Linking global change and deep-sea macrobenthos diversity – bathyal Atelostomata as a model taxon.

深海是地球上最大的生态系统，由于其巨大的规模和不可接近性，我们对全球深海生物群及其控制机制的认识仍然不明确。虽然化学合成生态系统逐渐被了解，但深海到深海平原和深海海沟仍未被广泛探索。由于陆上深海沉积物的地质记录较少，深海后生动物类群的连续地质/古生物记录较少，我们对深海古生物地理学和大型动物进化的认识更加初级。在ODP/DSDP/IODP岩心样品中提取下白垩世至上中新世深海深海大型底栖动物的遗骸，发现在深海中常见的棘皮类（海螺类、海蛇尾类、海星类、海百合类）没有，而只有不规则的棘皮类（Holasteroida、Spatangoida、Atelostomata）的刺类频繁出现。由于深海棘在形态上具有高度的可变性，因此对深海棘形态空间及其随时间的变化和棘积累速率的评估有可能反映深海生物多样性和生物量对全球变化的响应。特别是，由于初级生产力的降低，全球变暖导致出口生产力下降，特别是在开阔的海洋环境中，为什么热带东太平洋可以作为一个模型区来澄清两个假设。(1)无气孔棘多样性与新生代温暖期呈负相关，支持生产力-多样性关系；(2)无气孔棘丰度是生物量和出口生产力的表达，在温暖期值较低。考虑了快速变化的新生代世界中海面和海底水温发生巨大变化的特定区间的无气孔棘（中新世中期变冷、中新世中期气候最佳、渐新世晚期变暖、i-2c冰期及其后续、上渐新世、i-2b冰期及其后续）。棘的特征（如茎的形态、刺的排列和频率、气孔的形状/数量、针尖的形状等）包含在数据矩阵中并进行统计处理。脊柱多样性的变化被认为是生物多样性变化的表现，在变暖期间，多样性和生物量预计会减少。对上述间隔的脊椎组合进行主成分分析有助于识别特定时间间隔和多样性变化之间的形态空间差异。这为深海Atleostomata之间渐进（进化？）或突然（灭绝和物种形成/迁移？）的区系变化以及全球变化期间区系更替/变化与深海出口生产力波动的关系提供了额外的线索。

The deep-sea is the Earth’s largest ecosystem, and due to its sheer size and inaccessibility, our knowledge on global deep-sea biota and its controlling mechanisms is still ambiguous. While chemosynthetic ecosystems are progressively understood, the bathyal to abyssal plains and the hadal deep-sea trenches remain widely unexplored. Due to the scarce geologic record of deep-sea sediments onshore and the lack of continuous geological/palaeontological records of any group of higher deep-sea Metazoa, our knowledge on deep-sea palaeobiogeography and macrofauna evolution is even more rudimentary. A survey to extract remains of deep-sea macrobenthos from Lower Cretaceous to Upper Miocene sediments deposited at deep bathyal palaeo-waterdepths below 2000 m in ODP/DSDP/IODP core samples yielded astonishing results: Echinodermata (holothurians, brittle stars, sea stars, crinoids), today common in the deep-sea, are absent, while only spines of irregular echinoids (Holasteroida, Spatangoida: Atelostomata) occur frequently. Because the spines are morphologically highly variable, the assessment of spine morphospace, its changes in time and the spine accumulation rate bears the potential to map diversity and biomass changes in the deep-sea in response to global change. In particular, global warming results in decreasing export productivity due to lower primary productivity especially in open oceanic settings, why the eastern tropical Pacific serves as a model area to clarify two hypotheses. i) Atelostomate spine diversity correlates inversely with Cenozoic warm periods, supporting the productivity-diversity relation and ii) atelostomate spine abundance is expression of biomass and export productivity, showing lower values in warm phases. Atelostomate spines from selected intervals of the rapidly changing Cenozoic world with massive sea surface and bottom water temperature changes and were considered (Mid-Miocene cooling, Mid-Miocene climatic optimum, late Oligocene warming; Oi-2c glaciation and aftermath, Upper Oligocene; Oi-2b glaciation and aftermath). Spine characters (e.g. shaft morphology, arrangement and frequency of thorns, shape/number of pores, shape of tips etc.) are included in a data matrix and statistically processed. Variations in spine diversity are considered to express changing biodiversity, and decreasing diversity and biomass is expected during warming periods. A principal component analyses of the spine assemblages from the intervals above aid the recognition of morphospace disparity between the time-specific intervals and diversity changes. This give additionally clues on gradual (evolution?) or abrupt (extinction and speciation/immigration?) faunal changes between the deep-sea Atleostomata and the relation of faunal turnovers/changes to fluctuating export productivity into the dee-sea during global change.