ALBERT

Description: Global variations of the radionuclide 10Be that are almost simultaneous provide a powerful tool to synchronize 10Be records from different locations. We compared the 10Be record of the Akademii Nauk (AN) ice core (Russian Arctic) for the time period CE 1590-1950 to the 10Be records of two well-dated Greenland ice cores (Dye3 and NGRIP). A high correlation (r=0.60) was found between the AN and Dye3 records, which increases up to 0.78 in certain intervals, whereas the correlation to NGRIP was distinctly lower. Sources of deviations may include local fluctuations in the deposition of 10Be due to changes in the precipitation patterns, artefacts due to the core-sampling strategy and a general bias in the age model. In general, the existing age model was validated confirming the AN ice core to be a unique and well-dated source of palaeoclimate parameters for the Russian Arctic. Because of a possible minor bias in the earliest part of the studied ice-core section, the influence of the core-sampling strategy was studied, based on a numerical model that simulates sampling in a discrete and continuous mode with varying sample lengths. Based on the results of the model to sample continuously with individual samples lengths covering a time span of 4-8 years we developed a new sample strategy for the deeper layers.

Description: Lead pollution in Arctic ice reflects large-scale historical changes in midlatitude industrial activities such as ancient lead/silver production and recent fossil fuel burning. Here we used measurements in a broad array of 13 accurately dated ice cores from Greenland and Severnaya Zemlya to document spatial and temporal changes in Arctic lead pollution from 200 BCE to 2010 CE, with interpretation focused on 500 to 2010 CE. Atmospheric transport modeling indicates that Arctic lead pollution was primarily from European emissions before the 19th-century Industrial Revolution. Temporal variability was surprisingly similar across the large swath of the Arctic represented by the array, with 250- to 300-fold increases in lead pollution observed from the Early Middle Ages to the 1970s industrial peak. Superimposed on these exponential changes were pronounced, multiannual to multidecadal variations, marked by increases coincident with exploitation of new mining regions, improved technologies, and periods of economic prosperity; and decreases coincident with climate disruptions, famines, major wars, and plagues. Results suggest substantial overall growth in lead/silver mining and smelting emissions—and so silver production—from the Early through High Middle Ages, particularly in northern Europe, with lower growth during the Late Middle Ages into the Early Modern Period. Near the end of the second plague pandemic (1348 to ∼1700 CE), lead pollution increased sharply through the Industrial Revolution. North American and European pollution abatement policies have reduced Arctic lead pollution by 〉80% since the 1970s, but recent levels remain ∼60-fold higher than at the start of the Middle Ages.

Description: Wildfires and their emissions have significant impacts on ecosystems, climate, atmospheric chemistry, and carbon cycling. Well-dated proxy records are needed to study the long-term climatic controls on biomass burning and the associated climate feedbacks. There is a particular lack of information about long-term biomass burning variations in Siberia, the largest forested area in the Northern Hemisphere. In this study we report analyses of aromatic acids (vanillic and para-hydroxybenzoic acids) over the past 2600 years in the Eurasian Arctic Akademii Nauk ice core. These compounds are aerosol-borne, semi-volatile organic compounds derived from lignin combustion. The analyses were made using ion chromatography with electrospray mass spectrometric detection. The levels of these aromatic acids ranged from below the detection limit (0.01 to 0.05 ppb; 1 ppb  =  1000 ng L−1) to about 1 ppb, with roughly 30 % of the samples above the detection limit. In the preindustrial late Holocene, highly elevated aromatic acid levels are observed during three distinct periods (650–300 BCE, 340–660 CE, and 1460–1660 CE). The timing of the two most recent periods coincides with the episodic pulsing of ice-rafted debris in the North Atlantic known as Bond events and a weakened Asian monsoon, suggesting a link between fires and large-scale climate variability on millennial timescales. Aromatic acid levels also are elevated during the onset of the industrial period from 1780 to 1860 CE, but with a different ratio of vanillic and para-hydroxybenzoic acid than is observed during the preindustrial period. This study provides the first millennial-scale record of aromatic acids. This study clearly demonstrates that coherent aromatic acid signals are recorded in polar ice cores that can be used as proxies for past trends in biomass burning.

Description: Wildfires and their emissions have significant impacts on ecosystems, climate, atmospheric chemistry and carbon cycling. Well-dated proxy records are needed to study the long-term climatic controls on biomass burning and the associated climate feedbacks. There is a particular lack of information about long-term biomass burning variations in Siberia, the largest forested area in the Northern Hemisphere. In this study we report analyses of aromatic acids (vanillic and para-hydroxybenzoic acids) over the past 3145 years in the Eurasian Arctic Akademii Nauk ice core. These compounds are aerosol-borne, semi-volatile organic compounds derived from lignin combustion. The analyses were made using ion chromatography with electrospray mass spectrometric detection. The levels of these aromatic acids ranged from below the detection limit (.01 to .05 ppb) to about 1 ppb, with roughly 30 % of the samples above the detection limit. In the preindustrial late Holocene, highly elevated aromatic acid levels are observed during four distinct periods (1180–660 BCE, 180–220 CE, 380–660 CE, and 1460–1660 CE). The timing of these periods coincides with the episodic pulsing of ice-rafted debris in the North Atlantic known as Bond events. Aromatic acid levels also are elevated during the onset of the industrial period from 1780 to 1860 CE, but with a different ratio of vanillic and para-hydroxybenzoic acid than is observed during the preindustrial period. This study provides the first millennial scale record of aromatic acids. It clearly demonstrates that coherent aromatic acid signals are recorded in polar ice cores that can be used as proxies for past trends in biomass burning.

Description: Lead pollution in Arctic ice reflects large-scale historical changes in midlatitude industrial activities such as ancient lead/silver production and recent fossil fuel burning. Here we used measurements in a broad array of 13 accurately dated ice cores from Greenland and Severnaya Zemlya to document spatial and temporal changes in Arctic lead pollution from 200 BCE to 2010 CE, with interpretation focused on 500 to 2010 CE. Atmospheric transport modeling indicates that Arctic lead pollution was primarily from European emissions before the 19th-century Industrial Revolution. Temporal variability was surprisingly similar across the large swath of the Arctic represented by the array, with 250- to 300-fold increases in lead pollution observed from the Early Middle Ages to the 1970s industrial peak. Superimposed on these exponential changes were pronounced, multiannual to multidecadal variations, marked by increases coincident with exploitation of new mining regions, improved technologies, and periods of economic prosperity; and decreases coincident with climate disruptions, famines, major wars, and plagues. Results suggest substantial overall growth in lead/silver mining and smelting emissions—and so silver production—from the Early through High Middle Ages, particularly in northern Europe, with lower growth during the Late Middle Ages into the Early Modern Period. Near the end of the second plague pandemic (1348 to ∼1700 CE), lead pollution increased sharply through the Industrial Revolution. North American and European pollution abatement policies have reduced Arctic lead pollution by 〉80% since the 1970s, but recent levels remain ∼60-fold higher than at the start of the Middle Ages.

Description: Atmospheric nuclear weapons testing (NWT) resulted in the injection of plutonium (Pu) into the atmosphere and subsequent global deposition. We present a new method for continuous semiquantitative measurement of 239Pu in ice cores, which was used to develop annual records of fallout from NWT in ten ice cores from Greenland and Antarctica. The 239Pu was measured directly using an inductively coupled plasma-sector field mass spectrometer, thereby reducing analysis time and increasing depth-resolution with respect to previous methods. To validate this method, we compared our one year averaged results to published 239Pu records and other records of NWT. The 239Pu profiles from the Arctic ice cores reflected global trends in NWT and were in agreement with discrete Pu profiles from lower latitude ice cores. The 239Pu measurements in the Antarctic ice cores tracked low latitude NWT, consistent with previously published discrete records from Antarctica. Advantages of the continuous 239Pu measurement method are (1) reduced sample preparation and analysis time; (2) no requirement for additional ice samples for NWT fallout determinations; (3) measurements are exactly coregistered with all other chemical, elemental, isotopic, and gas measurements from the continuous analytical system; and (4) the long half-life means the 239Pu record is stable through time.

Description: Walther Bruns (1889-1955), Apothekersohn aus Danzig-Hochstrieß, war von 1910 bis 1918 als Offizier, Flugzeugführer und Zeppelin-Luftschiffer aktiv. Für den Einsatz von Luftschiffen als Transportmittel zwischen Europa und dem pazifischen Raum auf kürzestem transarktischen Weg warb er bereits im Januar 1919 in einem Vortrag vor der „Naturforschenden Gesellschaft“ in Görlitz. Zur Rettung des nach dem Versailler Vertrag zu demontierenden Luftschiffbaus „Zeppelin“ gründete er 1924 die „Internationale Studiengesellschaft zur Erforschung der Arktis mit dem Luftschiff“. Ihm gelang es, die bedeutendsten in- und ausländischen Wissenschaftler und Ingenieure für diese Gesellschaft zu gewinnen. Zu den Unterzeichnern einer entsprechenden Denkschrift in Berlin am 14. April 1924 gehörten bekannte Polarforscher wie Knud Rasmussen und Alfred Wegener, Luftfahrtspezialisten wie Johann Schütte und Umberto Nobile. Mitglieder wurden Wissenschaftler und Techniker aus 22 Ländern. Gründungspräsident war Fridtjof Nansen, mit dem Walther Bruns auch private Kontakte pflegte. Bruns selbst fungierte als Generalsekretär. Eine ausführliche Denkschrift „Das Luftschiff als Forschungsmittel in der Arktis“ gab die Gesellschaft am 7.10.1924 heraus. Innerhalb der Aeroarctic wurden Kommissionen für die Fachgebiete Geografie, Aeorologie/ Meteorologie, Ozeanografie, Erdmagnetismus, Biologie, Aerogeodäsie, Luftelektrizität und Funktelegrafie sowie für die Fragen von Ausrüstung und Technik gebildet. Die Wissenschaftler erörterten die Probleme des Einsatzes von Luftschiffen im jeweiligen Fachgebiet. Eine diesbezügliche „Acta des Preuss. Geodätischen Instituts betr. Schweremessung im Polargebiet“, ist erhalten und wird u.a. hier vorgestellt. Wissenschaftliche Programme für eine Arktisexpedition mit dem Luftschiff wurden entwickelt und auf der 2. ordentlichen Versammlung der Aeroarctic im Juni 1928 in Leningrad erstmals vorgestellt. Die Vierteljahresschrift „Arktis“ der Gesellschaft wurde von Fridtjof Nansen begründete und von Arthur Berson, Leonid Breitfuss und Walther Bruns zwischen 1928 und 1931 herausgegeben. Sie diente der Verbreitung von Gesellschaftsmitteilung, vor allem aber der zusammenfassenden Publikation relevanter arktischer Beobachtungsdaten aller Disziplinen sowie wissenschaftlich-technischer Ergebnisse der Vorbereitung der arktischen Luftschiffexpedition, die mit LZ 127 im Sommer 1931 zur Ausführung gelangte. Hugo Eckener, Kommandant von LZ 127, war seit dem Tode von Fridtjof Nansen Präsident der Gesellschaft, die auch einen Teil der Expeditionskosten übernahm. Die Aeroarctic wurde nach der Machtergreifung der NSDAP (1933) aufgelöst.