Université de Fribourg

Large-scale paleoceanographic variations in the western Mediterranean Sea during the last 34,000 years: From enhanced cold-water coral growth to declining mounds

Stalder, Claudio ; El Kateb, Akram ; Vertino, Agostina ; Rüggeberg, Andres ; Camozzi, Osvaldo ; Pirkenseer, Claudius M. ; Spangenberg, Jorge E. ; Hajdas, Irka ; Rooij, David Van ; Spezzaferri, Silvia

In: Marine Micropaleontology, 2018, vol. 143, p. 46–62

Quantitative and qualitative analyses of cold-water coral (CWC) fragments from two sediment cores obtained from the Melilla Mounds Field (MMF) in the Alboran Sea, western Mediterranean Sea, reveal an alternation of periods dominated by distinct CWC species. The lower parts of the cores are dominated by the CWC species Lophelia pertusa, which is successively replaced in the upper parts by the...

Université de Fribourg

Benthic foraminifera in a deep-sea high-energy environment: the Moira Mounds (Porcupine Seabight, SW of Ireland)

Fentimen, Robin ; Rüggeberg, Andres ; Lim, Aaron ; El Kateb, Akram ; Foubert, Anneleen ; Wheeler, Andrew J. ; Spezzaferri, Silvia

In: Swiss Journal of Geosciences, 2018, vol. 111, no. 3, p. 561–572

Cold-water coral ecosystems represent unique and exceptionally diverse environments in the deep-sea. They are well developed along the Irish margin, varying broadly in shape and size. The Moira Mounds, numerous small-sized mounds, are nestled in the Belgica Mound Province (Porcupine Seabight, North-East Atlantic). The investigation of living (Rose Bengal stained) and dead benthic...

Université de Fribourg

In situ observations of foraminiferal bleaching in the maldives, indian ocean

Spezzaferri, Silvia ; El Kateb, Akram ; Pisapia, Chiara ; Hallock, Pamela

In: Journal of Foraminiferal Research, 2018, vol. 48, no. 1, p. 75–84

Coral reefs are threatened worldwide by a variety of natural and human-induced stressors; anomalous temperatures are presently among the most serious threats by causing extensive coral bleaching. Amphistegina spp. exhibit similar bleaching as corals in the presence of photo-oxidative stress induced by either light or temperature, especially during times of maximum solar irradiance. At 11...

Université de Fribourg

Developing Foram-AMBI for biomonitoring in the Mediterranean: Species assignments to ecological categories

Jorissen, Frans ; Nardelli, Maria Pia ; Almogi-Labin, Ahuva ; Barras, Christine ; Bergamin, Luisa ; Bicchia, Erica ; El Kateb, Akram ; Ferraro, Luciana ; Gann, Mary Mc ; Morigi, Caterina ; Romano, Elena ; Sabbatini, Anna ; Schweizer, Magali ; Spezzaferri, Silvia

In: Marine Micropaleontology, 2018, vol. 140, p. 33–45

Most environmental bio-monitoring methods using the species composition of marine faunas define the Ecological Quality Status of soft bottom ecosystems based on the relative proportions of species assigned to a limited number of ecological categories. In this study we analyse the distribution patterns of benthic foraminifera in the Mediterranean as a function of organic carbon gradients on...

Université de Fribourg

Directional changes of the geomagnetic field in West Africa: Insights from the metallurgical site of Korsimoro

Donadini, Fabio ; Serneels, Vincent ; Kapper, Lisa ; El Kateb, Akram

In: Earth and Planetary Science Letters, 2015, vol. 430, p. 349–355

This work shows the first archeomagnetic directions from Western Africa measured on 32 iron smelting kilns dated between 650 and 1800 AD. The archeological excavation of the vast metallurgical site of Korsimoro established the existence of four distinct iron-smelting techniques. The time-frame of each technique could be clearly determined with radiocarbon dating. Many of the kilns investigated in...