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MARINFORSK-Marine ressurser og miljø

Effects of ocean chemistry changes on planktic foraminifera in the Fram Strait: Ocean Acidification from natural to anthropogenic changes

Tildelt: kr 4,0 mill.

The following report refers to actions and activities performed during period of project extension (until 2015.12.31). In September 21-25, 2015, Post. Doc. Katarzyna Zamelczyk, organized a workshop entitled: Greenhouse Gases in the Ocean and Climate Change. This workshop was organized as a part of activates within The Trainee School in Arctic Marine Geology and Geophysics (AMGG) at the Arctic University of Norway, Tromsø, The Norwegian Research School in Climate Dynamics (ResClim), and The Center of Excellence for Arctic Gas Hydrate, Environment and Climate (CAGE). The goal of the workshop was to share knowledge on paleoceanographic proxies, and a wide range of subjects related to marine sediments and foraminiferal research.research in particular ocean acidification. Project partner J. Bijma from AWI was the main speaker on ocean acidification. During autumn/winter 2015 Post. Doc. Katarzyna Zamelczyk finalized foraminiferal analysis in sediment cores in the Fram Strait and continued writing a paper on a sedimentary record from Storfjorden Fan. During the winter 2016 the Post. Doc. performed identification of live foraminiferal fauna assemblages in the Fram Strait and additional plankton net samples from the Barents Sea were analyzed and a database for Barents Sea was developed. In December 2015, Post. Doc. Katarzyna Zamelczyk had a second research stay in AWI, Bremerhaven. During the stay cleaning of samples required for trace elements analysis were performed and trace elements concentrations measured.

Increasing atmospheric CO2 levels results in increased seawater CO2 concentrations which consequently alter the seawater carbonate equilibrium and decreases the pH. This effect can influence planktic foraminifera and lead to loss of biodiversity and chang es in biocalcification. Because of the natural low water temperatures and concentration of carbonate ions, low buffering capacity, freshening and increased carbon uptake in response to accelerating sea ice retreat due to Arctic warming, the atmospheric CO 2 enters the Arctic waters more rapidly than elsewhere. The project focuses on reconstruction and quantification of the response of planktic foraminifera to changes in surface ocean chemistry in the Fram Strait. The proposed project aims to increase the u nderstanding of consequences of changes in Arctic Ocean carbonate chemistry due to increased atmospheric CO2 concentration on calcifying planktic foraminifera and study the past and present impacts of Arctic Ocean acidification. New geochemical proxies as well as well tested approaches reflecting sea water chemistry will be applied. Marine sediment cores, surface samples and sediment traps from the Fram Strait will be examined with the focus on polar planktic foraminifera. Shell weight, degree of fragment ation and measurements of degree of dissolution based on SEM images will be used to establish the state of dissolution/preservation. Boron isotopes (d11B, a proxy for pH), B/Ca ratios (a proxy for carbonate ion concentration), and Mg/Ca ratios will be per formed. The project will be carried out in collaboration with scientists from the University of Tromsø (Norway) and the Alfred Wegener Institute for Polar and Marine Research (Germany). It will be based on analyses of marine sediment samples collected in previous and new (planned for 2012 and 2013) research cruises to the Fram Strait and sediment traps collected in the HAUSGARTEN deep-sea observatory in the Fram Strait.


MARINFORSK-Marine ressurser og miljø