DIATOM PRESERVATION IN THE RECENT SEDIMENT RECORD OF SPANISH SALINE LAKES - IMPLICATIONS FOR PALEOCLIMATE STUDY

In palaeoclimate research, fossil diatoms from saline lakes can be exc ellent indicators of past salinity, a proxy for climate change, althou gh they are sometimes poorly preserved in sediment cores. Spain has nu merous salt lakes but the potential of diatoms for studies of climate change has never been investigated. A comprehensive survey of diatom p reservation is described based on modern and fossil diatoms from short cores (<50 cm depth) in a representative data-set of 59 sites, and th e main factors affecting preservation are investigated using principal components analysis (PCA). Most lakes do not preserve a diatom record ; four sites in southern Spain are identified which both contain diato ms and have suitable limnological characteristics for a climate study. Many lakes are ephemeral and the physical effects of desiccation, cou pled with other factors such as turbidity and high salinity, are the m ain factors enhancing diatom dissolution or their failure to be incorp orated into the sediment record.