Resumen

GARCIA-ROMERO, Felipe et al. Vertical fluxes of coccolithophores and foraminifera and their contributions to CaCO₃ flux off the coast of Ensenada, Mexico. Cienc. mar [online]. 2017, vol.43, n.4, pp.269-284.  Epub 30-Jul-2021. ISSN 0185-3880.  https://doi.org/10.7773/cm.v43i4.2765.

Coccoliths and foraminifera fluxes and their contributions to CaCO3 were estimated by analyzing the material collected by a sediment trap installed in the area adjacent to Ensenada, Baja California (Mexico). Coccoliths were identified and counted from images obtained with a Zeiss-Supra 55VP scanning electron microscope. Foraminifera were identified and analyzed with a Leica EZ4 stereoscope. Total CaCO3 was determined by coulometry. A total of 33 species of coccoliths were recorded; the most abundant species were Emiliania huxleyi type A, Gephyrocapsa oceanica (Equatorial), E. huxleyi type B, and G. oceanica (Larger), contributing 74% of total coccolith flux. The maximum flux of coccoliths was 1,539 × 106 m-2·d-1 in sample A-8, the minimum zero in sample A-10, and the average 1,028 × 106 m-2·d-1. Coccolith contribution to CaCO3 content ranged from 0.14 mg·m-2·d-1 in sample A-12 to 25.00 mg·m-2·d-1 in sample A-1, with an average of 5.60 mg·m-2·d-1. Helicosphaera carteri made the highest contribution with 10.00 mg·m-2·d-1 in sample A-1, and the rest of the species contributed <7.00 mg·m-2·d-1. Six genera of planktonic foraminifera were identified: Globigerina, Neogloboquadrina, Globorotalia, Pulleniatina, Globigerinoides, and Orbulina. The maximum flux of foraminifera was recorded in summer (513 m-2·d-1) and the minimum in spring (9 m-2·d-1). Benthic foraminifera were found to make an important contribution, even greater than the contribution from planktonic foraminifera, reflecting horizontal resuspension and/or transport processes. CaCO3 contributions by coccoliths and foraminifera were <1% of total CaCO3, and the rest was contributed by fragments of the other calcareous groups.

Palabras llave : coccolith fluxes; foraminifera fluxes; CaCO₃ fluxes; sediment traps; Baja California.

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