ESE/Ge 148c Global Biogeochemical Cycles

ESE/Ge 148c - Global Biogeochemical Cycles

Dr. Alex Sessions - Spring 2007

What's New

5/10/08 Uploaded lectures 18-21, problem set #4.

Where, When, and How

MWF 10 - 11am Arms 251
Office hours with Alex (108a N. Mudd, als@gps.caltech.edu) afternoons or by arrangement
Office hours with TA Gretchen Aleks (019 N. Mudd, gka@gps.caltech.edu) before problem sets are due and by arrangement
Textbook -"Earth System Science" by Michael Jacobson (ed.)
Syllabus

Late Policy: Assignments are due by 5pm on the due date. Work turned in after the deadline will be assessed a 10% penalty for each week they are late. Extensions are possible with a good excuse and permission of the instructor.

Collaboration Policy: You may work together on the problem sets, however the work you turn in must be your own. Since the problem sets all require writing or modifying scripts for MatLab, it is very easy (and tempting) to copy-and-paste scripts with other students. This is not allowed. You may talk with classmates about how best to implement or structure a script, and compare results, but you must write your own scripts and analyze your own results. Copying scripts, or parts of scripts, verbatim from your classmates is not allowed, and will be dealt with strictly.

Grading: 10% class participation, including presentations; 50% problem sets (5); 40% final exam.

Important Dates

April 7 - Problem Set #1 Due
April 16 - Problem Set #2 Due
April 25 - Problem Set #3 Due
May 9 - Problem Set #4 Due
May 10 (Saturday) - Field trip (Cancelled!)
May 23 - Problem Set #5 Due
May 26 - No class (Memorial Day)
May 30 - Last day of class
June 2-5 - Self-scheduled final exam

Class Assignments

Class Presentations - The link will provide you with guidelines for the presentations. The date should be scheduled in advance with Gretchen.

Problem Set 1 - Daisyworld, an introduction to box models and feedback processes.

Useful files: Daisyworld script (text file); Beta Function script (text file); Daisyworld review article (not required, but helpful).

Problem Set 2 - Construct a water-balance model for a small lake near Bakersfield, CA.

Useful files: Lakemodel script (text file)

Problem Set 3 - Construct an NPZ ecosystem model.

Useful files: Dailyinsolation script; declination_angle script; NPZeqns script (all are text files)

Problem Set 4 - Terrestrial-marine-atmosphere carbon cycle model.

Useful files: DailyMeanTemp script (text file)

Lecture Notes and Readings

Lecture 1 (Mon, 31-Mar)- Introduction and History of Biogeochemistry

Required Reading - ESS Chapter 1 ; Lovelock and Margulis (1973)

Lecture 2 (Wed, 2-Apr) - Coevolution of Life and the Earth

Required Reading - Beerling and Berner (2005) - Feedbacks and coevolution of plants and atmospheric CO2.

Extra Reading - ESS Chapters 2-3

Lecture 3 (Fri, 4-Apr) - Stable Isotope Fundamentals

Handout - Stable isotope nomenclature and definitions

Required Reading - Practice and Principles of Isotopic Measurements in Organic Geochemistry

Extra Reading: Notes on Isotopic Calculations by John M. Hayes

Lecture 3 (continued; Mon, 7-Apr) - Stable Isotope Fundamentals

Lecture 4 (Wed, 9-Apr) - The Hydrologic Cycle

Required Reading - ESS Chapter 6, Overpeck, et al (2006)

CCM3 precip movie (42 MB)

Extra Reading: Shindler and Donahue (2007) - Impending water crisis in western Canada; Kerr (2006) - Threat of rising sea level.

Lecture 5 (Fri, 11-Apr) - Isotopes in Hydrologic Studies

Required Reading - Clark and Fritz, Chapter 2 (14 MB); Feng et al (2007) - Changes in North American circulation patterns from cellulose dD and d18O.

Lecture 6 (Mon, 14-Apr) - The Atmosphere as Biogeochemical Agent

Required Reading - ESS Chapter 7. Andreae & Crutzen (1997): Atmospheric Aerosols: Biogeochemical sources and role in atmospheric chemistry.

Lecture 7 (Wed, 16-Apr) - The Oceans (guest lecture by Jess Adkins)

Required Reading - ESS Chapter 10.1-10.4; Tyrell (1999): The relative influences of nitrogen and phosphorous on marine primary production.

Supplemental Reading - Sarmiento and Gruber (2006), Ocean Biogeochemical Dynamics. On reserve.

Lecture 8 (Fri, 18-Apr) - Quantitative Box Models (guest lecture by Gretchen Aleks)

Required Reading - ESS Chapter 4.

Supplemental Reading - James Walker, Numerical Adventures with Geochemical Cycles. On Reserve.

Lecture 9 (Mon, 21-April) - Air/Sea Gas Exchange

Optional Reading - Libes (1992) Introduction to Marine Biogeochemistry. Chapter 6.

Lecture 10 (Wed, 23-Apr) - Marine Biosphere

Required Reading - Arrigo (2005): Marine microorganisms and global nutrient cycles

Lecture 11 (Fri, 25-Apr) - Quantitative Ecosystem Models

Optional Reading - Sarmiento & Gruber (2006) Ocean Biogeochemical Dynamics, Chapter 4.

Lecture 12 (Mon, 28-Apr) - Tectonics and the Rock Cycle

Required Reading - ESS Chapter 9. Edmond & Huh (2003) - Carbonate recylcing and implications for the evolution of atmospheric PCO2.

Lecture 13 (Wed, 30-Apr) - Weathering and erosion

Required Reading - ESS Chapter 8. Riebe et al (2001), Strong tectonic control of long-term chemical weathering rates.

Lecture 14 (Fri, 2-May) - Geologic controls on CO2

Required Reading - Jacobsen and Blum (2003) - Relationship between mechanical erosion and atmospheric CO2.

Lecture 15 (Mon, 5-May) - Soils

Required Reading - ESS Chapter 8. Chadwick et al (1999) - Changing sources of nutrients during four million years of ecosystem development.

Lecture 16 (Wed, 7-May) - Terrestrial Biosphere

Required Reading - ESS Chap 3.4-3.7. Norby et al (2005) - CO2 fertilization of terrestrial forests.

Global NPP movie (7Mb)

Lecture 17 (Fri, 9-May) - Photosynthesis

Required Reading - Kolber et al (2000) - Bacterial photosynthesis in surface waters of the open ocean.

Lecture 18 (Mon, 12-May) - Isotopes in Photosynthesis

Required Reading - Cerling et al (1993) - Expansion of C4 ecosystems as an indicator of global environmental change

Supplemental Reading - Farquahar et al (1989) - Carbon isotope discrimination and photosynthesis

Lecture 19 (Wed, 14-May) - The Carbon Cycle

Required Reading - ESS Chap 11; Piao et al (2008) - Net CO2 losses of northern ecosystems in response to autumn warming.

Lecture 20 (Fri, 16-May 21) - Soil Carbon

Required Reading - Davidson & Janssens (2006) - Temperature sensitivity of soil carbon decomposition and feedbacks to climate change; Smittenberg et al (2006) - Ongoing buildup of refractory organic carbon in boreal soils during the Holocene.

Supplemental Reading - ESS Chaps 8 and 11

Lecture 21 (Mon, 19-May) - Quantifying the CO2 Budget

Required Reading - ESS Chap 11; Schimel et al (2001) - Recent patterns and mechanisms of carbon exchange by terrestrial ecosystems.

May 21 is Ditch Day!

Lecture 22 (Fri, 23-May) - Methane Cycle

Required Reading - Keppler et al (2006) - Methane emissions from terrestrial plants under aerobic conditions.

Lecture 23 (Wed, 28-May) - Nitrogen Cycle

Required Reading - Altabet (2002) - The effect of millennial-scale changes in Arabian Sea denitrification on atmospheric CO2.

Lecture 24 (Fri, 30-May) - The Human Footprint

Required Reading: Wilkinson (2005) - Humans as geologic agents: A deep-time perspective; Vitousek (1997) - Human domination of Earth's ecosystems.

Exam Review (Mon, 2-June)