke S, Snowball I, Spiridonov M, Virtasalo JJ, Weckström K, Witkowski A, and Zhamoida V
- Subjects
- Baltic States, Geologic Sediments, Oceans and Seas, Climate Change, Ecosystem
- Abstract
Integrated sediment multiproxy studies and modeling were used to reconstruct past changes in the Baltic Sea ecosystem. Results of natural changes over the past 6000 years in the Baltic Sea ecosystem suggest that forecasted climate warming might enhance environmental problems of the Baltic Sea. Integrated modeling and sediment proxy studies reveal increased sea surface temperatures and expanded seafloor anoxia (in deep basins) during earlier natural warm climate phases, such as the Medieval Climate Anomaly. Under future IPCC scenarios of global warming, there is likely no improvement of bottom water conditions in the Baltic Sea. Thus, the measures already designed to produce a healthier Baltic Sea are insufficient in the long term. The interactions between climate change and anthropogenic impacts on the Baltic Sea should be considered in management, implementation of policy strategies in the Baltic Sea environmental issues, and adaptation to future climate change.
- Published
- 2014
- Full Text
- View/download PDF
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