Environmental Geology & Geochemistry Seminar (EGGS) Lecture Series: Tarhan

Thu, Dec 5, 2019, 12:30 pm to 1:20 pm
Guyot 220

Bioturbation—sediment mixing by burrowing animals—critically shapes seafloor ecology and sediment properties, as well as global marine biogeochemical cycling. Observation of strong bioturbation-biogeochemical feedbacks in modern marine environments suggests that the evolutionary development of bioturbation should have profoundly impacted contemporaneous biogeochemical (e.g., C, P, O and S) cycling. Stratigraphic archives indicate that the early Paleozoic development of bioturbation was a protracted process, and that the appearance of intensively and deeply mixed sediments lagged significantly behind relatively early advances in infaunal seafloor colonization. However, the precise biogeochemical impact of early Paleozoic bioturbation has remained debated. To further address this question, I use a new, multi-component diagenetic model to explore the relationship between bioturbation, porosity and biogeochemical (e.g., C, P, O and S) cycling. This approach indicates that these relationships are complex and non-linear, and that not only intensity but style of bioturbation (e.g., biodiffusion, bioirrigation and changes in porosity) influence the magnitude of both P recycling and S oxidation.