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Today we continued our coring and covered a much wider area than yesterday but at lower sampling resolution. We started a transect at a point due east of the Mississippi River Delta and took core samples roughly ever 30 miles. Following this, we turned southwest to a point at the same latitude as the Deepwater Horizon spill (28°N) but 20 miles to the east. During the entire transect (108 n.m. total length), we watched diligently for signs of oil on the surface and noted when we could and could not detect an oil odor.
Based on the various maps and satellite images available to us, we were expecting to encounter a considerable amount of oil in this area but instead, found none except for a thin sheen at the station northwest of our present position (site 22 in the attached table). At that site, there was a distinct oil odor and a very faint but visible sheen on the surface. This sheen was only apparent when the surface tension was broken by our instruments or the side of the ship. At our current site, we can discern no sheen (well after sunset) and only a very faint oil odor, in spite of being within 20 miles of the spill site. The wind has been nearly calm all day and is currently from the southeast at 9 knots with flat seas.
Our plan for tomorrow is to traverse back towards the spill site and acquire more cores to the north and west, in areas where the latest projections predict the presence of oil on the surface. In the evening, we will set course for Cocodrie where we will exchange personnel and pick up equipment on Sunday morning in preparation for our second leg next week. This work will involve more water sampling and the use of new sensors including a Wetlabs fluorometer intended to detect oil at depth. We will perform transects in every direction outside the main cleanup area, to avoid conflicts with the skimming vessels, to investigation the potential advection of oil at depth.