1. 7/14 10 203040 50 40N 74W 72W 10 305070 90 0.5 135 7 135 7 Gradient Strength (au) Boundary Frequency (%) SeaWiFS Chl a (mg m -3 ) Ocean Sat Chl a (mg m -3 )

2. Absorption (m -1 ) Attenuation (m -1 )

4. A) Salinity B) CDOM C) Phytoplankton D) CDOM slope CDOM absorption (m -1 ) CDOM slope (nm -1 ) Phytoplankton absorption (m -1 ) Salinity -84-83-82 -84-83-82 -84-83-82 -84-83-82 28 27 26 28 27 26 28 27 26 28 27 26 2.0 1.0 0.0 32 31 33 34 35 0.10 0.05 0.00 0.026 0.014 0.01 0.018 0.022

5. Cell Division unitless

8. A) B) C) D)