Végétation marine de l'Ile de Port-Cros (Parc National). XII: Sur Acrochaetium molinieri sp. nov. et Lophosiphonia cristata Falkenberg

Abstract

Marine vegetation of Port-Cros Island (National park). XII: on Acrochaetium molinieri sp. nov. and Lophosiphonia cristata Falkenberg. – Acrochaetium molinieri sp. nov. is characterized by its bicellular base; only one of these cells originates an erect filament. Lophosiphonia cristata, rarely mentioned from the Mediterranean, is richly illustrated and described in detail     

Unexpected response of the seagrass Posidonia oceanica to a warm-water episode in the north western Mediterranean Sea

The response of Posidonia oceanica (Linnaeus) Delile to the warm-water episode of summer 1999 was studied by means of the technique of lepidochronology. Study sites include three sites affected by the mass mortality event of benthic invertebrates and one not affected. The results showed a significant decline in some parameters (number of leaves and/or rhizome growth) for the three sites affected by the mass mortality event for the year following the warm-water episode (1999-2000). A similar decline was not observed for the unaffected site. The fact that high temperatures could have a negative impact on deep Posidonia oceanica near its cold limit of distribution is an unexpected result.