{"id":7147,"date":"2021-12-14T00:43:23","date_gmt":"2021-12-13T23:43:23","guid":{"rendered":"https:\/\/site.uit.no\/cage\/?p=7147"},"modified":"2023-04-04T10:29:03","modified_gmt":"2023-04-04T08:29:03","slug":"siri-ofstad-defends-thesis-on-arctic-planktonic-calcifiers-in-a-changing-ocean","status":"publish","type":"post","link":"https:\/\/site.uit.no\/cage\/2021\/12\/14\/siri-ofstad-defends-thesis-on-arctic-planktonic-calcifiers-in-a-changing-ocean\/","title":{"rendered":"Siri Ofstad defends thesis on “Arctic planktonic calcifiers in a changing ocean”"},"content":{"rendered":"

Siri Ofstad will publically defend her PhD thesis entitled, “Arctic planktonic calcifiers in a changing ocean – A study on recent planktonic foraminifera and shelled pteropods in the Fram Strait-Barents Sea region”<\/strong>\u00a0on December 16th 2021<\/strong> at UiT \u2013 The Arctic University of Norway. This work was funded by the Centre for Arctic Gas Hydrate, Environment, and Climate (CAGE) at UiT.<\/h4>\n

The trial lecture and public defense will be streamed online<\/a>.<\/p>\n

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Popular scientific abstract<\/h4>\n

The Arctic is changing. Small organisms (planktonic foraminifera and shelled pteropods) in the water column were studied in terms of their abundance, seasonality, diversity, life cycles, and calcification. This was done by collecting samples with a plankton net and collecting water and surface sediments. This thesis has shown that the Fram Strait-Barents Sea region is characterized by low species diversity and marked seasonality. We found a decrease in the relative abundance of the polar species Neogloboquadrina pachyderma on the Greenland shelf compared to the 1990s, and sub-tropical species in the Barents Sea. This thesis has helped in filling gaps in research into the impacts of ocean acidification in the Arctic. Lastly, we have been able to show that organisms in the same size class and water depth have a wide range of shell densities which is also true for foraminifera in surface sediments. These two points may complicate geochemical or ocean acidification studies as well as paleo-studies.<\/p>\n

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The plan for Siri Ofstad’s public defense for the PhD degree in Science, on December 16th 2021, is as follows:<\/h4>\n

Trial lecture at 10:15 on the following topic:<\/p>\n

\u00a0\u2018The role of marine calcifiers in the ocean carbon and carbonate pumps; past, present, and future\u2019<\/strong><\/p>\n

PhD thesis defense at 12:15:<\/p>\n

\u2018Arctic planktonic calcifiers in a changing ocean – A study on recent planktonic foraminifera and shelled pteropods in the Fram Strait-Barents Sea region\u2019<\/strong><\/p>\n

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PhD Thesis is published and available here<\/a>.<\/strong><\/p>\n

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Supervisors:<\/strong><\/p>\n