Ocean Microbiomes Under Pressure: From Holobiont Resilience to Deep-Sea Metal Stress
Hidden Architects of the Sea: Microbiomes of Marine Forest‑Forming Holobionts, by Aschwin Engelen (CCMAR)
Marine organisms rely on diverse microbial partners that support health, physiology, and adaptation. Yet, climate change is reshaping these associations in ways we do not fully understand. In this talk, I will explore microbiomes of corals, seagrasses, and algae respond to environmental stress, drawing on recent work from the Algarve, Macaronesia, and the Caribbean. By combining evolutionary perspectives with functional analyses, we uncover patterns of stability, flexibility, and disruption in key microbial groups. These insights reveal when microbiomes buffer hosts against stress, when they fail, and how this knowledge can guide conservation and restoration strategies. Understanding microbiome functionality across ecosystems is essential for predicting resilience in a rapidly changing ocean.
Metal impacts on deep-sea microbial communities: physiological and ecological insights, by Miguel Semedo (CIIMAR)
Deep-sea mining of earth minerals, as well as other emerging industries in this environment, are expected to grow in the coming decades. These activities may expose microbial communities to increased concentrations of metals, such as cadmium (Cd) and copper (Cu). Microbial communities in the deep-sea provide important ecosystem services, from genetic diversity to regulating the production of greenhouse gases, such as nitrous oxide (N2O). Nevertheless, the potential impacts of metal exposure on deep-sea microorganisms remain widely unknown. In this talk, I will present our initial findings and ongoing research on the potential effects of Cd and Cu exposure on N2O metabolism in deep-sea bacteria and sedimentary microbial diversity. We performed a series of bioreactor experiments with model deep-sea bacteria and shipboard exposure experiments with sediment microbial communities on oceanographic expeditions. Our preliminary results suggest that, while Cu has stronger effects on N2O metabolism, Cd exposure has a stronger effect on overall community diversity. These findings will contribute to the global efforts of predicting and monitoring potential impacts of emerging human activities in the deep-sea.
About the Speakers
Aschwin H. Engelen coordinates the research group Marine Microbial Ecology & Technology at CCMAR. Their research focuses on host–microbe interactions in corals, seagrasses, and algae, integrating evolutionary ecology, symbiosis, and environmental change. He combines field surveys, experimental approaches, and multi‑omics tools to understand how microbiomes shape organismal health and ecosystem resilience. His work aims to translate fundamental microbiome knowledge into applications for marine conservation, aquaculture, and restoration.
Miguel Semedo is a Junior Researcher at CIIMAR and co-PI of the Microbiome Ecology and Biogeochemistry group. As a microbial ecologist, Miguel is interested in investigating the diversity and function of microbial communities across multiple environments and their roles in biogeochemical processes. He is especially interested in understanding the impacts of human activities and pollution on these processes. For his research, he applies molecular, bioinformatic, and biogeochemical methodologies to understand the links between microbial community composition and biological activity.
The seminar will be delivered in hybrid format, in room 1.39 at CCMAR, and online via Zoom (Online Session Link).
Meeting ID: 944 8617 8086
Passcode: 363023
If you would like to receive a certificate, please email ccmarseminars@ualg.pt by 11 March.
If you are a CIIMAR member you can also access last seminars recordings through the LINK.
In case of any questions, please contact CIMAR-LA’s Seminar team.
