Gallery

Our lab has conducted 12 monthly research cruises (January till December of 2020) in the P-limited ultraoligotrophic Eastern Mediterranean Sea, to determine the mechanisms responsible for the regulation of rhodopsin-based photoheterotrophy in the ocean and to establish its contribution to marine microbial energy budgets. A parallel project is being run by our collaborator Dr. Laura Gomez-Consarnau and her team, in a N-limited upwelling region of the Pacific Ocean (San Pedro Ocean Time-Series, SPOT). Data analysis is presently under way.

During my sabbatical year in Trieste, Italy, I was lucky to meet a team of divers, who are passionate about the sea, and beautiful people. They helped me with the setup of the experiments and with the sampling throughout three intensive days, in which we dove every four hours. These were Andrea Furlan, Roberto Romeo, Michelle Gavagnin, Gianluca Calabrese and Sara De Gioia. Livio Steindler was our captain and kindly made his sailing boat ‘Colpo De Fulmine II’ available for this project. Sponges (Aplysina aerophoba) were sampled throughout the diel cycles and samples were preserved in RNALater immediately after collection using a specially devised underwater chamber. Dr. Gustavo Ramírez, a Zuckerman post-doctoral fellow in my lab, is now analyzing the gene expression data from the complex microbiome associated to the sampled sponges, and is investigating how microbial metabolism of symbionts is affected by diurnal-nocturnal cycles. The video was made Dr. Roberto Romeo.

Petrosia ficiformis is one of our favourite sponge model systems to study symbiosis. This due to the facultative nature of its interaction with the photosynthetic cyanobacterial symbionts. We have determined how biogeography is a main factor in the assembly of this sponge’s microbial community (Burgsdorf et al 2014), we have sequenced the genome of the highly specific cyanobacterial symbionts (Burgsdorf et al 2019), we have shown that this highly specific symbiont can be acquired by adult P. ficiformis specimens in situ and that the process of acquisition takes more than half a year (Britstein et al 2020), and that the innate immune system is likely involved in sponge-symbiont recognition (Steindler et al 2007).