I took another look at pix of the oil spill from Wednesday 5/20 and Thursday 5/21, and wished they were comparable. For instance, take this pic from the 20th of the beach in front of Las Flores Refinery. The entrance to the refinery is in the brown center of the lower horizontal green band.
You can pretty easily make out the streaks of oil sheen and some of the thicker goo that was blowing there (and beyond to El Capitan). I also got this zoom shot as we flew past. If you follow the freeway from the top in the above pic, this next one shows the beach across from where the thin green center divider gives way to brown. The path from the road up toward the water at the left of this pic corresponds to the bend in the small leftmost road where it disappears into the trees across from the upper horizontal green band in the top pic.
The streak of thicker goo at the top-right is easy to spot, and you can see a black line where the water meets the beach. Just about 28 hours later it looks much the same, yet quite different in this similar pic.
The thick goo’s gone, as it was in many places we’d seen it the day before. Whether old seaweed or oil, the dark spots on the beach have been cleaned up. The black water line is completely gone. But the brownish-gray area along the shallow water seems wider and darker. I guess that’s oil somehow mixed with the water, but maybe someone taking water samples will publish data on that. So far I’ve not seen any such reports, but I’ve heard from someone in a group of scientists studying all aspects of the spill so maybe one of them will publish something. We’d like to go again, and this time maybe I’ll get more similar views for comparison in case someone else expresses interest while gathering information for analysis.