资源环境科技发展态势分析平台

Metal/calcium ratios in two long‐lived deep‐sea gorgonian corals (Lepidisis and Corallium spp.) in the Southwest Pacific evidence periodic decadal variability at depths that correspond to Antarctic Intermediate Water (AAIW) and shallow Upper Circumpolar Deep Water, and a shift in the mid‐ to late 1930s in mean ambient temperatures, barium/silicate concentrations and possibly pH, the rate at which these properties change over time, and the relationship between temperatures at fixed depth and the Southern Annular Mode (SAM). The decadal periodicity, which is evident in other biological indices in the study area, can be accounted by water mass heave on the order of 100‐150 m, which is consistent with observed scales of variability in the AAIW. The proximate and ultimate causes of the mid‐century shifts are unclear, but could be related to suggested mid‐20^th century changes in climate parameters globally and, more specifically, in the sub‐polar SW Pacific.