Bitectatodinium spongium (Zonneveld, 1997) Zonneveld et Jurkschat, comb. nov. from modem sediments and sediment trap samples of the Arabian Sea (northwestern Indian Ocean): taxonomy and ecological affinity

We present an emended diagnosis of Bitectatodinium spongium (Zonneveld, 199 7) Zonneveld et Jurkschat, comb. nov. previously described as ?Algidasphaer idium spongium. New data from surface samples of the Pakistan shelf are com bined with information from sediment traps off Somalia and Arabian Sea surf ace sediments to elucidate the taxonomy, ecological affinity and preservati on of B. spongium. A pronounced relationship is detected between high conce ntrations of B. spongium and well-mixed, nutrient-rich surface waters, as o bserved in upwelling regions and in the vicinity of the Indus River outlet. High concentrations of this species are also found in coastal regions and regions with tropical sea surface temperature conditions. No relationship i s observed between its distribution and differences in sea-surface salinity nor evidence for decay of B. spongium in relation to oxygen availability i n bottom sediments. (C) 1999 Elsevier Science B.V. All rights reserved.