Benthic O-2 uptake rates and O-2 microprofiles were measured in the upwelli
ng area off central Chile. Measurements were performed both in situ and in
the laboratory on recovered sediment cores. Comparison between the 2 data s
ets confirmed retrieval and handling artifacts inferred from previous studi
es. Onboard measurements indicated that the effects were mainly associated
with core warming during recovery. Fauna mediated O-2 uptake was significan
t even at abyssal depths and generally in situ O-2 uptake rates were higher
and showed stronger attenuation with water depth than previous measurement
s performed in the NE Pacific. However, O-2 uptake rates and O-2 penetratio
n depths were very similar to measurements performed in the SE: Atlantic, a
nd the compiled data sets were approximated by simple exponential equations
relating the measurements to water depth. By comparing our total O-2 in si
tu uptake rates to simultaneous measurements of primary production (PP) and
new production (NP) of the overlying water column, it was calculated that
the benthic mineralization accounted for 13 to 66% of the PP and for 28 to
92% of the NP at water depths shallower than 1000 m. At water depths from 1
000 to 4000 m, the benthic mineralization equaled 2 to 11% of the PP and 22
to 38% of the NP. The benthic mineralization thereby accounted for a signi
ficant turnover of organic material even at the abyssal stations. The prese
nted data add to the limited number of in situ deep sea mineralization meas
urements from the southern hemisphere.