Diagenetic alteration of benthic foraminifera from a methane seep site on Vestnesa Ridge (NW Svalbard)

Cold-seep fossil macrofaunal assemblages from Vestnesa Ridge, eastern Fram Strait, during the past 45 000 years

“…The same applies for R. kolgae (Åström et al 2017; Åström et al 2018). The presence of vesicomyid/solemyid layers in H1 therefore most likely do not indicate a maximum in seepage as postulated by, for example, Ambrose et al (2015) and Schneider et al (2017), but rather higher bottom water temperatures at the time. Core HH12-928PC was recovered from an elevated aragonitic pavement area, presumably representing the most intense seeping in the pockmark (Figs.…”

“…Carbonate nodules are authigenic carbonate precipitated in sediments affected by methane seepage as another "by-product" of anaerobic methane oxidation and sulphate reduction by the bacteria and archaea (Boetius et al 2000). The precipitation of authigenic carbonate is related to high rates of methane oxidation taking place near the sediment surface (Borowski et al 1996;Fontanier et al 2014) and can be used as a sign of palaeo-seepage (Schneider et al 2017). These nodules are similar to the "carbonate mud clasts" described by Fontanier et al (2014), with sediment and foraminifera embedded.…”

Effectiveness of Fluorescent Viability Assays in Studies of Arctic Cold Seep Foraminifera

“…For the last decades, the carbon isotopic signature δ 13 C of benthic foraminifera has been commonly used as a proxy in the reconstruction of productivity and origin and ventilation of water masses in the past (e.g., Gooday, 1994Gooday, , 2003Smart et al, 1994;Rohling and Cooke, 1999;Murray, 2006;Ravelo and Hillaire-Marcel, 2007). Recent studies have shown that the δ 13 C incorporated into the calcareous (CaCO 3 ) tests of benthic foraminifera can record episodes of release of methane in the past (e.g., Torres et al, 2003;Millo et al, 2005;Martin et al, 2010;Schneider et al, 2017;Sztybor and Rasmussen, 2017). The δ 13 C in the shells of some fossil benthic foraminifera can be lower than −10 (e.g., Hill et al, 2004;Schneider et al, 2017;Sztybor and Rasmussen, 2017), while the signature of calcite of living foraminifera generally do not exceed −7.5 (Mackensen et al, 2006;Wollenburg et al, 2015), it remains unclear if, and to what extent live benthic foraminifera incorporate methanederived carbon during biomineralization, or whether the isotopic signature is mostly affected by authigenic overgrowth from carbonate precipitation.…”

Benthic Foraminifera in Arctic Methane Hydrate Bearing Sediments

“…Even so, the ability of benthic foraminifera to thrive during methane release remained debated (e.g., Torres et al, 2003;Herguera et al, 2014). In addition, it was demonstrated that the stable isotopic composition of benthic foraminifera from cold seeps can be significantly affected by the precipitation of methane-derived authigenic carbonate (MDAC), as highlighted by studies conducted on foraminifera from Vestnesa Ridge (Panieri et al, 2014(Panieri et al, , 2017Consolaro et al, 2015;Schneider et al, 2017;Dessandier et al, under review). Therefore, a good knowledge of species ecology could provide additional information to better understand how benthic foraminifera can live and record methane seepage episodes.…”