ALBERT

Description: Here we present the first high-resolution late-Holocene glacier record from the Lofoten archipelago in northern Norway. The study is based on analyses of lacustrine sediments from the distal glacier-fed lake Kveitvikvatnet (30.1 m a.s.l.), as well as glacial-geomorphological mapping of the ~4.2-km 2 surrounding catchment. The lake sediment cores have been examined for input of glacial-derived sediments by using physical, geochemical and magnetic sediment properties, including x-ray fluorescence (XRF), magnetic susceptibility (MS), grain size analyses, dry bulk density (DBD) and loss-on-ignition (LOI). Former glacier extent has been reconstructed using aerial photography and glacial-geomorphological mapping. Lichenometric dating has been used to construct a moraine chronology covering the recent fluctuations of the largest glacier (back to AD ~1740). AMS radiocarbon dating reveals that the lake sediment record covers the last 1200 years, thereby including both the ‘Little Ice Age’ (LIA) and the ‘Medieval Climate Anomaly’ (MCA). By linking continuously deposited lake sediment proxies of glacier fluctuation to known glacier frontal positions and an independent temperature reconstruction, former fluctuations in the equilibrium-line altitude (ELA) and winter precipitation have been reconstructed. Reconstructed winter precipitation estimates have also been correlated to instrumental data from the region back to AD 1895 and show a remarkable correlation, which further strengthens our approach. We found that both MCA and LIA were periods of substantial glacier variations with respect to the present, with a maximum lowering of the ELA of ~75 and ~85 m, respectively. Increased precipitation during these intervals, associated with more frequent and/or intense winter storms, is suggested to be the major driving force of glacier fluctuations in Lofoten.

Description: Holocene fluctuations of a small outlet glacier from the ice cap Høgtuvbreen at 65° N in coastal northern Norway are reconstructed based on distal glacier-fed lake sediments, complemented by a moraine sequence dated by lichenometry. Glaciers respond to changes in accumulation-season precipitation, ablation-season temperature and redistribution of snow by wind. Hence, reconstructions of glacier fluctuations based on distal glacier-fed lakes may give detailed information about past climate at a potentially high temporal resolution. Yet, the importance of any of these climate components is often difficult to solve. Here, we apply the ‘Liestøl-relationship’, which expresses the relationship between ablation-season temperature and annual accumulation of snow at the equilibrium line altitude (ELA), to the reconstructed local temperature–precipitation–wind ELA (TPW-ELA) to infer the relative importance of winter-balance and ablation-season temperature as causes of reconstructed glacier variation. The reconstructions show a large glacier readvance corresponding with the 8.2-ka cold event and a sequence of eight distinct glacier advances and retreats during the Neoglacial time period bracket between 4300 ± 40 cal. yr BP and AD 1900. The glacier reached its Holocene maximum position in AD 1773 ± 29, subsequently followed by an ongoing unprecedented retreat, interrupted only by some minor halts and readvances. Based on a detailed comparison of our results with similar studies of both continental and maritime glaciers, as well as independent temperature proxy records across Scandinavia, we argue that significant and consistent deviations in ELA fluctuations between continental and maritime glaciers in the region are caused by a north–south migration of the arctic polar front. Additionally, we suggest that deviations in ELA fluctuations between Scandinavian maritime and continental glaciers around 7150, 6560, 6000, 5150, 3200 and 2200 cal. yr BP reflect the different response of continental and maritime glaciers to drops in total solar irradiance (TSI).

Description: In an effort to reconstruct past aeolian activity, a foredune stratigraphy and a continuous lake sediment record from the largest dunefield on Andøya, northern Norway, have been investigated. The dunefield extends landwards in a north-eastward direction and consists of several parabolic dunes, foredunes and blowouts. The sediment record (169 cm) from the nearby lake Latjønna and the foredune stratigraphy (10 m) covers the last 6200 and 3700 cal. yr BP, respectively. Both sites possess sediments deposited after the Tapes transgression maximum (~6800 cal. yr BP), which reached a level of ~7–8 m a.s.l. at the study site. The lake sediment record consists of several units dominated by sand grains interspersed by more organic-rich beds. The core has been examined by x-ray fluorescence (XRF), magnetic susceptibility (MS) and loss-on-ignition (LOI). Mineral grains were detected by wet sieving of the ignition residue (IR), and the influx of sand grains to Latjønna was calculated based on the weight of sand grains 〉250 µm/cm divided by the accumulation rate determined from a radiocarbon ( 14 C)-based age–depth model. Phases with high influx of sand to Latjønna are recorded around 4800, 4250, 3000–2000, 1850–1750, 1600–600, 450, 300 and 150 cal. yr BP, which coincides with periods of increased storminess recorded in other studies around the North-Eastern Atlantic region. The two study sites show, however, quite contrasting results; high sedimentation rates in the lake record associated with greater aeolian influx correspond to stability in the foredune stratigraphy reflected by the presence of several palaeosols. Because of this out-of-phase behaviour, it is suggested that the foredune is mainly influenced by summer climate and relative sea level (RSL) change, whereas the lake record is more influenced by niveo-aeolian processes transporting sand grains farther inland during winter.

Description: Beyond noise annoyance and voice problems, little is known about the effects that noise and poor classroom acoustics have on teachers’ health and well-being. The aim of this field study was therefore to investigate the effects of perceived noise exposure and classroom reverberation on measures of well-being. Data on self-reported noise exposure, job satisfaction, fatigue after work, and interest in leaving the job were obtained from 283 teachers at 10 schools in Copenhagen, Denmark. In addition, the schools’ acoustical working environment was classified as "low reverberation time (RT)" (3 schools, RT = 0.41-0.47 s), "medium RT" (3 schools, RT = 0.50-0.53 s), or "high RT" (4 schools, RT = 0.59-0.73 s). Significant associations were found between high RT and noise exposure, and, respectively, low job satisfaction, lack of energy after work, and interest in leaving the job. Noise exposure was also associated with lack of motivation and sleepiness. The results demonstrate the importance of good classroom acoustic conditions for teachers’ well-being.