The vast majority of the 135 million gallons of oil that tainted the water, marshes and wildlife five years ago is gone. What is left shows up in tar balls and tar mats, unwelcome and environmentally hazardous reminders of the disaster that no one along the Gulf coast has forgotten.  More from NBC News:'Accountant of Auschwitz' faces trial on 300,000 countsDrug harnesses immune system to fight lung cancerDownsizing can have a lot of benefits for retirees  Scientists are looking for answers and many of them are expected to be included in the Natural Resource Damage Assessment that is still underway. It will determine the harm that was done and what needs to happen to bring the Gulf back to pre-spill conditions.  "Although we will not know the full extent of the damage until a final assessment is completed, response and recovery efforts are ongoing, and scientists say our habitats and ecosystems are slowly coming back," Governor Bobby Jindal said in a statement on Monday. "However, there is more work to do as oil continues to wash ashore here in our state -- and we won't stop working until our coast and wetlands are fully restored."  Read MoreFor crude oil, this looks like 2009 all over again  What we do know five years later is that the Gulf and her people are resilient. They took this punch and came back. Business may not be as good as before the spill, but they are still in business. They are still trying.  I met Louisiana businessman Matt O'Brien a few days after the Deepwater Horizon blew up in 2010. He proudly showed me the shrimp dock he was building in the tiny fishing community of Venice. And he kept building that dock, even as the fishing was shutdown.  "I am a warrior" he told me at the time. "You got to be. I mean, what's the alternative? Quit? Then that's a 100 percent guarantee you fail."  O'Brien, a former oilman who lost an earlier business to Hurricane Katrina, didn't succeed with his shrimping venture. He says his partners bought him out. He was forced to sell his trucks and move his family to Mississippi. Years later, he says he's trying again, hoping to start another seafood business.  Read MoreFed could be to blame for oil's decline: Analyst  While there are questions about the oysters, dolphins, turtles and so much else, what remains in abundant supply along the Gulf is determination and hope.  As we consider the environmental and economic impacts of the spill on Monday, please take a moment to remember the human toll, the eleven men who lost their lives: Adam Weise, Dewey Revette, Gordon Jones, Karl Kleppinger Jr., Keith Blair Manuel, Ron Wyatt Kemp, Shane Roshto, Jason Anderson, Aaron Dale Burkeen, Donald Clark, and Stephen Ray Curtis.
Most of the oil spilled in the disaster is gone, but effects on the Gulf of Mexico are still being gauged. NBC News reports.