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Dome−shaped cheilostome bryozoan colonies, most commonly about 2 cm in diameter, are common in Upper Eocene offshore deposits of southeastern North Carolina, USA.This colony−form is anachronistic in the Eocene, being more typical of Palaeozoic bryozoans.There are three types of domes: individual colonies of Parasmittina collum (Canu and Bassler), individual colonies of Osthimosia glomerata (Gabb and Horn) and multispecies intergrowths.The bryozoans grew laterally beyond initial shell substrata to become free−lying. P. collum colonies grew by local eruptive budding, forming subcolonies that extended radially over the underlying layer of zooids.Undersides of subcolonies that extended beyond the original substratum have basal exterior walls that are more commonly fouled by encrusters than is the upper side of the colony.By contrast, lateral growth of O. glomerata colonies was limited by size of the original substratum, subcolonies were not developed, and colony growth occurred by prolific frontal budding over the entire upper surface of the colony. Undersides of colonies beyond the substratum consist of the lateral interior walls of marginal zooids and are much less commonly fouled than are undersurfaces of P. collum.The upper surfaces of multispecies domes by definition are always fouled, and their undersurfaces are also commonly fouled.
Opoka, as a silica-calcite sedimentary rock, occurs in south-eastern Europe and Russia. Stratigraphical studies down to 8 m depth were performed in Bełżec, Poland, where samples were taken for further analyses. Vertical layers represented a heavy-weight opoka consisting of relatively more CaCO3 than the horizontal layers of lightweight opoka dominated by SiO2 . Opoka had a mean bulk density of 1.34 g/cm3, a porosity of 44.5 % and a specific surface area of 64 m2 /g. Opoka, especially after heated to over 900℃ can be used as reactive filter media for phosphorus removal. Maximum sorption capacity was 119.6 g PO4 -P/ kg. Element analysis of the rock did not reveal any anomaly from that expected, and it was concluded that its element content does not devaluate opoka as a sorbent used in ecological wastewater treatment .
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