Test Prep 2/4/25

Overview of Data Types

• Two main types of data presented:

  • Temperature data (covering 150 years and 1000 years).

  • Ice data (related to the same timeframes).

• Addition of other graphs on pH and CO2 levels.

Key Relationship

• Temperature rise leads to ice melting, causing CO2 to dissolve in water and subsequently lowers pH.

• This indicates a critical connection between temperature, ice, CO2, and ocean acidity.

pH and Acidity

• Common household acids:

  • Vinegar (Acetic acid)

  • Citrus Juices (Citric and Ascorbic acid)

  • Others include coffee, battery acid, etc.

• Common alkaline substances:

  • Seawater (Alkaline)

  • Ammonia and Bleach

  • Sodium hydroxide (found in many soaps).

Understanding pH

• Water is neutral with a pH of 7.

• Hydroxide Ion (OH-): Oxygen and hydrogen with a negative charge.

• Hydrogen Ion (H+): Simple hydrogen atom with a positive charge.

Acidity Scale

• If [OH-] > [H+]:

  • Water becomes alkaline (pH > 7). more baseis present, leading to a decrease in acidity and an increase in the pH level.

• If [H+] > [OH-]:

  • Water becomes acidic (pH < 7).

• Distilled water (pure) has a pH of 7 with no significant hydrogen or hydroxide ions.

• pH changes are not linear, but rather exponential.

Impact of CO2 on Ocean pH

• When CO2 is absorbed in ocean water, it forms carbonic acid, contributing to ocean acidification.

• Increased CO2 levels lower pH, leading to more H+ ions in the water.

• The reaction between CO2 and water diminishes the availability of carbonate ions, critical for organisms' shell formation (such as pteropods).

Effects on Marine Life

• Pteropods (sea butterflies), important in the marine food chain, experience shell deformation in more acidic waters.

• Food web disruption can occur as pteropods are prey for larger marine animals like whales.

• Phytoplankton also affected, further threatening marine ecosystems.

Ocean Chemistry Reactions

1. CO2 + H2O → Carbonic acid (H2CO3)

2. H2CO3 dissociates to H+ + HCO3-

3. HCO3- can further dissociate into H+ + CO3^2- (carbonate)

• This reaction decreases carbonate levels necessary for calcification in marine organisms (formation of shells).

Graph Interpretation

• Graphs presented include CO2 concentration and pH levels over time, indicating inverse relationships: as CO2 increases, pH decreases.

• With seasons affecting data (highest CO2 in summer), understanding peak/troughs in data is crucial.

Temperature and Ice Coverage

• Seasonal changes impact ice levels, with peaks in March/April and lowest in September.

• Distinction between types of graphs: bar vs line graphs presents data differently but essentially conveys the same information.

Conclusion

• The interaction of temperature rise, CO2 increase in oceans, and their effects on pH and marine life is fundamental to understanding climate change impacts.