Holocene size variations in two diatom species off East Antarctica: Productivity vs environmental conditions
Holocene size variations in two diatom species off East Antarctica: Productivity vs environmental conditions
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DOI：
10.1016/j.dsr.2009.06.009
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发表时间：
2009-11-01
影响因子：
2.4
通讯作者：
Crosta, Xavier
中科院分区：
文献类型：
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作者：
Crosta, Xavier
我在此介绍了对来自南极洲东部阿德利地南极大陆架沉积岩芯 MD03-2601 的全新世样本中的两种硅藻——Fragilariopsis kerguelensis (O'Meara) Hustedt 和 Fragilariopsis curta (Van Heurck) Hustedt 进行的生物识别研究。将两个物种的顶瓣长度测量值与其各自的绝对和相对丰度进行比较，作为物种生产力的代表。在较温暖的中全新世时期，Fragilariopsis kerguelensis 的瓣膜更长且更丰富，而在较冷的晚全新世时期则更小且数量更少。相反，在较温暖的中全新世时期，F. curta 瓣膜较小且较少丰富，而在较冷的晚全新世时期较长且较多。平均顶瓣长度变化甚至伴随着物种丰度从百年到千年的波动。在较温暖的全新世中期和较冷的全新世晚期，F. keguelensis 和 F. curta 的最大瓣膜长度和最小瓣膜长度也分别较大。观察到的正大小-丰度关系与核心位置的环境条件有关，该环境条件目前处于 E kerguelensis 的生态下限和 F curta 的生态上限。更有利的环境条件（F kerguelensis 较温暖、冰度较低，E curta 较冷、较冰）允许在有性诱导大小窗口的上限范围内进行有性繁殖，并随后恢复较大的初始细胞，从而导致物种种群的总体规模更大，尽管营养繁殖更为频繁。 (C) 2009 Elsevier Ltd. 保留所有权利。
I here present a biometric investigation on two diatom species, Fragilariopsis kerguelensis (O'Meara) Hustedt and Fragilariopsis curta (Van Heurck) Hustedt, in Holocene samples from sediment core MD03-2601 from the Antarctic Continental Shelf off Adelie Land, East Antarctica. Apical valve length measurements of the two species are compared to their respective absolute and relative abundances as a proxy for the species productivity. Fragilariopsis kerguelensis valves were longer and more abundant during the warmer Mid-Holocene period and smaller and less abundant during the colder Late-Holocene period. Conversely, F. curta valves were smaller and less abundant during the warmer Mid-Holocene period and longer and more abundant during the colder Late-Holocene period. Mean apical valve length variations even follow centennial-to-millennial oscillations in the species abundances. Maximal valve length and minimal valve length were also larger during the warmer Mid-Holocene period and during the colder Late-Holocene period for F. keguelensis and F curta, respectively. The observed positive size-abundance relationships are linked to the environmental conditions at the core location that stands today at the lower ecological limit for E kerguelensis and upper ecological limit for F curta. More favourable environmental conditions (warmer, less icy for F kerguelensis and colder, icier for E curta) allowed for sexual reproduction at the upper range of the sexually inducible size window and subsequent restoration of larger initial cells which, in turn, resulted in overall bigger size of the species populations, though vegetative multiplication was more frequent. (C) 2009 Elsevier Ltd. All rights reserved.