Surface water and N.digitalis inhalent/exhalent water sample nutrient and bacterioplankton metadata of Looe Key and Wonderland Reef conducted in 10-15 December 2023

Abstract

Sponges are sessile filter-feeders that can process vast amounts of water and are known to influence the chemistry of the surrounding seawater. In areas where sponges are abundant, there may be a unique nutrient profile or ‘reef signal’ produced by the metabolism of the reef benthic community and sponges may contribute significantly to this ‘signal’. This work provides an initial test of such a hypothesis, specifically that sponges can influence the dissolved nutrient profile in the overlying seawater.

We analyzed differences in dissolved nutrient concentration (total organic carbon and dissolved nitrogen, inorganic nutrients, fluorescent dissolved organic matter (fDOM), and metabolites) and bacterioplankton cell density in surface seawater between two Florida Key coral reefs with different benthic communities. Additionally, we analyzed the processing of these nutrients by one species of sponge, Niphates digitalis, observed at both sites. While picoplankton abundances and inorganic nutrients were not different between sites, the surface water at Wonderland reef was characterized by elevated humic-like fDOM components and concentrations of certain metabolites such as aromatic amino acids relative to Looe Key. There is also higher similarity in the metabolite profile between Looe Key reef and Wonderland reef compared to the surface water away from the reef. There was not corresponding net production of the quantified metabolites by N. digitalis and overall little processing of dissolved organic nutrients by this sponge species.

These results provide initial support for a ‘reef signal’ in metabolite profiles and there may be an impact of sponge abundance on the nutrient profile at Wonderland. However, the sponge N. digitalis is likely not a major contributor to the dissolved organic nutrient pool. Overall, these results have implications for better understanding the influence of the benthic community on coral reef nutrient dynamics.

For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/907559