Paleo-productivity in the SW Pacific Ocean during the early Holocene climatic optimum

In this study we examined a wide range of paleo-productivity proxies along a latitudinal transect (36-58°S) of 6 cores in the SW Pacific during the early Holocene climatic optimum, to explore regional patterns of productivity in a slightly warmer-than present world. We used a range of sedimentological, geochemical and paleontological proxies including carbonate content and mass accumulation rates, opal content and mass accumulation rates, alkenone concentrations, a foraminiferal productivity index and dinoflagellate cyst productivity index, nitrogen isotopes and elemental concentrations from micro-XRF. During the early Holocene there is a small increase in productivity in the subtropical waters, no change at the subtropical frontal zone, and conflicting evidence in records immediately south of the subtropical front, where an increase is inferred from one core site, but not at the other. Evidence for an increase in productivity in Antarctic Surface Waters south of the polar front, is also equivocal. We infer a small increase in productivity in subtropical waters and the ocean just south of the subtropical front was associated with changes in the ocean circulation of the SW Pacific, driven by changes in the Southern Hemisphere Westerly Winds split jet structure in this region.