SEASONAL PATTERN OF CYMODOCEA-NODOSA BIOMASS AND PRODUCTION IN THE LAGOON-OF-VENICE

Primary production and the biomass cycle of a shallow Cymodocea nodosa (Ucria) Ascherson meadow in the lagoon of Venice (Italy-Northern Adri atic) were measured from February 1993 to February 1994. Leaf growth w as estimated by the Zieman method; rhizome production was estimated by marking rhizome terminals. All data showed a clear seasonality. In ge neral, maximum growth was reached in July. Leaf production (a maximum of 12.3 g dry weight m(-2) day(-1) in July) and leaf biomass (a maximu m of 810 g dry weight m(-2)) were much higher than in other Mediterran ean localities. Cymodocea nodosa contributes significantly in stabiliz ing lagoon bottom sediments. The percentage of the belowground fractio n of total biomass varied from 85% in winter to 58% in summer, and max imum shoot density was 2302 shoots m(-2). (C) 1997 Elsevier Science B. V.