Seasonal variation in the flux of algal pigments to a deep-water site in the Panama Basin

During 1979–1980 a moored array of time-series sediment traps was deployed at a station in the Panama Basin with traps set at 890, 2 590, and 3 560 m below the surface. This time-series of samples allowed us to measure the seasonal variation in the flux of particulate materials to deep water. Even at 3 560 m the flux of algal pigments and organic carbon varied seasonally, with lowest values in June–July and highest values in February–March. This seasonality may be an important signal to benthic communities in the deep sea. Averaged over the year there were no significant differences in the quantities of these materials which arrived at the three depths, suggesting little dissolution or decomposition during settling in the deep part of the water column. The ratio of organic carbon:phaeopigment (mg:mg) had lowest values at 890 m (40:1) and highest values (285:1) at 3 560 m, but the average of all samples showed no trend with depth. Although the flux of most of the carbonate and much of the organic C was associated with the sinking of coccolithophorids, the flux of algal pigments was not associated with coccolithophorids. The quantity of pigment sinking to deep water (3 560 m) in the Panama Basin is roughly 50 to 100 times greater than the amount sinking to 2 000 m at the Tongue of the Ocean.