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

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

Foraminiferal-based biotic indices to assess the ecological quality status of the Gulf of Gabes (Tunisia): Present limitations and future perspectives

Kateb, Akram El ; Stalder, Claudio ; Martínez-Colón, Michael ; Mateu-Vicens, Guillem ; Francescangeli, Fabio ; Coletti, Giovanni ; Stainbank, Stephanie ; Spezzaferri, Silvia

In: Ecological Indicators, 2020, vol. 111, p. 105962

Biotic indices are tools to assess the ecological status of marine systems, and can be based on different metrics (such as ecological groups, specific diversity). The present study applies five biotic indices based on living (stained) benthic foraminiferal assemblages to assess ecological conditions in a wide area of the Mediterranean Sea in the heavily polluted Gulf of Gabes and along the...

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

Impact of industrial phosphate waste discharge on the marine environment in the Gulf of Gabes (Tunisia)

Kateb, Akram El ; Stalder, Claudio ; Rüggeberg, Andres ; Neururer, Christoph ; Spangenberg, Jorge E. ; Spezzaferri, Silvia

In: PLOS ONE, 2018, vol. 13, no. 5, p. e0197731

The marine environment in the Gulf of Gabes (southern Tunisia) is severely impacted by phosphate industries. Nowadays, three localities, Sfax, Skhira and Gabes produce phosphoric acid along the coasts of this Gulf and generate a large amount of phosphogypsum as a waste product. The Gabes phosphate industry is the major cause of pollution in the Gulf because most of the waste is directly...

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

Cold-water coral reefs along the european continental margin: the role of foraminifera

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

In: Atlas of benthic foraminifera from cold-water coral reefs - Special Publication / Cushman Foundation For Foraminiferal Research, 2014, vol. 44, p. 3-11

Université de Fribourg

Taxonomic notes and illustrations of benthicforaminifera from cold-water coral ecosystems

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

In: Atlas of benthic foraminifera from cold-water coral reefs - Special Publication / Cushman Foundation For Foraminiferal Research, 2014, vol. 44, p. 49-140

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...

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”...