Life at the Extremes

Oceans cover over 71% of the Earths surface at an average depth of 3800 metres and it is remarkable that we are still discovering hundreds of new species of marine life with every exploration. This reflects how the largest environment on earth remains the least explored and certainly least understood.
Although very few organisms are exposed to low pressures, high pressure is a physical hazard to which many must indeed adapt. In fact, life continues to thrive in the deepest ocean trenches which are 10 kilometres deep and with an increase in pressure of about 1 atmosphere every 10 metres, deep-sea organisms have to cope with pressures up to 1100 bar in places. These include barophiles which are microorganisms that are able to grow best at high-pressures (>400 bar) and piezotolerant organisms which grow best at 1 bar but can survive at pressures up to typically 600 bar. In addition to this, other high-pressure environments including deep lakes and the deep subsurface (Lake Baikal in Siberia and Lake Vostok located 3-4 km beneath the East Antartic Ice Sheet) have now been discovered with subsurface communities of microorganisms being detected as deep as 3500 m below the surface.
Given the extreme pressure in the deep sea, how can organisms cope with such crushing forces? Much like a chameleon changes colour to match it environment, barophiles and piezotolerant organisms are able to modify their molecular make-up in real time to ensure that they remain functional (e.g their membranes must remain fluid and not crystallise), however, the mechanisms behind this adaptation and the parameters that are regulated remain elusive. This is primarily due to the fact that the laboratory culture of extreme barophiles along with the development of analytical high-pressure apparatus is non-trivial. Our project aims to grow and study barophiles at pressures found in the deepest oceans on Earth-from and characterise their membrane behaviour from their molecular make up through to monitoring key biomechanical signatures as a function of pressure.
With the discovery of water at a depth of 10-100km on Jupiters moon Europa, understanding how life on Earth survives in extreme environments is pivotal not just to understanding life in local environments but also the molecules that may allow life to thrive on other planetary systems. As part of our studies we will study how barophiles from earth operate at the pressures found on Europa thereby redefining the boundaries within which life has been found to exist. As such high pressure astrobiology will go from being a theoretical discipline to one which can be tested under controlled laboratory conditions.
This fundamental understanding will subsequently be used to construct synthetic hybrid systems that are capable of surviving extremes of pressure - synthetic extremophiles. By fusing living and model membrane systems, we will generate ensembles that are able to modify their composition and make-up in response to external changes in hydrostatic pressure. This has the potential to transform the field of synthetic cells where the behaviour of adaptability remains an elusive trait. In addition, it will lead to the manufacture of biological components that are ideally suited to a wide range of industrial, bio-technical and consumer applications where performance under extreme conditions and the capability to respond to extreme operating conditions are fundamental prerequisites.