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Bazaruto’s ancient peat supports marine life beneath the sea

Ancient coastal vegetation has left a new kind of marine habitat around Mozambique’s Bazaruto Archipelago. A peer-reviewed field study describes consolidated peat colonised by seaweed, seagrass and other organisms, with fish using its crevices and overhangs. These communities differ from neighbouring coral reefs. Measurements establish the terrestrial origin of the peat without calculating the carbon stored across the entire habitat.

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Algae, seagrass and fish beside fibrous submerged peat.

Ancient peat forms a foundation for marine communities

Consolidated peat left by ancient coastal vegetation now supports marine life around Mozambique’s Bazaruto Archipelago. A newly published peer-reviewed field study describes algae, seagrass and other organisms living on this underwater substrate. Crevices and overhangs offer shelter, and juvenile fish were observed around the formations.[1], [2]

The fieldwork took place in 2023. Researchers surveyed three peat formations and a coral-reef comparison site using divers, photographic quadrats and peat sampling. Radiocarbon ages from approximately 800 to more than 4,500 years describe individual samples, rather than a continuous sediment chronology. Carbon isotopes indicate that the material came predominantly from terrestrial plants.[1]

Fish connect peat habitats with neighbouring coral reefs

No living hard coral was observed in the peat habitats, where macroalgae, seagrass and exposed peat dominated. Their benthic communities differed from those at the coral comparison site. Fish and larger mobile animals showed greater overlap: 41 small-fish species and 44 megafauna species occurred in both habitats. Some comparisons of these animal groups did not produce statistically significant habitat separation.[1]

Carbon-rich samples leave the total stock unmeasured

Carbon reached 20–40 per cent of dry weight in some peat samples, but the study did not calculate a habitat-wide stock per unit area. Waves and currents erode and redistribute the peat, and low tides can expose shallow areas to air. Peat thickness, erosion rates and greenhouse-gas fluxes were not jointly quantified, leaving its present carbon balance unresolved.[1]

References

  1. News sourceScientific ReportsAncient peat provides marine habitat off Mozambique↩1↩2↩3↩4
  2. News sourceECO MagazineAncient Submerged Forests off Mozambique Found Teeming with Marine Life↩
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