Distinguished Lectures in Earth Sciences - Exploring the limits of Earth's habitability by scientific ocean drilling

Giovedì 12 Dicembre alle 15:00, nell'aula  Geo 1 (DiSTAR, Edificio 10, Complesso Universitario di Monte Sant'Angelo), per il  ciclo delle Distinguished Lectures in Earth Sciences, Verena Heuer (MARUM - Bremen, Germany)  ECORD Distinguished Lecturer 2018-2019, terrà un seminario dal titolo:

Exploring the limits of Earth's habitability by scientific ocean drilling: The impact of temperature on microbial life and carbon flow in deep sub-seafloor sediments


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Exploring the limits of Earth's habitability by scientific ocean drilling: The impact of temperature on microbial life and carbon flow in deep sub-seafloor sediments
Verena Heuer (MARUM, Germany – Distinguished Lecturer ECORD 2018-2019)
https://www.marum.de/en/Verena-Heuer.html
 
The ocean floor is an important interface at which geological, physical, biological and chemical processes interact. Geological processes shape the ocean floor and result in vastly different environments, such as mid-ocean ridges where new ocean floor is formed, subduction zones where old ocean floor is transferred back into the Earth's interior, cold seeps and hot vents which release fluids and gases from within the ocean floor, and vast areas and volumes of sediment. In these environments, temperature varies widely, and microbial communities are widespread and surprisingly diverse despite energy limitations. Microbial life persists even in sediments of Cretaceous age, at sediment depths of up to 2.5 km below the seafloor, and in deeply buried oceanic crust. However, the total amount of subsurface biomass is still a matter of debate, the metabolic activities of deeply buried microbes are barely explored, and the factors posing ultimate limits to deep life and the habitability of Earth remain to be resolved. 
This lecture will specifically address the role of temperature in deep geosphere-biosphere interactions. It will investigate the impact of temperature on the abundance and activity of microorganisms, on the biotic and abiotic transformation of sedimentary organic matter, and on carbon flow within the ocean floor. To this end, we will discuss the results and technological challenges of recent scientific ocean drilling expeditions in high temperature environments, in particular IODP Expedition 337 Shimokita Deep Coalbed Biosphere and Expedition370 Temperature Limit of the Deep Biosphere off Cape Muroto. The former was the first scientific ocean drilling expedition to target a deep hydrocarbon reservoir by riser-drilling technology, and it recovered up to 2.5 km deep, 60°C coal-bearing sediments and associated fluids and gases. The latter aimed to probe the deepest extent of life in ocean-floor sediments, known as the biotic fringe, and applied particularly strict contamination control measures when up to 120°C sediments were retrieved from a 1.2 km deep borehole in the Nankai Trough subduction zone. The lecture will conclude with a discussion of open questions, future challenges and drilling targets within IODP's Biosphere Frontier Theme.
https://youtu.be/0ehPpK2rc58