Seasonal dynamics of biomass and nutrient content in the intertidal seagrass Zostera noltii Hornem. from Palmones River estuary, Spain

Abstract

The seasonal dynamics of above- and belowground biomass of Zostera noltii Hornem. were studied in a permanent quadrat in the Palmones River estuary, southern Spain (36° 11′ N, 5° 27′ W) from February 1988 to February 1990. Temporal changes in nitrogen, carbon, different phosphorus fractions (soluble reactive phosphorus, total soluble phosphorus, particulate phosphorus and total phosphorus) and nutrient ratios (C/N, N/P and C/P), were also investigated in the same population from January 1989 to January 1990. Biomass of above- and belowground structures showed a unimodal seasonal pattern with maxima in summer (180-200 g DW (dry weight)) m-2 and 70-75 g DW m-2 respectively) and minima in winter (30-50 g DW m-2 and 25-30 g DW m-2). Internal concentrations of carbon, nitrogen and phosphorus showed seasonal changes, with minima for nitrogen (3.0% for shoots and 1.2% for underground parts) and total phosphorus (0.45% for underground parts) in summer. Shoots and underground parts of Z. noltii contained maximum amounts of nitrogen (5.9 g m-2 and 2.1 g m-2, respectively), phosphorus (1.7 g m-2 and 0.6 g m-2) and carbon (66.9 g m-2 and 27.8 g m-2) in August. The annual flux of nutrients from Z. noltii to the detritus compartment has been estimated to be about 14.6 g H, 4.1 g P and 155.3 g C m-2 of sediment surface. © 1993.