Teal carbon eelgrass in tidal freshwater estuaries: successful laboratory trial before large‐scale field restoration

Abstract Introduction Vallisneria , a freshwater angiosperm critical to aquatic biodiversity and teal carbon storage in Great Barrier Reef catchments, has declined due to habitat degradation and poor water quality. Scalable restoration approaches are urgently needed to support ecological and climate outcomes. Objectives This study aimed to evaluate two Vallisneria restoration techniques—manual transplanting and anchoring—under controlled conditions to determine their viability for broader application in tropical freshwater systems. Methods Shoots collected from the Johnstone River (Queensland, Australia) were acclimated and deployed across eight experimental tanks. Growth over 6 weeks was measured using the Plastochrone method, alongside water quality monitoring and carbon sequestration estimates derived from shoot length. Results Both methods supported plant survival and rhizome expansion. Transplanting showed higher survivorship (87.5%) than anchoring (66.6%), though shoot growth was comparable: 98.1 cm (SE ± 33.9) for transplanting and 94.2 cm (SE ± 25.8) for anchoring ( F = 2.49, p = 0.14). Estimated carbon sequestration ranged from 0.12 ± 0.10 to 0.22 ± 0.20 g C/m 2 of shoot growth, with total accumulation of 2.42 g C/m 2 over 6 weeks. Conclusions Both restoration methods are viable, with anchoring offering a scalable alternative where manual planting is unsafe or impractical.