Short-term nitrogen enrichment induces sulfide intrusion in tropical oligotrophic seagrass meadows

Sediment sulfide stress on seagrasses is related to anthropogenic nutrient enrichment and substrate type (e.g., sandy or muddy). This study investigated if anthropogenic nitrogen (N) enrichment resulted in sulfide stress in tropical seagrass Thalassia hemprichii inhabiting sandy habitats. Anthropogenic input resulted in 3.4-fold increase in sediment δ15N, and increase in the sediment organic matter and fine fraction content. N enrichment increased sediment sulfur (S) content and caused higher δ34S depletion in sediment. Higher N availability contributed towards significant increase of T. hemprichii shoot density and leaf biomass. Conversely, it reduced the root biomass, and root branching index coinciding with depleted root δ34S values. Additionally, in the sandy sedi- ments the sediment Fe levels were lower than pristine conditions, suggesting Fe limitation and subsequent increased sediment sulfide intrusion into T. hemprichii roots. This highlights T. hemprichii growing in sandy sediments with low Fe levels are more prone to sulfide intrusion under N enrichment.

Rhizosphere

Rhizosphere

35

2452-2198

N/A

N/A

9