MORPHOCHRONOLOGICAL VARIATIONS IN THE GENUS POSIDONIA

Morphochronological variations have been observed in five marine phane rogams of the genus Posidonia in the two regions where they occur (Med iterranean and Western Australia), The occurrence of these variations, which is comparable to that of growth rings in trees (studied in dend rochronology), has provided a basis for developing new techniques for the investigation of characteristics of these underwater seagrass mead ows (e.g. primary production). The development of lepidochronology in the assessment of primary production has the advantage of being rapid and allowing the determination of the total foliar tissue production ( leaf blade and leaf sheath) including that of species for which no dat a were hitherto available.