Data from: Effects of small-scale, shading-induced seagrass loss on blue carbon storage: Implications for management of degraded seagrass ecosystems

1. Seagrass meadows are important global ‘blue carbon’ sinks. Despite a 30% loss of seagrasses globally during the last century, there is limited empirical research investigating the effects of disturbance and loss of seagrass on blue carbon stocks. 2. In this study, we hypothesised that seagrass loss would reduce blue carbon stocks. Using shading cloth, we simulated small-scale die-offs of two subtropical seagrass species, Halodule wrightii and Thalassia testudinum, in a dynamic northern Gulf of Mexico lagoon. The change in quantity and quality of sediment organic matter and organic carbon were compared among kill, control and bare plots before the kill treatment, shortly after the kill treatment and 11 months after the kill treatment. 210 Pb age dating was performed on bare and Thalassia plots at 11 months to evaluate the impact of sediment erosion in the absence of vegetation. 3. The small-scale die-off led to a 50-65% organic matter (OM) loss in the sediment in the top 8 cm of Halodule plots. Thalassia plots lost significant portions OM (50%) and organic carbon (C; 21-47%) in only the top 1 cm of sediment. The 210 Pb profiles indicated Thalassia die-off reduced the C sequestration rate by 10%, in addition to a loss of ~1 years’ worth of C stocks (~22 g m-2,Trevathan-Tackett_etal_JAE_rawdataAll data is included in one file and includes, sampling descriptions, GPS points, organic matter data, elemental and isotope data, thermogravimetric analysis data, and age-dating data.,