The effect of N. granulata bioturbation on benthic metabolism was
higher than those reported for other widely distributed bioturbators
such as fiddler crabs and polychaetes. The increase in CO2 production in bioturbated sediments was a combination of the
direct metabolic contribution of N. granulata and benthic macrofauna, but also it could be a result of the stimulation of the heterotrophic microbial activity by bioturbation. The stimulation of microbial metabolism induced by this crab seems to be due to O2 injection and the enhanced solute transport into sediment but also due to the increased bioavailability of the sedimentary OM showed that N. granulata enhance O2 uptake about 250% in the mudflat, and about 1600% in the saltmarsh; our results showed a 200% increment of CO2 flux in bioturbated mudflat and an increment of 8000% in the saltmarsh area. Given that oxygen is utilized both in aerobic metabolism and for chemical re-oxidation of reduced metabolites the oxygen uptake is not a direct measurement of aerobic metabolism. These results suggest that at mudflats, bioturbation enhances oxygen-consuming proccesses, but in saltmarshes strongly enhances both aerobic and anaerobic metabolism.