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In-Depth Notes on Coral Bleaching and the Carbon Cycle

Coral Bleaching Overview

  • Coral Bleaching: A phenomenon where corals expel their symbiotic algae (zooxanthellae) due to stress, leading to loss of color and food source.

Lesson Agenda

  • Coral Bleaching Phenomena: Discussion on the current state of coral bleaching in the Florida Keys (10 min).
  • Article: Carbon Cycle and Coral Bleaching.
  • Activity: Engaging with data and findings related to coral bleaching.
  • Homework: Finish any necessary tasks related to the lesson.

Learning Goals

  • Analyze real-life data on coral bleaching (temperature trends, health surveys).
  • Interpret visual data forms (graphs, tables, maps) regarding coral reef conditions.
  • Draw evidence-based conclusions about coral bleaching trends and potential solutions.

Coral Bleaching in the Florida Keys

  • Date: Mid-July 2023, coral bleaching observed.
  • Temperature Context:
    • Hottest water temperatures documented since satellite records began in 1985.
    • Normal Max Monthly Mean temperature (MMM) is 29.63 °C.
    • Bleaching threshold temperature is 30.63 °C, exceeded on June 14, 2023, and reached 33.60 °C on July 13, 2023.
  • Implications: Increased fears of a mass mortality event due to extended heat stress affecting fragile reefs.

Coral Reef Basics

  • Location: Found 23 degrees north and south of the equator.
  • Biodiversity: Known as the 'rainforests of the sea', hosting a vast array of marine species.

Understanding Corals

  • Corals: Living animals (Cnidarians) related to jellyfish and anemones.
  • Structure: Composed of colonies of polyps, which are invertebrates attached to rocks.
  • Relationship with Algae: Corals have a symbiotic relationship with photosynthetic algae (zooxanthellae), supplying glucose and oxygen, vital for coral survival.

Coral Bleaching and the Carbon Cycle

  • Coral health is closely linked to the carbon cycle.
  • Changes in carbon levels affect ocean temperatures and chemistry, influencing coral reefs' viability.

Coral Bleaching Activity

Task 1 (Lab Design)

  • Research Locations:
    • Asuncion Island
    • Abul Thama Reef, Bahrain
    • Clipperton Island, France
    • Martin, Florida.
  • Objective: Describe each location in 1-2 sentences, focusing on how heat stress affects coral health.

Task 2 (Data Analysis)

  • Analyze temperature and heat stress data across three time periods (2001-2002, 2009-2010, and 2013-2014).
  • Heat Stress Measurement: Derived from the duration sea surface temperature (SST) exceeds the maximum monthly mean (MMM).
  • Complete the following:
    1. Identify and describe the trends from each location.
    2. Compare and contrast data across time periods.
    3. Explain the relationship between increasing heat stress and coral bleaching.

Locations and Data Trends

  • Asuncion Island: Detailed graphs for 2001-2002, 2009-2010, and 2013-2014 included measurements of heat stress and temperature.
  • Abul Thama, Bahrain: Similar analysis with specific trends highlighted.
  • Clipperton Island, France: Studied according to heat stress levels and the corresponding temperature impact.
  • Martin, Florida: Trends tracked through similar methods as above.

Conclusion

  • Coral reefs are under severe stress relative to temperature thresholds critical to their survival.
  • Future research and efforts aimed at understanding and mitigating the effects of climate change on coral bleaching are essential for preservation.