Re. Sherman et al., SOIL-PLANT INTERACTIONS IN A NEOTROPICAL MANGROVE FOREST - IRON, PHOSPHORUS AND SULFUR DYNAMICS, Oecologia, 115(4), 1998, pp. 553-563
We examined soil porewater concentrations of sulfate, alkalinity, phos
phorus, nitrogen, and dissolved organic carbon and solid phase concent
rations of pyrite in relation to mangrove species distributions along
a 3.1-km-long transect that traversed a 47.1-km(2) mangrove forest in
the Dominican Republic. Iron, phosphorus, and sulfur dynamics are clos
ely coupled to the activity of sulfate-reducing bacteria, the primary
decomposers in anoxic soils of mangrove ecosystems. Patterns in the ch
emistry data suggested that sulfate reduction rates and storage of red
uced sulfur were greater in the inland basin forest dominated by Lagun
cularia racemosa than the Rhizophora mangle dominated forest of the lo
wer tidal region. The distribution of Laguncularia was significantly c
orrelated with concentrations of total phosphorus (r = 0.99) and disso
lved organic carbon (r = 0.86), alkalinity (r = 0.60), and the extent
of sulfate depletion (r = 0.77) in the soil porewater and soil pyrite
concentrations (r = 0.72) across the tidal gradient. Leaf tissue chemi
stry of Laguncularia in was characterized by lower C:N and C:P ratios
that could fuel the higher rates of decomposition in the Laguncularia-
dominated forest. We suggest that a plant-soil-microbial feedback cont
ributes to the spatial patterning of vegetation and soil variables acr
oss the intertidal zone of many mangrove forest communities.