Université de Fribourg

The genus Amphistegina (benthic foraminifera): distribution along the southern Tunisian coast

Kateb, Akram El ; Stalder, Claudio ; Stainbank, Stephanie ; Fentimen, Robin ; Spezzaferri, Silvia

In: BioInvasions Records, 2018, vol. 7, no. 4, p. 391–398

The benthic foraminiferal genus Amphistegina is currently expanding its range in the Mediterranean Sea after being introduced through the Suez Canal from the Red Sea. Over the previous decade, Amphistegina spp. has colonized the eastern part of the Mediterranean Sea including the Egyptian and Libyan coasts, but the present southern limit in the Mediterranean Sea is along the southern Tunisian...

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

Late glacial and Holocene Ostracoda from the Melilla cold-water coral mound field

Pirkenseer, Claudius M. ; Spezzaferri, Silvia ; Stalder, Claudio

In: Swiss Journal of Geosciences, 2018, vol. 111, no. 3, p. 549–560

The ostracod assemblages from sediment core TTR17-401G recovered from the Melilla cold-water coral mound field in the eastern Alboran Sea spanning the last 13 ka are analysed quantitatively, taxonomically and palaeoecologically. The core can be subdivided in three distinct assemblages linked to environmental shifts during the Younger Dryas and the Bølling–Allerød interstadial. A total of...

Université de Fribourg

High-resolution monitoring of water temperature and oxygen concentration in Lake Murten (Switzerland)

Kateb, Akram El ; Rüggeberg, Andres ; Stalder, Claudio ; Neururer, Christoph ; Spezzaferri, Silvia

In: Swiss Journal of Geosciences, 2018, vol. 111, no. 3, p. 501–510

Lake Murten is located in the Lake District in western Switzerland and so far, it has been poorly investigated. The Environmental Service of Fribourg (SEn) has monitored this lake once a month for several years by water profiles (water temperature, pH, dissolved oxygen, conductivity) at its deepest part. The SEn identified the stratification of water masses as one of the main causes for...

Université de Fribourg

Distribution of benthic foraminiferal assemblages in the transitional environment of the Djerba lagoon (Tunisia)

Kateb, Akram El ; Stalder, Claudio ; Neururer, Christoph ; Fentimen, Robin ; Spangenberg, Jorge E. ; Spezzaferri, Silvia

In: Swiss Journal of Geosciences, 2018, vol. 111, no. 3, p. 589–606

The eastern edge of the Djerba Island represents an important tourist pole. However, studies describing the environmental processes affecting this Island are scarce. Although never studied before, the peculiar Djerba lagoon is well known by the local population and by tourists. In July 2014, surface sediment and seawater samples were collected in this lagoon to measure grain size, organic...

Université de Fribourg

Schackoinella Spina, a new benthic foraminiferal species from cold-water coral ecosystems of the alboran sea and the gulf of Cádiz

Stalder, Claudio ; Székely-Szabolcs, Flavius ; Kateb, Akram El ; Rooij, David Van ; Spezzaferri, Silvia

In: The Journal of Foraminiferal Research, 2015, vol. 45, no. 4, p. 344–353

Schackoinella spina n. sp. has been found in the eastern Alboran Sea at five different stations in water depths ranging from 258–330 m, as well as in one 532 m deep station in the Gulf of Cádiz, north-eastern Atlantic Ocean. Three stations have been sampled with a giant box core (BC) and two stations with a gravity core (GC) system. The sediments of the BCs and the GCs are characterized by...

Université de Fribourg

Microfossils, a key to unravel cold-water carbonate mound evolution through time: Evidence from the eastern alboran sea

Stalder, Claudio ; Vertino, Agostina ; Rosso, Antonietta ; Rüggeberg, Andres ; Pirkenseer, Claudius ; Spangenberg, Jorge E. ; Spezzaferri, Silvia ; Camozzi, Osvaldo ; Rappo, Sacha ; Hajdas, Irka

In: PLoS ONE, 2015, vol. 10, no. 10, p. e0140223

Cold-water coral (CWC) ecosystems occur worldwide and play a major role in the ocean's carbonate budget and atmospheric CO2 balance since the Danian (~65 m.y. ago). However their temporal and spatial evolution against climatic and oceanographic variability is still unclear. For the first time, we combine the main macrofaunal components of a sediment core from a CWC mound of the Melilla Mounds...

Université de Fribourg

Fossil and genetic evidence for the polyphyletic nature of the planktonic foraminifera ‘Globigerinoides’, and description of the new genus Trilobatus

Spezzaferri, Silvia ; Kucera, Michal ; Pearson, Paul Nicholas ; Wade, Bridget Susan ; Rappo, Sacha ; Poole, Christopher Robert ; Morard, Raphaël ; Stalder, Claudio

In: PLoS ONE, 2015, vol. 10, no. 5, p. e0128108

Planktonic foraminifera are one of the most abundant and diverse protists in the oceans. Their utility as paleo proxies requires rigorous taxonomy and comparison with living and genetically related counterparts. We merge genetic and fossil evidence of “Globigerinoides”, characterized by supplementary apertures on spiral side, in a new approach to trace their “total evidence phylogeny”...

Université de Fribourg

Late Weichselian deglaciation and early Holocene development of a cold-water coral reef along the Lopphavet shelf (Northern Norway) recorded by benthic foraminifera and ostracoda

Stalder, Claudio ; Spezzaferri, Silvia ; Rüggeberg, Andres ; Pirkenseer, Claudius ; Gennari, Giordana

In: Deep Sea Research Part II: Topical Studies in Oceanography, 2014, vol. 99, p. 249–269

Cold-water coral (CWC) settlement in northern Norway is strongly related to the outlet-glaciers of the Fennoscandian Ice-sheet, and dating of known CWC structures show clearly post-glacial ages. Two gravity cores (POS391 559/2,277 cm long and POS391 559/3,282 cm long) were recovered on a CWC reef in the area of Lopphavet, northern Norway. Detailed investigations on lithology (sediment structures...

Université de Fribourg

Benthic foraminifer assemblages from norwegian cold-Water coral reefs

Spezzaferri, Silvia ; Rüggeberg, Andres ; Stalder, Claudio ; Margreth, Stephan

In: Journal of Foraminiferal Research, 2013, vol. 43, no. 1, p. 21-39

Quantitative investigations on the total (living + dead) benthic foraminiferal assemblages were performed on 32 surface-sediment samples (0–2 cm, .63-mm size fraction) from water depths ranging from 110–600 m (‘‘on-reef’’) to .2000 m (‘‘off-reef’’) in the Oslo Fjord (Skagerrak Basin), the mid-Norwegian slope (Sula, Røst, and Trænadjupet reefs), and the northern coral-reef...