A beleaguered northern gannet gets a clean-up at an animal treatment facility (Image: Tech. Sgt. Emily Alley)

UP TO 700 million litres of oil, plus nearly 7 million litres of dispersant chemicals, all threaten some of the most important marine and coastal habitats of the US. When the leak from the Deepwater Horizon well stopped – for now, at least (see “Oil spill memory will fade fast”) – on 15 July, it was time to take stock of a grim scene.

Even as the engineers complete their job, an army of ecologists is gearing up for an arduous campaign to document the …