Shallow-water coral reefs provide diverse ecosystem services and are thus considered a conservation priority. However, stony corals continue to face various threats. Lipids constitute ~30% of the dry tissue biomass in stony coral, which are vitally important for biological processes. Therefore, this study used a lipidomics approach to measure and characterize the lipidome of (1) three coral species, Porites rus, Porites lobata, and Pocillopora eydouxi, collected along a natural pH gradient created by the Maug Shallow Hydrothermal Vent (MSHV), and (2) from Acropora cervicornis, a coral species listed as threatened under the Endangered Species Act, following exposure to acute turbidity and sedimentation. Analyses of the (1) MSHV coral revealed lipidomic distinction across pH sites in P. lobata and P. rus. However, data from P. eydouxi may indicate resilience to acidification, supporting previous findings from metabolomics data. Of the top 25 most important spectral features driving distinctions across pH treatments, putatively annotated lipids classified as glycerophospholipids, glycerolipids, and sphingolipids were differently abundant in lower pH conditions for P. lobata and P. rus, while a single fatty acyl was also found to be altered in P. lobata under acidified conditions. Such lipids may help support and control cellular processes and maintain membrane stability and structure when exposed to lower pH conditions. Annotations were not assigned to over half of the features important for lipidomic distinction across pH sites in P. lobata and P. rus, limiting possible conclusions. Analyses of (2) A. cervicornis exposed to 96-h turbidity revealed no significant change in tissue regeneration or total lipids. Lipidomic changes were identified in the highest turbidity treatment (30 NTU), however, no significant differences in relative concentration of features important for lipidomic changes were detected. Tissue regrowth was significantly decreased in A. cervicornis exposed to turbidity and sedimentation during a 12-day experiment. Total lipids remained unchanged, although 12-day exposure to 15 NTU target turbidity and 96-h sedimentation periods impacted the A. cervicornis lipidome. Differences in relative concentration of features important for lipidomic distinction were not significant. This study provides important inaugural information regarding stony coral response to changes in environmental conditions that serves as a cornerstone for predicting coral composition shifts, may inform crucial conservation and management strategies, and will guide future investigations.
Saldana C. M., 2024. Effects of predicted future ocean acidification and dredging-induced turbidity on the scleractinian coral lipidome. MSc thesis, The College of Charleston, 169 p. Thesis (access restricted).
