Diatom recovery from core MD88-787: Raw counts

Core MD88-787 was recovered during the French ASPARA IV cruise in 1988, aboard the Marion Dufresne. The core was located on the Tasman Fracture Zone of the Mid-Ocean Ridge, within the Polar Front Zone. \n\nA total of 69 diatom species and taxa were recorded in core MD88-787. Over time, the core indicates a reduction in the number of diatom valves in the sediments for the last glacial. This trend is not observed during the previous 'glacial' period in isotope-stage 4, but is again noted in isotope-stage 6. Interglacial isotope-stages 3 and 5 indicate higher- or equivalent-diatom content comparable to isotope-stage 1. The reduced diatom signal during the glacials appears odd since the expectation was for an enhanced diatom signal produced by the northward shifting fronts. The decrease in signal could be interpreted as being affected by sea-ice cover and the resulting change towards more lightly silicified diatom species.