OCN 150 end of Chapter 12

Review Session Announcement

Review for Exam 3: Session scheduled for tomorrow from 3 to 5 PM at the Light in the Library located on the first floor.
Access Instructions: Please enter through the old doors, not the new wing, to reach the review room effectively.
Exam Instructions: Due to room reservation limitations, comprehensive instructions and materials related to the exam will be displayed prominently on a whiteboard.

Exam Date: Scheduled for the 11th, covering all material from Chapters 7 through 11.
Homework Submission: Please ensure that all homework assignments are submitted by Sunday night at 11:59 PM to avoid late penalties.

Extra Credit Seminar: A seminar will take place today at 4 PM offering 10 extra points on Exam 3.
Speaker Details: The seminar speaker will focus on crucial topics such as mountain chains and subduction zones, highlighting their geological significance and implications.
Attendance Requirement: Remember to sign in at the seminar to receive extra credit.

Course Content: Recent classes have thoroughly covered the transformations in Earth's climate across geological time and the significant impact of anthropogenic (human-caused) factors on these changes.
Key Observations: Emphasis was placed on the fact that the current pace of climate change is unprecedented when compared to historical records over the last couple of centuries.

Sea Surface Temperatures: As the Earth warms, there is a corresponding increase in sea surface temperatures which affects marine ecosystems.
Changing pH Levels: Elevated CO2 levels in the atmosphere lead to its absorption by oceans, increasing acidity due to the formation of carbonic acid. This change has serious repercussions for organisms that have calcium carbonate shells, including clams and corals.
- Graphic Example: As observed, when acid reacts with chalk (calcium carbonate), it dissolves it, thereby showcasing similar destructive effects on marine organisms.

Biodiversity Effects: Shifts in pH levels may result in reduced biodiversity, with some species thriving while others decline, leading to dynamic changes within the ecosystem.

CO2 Dissolution: CO2 gas dissolving in ocean water becomes carbonic acid, which subsequently dissociates into bicarbonate and carbonate ions. Increased hydrogen ion concentration reduces the availability of carbonate ions crucial for the health of marine life.
Understanding pH: pH is a measure of hydrogen ion concentration, with small changes in pH indicating significant shifts in ocean acidity, affecting overall marine health.

Polar Ecosystem Effects: The retreat of sea ice has profound effects on polar ecosystems, including species like polar bears, and impacts global heat absorption patterns.
Feedback Loop: The loss of ice cover leads to decreased sunlight reflection back into space, thus contributing to further warming, which accelerates ice melt.
Permafrost Consequences: Melting permafrost can cause erosion, particularly damaging coastal structures, and its impact is felt acutely in both Arctic and Antarctic regions.
- Note on Sea Level: The melting ice sheets will significantly contribute to Rising sea levels globally.

Influencing Factors: Multiple processes affect sea level, including thermal expansion of water and the melting of ice sheets. It is crucial to note that the effects of climate change are not uniform; local geography plays a vital role in how these factors manifest.
Regional Predictions: For example, North Carolina is predicted to experience a sea level rise ranging from 4 to 8 inches over the next 30 years, particularly impacting regions like the Outer Banks more severely.

Greenhouse Gas Reduction: Focus on reducing greenhouse gas emissions is imperative. Local efforts, such as wind and solar energy projects in North Carolina, exemplify measures being taken.
Encouraging Sustainable Practices: Promoting biking, walking, and energy conservation forms a crucial part of the strategy.
- Carbon Sequestration Techniques: Various techniques, including biochar and other engineered solutions, are being explored as effective ways to sequester CO2, aiming to mitigate climate impact.
- Phytoplankton Growth Experimentation: Prior experiments indicated stimulating phytoplankton growth may aid in carbon sequestration, highlighting potential innovative solutions.

All topics and materials discussed will be relevant for Exam 4; however, they are not applicable for Exam 3, which is approaching very soon.