Diatom data from multicores collected during voyage 1 of the Investigator, 2017 (IN2017_V01)

These data were generated by Alexa Russo, undergraduate student at Colgate University, and Amy Leventer ([e-mail]). All questions regarding the specifics of these data should be directed to Amy Leventer. These data are based on samples collected during research cruise IN2017_V01 of the RV Investigator, co-chief scientists, Leanne Armand and Phil O’Brien.

The IN2017-V01 post-cruise report is available through open access via the e-document portal through the ANU library.

https://openresearch-repository.anu.edu.au/handle/1885/142525

The document DOI:
10.4225/13/5acea64c48693

The preferred citation is:

L.K. Armand, P.E. O’Brien and On-board Scientific Party. 2018. Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles (IN2017-V01): Post-survey report, Research School of Earth Sciences, Australian National University: Canberra, http://dx.doi.org/10.4225/13/5acea64c48693

The three multicores studied were extruded on board ship, every 1 cm in the top 20 cm, and then at 2 cm intervals to the bottom of the cores. In the lab at Colgate University, 20-25 mg of sediment were weighed to the tenth of a mg and placed in 20 ml glass vials. Vials were placed on a warming tray set to 50 degrees C and 1 mL of hydrogen peroxide was added to each vial, followed by RH2O. This was done to oxidize organic material. Successive additions of 1 mL of hydrogen peroxide were done until samples had stopped reacting. RH2O was added as needed to avoid samples drying out. Slides then were made using the random settling and slide preparation methods in Warnock and Scherer (2015).

Diatoms were observed with an Olympus BX50 microscope using the 100x/1.30 oil immersion objective and 10x eyepieces, for a total magnification of 1000x. For each slide, at least 400 diatom valves were counted along non-overlapping transects. Valves were only counted if greater than 50% complete, and diatoms were identified to the species level when possible using identifications from Cremer et al. (2003), Cefarelli et al. (2010), and Al-Handal et al. (2022). Unidentified diatoms were placed in either the unidentified centric diatom or unidentified pennate diatom category.

The three multicores studied are listed below:
Station_core Longitude Latitude

A005_MC01 115.623 -64.471
C012_MC03 119.3012 -64.675
C015_MC06 118.696 -64.729

References:
Al-Handal, A., Torstensson, A. and Wulff, A. (2022). Revisiting Potter Cove, King George Island, Antarctica, 12 years later: new observations of marine benthic diatoms. Botanica Marina, 65(2), 81-103. https://doi.org/10.1515/bot-2021-0066

Cefarelli, A., Ferrario, M., Almandoz, G., Atencio, A., Akselman, R. and Vernet, M. (2010). Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: Morphology, distribution and abundance. Polar Biology, 33. 10.1007/s00300-010-0794-z.

Cremer, H., Roberts, D., McMinn, A., Gore, D. and Melles, M. (2003). The Holocene Diatom Flora of Marine Bays in the Windmill Islands, East Antarctica. Botanica Marina, 46(1), 82-106. https://doi.org/10.1515/BOT.2003.010

Warnock, J. and Scherer, R. (2015). A revised method for determining the absolute abundance of diatoms. Journal of Paleolimnology, 53, 157-163. 10.1007/s10933-014-9808-0.

本数据集由科尔盖特大学（Colgate University）本科生Alexa Russo与Amy Leventer（电子邮箱：[e-mail]）编制生成。有关本数据集具体细节的所有问询，请联系Amy Leventer。本数据集基于RV Investigator号科考船IN2017_V01航次采集的样品构建，该航次的联合首席科学家为Leanne Armand与Phil O’Brien。

IN2017-V01航次的航后报告可通过澳大利亚国立大学（ANU）图书馆的开放研究仓储门户免费获取，链接为：https://openresearch-repository.anu.edu.au/handle/1885/142525。该报告的数字对象唯一标识符（DOI）为：10.4225/13/5acea64c48693。

推荐引用方式如下：
L.K. Armand、P.E. O’Brien 及本航次现场科学工作组. 2018. 多冰期旋回背景下托滕冰川与南大洋的相互作用（IN2017-V01）：澳大利亚国立大学地球科学研究学院航后报告，堪培拉，http://dx.doi.org/10.4225/13/5acea64c48693

本次研究涉及的3根多管沉积物柱样（multicores）在科考船上进行了分层挤压：表层20 cm按每1 cm间隔切割，下部柱体则按每2 cm间隔切割至柱底。在科尔盖特大学实验室中，称取20~25 mg沉积物样品（精确至0.1 mg），置于20 mL玻璃样品瓶中。将样品瓶放置于设定为50℃的加热托盘上，向每个瓶中加入1 mL过氧化氢，随后加入反渗透水（RH₂O），该操作用于氧化样品中的有机质。后续反复加入1 mL过氧化氢，直至样品不再发生氧化反应。根据样品状态补充RH₂O，以防止样品干涸。随后采用Warnock与Scherer（2015）提出的随机沉降制片法制备显微观测载玻片。

使用奥林巴斯BX50显微镜（Olympus BX50 microscope），搭配100×/1.30油浸物镜与10×目镜，总放大倍数为1000×，对样品中的硅藻进行观测。每张载玻片沿不重叠的样带计数至少400个硅藻壳瓣（diatom valves）。仅统计完整度超过50%的壳瓣；尽可能依据Cremer等（2003）、Cefarelli等（2010）及Al-Handal等（2022）的分类鉴定标准，将硅藻鉴定至种级水平。无法鉴定至种级的硅藻，分别归入未鉴定中心硅藻（centric diatom）或未鉴定羽纹硅藻（pennate diatom）类别。

本次研究的3根多管沉积物柱样信息如下：
| 站位_岩芯 | 经度 | 纬度 |
| --- | --- | --- |
| A005_MC01 | 115.623 | -64.471 |
| C012_MC03 | 119.3012 | -64.675 |
| C015_MC06 | 118.696 | -64.729 |

参考文献：
1. Al-Handal, A., Torstensson, A. & Wulff, A. (2022). 时隔12年重返南极乔治王岛波特湾：海洋底栖硅藻的新观测记录. 《海洋植物学》（Botanica Marina）, 65(2), 81-103. https://doi.org/10.1515/bot-2021-0066
2. Cefarelli, A., Ferrario, M., Almandoz, G., Atencio, A., Akselman, R. & Vernet, M. (2010). 阿根廷海与南极水域脆杆藻属（*Fragilariopsis*）硅藻的多样性：形态学、分布与丰度. 《极地生物学》（Polar Biology）, 33, 10.1007/s00300-010-0794-z.
3. Cremer, H., Roberts, D., McMinn, A., Gore, D. & Melles, M. (2003). 南极东部风车群岛海湾全新世硅藻区系. 《海洋植物学》（Botanica Marina）, 46(1), 82-106. https://doi.org/10.1515/BOT.2003.010
4. Warnock, J. & Scherer, R. (2015). 一种测定硅藻绝对丰度的改进方法. 《古湖沼学杂志》（Journal of Paleolimnology）, 53, 157-163. 10.1007/s10933-014-9808-0.