Microbiome Composition and Diversity of the Ice-Dwelling Sea Anemone, Edwardsiella andrillae.

Edwardsiella andrillae is a sea anemone (Cnidaria: Anthozoa: Actiniaria) only known to live embedded in the ice at the seawater interface on the underside of the Ross Ice Shelf, Antarctica. Although the anatomy and morphological characteristics of E. andrillae have been described, the adaptations of this species to the under-ice ecosystem have yet to be examined. One feature that may be important to the physiology and ecology of E. andrillae is its microbiome, which may play a role in health and survival, as has been deduced in other metazoans, including anthozoans. Here we describe the microbiome of five specimens of E. andrillae, compare the diversity we recovered to that known for temperate anemones and another Antarctic cnidarian, and consider the phylogenetic and functional implications of microbial diversity for these animals. The E. andrillae microbiome was relatively low in diversity, with seven phyla detected, yet included substantial phylogenetic novelty. Among the five anemones investigated, the distribution of microbial taxa varied; this trait appears to be shared by many anthozoans. Most importantly, specimens either appeared to be dominated by Proteobacteria-affiliated members or by deeply branching Tenericute sequences. There were few closely related sequence types that were common to temperate and Antarctic sea anemone microbiomes, the exception being an Acinetobacter-related representative. Similar observations were made between microbes associated with E. andrillae and an Antarctic soft coral; however, there were several closely-related, low abundance Gammaproteobacteria in both Antarctic microbiomes, particularly from the soft coral, that are also commonly detected in Southern Ocean seawater. Although this preliminary study leaves open many questions concerning microbiome diversity and its role in host ecology, we identify major lineages of microbes (e.g., diverse deep-branching Alphaproteobacteria, Epsilonproteobacteria, and divergent Tenericutes affiliates) that may play critical roles, and we highlight the current understanding and the need for future studies of sea anemone-microbiome relationships.

Enabling clean access into Subglacial Lake Whillans: development and use of the WISSARD hot water drill system.

Clean hot water drill systems (CHWDSs) are used with clean access protocols for the exploration of subglacial lakes and other subglacial aquatic environments (e.g. ice-shelf cavities) in Antarctica. A CHWDS developed for the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project by the Science Management Office at the University of Nebraska-Lincoln (UNL-SMO), USA, was specifically designed for use in West Antarctica, where the US Antarctic Program's South Pole Traverse could assist with logistical support. The initial goal was to provide clean access holes through ice up to 1000 m thick following environmental stewardship guidelines; however, the existing design allows this CHWDS to be used for ice thicknesses up to 2000 m following modifications to accommodate longer hose lengths. In January 2013, the WISSARD CHWDS successfully provided for the first time a clean access borehole through 800 m of ice into Subglacial Lake Whillans beneath the West Antarctic Ice Sheet for the deployment of scientific instruments and sampling tools. The development and initial use of the WISSARD CHWDS required the project team to address a number of constraints while providing contingencies to meet the defined project scope, schedule and budget.