Standard Presentation Australian Marine Sciences Association Annual Meeting 2023

The role of energy stores in low-light resilience of the tropical seagrass Enhalus acoroides (#75)

Danica Lockett 1 , Timothy Smith 1 , Skye McKenna 1 , Michael Rasheed 1
  1. TropWater, James Cook University, Cairns, QUEENSLAND, Australia

Seagrass distribution is influenced by the availability of benthic light. In tropical seagrass habitats seasonal low light conditions due to increased turbidity during the wet season can result in prolonged periods of low benthic light causing biomass losses. The large Indo-pacific seagrass Enhalus acoroides can maintain biomass during extensive periods of low benthic light which might be related to large below-ground energy stores in their rhizomes. In this study E. acoroides carbohydrate (sucrose and starch) were compared to benthic light conditions throughout a tropical wet season. There was a linear relationship between rhizome sucrose concentration and benthic light with the highest rhizome sucrose concentrations being recorded at the beginning of the wet season and lowest toward the end of the wet season. Results of this study demonstrate that E. acoroides is able to utilize stored carbohydrates from their rhizomes to maintain respiratory demands during low light periods. This has important implications for managing seagrasses using light requirement approaches based on measuring a change in above ground plant condition that have been used for many other tropical seagrass species.