This is set amongst alkaline geothermal smokers. The title is symbolic: 'first life' rising, ie Dawn of Life. 'LUCA' stands for "Last Universal Common Ancestor". This image shows the protocells emanating from part of the geothermal vents. These would not have poured out from the structures, it is just to help the viewer see where the cells originally came from (in this scenario of course) and to show how small they are as the viewer will see them receding away down back to the structures. This is one theory of how life emerged, from volcanic 'smokers' under the oceans billions of years ago.