Biogeography of selected Holocene coccoliths in the Atlantic Ocean
Biogeography of selected Holocene coccoliths in the Atlantic Ocean
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DOI：
10.1007/978-3-662-06278-4_15
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发表时间：
2004
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影响因子：
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通讯作者：
P. Ziveri;K. Baumann;Babette Böckel;J. Bollmann;J. Young
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文献类型：
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作者：
P. Ziveri;K. Baumann;Babette Böckel;J. Bollmann;J. Young
在这一章中，我们介绍了五个球石目动物的生物地理分布的修订，在大西洋中的球虫属(Coccolisus pelagicus，Calcidisus Leptoporus，Heli-cosphaera carteri，Syracosphaera Pulchraera和Umbilicosphaera sibogae)和GePhyrocapsaus属。绘制地图的基础是表层沉积物样本。这里讨论的每个分类群都构成了一个明确的形态群，非常适合于组合的快速低分类分辨率分析，这是组合生态和古生态分析的诱人策略。然而，最近的研究表明，在每一种情况下，这些广泛的分类群实际上是由几个离散的物种或亚种组成的。最明显的例子就是C。Pelagicus，在亚北极和温带上升流地区具有离散的形态类型。对于草酸根和胆红素来说，分离不那么明显，但仍然是明确的。物种分离显然对了解这些分类群的生物地理是必不可少的。就是这样。地板房。所绘制的分布图相对简单，我们还不知道它们与最近证实的分类群内的基因变异之间的关系。在高纬度，温度和生产力带相互平行，其影响很难区分。然而，在较低的纬度，这些影响更明显地分开--例如，这是显而易见的。Pulchrash显示了温水低生产率的偏好，而H。卡特尔拥有温水更高的生产率分布。特别是，在一些情况下，北大西洋和南大西洋的分布模式截然不同。其中包括FC的缺席。在亚南极地区的水龙；水母丰度高得多。产于比北大西洋更温带的南大西洋；鱼类丰度高得多。在营养稀少的南大西洋而不是北大西洋。由于北大西洋和南大西洋在温度、盐度、生产力和常量营养素(硝酸盐、磷酸盐和硅酸盐)方面表现出大致相似的一组环境，Calciuses和UmbilicSphaeratteratterns更为对称。明显的可能假设是，两个大洋的种群充分分开，进化出了略有不同的生态容忍度，或者是另一个因素，如微量元素，导致了分布差异。更广泛地说，我们怀疑，所有海洋中相对宽广的球虫类生物地理带以及球虫物种分布没有明显的差异，可能阻碍了对海洋之间显著对比的认识，尽管这种对比可能为解释过去组合的时间变化提供关键线索。
In this chapter we present a revision of the biogeographical distribution of five coccolithophorid species(Coccolithus pelagicus, Calcidiscus leptoporus, Heli-cosphaera carteri, Syracosphaera pulchraandUmbilicosphaera sibogae)and the genusGephyrocapsain the Atlantic Ocean. The mapping is based on surface sediment samples. Each of the taxa considered here constitutes an unambiguous morphological group ideal for rapid low taxonomic resolution analysis of assemblages, which is a tempting strategy for ecological and paleoecological analysis of assemblages. However, in each case recent research has indicated that these broad taxa are in fact composed of several discrete species, or sub-species. The clearest example isC. pelagicus, with discrete morphotypes in sub-Arctic and temperate upwelling areas. ForGephyrocapsaandUmbilicosphaerathe separation is less obvious but still unambiguous. Species separation is manifestly essential to understanding the biogeography of these taxa. ForH. carteriandS. pulchrathe mapped distributions are relatively straightforward and we do not yet know how they relate to the recently proven genotypic variation within the taxa.At high latitudes temperature and productivity belts parallel each other and the effects are difficult to distinguish. At lower latitudes however, the effects are more clearly separable – it is for instance obvious thatS. pulchrashows a warm water low productivity preference whilstH. carterishows a warm water higher productivity distribution. In particular there are several cases where distribution patterns in the North and South Atlantic are strikingly different. These include the absence ofC. pelagicusin the sub-Antarctic; the much higher abundance ofC. leptoporusin temperate South Atlantic than North Atlantic; much higher abundance ofU. sibogaevar.sibogaein the oligotrophic South Atlantic than the North Atlantic. TheCalcidiscusandUmbilicosphaerapatterns are more symmetric, since the North and South Atlantic show broadly similar sets of environments in terms of temperature, salinity, productivity and macronutrients (nitrate, phosphate and silicate). Obvious possible hypotheses are that the populations in the two oceans are sufficiently separated to have evolved slightly different ecological tolerances or that an additional factor, such as a trace element is responsible for the distribution contrasts. More generally we suspect that the comparably broad coccolithophorid bio-geographic zones in all oceans and the absence of obvious vicariance in coccolith species distributions may have prevented recognition of significant contrasts between oceans, although such contrasts may provide key clues for interpreting past temporal shifts in assemblages.