Poster De Conférence Année : 2024

2D imaging combination of planar optode and DET 2D: application in Z. marina seagrass

Résumé

Biogeochemical processes in sediment and soil are of major importance for large-scale element cycling and ultimately regulate the chemical composition of the atmosphere and the aquatic environment via affecting the balance of complete remineralization and burial of organic matter. The intense biogeochemical activity in sediment, submerged soil or wetlands is often characterized by steep gradients of various physical and chemical parameters over submillimeter distances. In aquatic environments, mineralization of organic carbon induces strong changes in redox potential and the lability of several solutes in sediment. Moreover, animal-induced sediment reworking and bioirrigation as well as exudates from seagrass below-ground biomass can play a major role for carbon mineralization in marine sediments e.g. by affecting the oxygenation and distribution of labile carbon in deeper sediment layers and by inducing spatial and temporal heterogeneity in terms of redox conditions. A precise mapping of chemical gradients and their spatio-temporal dynamics in sediments is thus essential for understanding links between sediment biogeochemistry and marine organisms inhabiting/colonizing such sediments. In this context, we developed new multi-parameter chemical imaging techniques by combining luminescence-based optical sensor foils (planar optodes) with 2D-diffusional equilibrium in thin-film (DET) hydrogels enabling simultaneous sensing of pO2, dissolved iron, phosphate, nitrite/nitrate, sulfide, ammonium, manganese or pH. A first application was used in Zostera marina meadow to better understand biogeochemical interactions between the seagrass rhizosphere and the surrounding sediment in the actual context of climate change, ongoing seagrass decline and human activities modification. Seagrass beds are critical habitats that support important fisheries, protect shorelines from erosion, capture carbon and help regulate nutrient concentrations. Declines in seagrass coverage have been significant all over the world, but the specific mechanisms affecting seagrass fitness in marine sediments and the exchange of nutrients in the seagrass rhizosphere remain largely unknown.

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Dates et versions

hal-05289251 , version 1 (29-09-2025)

Identifiants

  • HAL Id : hal-05289251 , version 1

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Florian Cesbron, Marie Duverger, Kasper Elgetti Brodersen, Aurélia Mouret, Mickael Kühl. 2D imaging combination of planar optode and DET 2D: application in Z. marina seagrass. Ocean Science Meeting 2024, Feb 2024, New Orleans (Louisiana), United States. ⟨hal-05289251⟩
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