BIOGEOCHEMICAL PROCESSES: ENST 450/MASC 450/ENVR 415/GEOL 450
Christopher S. Martens, 4202F Venable Hall
919 962 0152: cmartens@email.unc.edu
Office hours: Wed 1:30-3:00 pm or by appointment
General course description:
Principles of chemistry, biology, physics and geology are applied to the analysis of the
fate and transport of materials in sedimentary, aqueous and atmospheric environments with an
emphasis on those elements whose biogeochemical cycles are controlled by microbial processes.
The course covers key biogeochemical processes occurring in oceans, lakes, rivers and the
atmosphere with a core focus on processes that occur at naturally occurring physical and
chemical interfaces. Readings will consist of specific scientific journal articles available on the
class Sakai site and through UNC’s E-journal finder found on the UNC Libraries web site.
Target audience:
This course is aimed at junior and senior science majors who have completed
basic coursework in disciplinary sciences including chemistry, biology, geosciences,
physics and mathematics. The course builds on other coursework offered in the CEE
curriculum. Formal prerequisites listed in the undergraduate bulletin can be waived with
permission of the instructor.
Course introduction and focus
Why Biogeochemical Processes? Lessons from the northern Gulf of Mexico
Why was it difficult to understand what was happening during the Macondo blowout?
What processes were dominant in controlling the fate of oil and gas?
How can we quantify those processes?
Submarine groundwater discharge: Tracing exchange with surface waters
Biogeochemical processes at physical interfaces: An introduction
Air-water gas exchange: Exchange between surface waters and troposphere
Particle adsorption and settling: Pollutant removal from surface waters
Sediment-water chemical exchange: Nutrient sources for coastal waters
Topic examples (coverage will change as course progresses):
The global carbon cycle, greenhouse gases and tropical rain forests
Review: Physical causes of the greenhouse effect
Carbon dioxide and methane: Global trace gas fluxes and budgets
Atmospheric trace gas concentrations: Accelerations in human impacts
FOCUS: Role of Amazonian rain forests in the global carbon budget
Organic matter transformations: The role of microbial processes
Sources, composition and reactivity: Organic geochemistry
REDOX reactions: Controls by microbial respiration
Biogeochemical zonation: Net results of microbial competitions
FOCUS: Biogeochemical zonation and chemical gradients in sediments
Ocean Acidification: Probable Chemical Impacts from Global CO2 Increase
Lowering of pH to date and future predictions
Drops in carbonate ion concentration and carbonate mineral saturation state
FOCUS: Distinguishing local from global impacts
Respiration Processes and Nutrient element cycling
Oxygen utilization and biogeochemical consequences
The nitrogen cycle: Coastal eutrophication
The phosphorus cycle: Mineral-water interactions
FOCUS: Coastal eutrophication and O2 depletion in shallow waters
Additional topics will be chosen through discussions
Class requirements:
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Completion of take-home problem sets
Writing assignments based on current scientific journal literature
 Regular attendance and participation in class discussions
 Late work is generally not accepted
Grading will be based on:
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Successful completion of problem sets in a timely fashion
Write-ups based on science journal articles
Participation in class discussions and fieldwork