CTD stations and logs for Araon 2018 ANA08D expedition to Larson C

Marine ecosystems under large ice shelves are thought to contain sparse, low-diversity plankton and seafloor communities due the low supply of food from productive sunlight waters. Past studies have shown sub-ice shelf ecosystems to change in response to altered oceanographic processes resulting from ice-shelve retreat. However, information on community changes and ecosystem structure under ice shelves are limited because sub-ice-shelf ecosystems have either been sampled many years after ice-shelf breakout, or have been sampled through small boreholes, yielding extremely limited spatial information. The recent breakout of the A-68 iceberg from the Larsen C ice shelf in the western Weddell Sea provides an opportunity to use a ship-based study to evaluate benthic communities and water column characteristics in an area recently vacated by a large overlying ice shelf. The opportunity will allow spatial assessments at the time of transition from an under ice-shelf environment to one initially exposed to conditions more typical of a coastal Antarctic marine setting.

This RAPID project will help determine the state of a coastal Antarctic ecosystem newly exposed from ice-shelf cover and will aid in understanding of rates of community change during transition. The project will conduct a 10-day field program, allowing contrasts to be made of phytoplankton and seafloor megafaunal communities in areas recently exposed by ice-shelf loss to areas exposed for many decades. The project will be undertaken in a collaborative manner with the South Korean Antarctic Agency, KOPRI, by participating in a cruise in March/May 2018. Combining new information in the area of Larsen C with existing observations after the Larsen A and B ice shelf breakups further to the north, the project is expected to generate a dataset that can elucidate fundamental processes of planktonic and benthic community development in transition from food-poor to food-rich ecosystems. The project will provide field experience to two graduate students, a post-doctoral associate and an undergraduate student. Material from the project will be incorporated into graduate courses and the project will communicate daily work and unfolding events through social media and blogs while they explore this area of the world that is largely underexplored.

人们此前认为，大型冰架（large ice shelf）下方的海洋生态系统中，浮游生物（plankton）与海底群落（seafloor community）较为稀少且多样性较低，这是因为光照充足的富营养表层海水所能提供的食物供给匮乏。过往研究表明，冰架消退（ice-shelf retreat）引发的海洋过程改变会使冰架下生态系统（sub-ice-shelf ecosystem）发生变化。然而，由于冰架下生态系统要么是在冰架崩解（ice-shelf breakout）多年后才被采样，要么是通过小型钻孔进行采样，导致空间信息极为有限，因此关于冰架下群落变化与生态系统结构的相关资料仍十分匮乏。近期威德尔海西部（western Weddell Sea）的拉尔森C冰架（Larsen C ice shelf）崩解出A-68冰山（A-68 iceberg），这为我们提供了开展船基调查（ship-based study）的契机，可对该大型覆冰冰架近期消退区域的底栖生物群落（benthic community）与水柱特征（water column characteristic）进行评估。此次调查可实现从冰架下环境向初始暴露于更典型南极沿海海洋环境的过渡阶段的空间观测。
本RAPID项目（RAPID project）旨在明确新近脱离冰架覆盖的南极沿海生态系统（coastal Antarctic ecosystem）的现状，并助力理解该过渡阶段的群落变化速率。项目将开展为期10天的野外作业，对比分析冰架新近消退区域与已暴露数十年区域的浮游植物（phytoplankton）及海底大型底栖生物群落（seafloor megafaunal community）。本项目将与韩国极地研究所（South Korean Antarctic Agency, KOPRI）开展合作，通过参与2018年3月/5月的科考航次完成此项研究。结合拉尔森C海域的新观测数据与更北部的拉森A、拉森B冰架崩解后的现有观测资料，本项目有望生成一套数据集，用以阐明从食物匮乏生态系统向食物丰富生态系统过渡过程中浮游与底栖群落发育的核心机制。本项目将为2名研究生、1名博士后研究员（post-doctoral associate）及1名本科生提供野外实践经验。项目产出的资料将融入研究生课程，并在探索这片极少被探索的南极海域期间，通过社交媒体（social media）与博客（blogs）同步展示日常工作及最新进展。