In September 2011, Al Jazeera spotted a large swath of silvery oil sheen located roughly 19km northeast of the now-capped well.
But now, on February 29, Al Jazeera conducted another over-flight of the area and found a larger area of sea covered in oil sheen in the same location.
Oil trackers with the organisation On Wings of Care, who have been monitoring the new oil since mid-August 2011, have for months found rainbow-tinted slicks and thick silvery globs of oil consistently visible in the area.
Schumaker has logged approximately 500 hours of flight time monitoring the area around the Macondo well, and has flown scientists from NASA, the US Geological Survey (USGS), and oil chemistry scientists to observe conditions resulting from BP's oil disaster that began in April 2010.
When Al Jazeera flew to the area on September 11, 2011, the oil sheen was approximately 25km long and 10 to 50 metres wide, at a location roughly 19km northeast of the Macondo 252 well.
On the recent over flight, the area covered in oil sheen was approximately 35km long, and ranged from 20 to 100 metres wide in approximately the same location. At times, fumes from the oil filled the aircraft, even at an altitude of 350 metres.
Shumaker, a career physicist with NASA who retired in 2011, is deeply concerned because she has spotted oil in the same location now at least 15 times since last August.
Edward Overton, professor emeritus at Louisiana State University's environmental sciences department, examined data from oil samples taken from this area last September and confirmed that the oil is from the Macondo reservoir.
Experts believe the oil is likely to be from a seep in the seabed, but there is debate about what caused the seep, as many believe it may well have been caused by BP's blowout well and the failed attempts to cap it during spring 2010.
Overton, who is also a National Oceanic and Atmospheric Administration (NOAA) contractor, told Al Jazeera in September, "After examining the data, I think it's a dead ringer for the MC252 [Macondo Well] oil, as good a match as I've seen."
He explained that the samples were analysed and compared to "the known Macondo oil fingerprint, and it was a very, very close match".
While not ruling out the possibility that oil could be seeping out of the giant reservoir, which would be the worst-case scenario, Overton believed the oil currently reaching the surface was probably from oil that was trapped in the damaged rigging on the seafloor.
However, given the fact that the oil sheen has existed in this area since at least as early as August 2010 and is continuing, the likelihood of it being residual oil from the Deepwater Horizon or damaged rigging is now slim.Other scientists remain concerned that the new oil could be coming from a seep from the same reservoir the Macondo well was drilled into. The oilfield, located 64km off the coast of Louisiana, is believed to hold as much 50 million barrels of producible oil reserves.
Natural oil seepage in the Gulf of Mexico is a common phenomenon and can cause sheens, but the current oil and sheen is suspect due to its size and location near the Macondo well.
"From what I've seen, this new oil and sheen definitely seemed larger than typical natural seepages found in the Gulf of Mexico," Dr Ira Leifer, a University of California scientist who is an expert on natural hydrocarbon oil and gas emissions from the seabed told Al Jazeera. "Because of the size and its location, there is a greater concern that should require a larger public investigation."
Fishermen and residents of the four states most heavily affected by BP's disaster continue to struggle to regain a sense of normalcy in their lives. Many still experience health problems they attribute to chemicals in BP's oil and the toxic dispersants used to sink it.
Shrimpers and oyster fishermen have seen their catches drop dramatically, and in some areas entire oyster populations have been annihilated.
BP's Gulf of Mexico disaster is, to date, the largest accidental marine oil spill in the history of the petroleum industry. BP has used at least 1.9 million gallons of toxic dispersants to sink the oil, in an effort the oil giant claimed was aimed at keeping the oil from reaching shore.
Meanwhile, fresh oil, either from natural seeps, oil platform wreckage, the Macondo 252 reservoir itself, or all four, continues to flow into the Gulf of Mexico.
New Orleans attorney Stuart Smith, who litigates against major oil companies, believes the burden of proof about where the oil is coming from lies on BP.
"Our worst fears have proven true," Smith said of the seep. "We have a chronic leak scenario caused by the Macondo well, and it is time for the feds and BP to come clean and tell the American public the truth. Unless/until the government and BP explain in a verifiable manner what the source of this oil is, in my opinion any thoughts of settlement are way premature."
BP has denied that the oil is coming from their well.
When reports surfaced last August that a large swath of oil sheen was reported near the site of the oil disaster, BP officials, in coordination with the US Coast Guard, deployed two submersibles to investigate the site.
BP said their visual inspection confirmed there wasn't any oil released from the Macondo well.
The Coast Guard also deployed a boat to the area and conducted an aerial survey of the site by helicopter.
"Both observed nothing," Coast Guard Captain Jonathan Burton, who is based in Morgan City, Louisiana, told Al Jazeera in at interview at his office.Captain Burton said after seeing footage from the submersible of BP's cap, he does not believe the Macondo well, or the relief wells BP drilled to stop it, are leaking, and he feels the oil is from natural seepage.
"Research shows the Macondo area is ripe for seeps, and I think that's what we're looking at here, and it's coming from the same reservoir," Burton said.
Burton is also the Federal On-Scene Coordinator for this region of the Gulf of Mexico that includes the Macondo area.
Burton, who was somewhat defensive for BP, added that he thinks that "the seep was there all along", and "doesn't know why BP has been silent on it."
Coast Guard Lieutenant Eric Brooks, also present in Al Jazeera's meeting with Captain Burton, later provided a link to the Bureau of Ocean Energy Management, Regulation and Enforcement (now the Bureau of Ocean Energy Management (BOEM) and the Bureau of Safety and Environmental Enforcement (BSEE)) website that he said "has commercially available pictures of areas of known natural seeps in the GOM [Gulf of Mexico] including around the Macondo Well".
However, the areas on the website provided are not anywhere near the area where the seep in question is located.
Specifically, the coordinates of a National Response Center report Schumaker submitted online after the flight on February 29, taken from the flight log she posted are N28 39.835 W88 09.475, in which she described "many lines of fresh-looking oil and sheen, this point marked a line of 'globules' like what we had seen frequently throughout this area between last August and December (2011)".
Al Jazeera is attempting to obtain clarification from the Coast Guard about the information they provided.
Lt Brooks suggested Al Jazeera contact officials with the Department of Interior for more information on the matter. Calls to said officials had not been returned at the time of this writing.
During the September over flight of the oil, Al Jazeera spotted two BP research vessels in the area in question.
"These vessels are conducting research on natural oil seeps as part of the Natural Resources Damage Assessment [NRDA] process," Tom Mueller, a press officer with BP America, told Al Jazeera. "They were parked over a known natural seep on the bottom of the Gulf, collecting samples and documenting the natural seep activity in that area using a remote operated submarine and acoustic sensing equipment."
According to Mueller, the intent of the NRDA study is to learn more about the locations of natural seeps and test samples taken from them."We can tell you that we recently sent a remote operated submarine down to inspect the Macondo well cap and the relief well cap," Mueller, added, "Both are intact and show no evidence of any oil leak. So no oil is leaking from the Macondo well."
But experts believe that is exactly the problem, since the work BP conducted to cap the gushing well could have caused oil to begin seeping from the reservoir in an area away from the capped well.
Leifer remains concerned that the seep, given its proximity to the Macondo well, could be oil in the reservoir that entered a layer of mud and has migrated into a natural pathway that leads to the seabed.
"I see these new observations [of the seep] as the canary in the coal mine that indicates something could be changing at the seabed and should not be ignored and hope it goes away," he said.
Given Overton's findings that the oil does appear to be from Macondo, Leifer added, "It's not necessary to be alarmist, but this is something that deserves setting an alarm off to investigate".
Of Captain Burton's comments about the oil coming from the Macondo reservoir, Smith had this to say:
"What is significant in my mind, as an attorney, is that a US government official admitted this is Macondo oil, and to me, absent BP producing evidence this seep existed prior to their drilling, they therefore must have caused it."
Leifer's concerns are that if the seep increases in volume, "It could be a persistent, significant, continuous oil spill again, and that would require BP to go back and re-drill, and block off the pipeline even deeper than they already did, or else they would be liable for whatever the emissions are, forever, because it's not going to stop for a very long time".
Dr Ian MacDonald, a professor of biological oceanography at Florida State University who uses satellite remote sensing to locate natural oil releases on the ocean surface, confirmed that there are natural seeps in this region of the Gulf of Mexico, but believes more investigation is necessary in order to determine the cause and source of this particular site.
"The question for science is: Are the rates of seepage consistent with what they were prior to the blowout?" MacDonald told Al Jazeera. "Is the amount of oil we're seeing now unusual with respect to historic levels? Can this oil be traced back to these formations?"
Leifer, like MacDonald, pointed to the natural seeps in the area.
"There is natural migration in the area around Macondo, and one of the sites we've studied is MC118, about 18km away," but added, "The concern is not that human activities caused a fault, but by creating pathways outside the [well] casing, they are allowing oil to travel along the well pipe then migrate horizontally until it intersects an existing vertical fault migration pathway, then reach the sea bed."
His concern, shared by other scientists, is the possibility that the volume of oil flowing from the seep, if it is related to the Macondo area, could increase with time.
"We should be having sonar works done of that area, and the public needs to be informed of the findings," Leifer said. "That survey should be repeated every three or six months to confirm that the seepage is not becoming larger and more widespread."
Meanwhile, Schumaker will continue her over-flights of the area and concern over ongoing oil seeps, whether they be natural or anthropogenic, persists, and scientists are calling for further investigations.Leifer, as aforementioned, has called for a broad investigation into the matter, as has MacDonald.
"I don't understand why we're seeing so much more oil out there right now than we've seen in the past," MacDonald said. "We need to dig in and investigate and see what is going on."
Smith agreed, and took it a step further.
"We demand a National Academy of Science investigation into this seep," and added, "BP has had six months to come up with evidence to prove they did not cause this seep. Considering that Al Jazeera and Associated Press have reported this [seep], you'd think BP would produce evidence they did not cause it."
The possibility that brings the greatest concern is that oil is leaking from the reservoir straight out of the ground. This situation could be impossible to stop, because the vent would increase in size over time due to the highly pressurised reservoir.