Assessing the link between chlorophyll concentration and absorption line height at 676 nm over a broad range of water types.
The relationship between absorption at 676 nm normalized to chlorophyll-a, i.e., specific absorption aph*(676), and various optical and environmental properties is examined in extensive data sets from Case I and Case II waters found globally to assess drivers of variability such as pigment packaging. A better understanding of this variability could lead to more accurate estimates of chlorophyll concentrations from in situ optical measurements that may be made autonomously. Values of aph*(676) ranged from 0.00006 to 0.0944 m2/mg Chl a across all sites studied, but converged on median and mean values (n = 563) of 0.0108 and 0.0139 m2/mg Chl a respectively, with no apparent relationship with various optical properties, latitude, coastal or open ocean environment, depth, temperature, salinity, photoadaptation, ecosystem health, or albedo. Relative consistency in aph* across such diverse water types and the full range in chlorophyll concentration suggests a single aph* may be used to estimate chlorophyll concentration from absorption measurements with better accuracy than currently thought.
Schuyler C
SC
Nardelli
Michael S
MS
Twardowski
D002734:Chlorophyll / Q000032:analysis*; D000077194:Chlorophyll A; D004784:Environmental Monitoring; D008027:Light; D055585:Physical Phenomena; D010839:Phytoplankton
D002734:Chlorophyll; D000077194:Chlorophyll A