Concentrations and fractionation of carbon, iron, sulfur, nitrogen and phosphorus in mangrove sediments along an intertidal gradient (semi-arid climate, New Caledonia)
|Author(s)||Deborde Jonathan1, Marchand Cyril1, Molnar Nathalie1, 2, Della Patrona Luc3, Meziane Tarik2|
|Affiliation(s)||1 : UMR 7590 IMPMC, UR 206, IRD, F-98848 New Caledonia, France.
2 : UMR BOREA 7208 CNRS MNHN UPMC IRD UCBN, Museum Natl Hist Nat, F-75231 Paris 05, France.
3 : Ctr IRD, Ifremer, Dept Lagons Ecosyst & Aquaculture Durable LEAD NC, Noumea, New Caledonia.
|Source||Journal Of Marine Science And Engineering (2077-1312) (Mdpi), 2015-03 , Vol. 3 , N. 1 , P. 52-72|
|WOS© Times Cited||20|
|Keyword(s)||mangrove, zonation, biogeochemistry, New Caledonia|
|Abstract||In mangrove ecosystems, strong reciprocal interactions exist between plant and substrate. Under semi-arid climate, Rhizophora spp. are usually predominant, colonizing the seashore, and Avicennia marina develops at the edge of salt-flats, which is the highest zone in the intertidal range. Along this zonation, distribution and speciation of C, Fe, S, N, and P in sediments and pore-waters were investigated. From the land-side to the sea-side of the mangrove, sediments were characterized by I/ increase in: (i) water content; (ii) TOC; (iii) mangrove-derived OM; II/ and decrease in: (i) salinity; (ii) redox; (iii) pH; (iv) solid Fe and solid P. Beneath Avicennia and Rhizophora, TS accumulated at depth, probably as a result of reduction of iron oxides and sulfate. The loss of total Fe observed towards the sea-side may be related to sulfur oxidation and to more intense tidal flushing of dissolved components. Except the organic forms, dissolved N and P concentrations were very low beneath Avicennia and Rhizophora stands, probably as a result of their uptake by the root systems. However, in the unvegetated salt-flat, NH4+ can accumulate in organic rich and anoxic layers. This study shows: (i) the evolution of mangrove sediment biogeochemistry along the intertidal zone as a result of the different duration of tidal inundation and organic enrichment; and (ii) the strong links between the distribution and speciation of the different elements.|