soils

Information Session for Environmental Students

• Target Audience: College students in environmental programs interested in a minor.

• Information Session Details:

  • Time: 5:00 PM

  • Significance of attendance for those potentially considering environmental studies.

• Marine Biology Students:

  • Encouraged to check with Dr. Moss (academic advisor).

• Class Break Announcement:

  • Students can stay after class for further inquiries about the minor.

Registration and Summer Classes

• Registration Process:

  • Students can register for summer classes through Auburn University.

  • Opportunity to earn academic credits during summer sessions.

• Informal gathering after class to discuss summer course offerings.

Water's Influence on Wetlands

• Previous Class Content:

  • Last week focused on water management, including:

  • Availability

  • Timing of water flow

  • Seasonal patterns

  • Spatial distribution and persistence of water

• Upcoming Focus:

  • The role of water in regulating biogeochemical cycles and soil properties in wetland environments.

World Wetlands Day

• Date: February 2

• Suggested Activities:

  • Students encouraged to celebrate in personal ways (e.g., making a cake, having a party).

  • Fun suggestion: Create a temporary wetland by using garden hoses in designated areas.

• Assignment in Honor of World Wetlands Day:

  • Students to visit a wetland with a friend/relative and submit a photo of the visit to earn bonus points on the next exam.

• Emphasis on educating others about the ecological significance of wetlands.

Soils in Wetland Environments

• Introduction to Biogeochemical Properties:

  • Hydrology affects the physiochemical environment of wetlands.

• Importance of Understanding Soil Characteristics:

  • Soil properties determine vegetation types and ecological dynamics.

• Definition of Soil:

  • A natural three-dimensional entity comprising distinct layers (horizons) formed through geological processes.

  • Soil Horizons:

  • O Horizon: Organic layer containing decomposed plant matter.

  • A Horizon: Topsoil, a mix of organic and mineral components.

  • Subsoil layers vary depending on water movement and mineral content.

• Hydrology Variability in Wetlands:

  • Water remains at or near the surface, causing unique soil development different from upland soils.

Factors Influencing Soil Formation

1. Parent Material: Geological origin of the soil.

2. Climate:

   • Determines precipitation levels and temperature ranges, influencing soil moisture and composition.

3. Biological Activity:

   • Varies with climate affecting nutrient levels and decomposition rates (microbial and invertebrate activity).

4. Topography:

   • Affects water drainage and saturation levels in soils.

5. Time:

   • Determines the degree of soil development and the duration of organic matter accumulation.

6. Flooding and Saturation:

   • Significantly alters soil formation, limiting oxygen availability and creating anaerobic conditions.

Hydric Soil Characteristics

• Definition of Hydric Soil:

  • Soils developed under conditions of saturation, flooding, or ponding that result in anaerobic conditions.

  • Characteristics include:

  • Reduced oxygen levels

  • Altered chemical conditions

• Importance of Growing Season:

  • Flooding during the growing season affects vegetation and soil stability differently than dormancy.

Types of Wetland Soils

Organic Soils

• Definition:

  • Soils that contain a significant organic matter component, which influences nutrients, appearance, and chemical processes.

• Peatlands:

  • Nearly 100% organic material, common in wetlands.

  • Slow decomposition due to water saturation leads to organic accumulation.

• Humification Process:

  • Conversion of organic material into humus through decay processes involving microbes and fungi.

• Characteristics:

  • Dark appearance due to high organic matter content, often indicating nutrient richness.

Mineral Soils

• Definition:

  • Predominantly composed of minerals, characterized by varying attributes of iron and manganese under redox conditions.

• Redoxomorphic Features:

  • Changes in soil color and composition due to redox chemistry influenced by water-saturation and anaerobic respiration.

  • Iron acts as a soil coloring agent, where its state changes from ferric (insoluble) to ferrous (soluble) in anaerobic conditions, allowing mobility in soil and impacting overall composition.

Connections to Biogeochemistry

• The presence of water at the soil surface influences microbial activity, organic matter decomposition, and nutrient availability.

• Understanding soil composition and characteristics aids in ecosystem management and restoration efforts in wetlands.

Discussion Points

• Student engagement encouraged regarding wetlands and soil management strategies.

• Emphasis on real-world applications of soil science principles in environmental contexts.