Greenland snow and ice cores: unique archives of large-scale pollution of the troposphere of the Northern Hemisphere by lead and other heavy metals

1995 ◽  
Vol 160-161 ◽  
pp. 233-241 ◽  
Author(s):  
Claude F. Boutron ◽  
Jean-Pierre Candelone ◽  
Sungmin Hong
1995 ◽  
Vol 3 (1) ◽  
pp. 1-28 ◽  
Author(s):  
Claude F. Boutron

During the past decades, the investigation of various elements, species, and isotopes in the frozen atmospheric archives stored in the Greenland and Antarctic ice caps for several hundred thousand years has provided a wealth of fascinating information on past and recent changes in the atmospheric environment of our planet. After a brief description of the Antarctic and Greenland ice caps, we give an overview of the procedures that are used in the field for collecting snow and ice from the surface down to great depths. We discuss the techniques used to date and analyse the samples. The main results obtained to date are then presented, with special emphasis on the very recent. The analysis of the snow and ice layers deposited during the past few centuries, especially since the Industrial Revolution, has allowed us to assess clearly the impact human activity has had on the atmosphere, for important constituents such as heavy metals, sulfur and nitrogen compounds, greenhouse gases, carbon and organic compounds, and artificial radionuclides. The analysis of ancient ice up to several hundred thousand years old has provided unique insight on the past natural changes that affected our atmosphere during glacial–interglacial transitions, especially the temperature, greenhouse gases, soil- and sea-derived aerosols, and heavy metals.Key words: Greenland, Antarctica, ice, global pollution, climate change, heavy metals.


2018 ◽  
Author(s):  
Amaëlle Landais ◽  
Emilie Capron ◽  
Valérie Masson-Delmotte ◽  
Samuel Toucanne ◽  
Rachael Rhodes ◽  
...  

Abstract. The last deglaciation represents the most recent example of natural global warming associated with large-scale climate changes. In addition to the long-term global temperature increase, the last deglaciation onset is punctuated by a sequence of abrupt changes in the Northern Hemisphere. Such interplay between orbital- and millennial-scale variability is widely documented in paleoclimatic records but the underlying mechanisms are not fully understood. Limitations arise from the difficulty in constraining the sequence of events between external forcing, high- and low- latitude climate and environmental changes. Greenland ice cores provide sub-decadal-scale records across the last deglaciation and contain fingerprints of climate variations occurring in different regions of the Northern Hemisphere. Here, we combine new ice d-excess and 17O-excess records, tracing changes in the mid-latitudes, with ice δ18O records of polar climate. Within Heinrich Stadial 1, we demonstrate a decoupling between climatic conditions in Greenland and those of the lower latitudes. While Greenland temperature remains mostly stable from 17.5 to 14.7 ka, significant change in the mid latitudes of northern Atlantic takes place at ~ 16.2 ka, associated with warmer and wetter conditions of Greenland moisture sources. We show that this climate modification is coincident with abrupt changes in atmospheric CO2 and CH4 concentrations recorded in an Antarctic ice core. Our coherent ice core chronological framework and comparison with other paleoclimate records suggests a mechanism involving two-step freshwater fluxes in the North Atlantic associated with a southward shift of the intertropical convergence zone.


2018 ◽  
Vol 14 (10) ◽  
pp. 1405-1415 ◽  
Author(s):  
Amaëlle Landais ◽  
Emilie Capron ◽  
Valérie Masson-Delmotte ◽  
Samuel Toucanne ◽  
Rachael Rhodes ◽  
...  

Abstract. The last deglaciation represents the most recent example of natural global warming associated with large-scale climate changes. In addition to the long-term global temperature increase, the last deglaciation onset is punctuated by a sequence of abrupt changes in the Northern Hemisphere. Such interplay between orbital- and millennial-scale variability is widely documented in paleoclimatic records but the underlying mechanisms are not fully understood. Limitations arise from the difficulty in constraining the sequence of events between external forcing, high- and low- latitude climate, and environmental changes. Greenland ice cores provide sub-decadal-scale records across the last deglaciation and contain fingerprints of climate variations occurring in different regions of the Northern Hemisphere. Here, we combine new ice d-excess and 17O-excess records, tracing changes in the midlatitudes, with ice δ18O records of polar climate. Within Heinrich Stadial 1, we demonstrate a decoupling between climatic conditions in Greenland and those of the lower latitudes. While Greenland temperature remains mostly stable from 17.5 to 14.7 ka, significant change in the midlatitudes of the northern Atlantic takes place at ∼16.2 ka, associated with warmer and wetter conditions of Greenland moisture sources. We show that this climate modification is coincident with abrupt changes in atmospheric CO2 and CH4 concentrations recorded in an Antarctic ice core. Our coherent ice core chronological framework and comparison with other paleoclimate records suggests a mechanism involving two-step freshwater fluxes in the North Atlantic associated with a southward shift of the Intertropical Convergence Zone.


1999 ◽  
Vol 28 ◽  
pp. 1-8 ◽  
Author(s):  
Ralf Greve ◽  
Karl-Heinz Wyrwoll ◽  
Anton Eisenhauer

AbstractHigh resolution (TIMS) U-series dating of sea-level events obtained from coral-reef complexes suggests that global deglaciation from the Saale (penultimate) glacial to the Eem Interglacial (marine δ18O stages 6/5) may have occurred earlier in relation to Milankovitch insolation forcing than that from the Wisconsinan glacial to the Holocene Interglacial (marine δ18O stages 2/1). However, the interpretation of these data has been problematic because of the possibility of isotope exchange. In order to investigate whether these different lead—lag relations between Milankovitch forcing and ice volume are feasible from the point of view of large-scale ice-sheet dynamics and thermodynamics, the three-dimensional polythermal ice-sheet model SICOPOLIS (Simulation Code for Poly- thermal Ice Sheets) is applied to the entire Northern Hemisphere (which gives the major contribution to global ice-volume changes due to the relative stability of the Antarctic ice sheet) and simulations through the last two climatic cycles are conducted. The simulations cover the interval from 250 kyr BP until today and are driven by surface-temperature reconstructions of deep ice cores (GRIP, Vostok) and simple parameterizations for the change of precipitation with time. Discussion of the results is focused on the Saale/Eem and the Wisconsinan/Holocene transitions. The amount and rate of deglaciation are in good agreement with the SPECMAP record for both cases, and the evidence of the data for an early start of the Eem Interglacial is supported.


2021 ◽  
Vol 9 (6) ◽  
pp. 615
Author(s):  
Sophie Steinhagen ◽  
Swantje Enge ◽  
Karin Larsson ◽  
Joakim Olsson ◽  
Göran M. Nylund ◽  
...  

The growing world population demands an increase in sustainable resources for biorefining. The opening of new farm grounds and the cultivation of extractive species, such as marine seaweeds, increases worldwide, aiming to provide renewable biomass for food and non-food applications. The potential for European large-scale open ocean farming of the commercial green seaweed crop Ulva is not yet fully realized. Here we conducted manipulative cultivation experiments in order to investigate the effects of hatchery temperature (10 and 15 °C), nutrient addition (PES and 3xPES) and swarmer density (500 and 10,000 swarmers ml−1) on the biomass yield and biochemical composition (fatty acid, protein, carbohydrate, pigment and phenolic content) of off-shore cultivated Ulva fenestrata in a Swedish seafarm. High seedling densities were optimal for the growth of this northern hemisphere crop strain and significantly increased the mean biomass yield by ~84% compared to low seedling densities. Variations of nutrients or changes in temperature levels during the hatchery phase were not necessary to increase the subsequent growth in an open-water seafarm, however effects of the factors on the thallus habitus (thallus length/width) were observed. We found no significant effect of the environmental factors applied in the hatchery on the total fatty acid or crude protein content in the off-shore cultivated Ulva. However, low seedling density and low temperature increased the total carbohydrate content and furthermore, high temperature in combination with high nutrient levels decreased the pigment content (chlorophyll a, b, carotenoids). Low temperature in combination with high nutrient levels increased the phenolic content. Our study confirms the successful and sustainable potential for large-scale off-shore cultivation of the Scandinavian crop U. fenestrata. We conclude that high seedling density in the hatchery is most important for increasing the total biomass yield of sea-farmed U. fenestrata, and that changing temperature or addition of nutrients overall does not have a large effect on the biochemical composition. To summarize, our study contributes novel insights into the large-scale off-shore cultivation potential of northern hemisphere U. fenestrata and underpins suitable pre-treatments during the hatchery phase of seedlings to facilitate a successful and cost-efficient large-scale rope cultivation.


Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 504 ◽  
Author(s):  
Siyi Huang ◽  
Ziyun You ◽  
Yanting Jiang ◽  
Fuxiang Zhang ◽  
Kaiyang Liu ◽  
...  

Owing to their peculiar structural characteristics and potential applications in various fields, the ultrathin MoS2 nanosheets, a typical two-dimensional material, have attracted numerous attentions. In this paper, a hybrid strategy with combination of quenching process and liquid-based exfoliation was employed to fabricate the ultrathin MoS2 nanosheets (MoS2 NS). The obtained MoS2 NS still maintained hexagonal phase (2H-MoS2) and exhibited evident thin layer-structure (1–2 layers) with inconspicuous wrinkle. Besides, the MoS2 NS dispersion showed excellent stability (over 60 days) and high concentration (0.65 ± 0.04 mg mL−1). The MoS2 NS dispersion also displayed evident optical properties, with two characteristic peaks at 615 and 670 nm, and could be quantitatively analyzed with the absorbance at 615 nm in the range of 0.01–0.5 mg mL−1. The adsorption experiments showed that the as-prepared MoS2 NS also exhibited remarkable adsorption performance on the dyes (344.8 and 123.5 mg g−1 of qm for methylene blue and methyl orange, respectively) and heavy metals (185.2, 169.5, and 70.4 mg g−1 of qm for Cd2+, Cu2+, and Ag+). During the adsorption, the main adsorption mechanisms involved the synergism of physical hole-filling effects and electrostatic interactions. This work provided an effective way for the large-scale fabrication of the two-dimensional nanosheets of transition metal dichalcogenides (TMDs) by liquid exfoliation.


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