Key biogeochemical factors affecting soil carbon storage in Posidonia meadows
Oscar Serrano1,2,Aurora M. Ricart1,3,Paul S. Lavery1,4,Miguel Angel Mateo1,4,Ariane Arias-Ortiz5,Pere Masque1,2,5,6,Mohammad Rozaimi1,7,Andy Steven8,and Carlos M. Duarte9Oscar Serrano et al.Oscar Serrano1,2,Aurora M. Ricart1,3,Paul S. Lavery1,4,Miguel Angel Mateo1,4,Ariane Arias-Ortiz5,Pere Masque1,2,5,6,Mohammad Rozaimi1,7,Andy Steven8,and Carlos M. Duarte9
1School of Sciences, Centre for Marine Ecosystems Research,
Edith Cowan University, Joondalup WA 6027, Australia
2The University of Western Australia Oceans Institute, University of
Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
3Departament d'Ecologia, Universitat de Barcelona, Av. Diagonal 643,
08028 Barcelona, Spain
4Centro de Estudios Avanzados de Blanes, Consejo Superior de
Investigaciones Científicas, 17300 Blanes, Spain
5Departament de Física & Institut de Ciència i Tecnologia
Ambientals, Universitat Autònoma de Barcelona, 08193 Bellaterra,
Catalonia, Spain
6School of Physics, the University of Western Australia, Crawley WA 6009, Australia
7School of Environmental and Natural Resource Sciences, Faculty of
Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi,
Selangor, Malaysia
8CSIRO, EcoSciences Precinct, 41 Boggo Road, Dutton Park QLD 4102, Australia
9Red Sea Research Center, King Abdullah University of Science and
Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
1School of Sciences, Centre for Marine Ecosystems Research,
Edith Cowan University, Joondalup WA 6027, Australia
2The University of Western Australia Oceans Institute, University of
Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
3Departament d'Ecologia, Universitat de Barcelona, Av. Diagonal 643,
08028 Barcelona, Spain
4Centro de Estudios Avanzados de Blanes, Consejo Superior de
Investigaciones Científicas, 17300 Blanes, Spain
5Departament de Física & Institut de Ciència i Tecnologia
Ambientals, Universitat Autònoma de Barcelona, 08193 Bellaterra,
Catalonia, Spain
6School of Physics, the University of Western Australia, Crawley WA 6009, Australia
7School of Environmental and Natural Resource Sciences, Faculty of
Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi,
Selangor, Malaysia
8CSIRO, EcoSciences Precinct, 41 Boggo Road, Dutton Park QLD 4102, Australia
9Red Sea Research Center, King Abdullah University of Science and
Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
Correspondence: Oscar Serrano (o.serranogras@ecu.edu.au)
Received: 15 Oct 2015 – Discussion started: 27 Nov 2015 – Revised: 08 Jul 2016 – Accepted: 13 Jul 2016 – Published: 15 Aug 2016
Abstract. Biotic and abiotic factors influence the accumulation of organic carbon (Corg) in seagrass ecosystems. We surveyed Posidonia sinuosa meadows growing in different water depths to assess the variability in the sources, stocks and accumulation rates of Corg. We show that over the last 500 years, P. sinuosa meadows closer to the upper limit of distribution (at 2–4 m depth) accumulated 3- to 4-fold higher Corg stocks (averaging 6.3 kg Corg m−2) at 3- to 4-fold higher rates (12.8 g Corg m−2 yr−1) compared to meadows closer to the deep limits of distribution (at 6–8 m depth; 1.8 kg Corg m−2 and 3.6 g Corg m−2 yr−1). In shallower meadows, Corg stocks were mostly derived from seagrass detritus (88 % in average) compared to meadows closer to the deep limit of distribution (45 % on average). In addition, soil accumulation rates and fine-grained sediment content (< 0.125 mm) in shallower meadows (2.0 mm yr−1 and 9 %, respectively) were approximately 2-fold higher than in deeper meadows (1.2 mm yr−1 and 5 %, respectively). The Corg stocks and accumulation rates accumulated over the last 500 years in bare sediments (0.6 kg Corg m−2 and 1.2 g Corg m−2 yr−1) were 3- to 11-fold lower than in P. sinuosa meadows, while fine-grained sediment content (1 %) and seagrass detritus contribution to the Corg pool (20 %) were 8- and 3-fold lower than in Posidonia meadows, respectively. The patterns found support the hypothesis that Corg storage in seagrass soils is influenced by interactions of biological (e.g., meadow productivity, cover and density), chemical (e.g., recalcitrance of Corg stocks) and physical (e.g., hydrodynamic energy and soil accumulation rates) factors within the meadow. We conclude that there is a need to improve global estimates of seagrass carbon storage accounting for biogeochemical factors driving variability within habitats.
The recent focus on carbon (C) trading has intensified interest in "Blue Carbon" – C sequestered by coastal vegetation. However, the factors influencing C storage are poorly understood. The patterns found in this study support that C storage in Posidonia seagrass soils is influenced by interactions of biological, chemical and physical factors within the meadow. We conclude that there is a need to improve global estimates accounting for biogeochemical factors driving variability within habitats.
The recent focus on carbon (C) trading has intensified interest in "Blue Carbon" – C...