Hmmm. When I watched this back before all the comments were added, I just saw water filling the spaces created. It never occurred to me to question where the water was coming from.
But, I plant a seed. Water fills it's cells and give it turgidity to hold it upright. Soil supplies minerals, etc. But, I was taught that the sun supplied the vast majority of a plant's energy and therefore growth.
I was also taught that the universe is expanding. So possibly all those suns out there giving up their energy to the cosmos. Maybe that energy is being captured by planets like ours allowing us to grow?