ESTABLISHING HISTORICAL SEA-LEVEL TRENDS USING SALT-MARSH FORAMINIFERA. A NEW RECORD FOR THE CROATIAN COAST OF THE ADRIATIC SEA

The application of salt-marsh foraminifera to reconstruct historical sea-level trends was investigated for the Croatian coast of the Adriatic Sea using a transfer function approach. This technique, whilst well practiced from north Atlantic sites along the shores of America and UK, has previously evaded the Mediterranean region. The long-term tide gauges in the Mediterranean show sea-level trends for the 20^th century in the range of 1.1 - 1.3mm/yr whilst more recent satellite altimetry data reveals much larger increases in sea-level throughout the basin towards the latter part of the century. Here, we present a comparable record of sea-level change using a modern dataset of foraminifera collected from two micro-tidal (<0.4m) salt-marsh sites along the central Croatian coastline. The relationship between modern foraminiferal assemblages and tidal level is well constrained and confirms their suitability as proxies for sea-level in transfer function reconstructions. Further quantitative analyses of species environment relationships suggested the use of linear regression models. Transfer functions were then created for both site specific and total combined datasets and applied to two sediment cores sampled for fossil foraminifera coupled with composite chronologies involving short-lived radionuclides and radiocarbon dating. A total combined dataset was chosen and screened to remove sample outliers improving model performance before being applied to core sediments to reconstruct mean sea-level. An inflexion observed at ~AD 1940 showed an acceleration in sea-level comparable to other proxy reconstructions. Indeed this trend was similar to instrumental records from the tide-gauge at Trieste. Similarly the transfer function reconstruction also identifies the sharp increase in mean sea-level observed in both instrumental and satellite data since the early 1990s.