Chapters_2

Chapter 2: Environmental Systems Matter, Energy, and Ecosystems

Overview of Chapter Objectives

• Environmental Systems: Understanding the interplay between living organisms and their surroundings.

• Matter and Chemistry: Basics of matter's composition and real-world applications.

• Energy Forms and Thermodynamics: Differentiation among energy types and understanding thermodynamics principles.

• Photosynthesis and Respiration Processes: Importance of photosynthesis, cellular respiration, and chemosynthesis.

• Ecosystems: Definition and interaction between biotic and abiotic factors.

• Landscape Ecology and Modeling: Understanding ecosystems within landscapes and ecological modeling applications.

• Ecosystem Services: Explanation and benefits to human life.

• Nutrient Cycling: Examination of water, carbon, nitrogen, and phosphorus cycles and human impacts on these cycles.

Central Case Study: The Vanishing Oysters of the Chesapeake Bay

• Economic Decline: Grant Corbin (oysterman) highlights the aging workforce in Deal Island, Maryland, emphasizing economic difficulties prompting youth to leave.

• Historical Context: Population drop from 1237 in 1930 to 471 by 2010, linked to oyster fishery collapse, affecting local economies and cultures.

• Environmental Impact: Interconnected ecosystem of the Bay once supported diverse marine life, with oysters maintaining water clarity.

• Overharvesting and Pollution: While oyster harvesting began in the 1830s, by 2010, only 1% of oysters remained due to:

  • Overharvesting

  • Habitat destruction

  • Disease

  • Pollution (high nitrogen and phosphorus levels leading to hypoxia and dead zones, threatening numerous species).

  • Estimated economic losses in Maryland and Virginia: $4 billion (1980-2010).

Hope for Recovery of Chesapeake Bay

• Legal Action: Chesapeake Bay Foundation sued EPA in 2009, leading to federal responses and pollution budget implementation.

• Restoration Efforts: Promising results seen in oyster restoration initiatives, providing optimism for the economic revival of local communities.

Understanding Environmental Systems

• Definition of a System: A network of interrelated components that exchange energy, matter, or information.

• Earth's Natural Systems: Includes lithosphere, atmosphere, hydrosphere, and biosphere, each contributing to ecosystem function.

• Boundaries of Systems: Complex and difficult to define; interactions can depend on spatial or temporal scales.

Feedback Loops

• Inputs and Outputs: Systems process inputs (e.g., water, nutrients) and produce outputs (e.g., seafood). A feedback loop stabilizes systems.

  • Negative Feedback: Stabilizes the system (e.g., body temperature regulation).

  • Positive Feedback: Drives systems toward extremes (e.g., climatic changes from ice melt).

Ecosystem Functionality

• Energy Flow: Energy flows through ecosystems; autotrophs convert solar energy into chemical energy via photosynthesis.

• Matter Cycling: Matter (nutrients) is recycled in ecosystems; decomposition returns nutrients to the soil.

Productivity Variations in Ecosystems

• Net Primary Productivity (NPP): The difference between energy produced by photosynthesis and that used for respiration. Varies significantly across different ecosystems (e.g., high in wetlands, low in deserts).

Interconnectedness of Ecosystems

• Ecological Model Definitions: Includes studying how systems interact across landscapes and their influence on biodiversity.

• Tools for Analysis: GIS and ecological modeling help analyze data to predict ecosystem behavior and guide restoration efforts.

Ecosystem Services

• Definition: Benefits provided by ecosystems that support human life, including nutrient cycling and water purification.

• Biogeochemical Cycles: Illustrate the complex paths nutrients travel through ecosystems (water, carbon, nitrogen, phosphorus cycles).

• Impact of Human Activity: Excessive nutrient runoff leading to alterations in these cycles and affecting marine ecosystems.

Chemical Foundations in Ecosystems

• Matter and its Conservation: Matter cannot be created or destroyed; it cycles continually through ecosystems.

  • Atoms, Elements, and Compounds: Building blocks of matter. Essential elements for life include carbon, nitrogen, phosphorus, and their roles in biological processes.

  • Chemical Bonds: Atoms form molecules through ionic and covalent bonds; ions form from electron gain/loss.

Energy Types and Transformation

• Energy Forms: Different forms of energy include kinetic and potential energy.

• Thermodynamics Laws:

  • First Law: Energy is conserved; it cannot be created or destroyed.

  • Second Law: Energy tends toward dispersal and disorder (entropy).

Photosynthesis and Cellular Respiration Processes

• Photosynthesis Overview: Converts sunlight into chemical energy; essential for autotrophs (e.g., plants).

• Cellular Respiration: Utilized by both autotrophs and heterotrophs to produce main energy currency, ATP, from glucose.

Eutrophication and Nutrient Cycles

• Eutrophication Process: Nutrient over enrichment leads to phytoplankton blooms, hypoxic conditions, and aquatic life loss.

• Specific Nutrient Cycles:

  • Water Cycle: Essential for transporting nutrients and supporting life.

  • Carbon Cycle: Active in respiration and photosynthesis; human impacts increase atmospheric CO2 levels.

  • Nitrogen Cycle: Involves nitrogen fixation and denitrification; human activities cause nitrogen surplus.

  • Phosphorus Cycle: Phosphorus released from rocks by weathering and affects plant growth; human runoff can lead to algal blooms.