Climate change impacts on tropical sponges and associated microbial communities

• Main Author: Nora Kandler
• Format: Thesis
• Language: unknown
• Published: 2024
• Subjects: Microbial ecology; Global change biology; Sponges; Climate change; Microbiome; School: School of Biological Sciences; 310703 Microbial ecology; 319902 Global change biology; 280102 Expanding knowledge in the biological sciences; Degree Discipline: Marine Biology; Degree Name: Doctor of Philosophy; Degree Level: Doctoral; Ocean acidification
• Online Access: https://doi.org/10.26686/wgtn.25708995; https://figshare.com/articles/thesis/Climate_change_impacts_on_tropical_sponges_and_associated_microbial_communities/25708995

Climate change is causing rapid changes in reef structure, biodiversity, and function as a response to ocean warming and acidification. The negative impacts of climate change on corals are well-documented, but most sponges are predicted to tolerate conditions projected for 2100, making them a viable option for stable alternative reef states. Sponges maintain an intimate relationship with microbial communities, whose general stability in a given sponge species makes them suitable indicators of host responses to stressful environmental conditions such as ocean warming and acidification. The overall aim of this thesis is to examine the impacts of climate change on sponges and their associated microbial communities, with a focus on microbial community composition and abundance and sponge protein expression. The first data chapter examines the results from a reciprocal transplantation of the coral reef sponges Coelocarteria singaporensis and Stylissa cf. flabelliformis between a control reef site and an adjacent CO2 vent site in Papua New Guinea to explore how the sponge microbiome responds to ocean acidification in situ. Microbial communities of C. singaporensis, which differed initially between sites, did not shift towards characteristic control or vent microbiomes. Microbial communities of S. cf. flabelliformis, which were initially stable between sites, did not respond specifically to transplantation but collectively exhibited a significant change over time, with a relative increase in Thaumarchaeota and decrease in Proteobacteria in all treatment groups. The lack of a community shift upon transplantation to the vent site suggests that microbial flexibility, at least in the adult life-history stage, does not necessarily underpin host survival under ocean acidification. The second data chapter compares the symbiotic microbial community composition of tropical sponge Stylissa flabelliformis after an eight-week exposure to nine different treatments of three temperatures (28.5 °C, 30 °C, 31.5 °C) and three pH levels ...