Module 6: Geochemistry and biogeochemistry
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This page first made public: May 15, 2017
Summary and Overview
This module examines the integrated roles that biology, geology, and chemistry play in the CZ. Engaging students in examining data from real world systems, this module highlights the biogeochemical functions the CZ plays and the functions the CZ play. Through the subunits of phosphorus and eutrophication, and nutrient inputs and transformations, students will come to understand the role of biogeochemistry in Critical Zone processes. Lastly, students will consider how they can use biogeochemical-based knowledge in solving humanity's grand challenges including climate change and environmental stability.
Instructors should note that this section primarily focuses on the carbon, nitrogen, and phosphorous cycles with a smaller emphasis placed on the sulfur cycle. For lessons focused on the water cycle please see the sections: Water Transfer Through the Critical Zone and Land-Atmosphere Exchange.Jump down to: Strengths of the Module | Module Goals | Assessment | Module Outline
Strengths of the Module
This module addresses the following central InTeGrate goals in the following ways:
- Use geoscience-related grand challenges facing society (eutrophication, erosion, environmental stability, climate change)
- Develop students' ability to address interdisciplinary problems (sustainable agriculture, conservation, resource management)
- Improve student understanding of the nature and methods of geoscience and developing scientific and geoscientific habits of mind (examine how biogeochemistry is examined using hands-on activities)
- Make use of authentic and credible geoscience data such as real CZO data from the geochemical and biogeochemical literature base.
- Incorporate systems thinking by incorporating examples and activities that demonstrate the connection between water, air, soil, and organisms in biogeochemical processes within the CZ.
Specific Module Goals
- Apply data sets and observations from six existing CZOs to test ideas and summarize Critical Zone services.
- Describe the CZ as a complex system of interacting regolith, water, air, nutrients, and organisms.
Specific Module Learning Objectives
- Students will further develop scientific and geoscientific habit of mind through biogeochemical-based activities.
- Students will be able to evaluate the chemical and biological processes and reactions that govern the composition of the CZ.
- Explain the role of CZ services in supporting terrestrial life, including humanity.
- Students will be able to explain and use examples of how organisms and biodiversity affect biogeochemical processes.
- Students will be able to use data, and examples from published scientific literature to explain critical zone functions.
- Students will be able to explain some of the common methods used in biogeochemical research.
- Students will be able to explain the effect of differences in land-use on nutrient cycling and critical zone functions.
Linking Unit Content to Course Objectives
Below is a brief outline of examples within each Learning Unit where instructors can find resources that meet the overarching learning objective for the whole curriculum and each of the four primary learning objectives of the Critical Zone curriculum:Overarching Learning Objective: Describe and characterize how interaction among the atmosphere, lithosphere, hydrosphere, biosphere, and soil (The Critical Zone) support and influence life.
- Unit 6.1: Scientific articles on atmospheric inputs into tropical rain forests (e.g. Gioda et al. 2013, McDowell et al. 1998) and the movement of nutrients through the biosphere (e.g. Helfield and Naiman 2001, Bump et al. 2009, Lavery et al. 2010) and within aquatic ecosystems (McDowell and Fisher 1976, Mulholland et al. 2008).
- Unit 6.2: The Carpenter (2008) commentary paper examines the role of phosphorous loading into water-based resources as does the interactions of nutrients in agricultural systems examined in relevant data sets.
Four primary objectives:
Objective 1) Identify grand challenges that face humanity and societies, ways in which humans depend upon and alter the Critical Zone, and the potential role for Critical Zone science to offer solutions for these challenges.Back to top
- Unit 6.1: The following articles in this section highlight the effects of anthropogenic activities on local to global critical zone processes: Gioda et al. (2013), Hungate et al. (2003), Mulholland et al. (2008), and Weiss (1999).
- Unit 6.2: Activities focus on how humanity's use of land and water for food and water supply influences Critical Zone processes (e.g. Carpenter 2008).
Objective 2) Use and interpret multiple lines of data to explain Critical Zone processes.
- Throughout this module multiple types and sources of data are presented to explain critical zone geochemical and biogeochemical processes.
- Unit 6.1: Carbon and nitrogen isotopic data sets are provided to look at influence of drought on trees and the effect of non-native fish on food webs. Additionally, all scientific papers are data based and many of the Reading Questions require students to interpret data sets and/or graphs. For example, the research presented in both the Gioda et al. (2013) and McDowell (1998) papers focus on the atmospheric input of nutrients into tropical forests are from the Luquillo Mountains Critical Zone Observatory in Puerto Rico.
- Unit 6.2: Students will utilize water chemistry data regarding dead zones and the relation to agricultural runoff and then examine how best management practices work by finding data, creating visuals, and explaining the Critical Zone processes.The research activity related to the dissolution of apatite (Buss, 2010) at the Luquillo Mountains Critical Zone Observatory in Puerto Rico provide these experiences.
Objective 3) Evaluate how the structure of the Critical Zone influences Critical Zone processes/services.
- Unit 6.1: The Vitousek and Rainers (1975) article focuses on how forest ecosystems change over time (succession) in relation to rates of nutrient uptake.
- Unit 6.2: The nutrient challenge activity examines the relationship between nutrients and Critical Zone processes.
Objective 4) Analyze how water, carbon, nutrients, and energy flow through the Critical Zone and drive Critical Zone processes.
- Activities, assignments, assessment in this module focus primarily on carbon, nitrogen, and phosphorous cycling within the critical zone.
- Unit 6.1: Example papers that focus primarily on C, N, and P cycling include: Helfield and Naiman (2001), Hungate et al. (2003), Mulholland et al. (2008), Vitousek and Rainers (1975), Weiss (1999), Bump et al. (2009), and Tilman et al. (1996). The carbon and nitrogen isotope activities are also useful here.
- Unit 6.2: Example papers that focus on C, N, and P cycling include: Alexander et al. (2008), Buss et al. (2010), Filippelli (2002), Carpenter et al. (1998); in addition, the nutrient challenge activity examines the relationship between nutrients and Critical Zone processes.
- Reading and Interpreting the Scientific Literature (Units 1 and 2): Students are provided multiple articles from the geoscientific and biogeochemical literature and practice interpreting and understanding the presented data and methods through group discussions and thought-provoking and critical questions.
- Scientific Presentation (Unit 1): Students give a method based scientific presentation to extend upon biogeochemical research read in a scientific paper of their choosing.
- Nutrient Challenge (Unit 2): Working individually or in groups, students will complete this activity, based on a real world challenge grant to apply their knowledge learned in the course of the geochemistry and biogeochemistry unit to devise a transformative strategy for reducing excess nutrients in the waterways.
- Unit 6.1: Biogeochemical Modeling Framework - Biogeochemistry: Inputs and transformation (Three 75 min class sessions)
- Unit 6.2: Biogeochemical Examples - Geochemistry: Phosphorus and eutrophication (Two 75 min class sessions)