99147 - ISOTOPES AS TRACERS OF THE SEA

Learning outcomes

The course focuses on the diagnostic value of natural and anthropogenic isotopes as tracers of sea processes and cycling of carbon. At the end of the course, the student will have an overall understanding on the application of various isotopic techniques to determine the sources, pathways, dynamics and fate of carbon, as well as pollutants and particles that enter the sea from land and atmosphere.

Course contents

Introduction: properties of seawater, chemistry of seawater, conservative and non-conservative sea tracers, radioactive decay and radioactive dating;

Natural isotopes in the oceans: uranium and thorium decay series as particle-scavenged ‘clocks’ to derive information on sources and fluxes of marine and terrestrial particles, carbon, as well as on inputs of pollutants in the present ocean;

Anthropogenic isotopes in the ocean: weapon-derived radionuclides to trace and clock both near-shore and open ocean process including circulation, sedimentation, and biological productivity.

Ocean uptake of CO2 and its impacts: anthropogenic changes in carbon isotopes to quantify past and present ocean carbon uptake; acidification of the ocean; ocean carbon export and fluxes;

Climate change records: radio- and stable-isotopes tracers in natural archives including marine sediments, ice cores, and corals as recorders of past changes in salinity, productivity and oceanic nutrient levels in seawater.

Readings/Bibliography

Lecture notes, slides, supplementary articles and open codes are provided at https://virtuale.unibo.it [https://virtuale.unibo.it/] or on a shared OneDrive folder.

Most of the topics presented in the course can be found in:

Wallace S Broecker, Tsung-hung Peng, 1982. Tracers in the Sea. The Lamont-Doherty Geological Observatory, Columbia University, Palisades, New York. 705 pp. https://www.ldeo.columbia.edu/~broecker/Home_files/TracersInTheSea_searchable.pdf

Schlesinger W. H., Bernhardt E. S. Chapter 9 - The Oceans. Biogeochemistry (Fourth Edition) An Analysis of Global Change, Elsevier (2020), pp. 361-429. https://doi.org/10.1016/B978-0-12-814608-8.00009-8

Steven R. Emerson, John I. Edges, 2012. Chemical oceanography and the carbon cycle. Eds. Cambridge University Press, Cambridge. 454 pp. https://doi.org/10.1017/CBO9780511793202

Michael F. L'Annunziata. Chapter 2 - Basic Concepts and Definitions. Radioactivity (Second Edition) Introduction and History, from the Quantum to Quarks, Elsevier (2016), pp. 67-78. https://doi.org/10.1016/B978-0-444-63489-4.00002-2

Michael F. L'Annunziata. Chapter 3 - Hall of Fame: Part I. Radioactivity (Second Edition) Introduction and History, from the Quantum to Quarks, Elsevier (2016), pp. 79-122. https://doi.org/10.1016/B978-0-444-63489-4.00003-4

Michael F. L'Annunziata. Chapter 18 - Radionuclide Decay, Radioactivity Units, and Radionuclide Mass. Radioactivity (Second Edition) Introduction and History, from the Quantum to Quarks, Elsevier (2016), pp. 621-638. https://doi.org/10.1016/B978-0-444-63489-4.00018-6

Introduction to U-series Geochemistry. Volume 52 Uranium-series Geochemistry, Bernard Bourdon, Gideon M. Henderson, Craig C. Lundstrom, and Simon P. Turner (Eds), De Gruyter (2003), pp. 1-23. https://doi.org/10.1515/9781501509308

M. Ješkovský, J. Kaizer, I. Kontuĺ, G. Lujaniené, M. Müllerová, P.P. Povinec. Analysis of environmental radionuclides, Handbook of Radioactivity Analysis 2, Elsevier (2019), pp. 137-261. https://doi.org/10.1016/B978-0-12-814395-7.00005-2

P.P. Povinec, M. Eriksson, J. Scholten, M. Betti. Marine radioactivity analysis Handbook of Radioactivity Analysis, 2, Elsevier (2020), pp. 315-392, https://doi.org/10.1016/B978-0-12-814395-7.00005-2

Uranium-series disequilibrium: Applications to Earth, Marine and Environmental Sciences, 2nd Edition, edited by M. Ivanovich and R. S. Harmon. Oxford : Clarendon Press ; Oxford; New York: Oxford University Press, 1992.

Open source codes

Ocean Data View (ODV) free software package and webODV including manual are available for download at https://www.seadatanet.org/Software/ODV, https://odv.awi.de/, https://explore.webodv.awi.de/

Bruel, R., Sabatier, P., 2020. serac: an R package for ShortlivEd RAdionuclide chronology of recent sediment cores. Journal of Environmental Radioactivity 225, 106449. https://doi.org/10.1016/j.jenvrad.2020.106449

Teaching methods

The course consists of classroom lectures. Seminars on specific applications are also organized. These seminars (ca. 2 hours) target topics of broad interest and serve to show how an isotope-based integrated approach can be useful to understand processes in the coastal and deep sea.

The course will be complemented by practical sessions on interactive exploration, analysis and visualization of ocean data (profiles, time-series data) in regional seas with Ocean Data View (ODV) software package, and computational methods to determine times or rates of geologic events and processes with open source software packages in rstudio.

Attendance of lectures and practical sessions is strongly encouraged since complementary material, in addition to required readings, will be presented in lectures and included in examinations.

Assessment methods

The learning assessment consists of a written examination. The examination, which usually foresees 3-5 multiple choice questions, 1 numerical exercise, and 1 open question on different topics, aims at evaluating the fulfilment of the course learning outcomes.

The exam duration is two hours on average.

Teaching tools

Slides, videos and practical sessions with personal laptops.

Students who need compensatory tools for reasons related to disabilities or specific learning disorders (SLD) can directly contact the Service for Students with Disabilities (disabilita@unibo.it) and the Service for Students with learning disabilities (dsa@unibo.it) to agree on the adoption of the most appropriate measures.

Office hours

See the website of Roberta Guerra