MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps14448

ABSTRACT: Abundance, biomass and respiration rates of dominant medium- to larger-sized copepod species (ML class) from the upwelling system off Peru (8.5°-16°S) were determined as well as their carbon ingestion and egestion rates. Additionally, small copepods (S class) were included for comparisons of community rates. Overall, abundance/biomass was highest in the upper 50 m and decreased with depth and thus community ingestion and egestion. Ingestion of the ML class (0-50 m) in shelf regions (14-515 mg C m^-2 d^-1) was lower in the South compared to the North and central study area, while their offshore ingestion (11-502 mg C m^-2 d^-1) was comparable across the regions (8.5°-16°S). Ingestion rates (0-50 m) of the S class were in a similar range as those of the ML class in shelf regions (100 to 417 mg C m^-2 d^-1) but higher offshore (177 to 932 mg C m^-2 d^-1). Calanus chilensis and the S class contributed most to total ingestion in the North, while in the South Centropages brachiatus had the highest community ingestion besides the S class. Egestion varied from 4 to 155 mg C m^-2 d^-1 for the ML class and from 2 to 280 mg C m^-2 d^-1 for the S class. The high community rates highlight the crucial role of both size classes for carbon budgets of the northern HCS off Peru and indicate that the ML class may enhance the passive vertical carbon flux, whereas the S class may support carbon remineralization rates in surface waters.