A new type of Halimeda bioherm on the Queensland Plateau, NE Australia
Metadatos
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Reolid Pérez, Jesús; M. Bialik, Or; Lindhorst, Sebastian; Eisermann, Jan Oliver; Petrovic, Alexander; Hincke, Carola; J. Beaman, Robin; M. Webster, Jody; Betzler, ChristianEditorial
Springer Nature
Materia
Bioherm Mesophotic reef Green algae
Date
2024-05-30Referencia bibliográfica
Reolid, J., Bialik, O.M., Lindhorst, S. et al. A new type of Halimeda bioherm on the Queensland Plateau, NE Australia. Coral Reefs (2024). [https://doi.org/10.1007/s00338-024-02500-0]
Patrocinador
03G0292A—ICECARB from the Bundesministerium für Bildung und Forschung (Germany) to CB; Spanish Ministry of Science and Innovation (MCIN) through the Ramón y Cajal Project RYC2021-034362-I (MCIN/ AEI/https:// doi. org/ 10. 13039/ 50110 00110 33 and NextGenerationEU/ PRTR); Parks Australia for the research permit for Cruise SO292 (permit EPBC 2022/9168); The Schmidt Ocean Institute is thanked for the RV Falkor multibeam data acquired during cruises FK200429 and FK200802.Résumé
Morphology, internal structure, and in situ facies distribution of mesophotic Halimeda bioherms from the Queensland Plateau (NE Australia) are presented based on hydroacoustic and oceanographic data, seafloor observations, and discrete sediment sampling carried out during RV SONNE cruise SO292 in 2022. Halimeda buildups consist of cone-like mounds up to 500 m in diameter and 3–10 m high, with gentle slopes (2°–5° on the top of Tregrosse Bank). Bioherms occur in water depths of 10–70 m, with most bioherm between 50 and 65 m. Their internal structure consists of aggrading low-amplitude reflections at the core of the bioherm interfingering with high-amplitude reflections to the flanks. Surface facies distribution displays one to four facies belts, from distal to proximal: Halimeda rudstone, Halimeda rudstone with living plants, Halimeda rudstone with coralgal debris, and coralgal boundstone (when present, occupied the top of the bioherms). It is proposed that the alternation of two key processes contributes to the formation of these bioherms: (1) in situ accumulation of Halimeda debris and (2) episodic dismantling of the mesophotic coralgal boundstone at the centre of the bioherm by severe storms. These storms may dismantle the mesophotic reef and export coralgal rubble to the flanks. Flanks may be recolonized by Halimeda during fair-weather periods. Due to their different geomorphic expressions, complex internal structure, and surficial facies distribution, we suggest that the buildups of the Queensland Plateau represent a new Halimeda bioherm morphotype, distinct from previously described bioherms on the adjacent Great Barrier Reef and elsewhere globally.