Université de Fribourg

Early diagenetic imprint on temperature proxies in holocene corals: a case study from french polynesia

Rashid, Rashid ; Eisenhauer, Anton ; Liebetrau, Volker ; Fietzke, Jan ; Böhm, Florian ; Wall, Marlene ; Krause, Stefan ; Rüggeberg, Andres ; Dullo, Wolf-Christian ; Jurikova, Hana ; Samankassou, Elias ; Lazar, Boaz

In: Frontiers in Earth Science, 2020, vol. 8, p. -

Coral-based reconstructions of sea surface temperatures (SSTs) using Sr/Ca, U/Ca and δ18O ratios are important tools for quantitative analysis of past climate variabilities. However, post-depositional alteration of coral aragonite, particularly early diagenesis, restrict the accuracy of calibrated proxies even on young corals. Considering the diagenetic effects, we present new Mid to Late...

Université de Fribourg

Environmental and biological controls on Na∕Ca ratios in scleractinian cold-water corals

Schleinkofer, Nicolai ; Raddatz, Jacek ; Freiwald, André ; Evans, David ; Beuck, Lydia ; Rüggeberg, Andres ; Liebetrau, Volker

In: Biogeosciences, 2019, vol. 16, no. 18, p. 3565–3582

Here we present a comprehensive attempt to correlate aragonitic Na∕Ca ratios from Desmophyllum pertusum (formerly known as Lophelia pertusa), Madrepora oculata and a caryophylliid cold-water coral (CWC) species with different seawater parameters such as temperature, salinity and pH. Living CWC specimens were collected from 16 different locations and analyzed for their Na∕Ca ratios using...

Université de Fribourg

Boron isotope composition of the cold-water coral Lophelia pertusa along the Norwegian margin: Zooming into a potential pH-proxy by combining bulk and high-resolution approaches

Jurikova, Hana ; Liebetrau, Volker ; Raddatz, Jacek ; Fietzke, Jan ; Trotter, Julie ; Rocholl, Alexander ; Krause, Stefan ; Mc Culloch, Malcolm ; Rüggeber, Andres ; Eisenhauer, Anton

In: Chemical Geology, 2019, vol. 513, p. 143–152

High-latitude cold-water coral reefs are particularly vulnerable to climate change due to enhanced CO2 uptake in these regions. To evaluate their physiological functioning and potential application as pH archives, we retrieved both recent and fossil samples of Lophelia pertusa along the Norwegian margin from Oslofjord (59°N), over to Trondheimsfjord, Sula and Lopphavet (70.6°N). Boron...

Université de Fribourg

Environmental constraints on Holocene cold‐water coral reef growth off Norway: Insights from a multiproxy approach

Raddatz, Jacek ; Liebetrau, Volker ; Trotter, Julie ; Rüggeberg, Andres ; Flögel, Sascha ; Dullo, Wolf-Christian ; Eisenhauer, Anton ; Voigt, Silke ; McCulloch, Malcolm

In: Paleoceanography, 2016, vol. 31, no. 10, p. 1350–1367

High-latitude cold-water coral (CWC) reefs are particularly susceptible due to enhanced CO₂ uptake in these regions. Using precisely dated (U/Th) CWCs (Lophelia pertusa) retrieved during research cruise POS 391 (Lopphavet 70.6°N, Oslofjord 59°N) we applied boron isotopes (δ¹¹B), Ba/Ca, Li/Mg, and U/Ca ratios to reconstruct the environmental boundary conditions of CWC reef growth. The...

Université de Fribourg

Paleoseawater density reconstruction and its implication for cold-water coral carbonate mounds in the northeast Atlantic through time

Rüggeberg, Andres ; Flögel, Sascha ; Dullo, Wolf-Christian ; Raddatz, Jacek ; Liebetrau, Volker

In: Paleoceanography, 2016, vol. 31, no. 3, p. 2015PA002859

Carbonate buildups and mounds are impressive biogenic structures throughout Earth history. In the recent NE Atlantic, cold-water coral (CWC) reefs form giant carbonate mounds of up to 300 m of elevation. The expansion of these coral carbonate mounds is paced by climatic changes during the past 2.7 Myr. Environmental control on their development is directly linked to controls on its main...

Université de Fribourg

Environmental boundary conditions of cold-water coral mound growth over the last 3 million years in the Porcupine Seabight, Northeast Atlantic

Raddatz, Jacek ; Rüggeberg, Andres ; Liebetrau, Volker ; Foubert, Anneleen ; Hathorne, Ed C. ; Fietzke, Jan ; Eisenhauer, Anton ; Dullo, Wolf-Christian

In: Deep Sea Research Part II: Topical Studies in Oceanography, 2014, vol. 99, p. 227–236

IODP Expedition 307 made it for the first time possible to investigate the entire body of a cold-water coral carbonate mound. Here we provide new insights into the long-term history of Challenger Mound on the European continental margin off Ireland. This study is based on age determinations (230Th/U, 87Sr/86Sr) and geochemical signals (Mg/Li and Ba/Ca) measured in the scleractinian cold-water...