The Dry Valley Lakes, Antarctica: from sulfur stains on Earth to sulfur stains in the Jovian system
Most organisms dwell in what we consider to be normal environments, while others, which are called extremophiles,
may thrive in harsher conditions. These living organisms are mainly of unicellular (both prokaryotes and, to a lesser
extent, there are some eukaryotes) But the extremophiles also include multicellular organisms, including worms, insects
and crustaceans. In the present work we survey specific extremophiles in some detail. Astrobiology is concerned with all
of these extremophiles, as they may be models for extant life in similar environments elsewhere in the universe. In the
more restricted search for life through exploration of the Solar System, the main focus is on the preparation of suites of
experiments that may attempt to discover the habitability of planets and their satellites. In this context we ask ourselves:
What biosignatures can facilitate life detection, both unicellular and multicellular, in extreme environments? The
environments that are within reach of present and future space missions include the Jupiter satellite Europa. The icecovered
lakes of Antarctica's McMurdo Dry Valleys have long been of interest to astrobiology. These environments
harbor unique microbial ecosystems that could orient us how to plan our experiments on Europa.