Primary production in coastal lagoons supported by groundwater discharge and porewater fluxes inferred from nitrogen and carbon isotope signatures

Andrisoa, Aladin, Stieglitz, Thomas C., Rodellas, Valenti, and Raimbault, Patrick (2019) Primary production in coastal lagoons supported by groundwater discharge and porewater fluxes inferred from nitrogen and carbon isotope signatures. Marine Chemistry, 210. pp. 48-60.

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Abstract

The role of groundwater and porewater fluxes as a source of nutrients to coastal ecosystems and their ecological implications are increasingly being recognized. In this study, the role of groundwater discharge and porewater fluxes in supporting primary production of coastal lagoons was evaluated by stable nitrogen and carbon isotope signature tracing of the transfer of nitrogen and carbon to primary producers. We determined the isotope signatures in macrophytes and phytoplankton (via particulate organic matter) and in the potential sources of inorganic nitrogen and carbon in two coastal lagoons on the French Mediterranean coastline. The delta N-15 of both macrophytes and phytoplankton reflect predominantly the nitrogen isotopic signatures of the karstic ground-water and porewater sources, indicating that they must have sourced the majority of their nitrogen from these sources, with punctual contributions from sewage input characterised by a significantly different isotopic signature. The delta C-13 signature of primary producers also shows the contribution of karstic groundwater discharge and porewater exchange as significant sources of dissolved inorganic carbon to primary production. This study links physical (nutrient delivery) and ecological (nutrient uptake) processes associated with primary production, thereby providing direct evidence for the ecological role groundwater discharge and porewater fluxes can play in coastal ecosystems.

Item ID: 58132
Item Type: Article (Research - C1)
ISSN: 0304-4203
Keywords: coastal lagoons; groundwater discharge; porewater fluxes; primary production; nitrogen isotopes; carbon isotopes
Copyright Information: © 2019 Elsevier B.V. All rights reserved.
Funders: French National Research Agency (ANR), European Research Council
Projects and Grants: ANR-14-ACHN-0007-01, project medLOC, ANR-11-LABEX-0061, ERC Horizon 2020 Marie Skłodowska‐Curie grant 748896
Date Deposited: 24 Apr 2019 07:31
FoR Codes: 04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040608 Surfacewater Hydrology @ 40%
04 EARTH SCIENCES > 0405 Oceanography > 040501 Biological Oceanography @ 40%
04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040603 Hydrogeology @ 20%
SEO Codes: 96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960503 Ecosystem Assessment and Management of Coastal and Estuarine Environments @ 50%
96 ENVIRONMENT > 9609 Land and Water Management > 960903 Coastal and Estuarine Water Management @ 50%
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