Skeletal carbonate mineralogy of Scottish bryozoans

Abstract

This paper describes the skeletal carbonate mineralogy of 156 bryozoan species collected from Scotland (sourced both from museum collections and from waters around Scotland) and collated from literature. This collection represents 79% of the species which inhabit Scottish waters and is a greater number and proportion of extant species than any previous regional study. The study is also of significance globally where the data augment the growing database of mineralogical analyses and offers first analyses for 26 genera and four families. Specimens were collated through a combination of field sampling and existing collections and were analysed by X-ray diffraction (XRD) and micro-XRD to determine wt% MgCO3 in calcite and wt% aragonite. Species distribution data and phylogenetic organisation were applied to understand distributional, taxonomic and phylo-mineralogical patterns. Analysis of the skeletal composition of Scottish bryozoans shows that the group is statistically different from neighbouring Arctic fauna but features a range of mineralogy comparable to other temperate regions. As has been previously reported, cyclostomes feature low Mg in calcite and very little aragonite, whereas cheilostomes show much more variability, including bimineralic species. Scotland is a highly variable region, open to biological and environmental influx from all directions, and bryozoans exhibit this in the wide range of within-species mineralogical variability they present. This plasticity in skeletal composition may be driven by a combination of environmentally-induced phenotypic variation, or physiological factors. A flexible response to environment, as manifested in a wide range of skeletal mineralogy within a species, may be one characteristic of successful invasive bryozoans.

NEXAFS imaging to characterize the physio-chemical composition of cuticle from African Flower Scarab Eudicella gralli

“…Some fossil evidences and molecular biology data suggest that aragonite shell is more ancient than calcite shell for the Bivalvia 39 . Bryozoan skeletons are mineralogically variable, and can be entirely calcitic, entirely aragonitic or bimineralic 40,41 . Ediacaran Cloudina and Namacalathus , which are among the earliest shell-forming organisms, originally produced aragonitic skeletons, which later underwent diagenetic conversion to calcite 42 .…”

Polymorphism ofCaCO3and the variability of elemental composition of the calcareous skeletons secreted by invertebrates along the salinity gradient of the Baltic Sea

“…Instead, the mineralogical composition of the studied taxa is in line with their mineralogy recorded in different regions of the ocean, regardless of the prevailing environmental conditions (Krzeminska et al, 2016; Kuklinski & Taylor, 2009; Lombardi et al, 2008; Taylor et al, 2016). For example, the studied bryozoans Einhornia crustulenta , Cryptosula cryptooecium and Electra pilosa have previously been found outside the Baltic Sea as calcitic (Kuklinski & Taylor, 2009), while bryozoans Escharella immersa and Cryptosula pallasiana are bimineralic (Kuklinski & Taylor, 2009; Loxton et al, 2018; Smith et al, 2006). The data presented in this study also provide evidence of calcitic skeleton of barnacles Amphibalanus improvisus and Semibalanus balanoides (Ullmann et al, 2018) and bimineralic skeleton of mussels Mytilus spp.…”

“…Yet, the Baltic population of calcifying organisms does not seem to reflect this environmental trend in the mineralogical composition (calcite to aragonite ratio) of their skeleton (Tables 2 and S2). For more details about sampling stations, see Table 1 cryptooecium and Electra pilosa have previously been found outside the Baltic Sea as calcitic (Kuklinski & Taylor, 2009), while bryozoans Escharella immersa and Cryptosula pallasiana are bimineralic (Kuklinski & Taylor, 2009;Loxton et al, 2018;Smith et al, 2006).…”

Skeletal resorption in bryozoans: occurrence, function and recognition

“… * Representative value for family marked with an asterisk where species/genus level data unavailable, in which case a pooled family or superfamily value was used. Mineralogical data from Smith et al ., 2006, supplemented by Taylor & Monks, 1997 and Loxton et al ., 2018. …”