Biochemical parameters as early indicators of seagrass transplant's health

Seagrass restoration efforts have multiplied in the last years, with very diverse success rates, justifying the need for a better understanding of the physiological aspect of transplant operations. For the first time, biochemical parameters were used as early indicators of transplant's health. In this study, two seagrass species were transplanted using two distinct modalities per species. Zostera marina was transplanted in bundles of five and ten shoots and Cymodocea nodosa was transplanted with original sediment in trays and as bare rhizome segments of at least three shoots. Oxidative stress, antioxidant activity, photosynthetic pigment and non-structural carbohydrate (NSC) content in leaves and rhizomes were investigated before transplant and four weeks after transplant. Results revealed some significant method-specific early biochemical responses to transplant for C. nodosa. Cymodocea nodosa shoots transplanted in segments showed radical shifts in NSC storage and chlorophyll content whereas antioxidant activity was further triggered in C. nodosa transplanted in trays. Shoot density may be an important factor to consider when selecting the best transplant method for Z. marina, but no differences were observed in the early biochemical parameters measured. The results of this short-term biochemical monitoring suggest that transplanting C. nodosa in trays could be less disruptive for the plant's biochemistry than bare-rhizome methods. This study provides insights into biochemical responses post-transplantation and emphasizes the need for adaptable restoration strategies. Coupled with transplant survival, morphological parameters and long-term monitoring, biochemical metrics can be used as a sensitive tool to monitor short-term responses in seagrass meadows.