powerpoint lecture 13

• Ocean Effects of Climate Change

  • Warmer temps
  • Species range shifts and extinctions
  • Facilitation of invasive species
  • Increased hypoxia
  • Altered circulation
  • Sea level rise
  • Ocean acidification
• Ocean Acidification

  1. The ocean absorbs CO2 from the atmosphere

  2. Interacts with water to create carbonic acid

  3. Carbonic acid breaks down easily, releasing H+

  4. CO2(aq) + H2O -> H2CO3 -> HCO3- + H+
• First major studies on Ocean Acidification published

  2008
• pH

  A measure of how acidic or basic a substance is, goes from 0 to 14, lower numbers are acidic, higher numbers are basic, 7 is perfectly neutral
• Acidity and H+


  pH is actually measuring the concentration of hydrogen ion (H+), the more H+, the lower the pH (more acidic), acids release H+ into a solution like the ocean
• Ocean Acidification Process

  Carbon dioxide is absorbed by the ocean, interacts with water to create carbonic acid, carbonic acid breaks down easily, releasing H+, resulting in decreased ocean pH
• Lower pH = more acidic, so more carbon dioxide entering the oceans means more acidic oceans
• Numbers seem small, pH is on a log scale: 0.1 decrease in pH means it’s 30% more acidic
• If animals have a shell in the ocean, it's made of calcium carbonate. The more acidic the ocean gets, the less calcium carbonate there is, making it harder for animals to make shells
• Forces animals to spend their energy maintaining a shell rather than growing and reproducing
• Fish and shellfish grow slowly in acidified conditions, smaller animals are more vulnerable
• Larval fish don’t respond to predator cues, larval fish can’t identify good habitats, making them more vulnerable to die
• Ocean Acidification makes other stressors like warming, hypoxia, and pollution more deadly, fish exposed to acidification and hypoxia died sooner than fish only exposed to hypoxia
• Effects of Ocean Acidification

  • Acidification makes it harder to build a shell
  • Animals take longer to develop and mature
  • Confuses fish
  • Makes organisms less resilient to other stressors
• Kroeker et al. 2013: 'Effects of Ocean Acidification'