Monitoring changes in marine phytoplankton is important as they form the foundation of the marine food web and are crucial in the carbon cycle. Often Chlorophyll-a (Chl-a) is used to track changes in phytoplankton, since there are global, regular satellite-derived estimates. However, satellite sensors do not measure Chl-a directly. Instead, Chl-a is estimated from remote sensing reflectance (R-RS): the ratio of upwelling radiance to the downwelling irradiance at the ocean's surface. Using a model, we show that R-RS in the blue-green spectrum is likely to have a stronger and earlier climate-change-driven signal than Chl-a. This is because R-RS has lower natural variability and integrates not only changes to in-water Chl-a, but also alterations in other optically important constituents. Phytoplankton community structure, which strongly affects ocean optics, is likely to show one of the clearest and most rapid signatures of changes to the base of the marine ecosystem.
1.MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA 2.MIT, Ctr Climate Change Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA 3.Univ Southampton, Natl Oceanog Ctr Southampton, Ocean & Earth Sci, Southampton SO14 3ZH, Hants, England 4.Natl Oceanog Ctr Southampton, Southampton SO14 3ZH, Hants, England 5.Univ Calif Santa Cruz, Ocean Sci Dept, Santa Cruz, CA 95064 USA 6.Univ Calif Davis, Dept Land Air & Water Resources, Davis, CA 95616 USA
Recommended Citation:
Dutkiewicz, Stephanie,Hickman, Anna E.,Jahn, Oliver,et al. Ocean colour signature of climate change[J]. NATURE COMMUNICATIONS,2019-01-01,10