Abstract:
Vertical fluxes of silicoflagellate skeletons were measured in meso- and bathypelagic zones
at four PARFLUX sediment trap stations located in the Pacific and Atlantic oceans. The
average flux measured at several depths ranged from 35 X 103 skeletons/m2/day at the Pacific
gyre (P1) station to 424 X 103 skeletons/m2/day at the Panama Basin (PB1) station.
The skeletal fluxes at these stations constituted a few weight percent or less of the total
biogenic opal flux.
The fluxes measured at Station P1, as well as the relative abundance of different assemblages,
were fairly constant with depth. At Station PB1, while relative abundance of
assemblages was constant with depth, the flux measured at mesopelagic depths was threefold
greater than that in the bathypelagic zone. At equatorial Atlantic Station E a slight increase
toward the bathypelagic zone is correlated with gradual change in the relative abundance
of two predominant taxa, suggesting seasonality in the production of each taxa. Aggregate
forms of vertical settling were observed at Station E; the number of skeletons in the aggregates
was more than one-half of the total number in the mesopelagic zone and it decreased
with increasing depth.
The percent abundances of Dictyocha messanensis messanensis and Distephanus pulchra
are correlated with organic carbon flux at four stations. Preservation of the skeletons in
Holocene sediment at Station P1 is less than one percent of the silicoflagellate flux.
