Project description:<p>Sponges are sessile filter-feeders that can process vast amounts of water and are known to influence the chemistry of the surrounding seawater. There has been limited work however to understand the extent to which sponges alter dissolved organic matter (DOM), yet in areas where sponges are abundant, sponges may contribute significantly to the reef seawater profile of DOM. This work provides an in-depth examination of six prevalent sponges on Caribbean reefs and how they alter DOM and other seawater nutrients. Incurrent and excurrent seawater samples were collected for each of the six sponge species and processed for: inorganic nutrients, fluorescent dissolved organic matter (fDOM), untargeted and targeted metabolomics, and particulate matter by flow cytometry. Sponges were sampled from two coral reef sites in the Florida Keys (Florida, USA): Looe Key reef and Wonderland reef in the southern Florida Keys. We found higher that sponges altered a relatively small subset of the DOM profile and were a net sink of most mass features from untargeted metabolomics. However, sponges also released some putatively labile metabolites and processed DOM in a species-specific manner. These results provide additional support for the large impact that sponges have in the dissolved nutrient profile on coral reefs and provide support for a species-specific impact, with some species altering the DOM profile, fDOM profile, and/or inorganic nutrients to a greater extent than other species. These results have implications for better understanding the influence of the sponge community on coral reef nutrient dynamics.</p>
Project description:Measure changes in dissolved organic matter composition and resulting microbial decomposition rates in an experimentally warmed peatland.
Project description:Demosponge Cinachyrella cf cavernosa is an inter-tidal sponge. It is found in competition with soft coral Zoanthus sansibaricus and macroalgae Dictyota ciliatum. The effect of these two spatial competitors on the gene expression profile of the sponge is checked. Sponges are collected from three distinct situations, 1. sponge without competitors, 2. sponge in competition with algae, and 3. sponge in competition with soft coral. Each group has three biological replicates.
Project description:Sponges are efficient filter feeders, removing significant portions of particulate and dissolved organic matter (POM, DOM) from the water column. While the assimilation and respiration of POM and DOM by sponges and their abundant microbial symbiont communities have received much attention, there is virtually no information on the impact of sponge holobiont metabolism on the composition of DOM at a molecular-level. We applied untargeted and targeted metabolomics techniques to characterize DOM in seawater samples prior to entering the sponge (inhalant reef water), in samples exiting the sponge (exhalent seawater), and in samples collected just outside the reef area (off reef seawater). Samples were collected from two sponge species, Ircinia campana and Spheciospongia vesparium, on a near-shore hard bottom reef in the Florida Keys. Metabolic profiles generated from untargeted metabolomics analysis indicated that many more compounds were enhanced in the exhalent samples than in the inhalant samples. Targeted metabolomics analysis revealed differences in diversity and concentration of metabolites between exhalent and off reef seawater. For example, most of the nucleosides were enriched in the exhalent seawater, while the aromatic amino acids, caffeine and the nucleoside xanthosine were elevated in the off reef water samples. Although the metabolic profile of the exhalent seawater was unique, the impact of sponge metabolism on the overall reef DOM profile was spatially limited in our study. There were also no significant differences in the metabolic profiles of exhalent water between the two sponge species, potentially indicating that there is a characteristic DOM profile in the exhalent seawater of Caribbean sponges. Additional work is needed to determine whether the impact of sponge DOM is greater in habitats with higher sponge cover and diversity. This work provides the first insight into the molecular-level impact of sponge holobiont metabolism on reef DOM and establishes a foundation for future experimental studies addressing the influence of sponge-derived DOM on chemical and ecological processes in coral reef ecosystems.
2016-02-01 | MTBLS281 | MetaboLights
Project description:Heterotroph response to phytoplankton dissolved organic matter