Dinoflagellate cyst species composition of recent surface samples (Appendix)

<p>Dinoflagellate cysts and other organic-walled microfossils have been studied in recent surface sediments from the entire Norwegian-Greenland Sea. More than 30 taxa have been recognized, of which only few show a distinct distribution pattern, and allow description of four assemblages. The occurrence of most taxa is related to the relatively warmer waters of the Norwegian Sea. Algidaspaeridium? minutum s.1., Brigantedinium simplex and Impagidinium? pallidum are the only species showing a preference for colder water masses. Two species, I.? pallidum and Nematosphaeropsis labyrinthus are mainly restricted to the oceanic environment, whereas the other species have also been reported from neritic environments in previous studies. Due to the limited knowledge of the ecological and sedimentological factors influencing the occurrence of dinoflagellate cysts in oceanic environments, their distribution in recent sediments can be only related to surface water masses in a broad sense.
Although the distribution of assemblages correlates with specific surface water masses, comparison with assemblages recovered from sediment traps deployed basinwide in the Norwegian-Greenland Sea (Dale and Dale, 1992) revealed some major discrepancies in species composition and percentage abundances. The differences cannot be explained with certainty at the moment, although there is some evidence that transport of dinoflagellate cysts and other fossilizable microplankton in water masses by currents, in sea-ice and sediments may modify the assemblages found in recent oceanic surface sediments from the Norwegian-Greenland Sea.</p>

近年来，对挪威-格陵兰海整个海域的表层沉积物中的硅藻球和其它有机壁微化石进行了研究。已识别出30余种分类单元，其中仅有少数表现出明显的分布模式，从而描述了四个组合群。多数分类单元的出现与挪威海相对较暖的水温有关。Algidaspaeridium? minutum s.1.、Brigantedinium simplex以及Impagidinium? pallidum是唯一偏好较冷水团的物种。其中两种物种，即I.? pallidum和Nematosphaeropsis labyrinthus，主要局限于海洋环境，而其他物种在先前的研究中也已从近岸环境中被发现。鉴于对影响海洋环境中硅藻球出现的生态和沉积学因素的有限认识，其分布只能广义上与表层水团相关联。尽管组合群的分布与特定表层水团相关，但与在挪威-格陵兰海全海域布设的沉积陷阱中恢复的组合群（Dale和Dale，1992年）相比，在物种组成和百分比丰度上存在一些显著差异。目前尚无法确切解释这些差异，尽管有证据表明，通过洋流、海冰和沉积物中硅藻球及其他可化石微浮游生物的水团运输可能改变了挪威-格陵兰海近期海洋表层沉积物中发现的组合群。