Final answer:
Halophiles are the type of archaebacteria that flourish in high salinity environments such as the Dead Sea, requiring extreme salt concentrations for survival.
Step-by-step explanation:
The type of archaebacteria that thrives in a high salinity environment is known as halophiles. These organisms are highly adapted to environments with extreme salt concentrations, such as the Dead Sea and other hypersaline areas around the world. The class Halobacteria, part of the phylum Euryarchaeota, includes these halophilic archaea which require very high levels of sodium chloride to survive, often near saturation levels. Additionally, these halophiles are known for performing photosynthesis using the protein bacteriorhodopsin, adding a distinctive purple color to the waters they inhabit.