Tar seeps found in 100-200 feet of water offshore Point Conception exhibit heavy oil and little gas. Benthic communities common on rocky reefs colonize older portions of the tar.
Reminds me of:
http://www.datadubai.com/oil2.htm
The “bulls,” Hieronymus discovered, were great iceberg-like mounds of jellied crude oil - bitumen - that floated up from the depths of the murky water and drifted aimlessly with the wind...
Harvesting bitumen 'bulls' on the Dead Sea.
