气候变化领域集成服务门户(CCPortal): Helicosphaera spp. coccolith morphometry and nannofossil fluxes at DSDP Site 74-525 and ODP Site 115-707 during the past 15 Ma

CCPortal

DOI	https://doi.pangaea.de/10.1594/PANGAEA.915595
	Helicosphaera spp. coccolith morphometry and nannofossil fluxes at DSDP Site 74-525 and ODP Site 115-707 during the past 15 Ma
	Šupraha; Luka; Henderiks; Jorijntje
发布日期	2020-04-28
数据集类型	dataset
英文关键词	biogeochemistry ; coccolith ; Morphometry ; nannofossils ; phenotypic evolution
英文简介	The biogeochemical impact of coccolithophores is defined by their overall abundance in the oceans, but also by a wide range in physiological traits such as cell size, degree of calcification and carbon production rates between different species. Species' "sensitivity" to environmental forcing has been suggested to relate to their cellular PIC:POC ratio and other physiological constraints. Understanding both the short and longer-term adaptive strategies of different coccolithophore lineages, and how these in turn shape the biogeochemical role of the group, is therefore crucial for modeling the ongoing changes in the global carbon cycle. Here we present data on the phenotypic evolution of a large and heavily-calcified genus Helicosphaera (order Zygodiscales) over the past 15 million years (Ma), at two deep-sea drill sites from the tropical Indian Ocean and temperate South Atlantic. The modern species Helicosphaera carteri, which displays eco-physiological adaptations in modern strains, was used to benchmark the use of its coccolith morphology as a physiological proxy in the fossil record. Our results show that, on the single-genotype level, coccolith morphology has no correlation with growth rates, cell size or PIC and POC production rates in H. carteri. However, significant correlations of coccolith morphometric parameters with cell size and physiological rates do emerge once multiple genotypes or closely related lineages are pooled together. Using this insight, we interpret the phenotypic evolution in Helicosphaera as a global, resource limitation-driven selection for smaller cells, which appears to be a common adaptive trait among different coccolithophore lineages, from the warm and high-CO2 world of the middle Miocene to the cooler and low-CO2 conditions of the Pleistocene. However, despite a significant decrease in mean coccolith and cell size, Helicosphaera kept relatively stable PIC:POC (as inferred from the coccolith "aspect ratio") and thus highly conservative biogeochemical output on the cellular level. We argue that this supports its status as an "obligate calcifier", like other large and heavily-calcified genera such as Calcidiscus and Coccolithus, and that other adaptive strategies, beyond size-adaptation, must support the persistent, albeit less abundant, occurrence of these taxa. This is in stark contrast with the ancestral lineage of Emiliania and Gephyrocapsa, which not only decreased in mean size but also displayed much higher phenotypic plasticity in degree of calcification while becoming globally more dominant in plankton communities.
空间范围	Median Latitude: -18.308000 * Median Longitude: 31.001050 * South-bound Latitude: -29.070700 * West-bound Longitude: 2.985300 * North-bound Latitude: -7.545300 * East-bound Longitude: 59.016800
时间范围	1980-06-10T00:00:00 - 1987-05-28T18:30:00
语种	英语
国家	国际
学科大类	气候变化
学科子类	气候变化
文献类型	数据集
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/235731
推荐引用方式 GB/T 7714	Šupraha,Luka,Henderiks,et al. Helicosphaera spp. coccolith morphometry and nannofossil fluxes at DSDP Site 74-525 and ODP Site 115-707 during the past 15 Ma.2020-04-28.https://doi.pangaea.de/10.1594/PANGAEA.915595.