Biomass and Net Aboveground Primary Productivity of Spartina Densiflora in a Mar Chiquita Coastal Marsh, Argentina

GONZÁLEZ TRILLA, G; DE MARCO, S.; VICARI, R.; MARCOVECCHIO, J.; KANDUS, P

Cuiabá, Brazil

Conferencia; 8th INTECOL International Weltands Conference; 2008

Society of Wetland Scientists

Coastal wetlands are highly productive environments exporting great amounts of organic matter (OM) to the estuarine-marine adjacent systems. The goal of this work is to study standing biomass, Net Aboveground Primary Productivity (NAPP), OM exportation and their patterns in a S. densiflora coastal marsh, using a nondestructive method applied to permanent sample plots located in low marsh (LM) and high marsh (HM). Tillers were measured every two months during the 2005-2007 period (N=752). Tiller biomass (b) was estimated using tiller height (h) and the regression equation  (R2=0,898, N=641). Green standing and total standing biomass showed the same seasonal pattern, peaking in summer and showing between-years differences in the LM. Dry standing biomass peaked in autumn-winter showing higher values in the HM than in the LM. Dry mass production exported from the marsh showed maximum values in winter, in coincidence with the minimum values of productivity. The annual NAPP was estimated to be 2599±705 g•m-2•yr-1 for the HM and 2181±605 g•m-2•yr-1 and 602±154 g•m-2•yr-1 for the first and second period in the LM, respectively, showing a seasonal pattern reaching maximum values in summer. The annual dry mass exported from the marsh was 2386±849 g•m-2 in the HM and 2155±316 g•m-2 and 1465±316 g•m-2 in the LM in the first and second year respectively. The system behaves as a producer of OM  in summer (positive differences between NAPP and OM exportation) and as an exporter of OM in winter (negative values), showing differences between sites, due to different exposure to the tides, and between years due to climate variations.