Modeling growth, carbon allocation and nutrient budgets of Phragmites australis in Lake Burullus, Egypt

Abstract

Phragmites australis is the major component of reed stands covering some 8200 ha along the shores of Lake Burullus (Egypt). We applied a published temperate zone reed model to assess growth and cycling of C and nutrients among the various organs of P. australis in this sub-tropical lake. We aim to quantify the role of reed stands for the C balance and nutrients cycling in the south Mediterranean wetland. Above-ground biomass was 3.5 times higher than the below-ground biomass. Root biomass represented 13% of the total below-ground, while leaves and panicles represented 16 and 3% of the above-ground biomass, respectively. Remobilization from rhizomes (15%) and reallocation from leaves (1%) were of little importance as assimilated sources. Nutrients accumulation by total above-ground biomass ranged between 2.7 to 46.8 g m−2 yr−1 for P and K, respectively. We calculated a C sequestration rate of 38.4 g C m−2 yr−1 for the dead rhizomes in the sediments. This value stresses the importance of P. australis stands for C sequestration in Lake Burullus. Further, as much as 254 t P and 5527 t N could potentially be removed annually from Lake Burullus by harvesting P. australis at maximum total above-ground biomass.