Can crab bioturbation and herbivory regulate carbon sequestration and stocks in south american salt marshes?

MARTINETTO, P.; MONTEMAYOR, D.I.; ALBERTI, J.; IRIBARNE, O.

Mar del Plata

Congreso; IV Congreso Internacional de Servicios Ecosistémicos en los Neotrópicos: de la investigación a la acción; 2015

The role of coastal vegetation for climate change mitigation has been highlighted during the past decade. In particular, the high rates of atmospheric CO 2 uptake and the efficient retention of C in sediments in comparison with terrestrial ecosystems has been noted. Salt marshes in the South West Atlantic (SWA) coast are densely populated by the burrowing and herbivore crab Neohelice granulata. Given the presence of this crab species salt marshes are subject to intense bioturbation and herbivory rates. In the present study we compile the information available regarding C sequestration and accumulation in SWA coastal salt marshes and propose a hypothetical model including the mechanisms mediated by N. granulata that interfere the transformation paths of C in salt marshes. The compiled data suggest that mechanisms top-down regulated affect negatively C accumulation especially in salt marshes dominated by Spartina alterniflora. Mechanisms mediated by bioturbation affect negatively (increasing oxygenation and thus facilitating aerobic degradation) as well as positively (increasing retation of macrodetritus) the accumulation of C in sediments, being the later of greater magnitude in Spartina densiflora salt marshes.