Evaluating the potential for autonomous measurements of net community production and calcification as a tool for monitoring coral restoration

Abstract

As coral restoration efforts increase globally, there is a growing need to not only increase post-restoration monitoring, but also advance reef restoration monitoring methods. Utilizing autonomous technology to compliment manual, SCUBA-based monitoring will diversify the types of data available to coral restoration practitioners and aid in determining the efficacy of restoration efforts. This study sought to investigate how existing reef monitoring technologies can be applied to coral restoration to improve monitoring resolution and assess restoration progress. The Benthic Ecosystem and Acidification Measurement System, which uses the gradient flux approach to measure benthic community metabolism, was used to monitor two arrays of nursery grown Acropora cervicornis within an offshore coral nursery in the Florida Keys. The first deployment monitored corals arranged in a density mimicking pre-restoration coral cover, while the second deployment monitored corals arranged in a density mimicking a reef site recently restored with nursery-grown A. cervicornis. The post-restoration density demonstrated a 36% increase in the observed ratio of net community calcification to net community production as compared to the pre-restoration density. Additionally, the post-restoration density demonstrated net accretion throughout the observation period (20 mmol CaCO3 m−2d−1) as compared to the pre-restoration density which experienced net dissolution (−5.0 mmol CaCO3 m−2d−1). Overall, the results of this study are promising indicators that metabolic monitoring could one day be widely utilized within the coral restoration field to remotely monitor benthic composition changes associated with coral restoration progress over time, providing valuable information to restoration practitioners, stakeholders, and resource managers.