Palmer LTER: Hydrogen peroxide in the Palmer LTER region: II. Water column distributions

tions range between 10 and 400 nanomolar (nM) decreasing with depth to undetectable levels (less than 1 nM) below the mixed layer. The two major suspected source terms for H202 are photochemical interactions with dissolved organic matter (DOM) and atmosphere-to-ocean transport (see Karl et al., Antarctic Journal, in this issue). In general, the global "pristine " ocean data demonstrate a strong latitudinal dependence with maximum H202 con centrations of 100-200 nM in low latitudes (15°S to 15°N) decreasing to approximately 30 nM at 62°S (Weiler and Schrems 1993). To our knowledge, these are the only data for oceanic samples collected south of 60°S. The data of Weiler and Schrems (1993), however, are limited to only a few sam ples in the region of the Bransfield Strait. Aside from short-term diel variations, temporal H202 variations on seasonal time scales have been reported only for the Caribbean Se