A model study of the effects of sulfide-oxidizing bacteria (Beggiatoa spp.) on phosphorus retention processes in hypoxic sediments : Implications for phosphorus management in the Baltic Sea

Ongoing eutrophication increases phosphorus storage in surficial sediments of the Baltic Sea which can then be released during hypoxic/anoxic events. Such sediments are suitable habitats for sulfide-oxidizing bacteria, Beggiatoa spp. The objective of this paper is to investigate the effects of these bacteria on the P retention processes in hypoxic sediments using a diagenetic model. This model simulates interactions of the processes controlling P mobility in the sediments with redox reactions from the Beggiatoa metabolism. Modeling results demonstrate that P retention capability is limited when dissolved iron is mineralized as iron sulfides in the sediments. In this regard, sulfide consumption by Beggiatoa spp. potentially decreases the rate of iron sulfide formation and consequently increases the P retention capability in local-scale sediment.