subtr.-trop species group = Discosphaera tubifera, Florisphaera profunda, Gladiolithus flabellatus, Rhabdosphaera clavigera, Syracosphaera spp., Umbellosphaera spp., Umbilicosphaera sibogae) / number of coccoliths g-1 sediment =FNS/A*W / where F = effective filtration area (mm2); N = number of coccoliths counted; S = split factor; A= investigated filter area (mm2); W = weight of dry sediment (g) following Andruleit (1996) / Andruleit, H., 1996. A filtration technique for quantitative studies of coccoliths. Micropaleontology 42/4, 403-406.