L’invasione di Amphistegina Lobifera (Foraminifera) "sull'onda" del riscaldamento del Mar Mediterraneo

Abstract

The benthic foraminifer Amphistegina lobifera Larsen, 1976, a non-indigenous unicellular species coming from the Red Sea through the Suez Canal, is currently well-established and abundant in the Maltese Islands (Central Mediterranean), where it was recorded for the first time in 2006. Here, we backdate of several decades its first arrival, from the analysis of two sediment cores collected in the Marsamxett Harbour, Malta. Results show that A. lobifera had already occurred in Malta in the 1940s with considerable implications for previous hypothesis of its spreading patterns and rates. Nonetheless the species occurred with low abundance until 1990, when it sharply increased in abundance. We suggest that this abundance pattern has been favoured by the rising sea-surface temperature experienced by the Mediterranean Sea during the last decades.