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Research article - Peer-reviewed, 2021

Dynamics and fate of blue carbon in a mangrove-seagrass seascape: influence of landscape configuration and land-use change

Asplund, Maria E.; Dahl, Martin; Ismail, Rashid O.; Arias-Ortiz, Ariane; Deyanova, Diana; Franco, Joao N.; Hammar, Linus; Hoamby, Arielle, I; Linderholm, Hans W.; Lyimo, Liberatus D.; Perry, Diana; Rasmusson, Lina M.; Ridgway, Samantha N.; Gispert, Gloria Salgado; D'Agata, Stephanie; Glass, Leah; Mahafina, Jamal Angelot; Ramahery, Volanirina; Masque, Pere; Bjork, Mats;
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Abstract

Context Seagrass meadows act as efficient natural carbon sinks by sequestering atmospheric CO2 and through trapping of allochthonous organic material, thereby preserving organic carbon (C-org) in their sediments. Less understood is the influence of landscape configuration and transformation (land-use change) on carbon sequestration dynamics in coastal seascapes across the land-sea interface. Objectives We explored the influence of landscape configuration and degradation of adjacent mangroves on the dynamics and fate of C-org in seagrass habitats. Methods Through predictive modelling, we assessed sedimentary C-org content, stocks and source composition in multiple seascapes (km-wide buffer zones) dominated by different seagrass communities in northwest Madagascar. The study area encompassed seagrass meadows adjacent to intact and deforested mangroves. Results The sedimentary C-org content was influenced by a combination of landscape metrics and inherent habitat plant- and sediment-properties. We found a strong land-to-sea gradient, likely driven by hydrodynamic forces, generating distinct patterns in sedimentary C-org levels in seagrass seascapes. There was higher C-org content and a mangrove signal in seagrass surface sediments closer to the deforested mangrove area, possibly due to an escalated export of C-org from deforested mangrove soils. Seascapes comprising large continuous seagrass meadows had higher sedimentary C-org levels in comparison to more diverse and patchy seascapes. Conclusion Our results emphasize the benefit to consider the influence of seascape configuration and connectivity to accurately assess C-org content in coastal habitats. Understanding spatial patterns of variability and what is driving the observed patterns is useful for identifying carbon sink hotspots and develop management prioritizations.

Keywords

Seascape connectivity; Land–sea interface; Mangrove deforestation; Seagrass meadows; Sedimentary carbon storage

Published in

Landscape Ecology

2021,
Publisher: SPRINGER

Authors' information

Asplund, Maria E.
University of Gothenburg
Dahl, Martin
Stockholm University
Ismail, Rashid O.
Stockholm University
Arias-Ortiz, Ariane
University of California Berkeley
Deyanova, Diana
University of Gothenburg
Franco, Joao N.
Polytechnic Institute of Leiria
Hammar, Linus
Octopus Ink Research & Analysis
Hoamby, Arielle I.
University of Toliara
Linderholm, Hans W.
University of Gothenburg
Lyimo, Liberatus D.
Univ Dodoma
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Rasmusson, Lina M.
University of Gothenburg
Ridgway, Samantha N.
Edith Cowan University
Gispert, Gloria Salgado
Edith Cowan University
D'Agata, Stephanie
Macquarie University
Glass, Leah
Blue Ventures
Mahafina, Jamal Angelot
University of Toliara
Ramahery, Volanirina
Nexus Madagascar
Masque, Pere
Autonomous University of Barcelona
Bjork, Mats
Stockholm University
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Sustainable Development Goals

SDG15 Life on land

UKÄ Subject classification

Physical Geography
Environmental Sciences

Publication Identifiers

DOI: https://doi.org/10.1007/s10980-021-01216-8

URI (permanent link to this page)

https://res.slu.se/id/publ/110996