Edwardsiella andrillae
| Edwardsiella andrillae | ||||||||||||
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Edwardsiella andrillae under the ice shelf |
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| Scientific name | ||||||||||||
| Edwardsiella andrillae | ||||||||||||
| Daly , Rack & Zook , 2013 |
Edwardsiella andrillae is a sea anemone from the Southern Ocean that was discovered under the Ross Ice Shelf in the Antarctic Ross Sea and was first described in2013. It is the only known species of the genus Edwardsiella in Antarctica and lives in the water channels at the bottom of the ice shelf .
features
Edwardsiella andrillae is a sea anemone that lives in the sea ice in the form of a sessile polyp . It differs from other species of the genus mainly by the number of tentacles and the size and arrangement of the stinging cells . The species of the genus Edwardsiella are elongated polyps with a long stalk ( Scapus ) and a capitulum that carries the tentacles that are present in 6 numbers. The tentacles are furrowed, in the furrows are usually the nettle cells.
Edwardsiella andrillae has a long body with 20 to 24 tentacles that taper towards the end. The inner tentacles are noticeably longer than the outer ones. Both the scapus and the tentacles are translucent white and have no periderm . When contracted, the body is 16 to 20 millimeters long and 6 millimeters in diameter. Edwardsiella andrillae differs from the only other species of the genus from the southern hemisphere, Edwardsiella ignota from Chile , by the arrangement of the nettle cells.
distribution
Edwardsiella andrillae is only known from samples from the bottom of the Ross Ice Shelf in the Antarctic Ross Sea. The animals live on the underside of the 250 to 260 meter thick layer of ice, under which there is a layer of water about 40 meters deep down to the sea floor. It is the only known species of the genus in the Southern Ocean and in the Antarctic area , only Edwardsiella ignota from the Chilean coast is known from the southern hemisphere . In addition, only two other species of the Edwardsiidae are known from the Antarctic, Edwardsia meridionalis (Williams 1981) and Scolanthus intermedius (McMurrich 1893).
Way of life
Edwardsiella andrillae , like other sea anemones, is sessile and it is the first known species of sea anemone to live in ice; other species in the Antarctic live on rocks or in soft substrates on the sea floor. Most of its body is in the ice channels at the bottom of the ice shelf, from which only the tentacle crown protrudes into the sea water below the ice.
Due to the very limited material and the difficult possibilities of observation, the way of life and the physiological adaptations to the life of the species in the ice are largely unknown. While other polyps dig their living tubes either by extracting their basal parts or with the help of the tentacles, these two options are rather unsuitable for the ice channels. Physiological adaptations to the extremely low temperatures, such as those for segmented worms as mesenchytraeus solifugus are known, were at andrillae Edwardsiella not be detected.
In an analysis in 2016, the microbiome of the species was analyzed using five individuals to examine its importance in adapting to lifestyle. A relatively poor microbiome was identified, which consists of representatives of seven bacterial strains and is dominated by Proteobacteria or Tenericutes . In addition, it is comparatively variable in composition between the examined individuals and, with the exception of one Acinetobacter relative, differs significantly from that of other sea anemones from temperate and tropical marine regions. At the same time, it shows some agreement with the microbiome of the soft coral Alcyonium antarcticum , which also lives in Antarctica , especially the presence of gammaproteobacteria . Inferences for the way of life could not be made.
Discovery story
Edwardsiella andrillae was discovered during the Coulman High Project (CHP) as part of the ANDRILL (ANtarctic geologic DRILLing) research project , funded by the US National Science Foundation , Office of Polar Programs, and in New Zealand by the NZ Foundation for Research, Science and Technology and described. From 2010 to 2011, the program was dedicated to exploring this inaccessible and largely unexplored habitat beneath the sea ice. The animals were discovered by the Submersible Capable of Under-Ice Navigation and Imaging (SCINI), an automatic research submersible lowered in two places through a hole in the ice. With the help of the SCINI cameras, it was possible to film an area below the ice in two places, which was covered by the polyps of Edwardsiella andrillae .
With the help of an improvised gripper and collector attached to the SCINI, more than 20 individual individuals could be removed from the ice and collected. To support this, hot water was pumped from the ice surface through a hose to the gripper to enable the animals to be removed from the ice. The individuals immersed in ethanol were taken by helicopter to McMurdo Station for examination and preservation in formalin .
Systematics
Edwardsiella andrillae was described in 2013 as a separate species of the genus Edwardsiella by the researchers Marymegan Daly , Frank Rack and Robert Zook . The species of the genus Edwardsiella are assigned to the Edwardsiidae , which is composed of numerous species of sessile and burrowing sea anemones in numerous coastal habitats, including deep-sea trenches or hypo- to hypersaline estuaries .
The naming with the species name andrillae was based on the research program Antarctic Drilling ANDRILL, in the context of which the polyps were found.
supporting documents
- ↑ a b c d e f Marymegan Daly, Frank Rack, Robert Zook: Edwardsiella andrillae, a New Species of Sea Anemone from Antarctic Ice. PLoS ONE 8 (12): e83476; December 11, 2013 doi : 10.1371 / journal.pone.0083476
- ↑ Alison E. Murray, Frank R. Rack, Robert Zook, Michael JM Williams, Mary L. Higham, Michael Broe, Ronald S. Kaufmann, Marymegan Daly: Microbiome Composition and Diversity of the Ice-Dwelling Sea Anemone, Edwardsiella andrillae. Integrative and Comparative Biology 56 (4), October 2016; Pp. 542-555, doi : 10.1093 / icb / icw095
literature
- Marymegan Daly, Frank Rack, Robert Zook: Edwardsiella andrillae, a New Species of Sea Anemone from Antarctic Ice. PLoS ONE 8 (12): e83476; December 11, 2013 doi : 10.1371 / journal.pone.0083476
