Biomass dynamics of the two dominant SW Atlantic Spartina species and its implications on the marsh organic matter accumulation/exportation

MONTEMAYOR, DIANA I; ADDINO, MARIANA; VALIÑAS, MACARENA; FANJUL, EUGENIA; ALVAREZ, M FERNANDA; IRIBARNE, OSCAR

AQUATIC BOTANY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 120 p. 201 - 204

0304-3770

We present a comparative analysis of the biomass dynamics of the two dominant Spartina plant species inSouth West Atlantic saltmarshes: Spartina densiflora Brong. (high intertidal zone) and Spartina alternifloraLoesel. (mid-low intertidal zone). We assessed aboveground biomass, live: dead ratios, net production,mortality and turnover rates, and then used this information to understand if saltmarshes dominatedby one or the other Spartina species have different ecosystemic roles in the recycling of organic matter.Through field sampling we found that S. densiflora had larger live, dead and total biomass than S. alterni-flora. When comparing within each species, S. alterniflora had larger live than dead biomass for most ofthe year, while S. densiflora had more dead than live biomass. Through the Weigert and Evans (1964) netaerial primary production (NAPP) estimating method we found that S. densiflora had larger annual NAPP,annual mortality and live turnover rates than S. alterniflora. In both species the amount of NAPP wassimilar to the amount of annual mortality. These results suggest that S. densiflora aboveground biomassis a carbon accumulation zone, while S. alterniflora is a carbon recycling one.