Observations of pigment and particle distributions in the western North Atlantic from an autonomous float and ocean color satellite

• Published in: Limnology and Oceanography
• Main Authors: Boss, E, Swift, D, Taylor, L, Brickley, P, Zaneveld, R, Riser, S, Perry, MJ, Strutton, PG
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Soc Limnology Oceanography 2008
• Subjects: Earth Sciences; Oceanography; Biological Oceanography; Greenland; Newfoundland; north atlantic current; North Atlantic
• Online Access: https://doi.org/10.4319/lo.2008.53.5_part_2.2112; http://ecite.utas.edu.au/80203

Profiling floats with optical sensors can provide important complementary data to satellite ocean colordeterminations by providing information about the vertical structure of ocean waters, as well as surface watersobscured by clouds. Here we demonstrate this ability by pairing satellite ocean color data with records from aprofiling float that obtained continuous, high-quality optical data for 3 yr in the North Atlantic Ocean. Goodagreement was found between satellite and float data, and the relationship between satellite chlorophyll and floatderivedparticulate backscattering was consistent with previously published data. Upper ocean biogeochemicaldynamics were evidenced in float measurements, which displayed strong seasonal patterns associated withphytoplankton blooms, and depth and seasonal patterns associated with an increase in pigmentation per particleat low light. Surface optical variables had shorter decorrelation timescales than did physical variables (unlike atlow latitudes), suggesting that biogeochemical rather than physical processes controlled much of the observedvariability. After 2.25 yr in the subpolar North Atlantic between Newfoundland and Greenland, the float crossedthe North Atlantic Current to warmer waters, where it sampled an unusual eddy for 3 months. This anticyclonicfeature contained elevated particulate material from surface to 1000-m depth and was the only such event in thefloats record. This eddy was associated with weakly elevated surface pigment and backscattering, but depthintegratedbackscattering was similar to that previously observed during spring blooms. Such seldom-observededdies, if frequent, are likely to make an important contribution to the delivery of particles to depth.