Abstract
Sea grass meadows and areas of rhodophyte algae (maerl) are important biodiversity ’hot spots’ around the south western coastline of the British Isles, many of which are found in Special Areas of Conservation (SAC) or Marine Conservation Zones (MCZ). Both environments are host to a wide range of other taxa including foraminifera (marine protists), ostracods, sponges and bryozoans – all of which can be found in sediment samples collected in these shallow water, marine environments. The foraminifera associated with sea grass meadows are quite distinctive and change composition with latitude (an indicator of sea temperature); the Zostera meadows of more northerly latitudes contain a quite different assemblage of benthic foraminifera compared to those in the Posidonia meadows of the Mediterranean Sea. Recently fossil sea grass meadows have been recorded in the chalks of the Maastricht area which are ~70 million years old. Here the Posidonia like rhizomes and fronds are preserved both as impressions and, in some cases, in three dimensions. The latter provide an opportunity to study the internal structure in amazing detail, as well as investigate the associated Cretaceous epifauna. These are the earliest known sea grass fossils and provide a unique window into the evolution of this (palaeo)environment.