Leaf phenology, growth and primary production of the seagrass Cymodocea nodosa in El Médano (South of Tenerife, Canary Islands)

Abstract

Data on density, biometry, growth and biomass of Cymodocea nodosa (Ucria) Ascherson at El Médano (South of Tenerife, Canary Islands) are presented. Monthly data of all these parameters showed regular seasonal variations, with their mean highest values in spring-summer and their mean lowest ones in autumn-winter. The mean number of leaves per shoot varied from 2.4 to 3.4 leaves shoot!, the oldest leaf length varied from 14.7 to 31 cm and the leaf width from 1.7 to 3.4 mm, with the shoot density varying from 934 to 1928 shoots m? Leaf growth measurements were estimated by a slightly modified hole punching method. The leaf growth was between 0.8 and 1.9 mg dw shoot' day!, the shoot production/biomass (P/B) ratio varied from 0.012 to 0.018 day-1 and the leaf appearance rate from 0.025 to 0.056 leaves shoot' day !, with the leaf production varying from 0.9 to 3.6 g dw m ? of meadow day-! The above-ground biomass was between 55 and 249 g dw m-2 and the below-ground one varied from 181 to 385 g dw m-?. The annual leaf production was 752 g dw m ² year-!, with a P/B ratio of 3.5 year! The annual rhizome production was 30-37 g dw m 2 year!, with a P/B ratio of 0.14-0.16 year and an annual growth of 2.2 m of rhizomes per m² of meadow. In general, Cymodocea nodosa presented a similar behaviour to that known for this seagrass species from the Mediterranean Sea.