Handledare: Karl Ljung (Karl.Ljung@geol.lu.se) och Dan Hammarlund (Dan.Hammarlund@geol.lu.se)

Map showing the localities of sample sites.

As part of the ice-breaker-based expedition Ryder19 to northern Greenland arranged by the Swedish Polar Research Secretariate in August-September 2019, sediment records from several small lakes on the ice-free peninsulas adjacent to Nares Strait were collected. These records are expected to cover the last few centuries, including the recent past, providing opportunities for highly resolved environmental reconstructions in a remote region of the Arctic where few such studies have been performed previously. The sediment archives open the possibility to study long-term pollution history in the high arctic. It is well established that air pollution travels far and deposits in regions far from their sources. But the spatial patterns or historical evolution are not fully known or understood.

In this project, we will study the historical deposition of pollution from fossil fuels and biomass combustion in three lakes on Washington Land, Warming Land and Wulff Land (blue symbols on the map). We have gravity-core sequences, 30-45 cm in length, that are subsampled into 1 cm contiguous samples. Precise chronologies will be based on ²¹⁰Pb and ¹³⁷Cs radioisotope analyses.

The pollution histories will be based on measurements of black carbon (BC) and spheroidal carbonaceous particles (SCP) on the sediment samples. BC is formed by the incomplete combustion of fossil fuels and biomass and is part of the particulate pollution. SCPs are only formed by the combustion of fossil fuels at high temperatures in engines. By combining these two proxies it is possible to assess the loading of pollution from fossil fuel use and biomass burning.

The research questions we will address in the project are:

what were the historical trends of BC and SCP deposition?
how high are the current loads of BC and SCP deposition?
what are the drivers of the deposition of BC and SCP in these high arctic environments?

You will quantify BC using chemical and thermal treatment followed by elemental analysis and quantify SCPs by particle counting under a microscope. Laboratory work is a major part of the project, and you will learn lab skills, quality control and instrument maintenance. The temporal trends of BC and SCP deposition will be evaluated in relation to industrial developments and prevailing weather patterns bringing pollution to these high arctic environments. The results will be an important piece for understanding the long-term and future fate of pollutants in the high arctic.

Uppdaterat: Nina Reistad | 2022-11-23