A Seep

1. A small spring, pool, or other spot where liquid from the ground (e.g. water, petroleum or tar) has oozed to the surface; a place of seeping. Seep (hydrology) - Wikipedia
2. Moisture, liquid, gas, etc. that seeps out; a seepage.
3. The seeping away of a liquid, etc.
4. A seafloor vent.