The Census of Marine Life reported that phytoplankton, the microscopic plants producing most of the oxygen from the oceans, have been declining by around 1% a year since 1900.

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"The dispersant is moving the oil down out of the surface and into the deeper waters, where it can affect phytoplankton and other marine life, " said John Paul, a marine microbiologist at the University of South Florida.

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Marine Scotland Scientists have sampled the foam and seawater around Footdee, using a microscope to examine the phytoplankton - very small algae - present.

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