WHOI-MAT253



Hydrogen Peroxide

We do not routinely vacumn roast our samples to remove organic matter. Instead, when we process our sediment material we soak it for 5 -10 minutes in a solution of 3% hydrogen peroxide and sodium hexametaphosphate. In 1997 we analyzed a set of rose Bengel stained live benthic forams for Dr. Bruce Corliss at Duke University. These forams contained a large plug of organic matter inside the shell test. We ran two series of individuals from core EN293-1-2, 0-0.5 cm, 500-650 um size fraction. The first series we ran as we normally do, doing nothing to the shell tests. The organic matter was still visible in the reaction vessel at the end of the reaction time. The file associated with this data is en293.nothing. For the second series of analyses we pretreated the shell tests with 3% hydrogen peroxide and sonication for 10 minutes or until the organic matter was fully oxidized. The file associated with this data is en293.peroxide. The following table summarizes the data:

Peroxide and Sonication
Dev. Average O18 Average C13
Std. Dev.
Std. N=
2.18
4.19
0.09 0.17 6

No Pretreatment
Dev. Average O18 Average C13
Std. Dev.
Std. N=
2.32
4.16
0.06 0.15 6

Peroxide minus No Pretreatment
Delta of O18 Delta of C13
Std. Dev.
0.03 -0.14

We believe that the depletion of 0.14 per mil in C13 falls within the standard deviation of the analysis of the individual shell tests and is not significant.This test was a worst case scenario as most foraminiferans recovered from the sediments have little organic matter left in the test.