Scale-dependent feedbacks in seagrasses drive multiple spatial patterns at the seascape scale, with clear implications for ecological resilience, functioning, and service provision. Seagrass fairy rings may be a consequence of the accumulation of hydrogen sulfide in the sediment. However, the mechanisms underlying the sulfide-plant interaction for their formation is far from being fully understood. Here, we provide a description of the development of fairy rings of the seagrass Posidonia oceanica in Pollença bay (Mallorca, NW Mediterranean), emphasizing the self-organized dynamics of vegetation under stress. First, we investigate sediment biogeochemical composition and seagrass demography and then, we explore the long-term (1956 - 2020) development of fairy rings by inspecting historical images. We demonstrate that (i) the ring-shaped patches are maintained by inherent vegetation dynamics coupled with sulfide accumulation and (ii) the formation of the ring pattern at the studied area, triggered by ecological feedbacks, coincides with a bifurcation of the ecosystem regime due to sulfide persistent stress.

Primary Presenter: Elvira Mayol Alcover, Mediterranean Institute for Advanced Studies (Imedea - CSIC) (elvira.mayol@imedea.uib-csic.es)

Authors:

Elvira Mayol, Mediterranean Institute for Advanced Studies (Imedea - CSIC)  (elvira.mayol@imedea.uib-csic.es)

Daniel Ruiz-Reynés, Institute for Cross-Disciplinary Physics and Complex Systems (Ifisc - CSIC)  (druiz@ifisc.uib-csic.es)

Damià Gomila, Institute for Cross-Disciplinary Physics and Complex Systems (Ifisc - CSIC)  (damia@ifisc.uib-csic.es)

Alex Gimenez, Institute for Cross-Disciplinary Physics and Complex Systems (Ifisc - CSIC)  (alex@ifisc.uib-csic.es)

Carlos Morell, Mediterranean Institute for Advanced Studies (Imedea - CSIC)  (amorell@imedea.uib-csic.es)

Manuel Matías, Institute for Cross-Disciplinary Physics and Complex Systems (Ifisc - CSIC)  (manuel.matias@ifisc.uib-csic.es)

Tomàs Sintes, Institute for Cross-Disciplinary Physics and Complex Systems (Ifisc - CSIC)  (tomas@ifisc.uib-csic.es)

Emilio Hernández-García, Institute for Cross-Disciplinary Physics and Complex Systems (Ifisc - CSIC)  (emilio@ifisc.uib-csic.es)

Carlos Duarte, King Abdullah University of Science and Technology (KAUST)  (carlos.duarte@kaust.edu.sa)

Iris Hendriks, Mediterranean Institute for Advanced Studies (Imedea - CSIC)  (iris@imedea.uib-csic.es)

Núria Marbà, Mediterranean Institute for Advanced Studies (Imedea - CSIC)  (nmarba@imedea.uib-csic.es)