Carbonyl sulfide hydrolysis in Antarctic ice cores and an atmospheric history for the last 8000 years

Abstract

Carbonyl sulfide (COS) was measured in Antarctic ice core samples from the Byrd, Siple Dome, Taylor Dome, and West Antarctic Ice Sheet Divide sites covering the last 8000 years of the Holocene. COS levels decrease downcore in most of these ice cores. The magnitude of the downcore trends varies among the different ice cores and is related to the thermal histories of the ice sheet at each site. We hypothesize that this is due to the temperature-dependent hydrolysis of COS that occurs in situ. We use a one-dimensional ice flow and heat flux model to infer temperature histories for the ice core samples from different sites and empirically determine the kinetic parameters for COS hydrolysis. We estimate e-folding lifetimes for COS hydrolysis ranging from 10 2 years to 10 6 years over a temperature range of 0°C to À50°C. The reaction kinetics are used to estimate and correct for the in situ COS loss, allowing us to reconstruct paleoatmospheric COS trends during the mid-to-late Holocene. The results suggest a slow, long-term increase in atmospheric COS that may have started as early as 5000 years ago. Given that the largest term in the COS budget is uptake by terrestrial plants, this could indicate a decline in terrestrial productivity during the late Holocene.

Low atmospheric CO2 levels during the Little Ice Age due to cooling-induced terrestrial uptake

“…12 The positive LIA COS anomaly found in the LIA 7 needs to be confirmed in order to constrain more sophisticated CO 2 /COS models. A recent study 37 has focused on the last 8000 years and does not have the resolution required to look at the LIA in detail. A new high resolution record of COS is needed for further investigation of the change of atmospheric COS during the LIA.…”

Changes in atmospheric carbonyl sulfide over the last 54,000 years inferred from measurements in Antarctic ice cores

“…Previous analyses of ice cores from several Antarctic sites show that atmospheric COS generally remained in the 330–350 ppt range over the few hundred years preceding the industrial era [ Aydin et al , , ]. In contrast, there have been significant changes in atmospheric COS levels during the past century.…”

“…On timescales longer than a few thousand years, ice core COS measurements from different Antarctic sites exhibit systematic differences related to the thermal history of the ice cores [ Aydin et al , ]. COS in ice from warmer sites is increasingly more depleted with depth (and age) relative to the measurements from colder sites.…”

Influence of the preparation conditions of MgAlCe catalysts on the catalytic hydrolysis of carbonyl sulfide at low temperature

“…Subsequently, the precipitation was separated, using the suction filter machine and washed with deionized water until pH= 7. The acquired HTLCs samples were called Mg 2 Al x Ce 1-x , x and (1-x) are values combined the molar ratio of Al/Ce(=2, 4,8,16) with (Al+Ce) is 0.1. Finally, it was calcined with oxygen in roaster for 3h.…”

“…Several removal methods exist for COS, including adsorption, reduction, photolysis and oxidation, etc [3] . A promising future exists for the hydrolysis method as it produces modest reaction conditions to achieve high removal efficiency [4] . Simple water vapor in yellow phosphorus tail gas is effective in promoting the occurrence of hydrolysis.…”