The Arctic Sunrise is currently alongside in Galveston Texas – the winches and other equipment that was used on the most recent leg have been craned off, and out on deck, a whole lot of new equipment is being welded on for the submarine work we’ll be doing in a few weeks (yeah, that’s right, submarines!)

We left Galveston 11 days ago with a four-person independent science team, led by Rainer Amon, with Cliff Nunnally, Sally Walker and Chuck Folden on a mission to track down the oil beneath the surface of the Gulf. They crew of the Arctic Sunrise worked their asses off about 24 hours a day, to get the research work carried out in the short window of time available. Kert has written in more detail about the work, but now that we’re back in port, and able to take stock, we can talk about what Rainer and Cliff found, and what it means in the grand scheme of things.

While the water samples taken from way down deep during the trip are off to the lab to get analyzed, the immediate, measurable data obtained by Rainer tells us this; that there’s a clear indication of an oxygen deficiency in the Gulf’s waters, in an area stretching from around the Deepwater Horizon disaster site to 300 miles (500km) to the west. The infamous plume still exists – perhaps not visibly, but the essence of it is still there.

This oxygen deficiency tells us that a certain amount of the oil and gas released during the disaster has been consumed by bacteria in the water; bacteria needs oxygen to metabolise the petrochemicals, so, very simply put, the lower the amount of oxygen, the higher the amount of oil has been consumed. However, and here’s the really interesting bit; Rainer’s observations, and the observations of other scientists, have indicated that there the levels of dissolved oxygen in the Gulf are not low enough to suggest that any major amount of the oil and gas from the Macando wellhead been consumed by bacteria. The government and BP would like us to believe that all the otherwise unaccounted for oil has magically disappeared, all three or four million barrels of it (remember that’s 55 gallons, or 200 litres). So where is it all gone?

Several scientists, including Rainer, have wondered if the missing oil might be on the bottom of the Gulf, and that’s where Cliff’s work comes in. Last weekend, we hauled a lot of mud on to the deck of the ship, each time, a 2ft (60cm) thick core, from 4000ft (1300m) below the Arctic Sunrise, just a few miles away from the cluster of rigs and ships that now occupy the disaster area. Kert has also written about this in more detail, so I’ll just say this – there was most definitely oil in some of the samples drawn up from the floor of the Gulf – you could see it, and smell it. While this is hardly surprising, given that we were close to the disaster site, it’s these samples, when compared to baseline samples collected from the Gulf over the years that will tell Cliff and his colleagues how the “benthos” – the ecosystem of the sediment – has been dealing with a major influx of oil.

Hopefully, all this work, and the papers that will be produced by Rainer and Cliff will not only add to the pool of knowledge on this issue, but will also help counter the claims from both BP and the government that the “oil spill is over”.

In fact, the observations of the last seem to reinforce the testimony given by biological oceanographer Dr Ian MacDonald at this week’s Oil Commission hearings in Washington DC.

While Dr MacDonald said that some of the oil was dispersed, evaporated, burned or skimmed, the "remaining fraction -- over 50 percent of the total discharge -- is a highly durable material that resists further dissipation". Dr MacDonald suggests that there’s at least 2.5 million barrels out there in the Gulf’s ecosystem, and that "much of it is now buried in marine and coastal sediments". He added there was "scant evidence for bacterial degradation of this material prior to burial."

Also, Samantha Joye, from the University of George, has been blogging about the oil she's found in the Gulf sediment.

The “oil spill” (it wasn’t really a ‘spill’, as much as a deep sea ‘release’ of oil) isn’t ‘over’. The scientific community knows this, the people of the Gulf region know this, and the clean up crews that are still out on the coast, picking up tarballs. It’s up to all of us to keep pushing for the truth, and to keep BP and the government under pressure to ‘fess up, and come clean. Oh, and while they’re at it, they should continue the moratorium on deepwater drilling too!

- Dave on the Arctic Sunrise

Photos: © Mannie Garcia / Greenpeace