GC-MS total ion chromatograms.

<p>Open top mesocosm incubations contained an initial loading of 2.5 ppm ANS crude oil without and with Corexit 9500 (1∶15 DOR), and no added nutrients. Chromatograms show the pattern of biodegradation after 10 days, 28 days and 63 days.</p

Biodegradation index (C₁₈/Phytane) of mesocosms containing 2.5 ppm fresh ANS crude oil without nutrient addition incubated at −1° with and without Corexit 9500 (DOR 1:15) analyzed at 10, 28 and 63 days.

<p>Biodegradation index (C₁₈/Phytane) of mesocosms containing 2.5 ppm fresh ANS crude oil without nutrient addition incubated at −1° with and without Corexit 9500 (DOR 1:15) analyzed at 10, 28 and 63 days.</p

Percent mineralization at −1°C.

<p>Sealed respirometer experiments contained Corexit 9500 (50 ppm) alone or 20% weathered ANS crude (15 ppm) with and without Corexit 9500 (1∶20 DOR). All treatments contained seawater and 16 ppm of Bushnell Haas.</p

Percent loss of weathered oil after 56 days without nutrient addition at −1°C.

<p>Open top mesocosms contained an initial concentration of 2.5 ppm of 20% weathered oil with and without the chemical dispersant Corexit 9500 at a 1∶20 DOR. Standard errors are displayed. Results are normalized to hopane. *Denotes a significant difference between treatments with and without Corexit 9500 (p<0.05).</p

Percent loss of fresh oil after 63 days without nutrient addition at −1°C.

<p>Open top mesocosms contained an initial concentration of 2.5 ppm of fresh oil with and without the chemical dispersant Corexit 9500 at a 1:15 DOR. Standard errors are displayed. Results are normalized to hopane. No significant differences (p<0.05) were observed.</p