Paleo-Ecology of the Yedoma Ice Complex on Sobo-Sise Island (EasternLena Delta, Siberian Arctic)

Late Pleistocene permafrost of the Yedoma type constitutes a valuable paleo-environmental archive due to the presence of numerous and well-preserved floral and faunal fossils. The study of the fossil Yedoma inventory allows for qualitative and quantitative reconstructions of past ecosystem and climate conditions and variations over time. Here, we present the results of combined paleo-proxy studies including pollen, chironomid, diatom and mammal fossil analyses from a prominent Yedoma cliff on Sobo-Sise Island in the eastern Lena Delta, NE Siberia to complement previous and ongoing paleo-ecological research in western Beringia. The Yedoma Ice Complex (IC) cliff on Sobo-Sise Island (up to 28 m high, 1.7 km long) was continuously sampled at 0.5 m resolution. The entire sequence covers the last about 52 cal kyr BP, but is not continuous as it shows substantial hiatuses at 36–29 cal kyr BP, at 20–17 cal kyr BP and at 15–7 cal kyr BP. The Marine Isotope Stage (MIS) 3 Yedoma IC (52–28 cal kyr BP) pollen spectra show typical features of tundra–steppe vegetation. Green algae remains indicate freshwater conditions. The chironomid assemblages vary considerably in abundance and diversity. Chironomid-based TJuly reconstructions during MIS 3 reveal warmer-than-today TJuly at about 51 cal kyr BP, 46-44 and 41 cal kyr BP. The MIS 2 Yedoma IC (28–15 cal kyr BP) pollen spectra represent tundra-steppe vegetation as during MIS 3, but higher abundance of Artemisia and lower abundances of algae remains indicate drier summer conditions. The chironomid records are poor. The MIS 1 (7–0 cal kyr BP) pollen spectra indicate shrub-tundra vegetation. The chironomid fauna is sparse and not diverse. The chironomid-based TJuly reconstruction supports similar-as-today temperatures at 6.4–4.4 cal kyr BP. Diatoms were recorded only after about 6.4 cal kyr BP. The Sobo-Sise Yedoma record preserves traces of the West Beringian tundra-steppe that maintained the Mammoth fauna including rare evidence for woolly rhinoceros’ presence. Chironomid-based TJuly reconstructions complement previous plant-macrofossil based TJuly of regional MIS 3 records. Our study from the eastern Lena Delta fits into and extends previous paleo-ecological Yedoma studies to characterize Beringian paleo-environments in the Laptev Sea coastal region.

Using laboratory investigations to reveal the palaeohydrological implications of aragonite laminae deposition in the endorheic Dead Sea and its precursors under different climatic conditions

<p>The sedimentary record of the endorheic Dead Sea and its precursors comprises aragonite laminae that make up an environmental archive extending into the Pleistocene, partially in annual resolution. Nevertheless, despite the importance of resolving the conditions that facilitate aragonite precipitation in the Dead Sea, contradictions exist between recent studies that utilized modern observations and the late Pleistocene geological record. The implications of aragonite precipitation in the Dead Sea and in its late Pleistocene predecessor Lake Lisan were investigated in this study by mixing natural and synthetic brines with a synthetic bicarbonate solution representing flood water entering the lake (4mM), with and without additions of extracellular polymeric substances (EPS). This was followed by measurements of aragonite precipitation incubation, rates, yields. Aragonite precipitation took place within days to few weeks after mixing of the brine with the synthetic bicarbonate solution and its incubation time was proportional to bicarbonate concentrations, while precipitation rates were also influenced by ionic strength. The addition of EPS inhibited aragonite precipitation for several months, which provides a reasonable explanation for the proposed summer-time precipitation of aragonite during the late Pleistocene glacials. We suggest that under increased inflow, increased biological activity would result in increased EPS production that could inhibit aragonite precipitation for several months. Finally, previous estimates of the freshwater inflow required to provide the carbonate for a uniform aragonite lamina of a typical thickness deposited during glacials are unreasonably high. This can be resolved by various processes: (1) Patchy aragonite deposition over limited segments of the lake’s floor; (2) Supply of additional carbonate to the lake from aeolian dust and recycled dust deposits; (3) Carbonate production through the oxidation of organic carbon by sulfate-reducing bacteria at the hypolimnion. Altogether, these results indicate that aragonite laminae thicknesses are insufficient to quantitatively reconstruct the hydrological balance for the entire lake, but may still be valuable for identifying climatic periodicities over a continuous record in a specific study site.</p>

Environmental impact assessment of a Pb, Zn smelter using soil, slag and tree ring elemental and isotopic geochemistry in Kabwe, Zambia

<p>Due to its historical Pb, Zn, Ag, Cd and Cu mines and associated smelter, Kabwe in Zambia is known to be one of the most polluted cities in the world.</p><p><span>Contamination by </span><span>Pb, Zn and Cu </span><span>was assessed in </span><span>four soil profiles around the smelter and remote locations, using Q-ICPMS for trace metal elemental and Pb isotopic measurements. A sequential extraction procedure (SEP) approach was used to obtain a detailed understanding of the vertical behaviour of the contaminants and its availability for plant uptake. Slags Pb isotopic ratios were also determined. Furthermore, tree rings of local pine trees (Pinus Montezumae) were collected and analysed for the same contaminants and Pb isotopes coupled with C isotopes. Results were compared to the smelter production historical records to assess the viability of these trees as environmental archive.</span></p><p>Results show that contamination is exclusive to the top layers of soil and is greater in soils closer to the smelter, which are highly contaminated (max: 16000 mg/kg Pb; 140000 mg/kg Zn; 600 mg/kg Cu). Remote soils have much lower topsoil concentrations (min: 61 mg/kg Pb; 351 mg/kg Zn; 21 mg/kg Cu). Interestingly, the greatest contaminant concentrations were found in the tree furthest from the source of pollution (max.: Pb, 6.48 mg/kg; Zn, 10.6 mg/kg; Cu, 10.2 mg/kg). Particle size of wind-blown dump dust decreases with distance. A hypothesis is considering that these would be more easily adsorbed and absorbed by tree bark and leaves. This suggests that above-ground tree uptake is more important than soil uptake for the selected elements.</p><p>Slag Pb isotopic ratios average at <sup>206</sup>Pb/<sup>207</sup>Pb = 1.15; <sup>208</sup>Pb/<sup>206</sup>Pb = 2.15; for tree rings; both sites: <sup>206</sup>Pb/<sup>207</sup>Pb = 1.15; <sup>208</sup>Pb/<sup>206</sup>Pb = 2.13; and in top soils, close to smelter: <sup>206</sup>Pb/<sup>207</sup>Pb = 1.15; <sup>208</sup>Pb/<sup>206</sup>Pb = 2.12; and in remote location: <sup>206</sup>Pb/<sup>207</sup>Pb =1.14; <sup>208</sup>Pb/<sup>206</sup>Pb = 2.15. Isotopic ratios confirm the mine and smelter to be the main source of contamination.</p><p>Smelter production records show three major shifts in production amount; increase from the late 1950s to early 1970s and a subsequent decrease till the closure of the smelter in 1994 with a peak in production in the early 1980s. There seems to be a correlation between Pb production and Pb uptake and Pb and C isotopic ratio variations within a 5 to 10 years delay.</p><p>This study was supported by the Czech Science Foundation project (GAČR 19-18513S) and received institutional funding from the Center for Geosphere Dynamics (UNCE/SCI/006). Part of the equipment used for this study was purchased from the Operational Program Prague - Competitiveness (Project CZ.2.16/3.1.00/21516).</p>

Information

This chapter is dedicated to the resource Information, which has become an indispensable key resource for both public and private actors involved in public policy processes in recent years. Information has become a real common pool resource. Nevertheless, each of the actors will try to obtain advantages from exclusive access to Information and secrecy. This is particularly true of target groups, which are the most important owners of such resources in technical policy fields. The examples presented in this chapter stem from security and risk policies, (institutional) transparency policies, economic, environmental, archive and pharmaceutical product policies. The chapter illustrates strategies of exclusion and proliferation for each of the three actor groups and other specific uses of the resource Information, particularly in policy implementation processes.

Boiled or Raw, Snail Shells Keep an Environmental Archive

Snail shells discovered at archaeological sites might still accurately record past weather and vegetation despite being the leftovers of a past meal.

A sclerochronological archive for Antarctic coastal waters based on the marine bivalve Yoldia eightsi (Jay, 1839) from the South Orkney Islands

The scarcity of long instrumental series from the Southern Ocean limits our understanding of key climate and environmental feedbacks within the Antarctic system. We present an assessment for the Antarctic mollusc bivalve Yoldia eightsi as an Antarctic coastal climatological archive, based on annually-resolved growth pattern of 20 live-collected specimens in 1988 from Factory Cove, Signy Island (South Orkney Islands). Two detrending methods were applied to the growth increment series: negative exponential detrending and regional curve standardization (RCS) detrending. The RCS-chronology showed consistent synchronous growth in the population for a 20 year period (1968-1988; expressed population signal ⩾ 0.85), a negative correlation between the RCS-chronology and the fast-ice duration record (r= -0.41, N= 24, P⩽ 0.05) and winter duration (r= -0.52, N=24, P⩽ 0.01) and positive correlations with mean winter sea surface temperature (SST; r= 0.57, N= 24, P⩽ 0.01), mean summer SST (r= 0.46, N= 24, P⩽ 0.05) and mean annual SST (r= 0.48, N= 24, P⩽ 0.05). The chronology appears to record the environmental conditions generated during the Weddell Polynya event (1973 -1976) as detectable abrupt changes in the annual growth patterns. Over eight years (1973-1980) a negative relationship between shell growth and suspended chlorophyll (i.e. a proxy for surface productivity) is apparent which is likely influenced by the seasonal deposition of organic phytodetritus on the seabed following surface water phytoplankton blooms. Our results form a basis for establishing Y. eightsi as an environmental archive for coastal Antarctic waters.