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MSc defence: Michael Kristiansen

Michael Kristiansen defends his MSc thesis "A decade-long time series from a high Arctic fjord: Climate change affects sedimentation and benthic degradation of organic matter on an interannual basis"

Info about event


Tuesday 26 January 2016,  at 09:00 - 11:00


Department of Bioscience, Ny Munkegade 114, building 1540, meeting room 1540-116

Satellite image showing condition 11 July 2011 when ice broke up in the outer part of Young Sund. Photo Zackenberg Ecological Research Operations, 17th Annual Report 2011.

The mean surface temperature of the Earth is rising at a faster pace since the industrial evolution. This is more pronounced in high latitudes. As a consequence more sea ice melts each summer and high Arctic fjords become ice free for a longer period. More solar radiation is available to pelagic primary producers each season. This might affect primary production and export in and from the water column feeding the benthic environment with fresh organic material and thereby changing the geochemistry of the sediment. Previous studies have used comparisons of investigations of different natural climates to predict future consequences of climate change on fjord sedimentation and sediment geochemistry in the Arctic.

To contribute to the climate research, this Master project focuses on the temporal variation at one high Arctic location. I present an analysis of a decade long time series of parameters including open water period, sediment total oxygen uptake, dissolved inorganic carbon efflux and sediment sulphate reduction rate from the Young Sound fjord, Northeast Greenland (part of Greenland Ecosystem Monitoring programme - Zackenberg MarineBasis ).

None of the parameters increased significantly throughout the decade. Ice break and formation have been observed and logged sporadically since 1929 and more consistently since 1950. The available data show a steady significant increase of open water period. We hypothesized that maximum sedimentation and sediment mineralization are correlated to the open water period in the period 2003-2013. The data analyses showed significant correlations between open water period and maximum sedimentation rate and dissolved inorganic carbon efflux. Based on these findings we suggest that maximum sedimentation rate and aerobic sediment mineralisation evolve similarly to the duration of the open water period.

Text by Michael Kristiansen