Fig. 6. A schematic representation of an aggregation of L. luymesi, depicting a nutrient exchange model for this species. Seawater and sediment pore-water sulfate concentration and pH are from Aharon and Fu (Aharon and Fu, 2000). The equation for microbial sulfate reduction shows sulfate reduction coupled with methane oxidation. However, sulfate reduction coupled with higher molecular mass hydrocarbons can also occur (Joye et al., 2004). Bicarbonate uptake across roots is suggested, but has not been directly demonstrated in this study.