Dr. Sepúlveda is a broadly trained biogeochemist who uses organic and stable isotope geochemical tools to study the co-evolution of biology, biogeochemical cycles and climate. His research focuses on elucidating how microbial and biogeochemical processes respond to environmental perturbations in both contemporary (e.g., continental margins, marine oxygen minimum zones, soils, lakes, extreme environments) and ancient (glacial-interglacial transitions, greenhouse climates, extinction events) settings. More specifically, he achieves this by studying and validating the biogeochemical and isotopic information encoded in organic molecules (biomarkers) present in modern environments, and in their fossilized counterparts preserved in sedimentary records.
keywords
Organic and isotope biogeochemistry, lipid biomarkers as tracers for microbial processes and biogeochemical cycles, paleoenvironmental sciences, geobiology, CO2 forcing and climate change, co-evolution of climate and biology
GEOL 1060 - Global Change: An Earth Science Perspective
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Spring 2019 / Spring 2021 / Fall 2023
Focuses on evidence for planetary warming, climate change, glacier and ice-sheet melting and sea level rise both now and in the recent past. Attempts to develop understanding of the interactions within the coupled Earth system that regulate such changes. Utilizes examples from the geological and instrumental records, and evaluates the global warming forecast.
GEOL 3040 - Global Change: The Recent Geological Record
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Fall 2018 / Fall 2019 / Fall 2020 / Fall 2021 / Fall 2024
Geological records in lakes, oceans, deserts, and around glaciers indicate the significant changes in the global systems that have taken place over the last few hundred or thousand years. Explores the timing and nature of these changes. Department enforced prerequisites: any two-course sequence of natural science core courses.
GEOL 4611 - Organic Geochemistry
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Spring 2020 / Spring 2022 / Spring 2024
Explores the �biomarker concept� as a tool to elucidate microbial, biogeochemical, and climatic processes in natural systems through three fundamental goals: a) characterization and classification of organic molecules in complex, natural mixtures; b) biosynthesis, transport, transformation, preservation and destruction of organic matter in nature; c) application of lipid biomarkers and their stable isotope composition to study biological, biogeochemical, and climatic processes in modern and ancient systems. Recommended prerequisite: GEOL 3320 or GEOL 4270. Same as GEOL 5611.
GEOL 4700 - Special Geological Topics
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Spring 2019
Studies in selected geological subjects of special current interest (for undergraduates). May be repeated up to 9 total credit hours within a term.
GEOL 5611 - Organic Geochemistry
Primary Instructor
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Spring 2022 / Spring 2024
Explores the �biomarker concept� as a tool to elucidate microbial, biogeochemical, and climatic processes in natural systems through three fundamental goals: a) characterization and classification of organic molecules in complex, natural mixtures; b) biosynthesis, transport, transformation, preservation and destruction of organic matter in nature; c) application of lipid biomarkers and their stable isotope composition to study biological, biogeochemical, and climatic processes in modern and ancient systems. Recommended prerequisites: CHEM 1113 or equivalent from undergraduate degree and GEOL 5270 or GEOL 5280 or GEOL 5305 or GEOL 5675. Same as GEOL 4611.
GEOL 5612 - Techniques in Organic Geochemistry
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Fall 2020
Explores the techniques in analytical chemistry and organic geochemistry for the study of lipid biomarkers in the environment, which include the following topics: a) Extraction of environmental samples and separation of lipid classes; b) Analysis of apolar lipids using gas chromatography-mass spectrometry (GC-MS); c) Determine the stable isotope composition of lipids using GC-isotope ratio-MS (GC-IR-MS); d) Analysis of polar lipids using high performance liquid chromatography-MS (HPLC-MS). Requires previous coursework in general chemistry and Organic Geochemistry. Recommended prerequisites: Introductory or advanced courses in organic chemistry, biochemistry, biogeochemistry, geochemistry, geomicrobiology, paleoclimate, or geology.
GEOL 5700 - Geological Topics Seminar
Primary Instructor
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Spring 2019
Offers seminar studies in geological subjects of special current interest. Primarily for graduate students, as departmental staff and facilities permit. May be repeated up to 15 total credit hours provided that topics vary.
