Area, depth and elevation of cryoconite holes in the Arctic do not influence Tardigrada densities

Abstract

Water bears (Tardigrada) are known as one of the most extremophile animals in the world. They inhabit environments from the deepest parts of the oceans up to the highest mountains. One of the most extreme and still poorly studied habitats which tardigrades inhabit are cryoconite holes. We analysed the relation between area, depth, elevation and tardigrades densities in cryoconite holes on four glaciers on Spitsbergen. The mean (±SD) of cryoconite area was 1287.21±2400.8 cm 2 , while the depth was on average 10.8±11.2 cm, the elevation 172.6±109.66 m a.s.l., and tardigrade density 24.9±33.0 individuals per gram of wet material (n = 38). The densities of tardigrades on Hans Glacier reached values of up to 168 ind. cm 3 , 104 ind. g -1 wet weight, and 275 ind. g -1 dry weight. The densities of tardigrades of the three glaciers in Billefjorden were up to 82 ind. cm 2 , 326 ind. g -1 wet weight and 624 ind. g -1 dry weight. Surprisingly, although the model included area, depth and elevation as independent variables, it cannot explain Tardigrada density in cryoconite holes. We propose that due to the rapid melting of the glacier surface in the Arctic, the constant flushing of cryoconite sediments, and inter-hole water-sediment mixing, the functioning of these ecosystems is disrupted. We conclude that cryoconite holes are dynamic ecosystems for microinvertebrates in the Arctic.

Diversity and distribution of Tardigrada in Arctic cryoconite holes

“…Densities of the tardigrades from Hans Glacier and glaciers in Billefjorden are presented in Zawierucha et al (2016b). However, the number of analysed samples from Billefjorden in the present study is different.…”

“…Tardigrades reported from Buchan Glacier are northernmost record of tardigrades from cryoconite holes. Densities of the tardigrades from Hans Glacier and glaciers in Billefjorden presented in this paper, in terms of cryoconite hole area, depth and elevation are covered in Zawierucha et al (2016b).…”

“…Despite extreme conditions and high ice melt, tardigrades can inhabit cryoconite sediments in high densities (Zawierucha et al, 2016b). Glacier organisms may influence the size of cryoconite holes (McIntyre, 1984).…”

“…Some of the samples that were analysed in terms of abundance are currently not available for taxonomic and faunistic analysis. Because of losing a piece of material during sampling, quantitative data from cryoconite holes from Buchan and Waldemar Glaciers were omitted in Zawierucha et al, (2016b). In total, we analysed 33 samples in terms of tardigrade diversity (instead of the 48 mentioned in Zawierucha et al, 2016b).…”

A checklist of Norwegian Tardigrada

“…Bertolanius nebulosus (Dastych, 1983) Sv, ST Durante Pasa & Maucci 1979(see Maucci 1996; Dastych 1983Dastych , 1985Meier 1996 Bertolanius smreczynskii (Węglarska, 1970) Sv Klekowski & Opaliński 1986, 1989De Smet et al 1988;Janiec 1996Bertolanius volubilis (Durante Pasa & Maucci, 1975 No, ST Durante Pasa & Maucci 1975, 1979Meier 1996 Bertolanius weglarskae (Dastych, 1972 Smet 1991Smet , 1996Maucci 1996;Kaczmarek et al 2012;Zawierucha et al 2015cZawierucha et al , 2016bZawierucha et al , 2017 Richters 1903Richters , 1904bRichters , 1911aMarcus 1936;Węglarska 1965;Dastych 1985;De Smet et al 1987, 1988Janiec 1996;Maucci 1996;Meier 1996;Zawierucha et al 2013Zawierucha et al , 2015bZawierucha et al , 2016aZawierucha et al ,b,d, 2017 Adropion behanae (Dastych, 1987) Sv Dastych 1985 Adropion belgicae (Richters, 1911) Sv, Bu Richters 1911a,b;…”