1. Ocean Acidification
A conceptual illustration to show the potential effects of ocean acidification on various aspects of the oceanic food web. This cover image represents a timeline of the health of the oceans in reference to pH from pre-human times (upper left-Pleistocene) to future (upper right – 2100). The top line is time
source -

2. Simplified Carbon Cycle
Atmospheric carbon dioxide is one of the pools carbon resides in as it moves through the carbon cycle. This portion of the tutorial will help you understand the movement of carbon in and out of the atmospheric pool. This cartoon, created by the University Corporation for Atmospheric Research, shows all of the major movements of carbon dioxide in and out of the atmosphere

3. Keeling Curve
Keeling was the first to confirm the rise of atmospheric carbon dioxide by very precise measurements that produced a data set now known widely as the "Keeling Curve." Prior to his investigations, it was unknown whether the carbon dioxide released from the burning of fossil fuels and other industrial activities would accumulate in the atmosphere instead of being fully absorbed by the oceans and vegetated areas on land. He became the first to determine definitively the fraction of carbon dioxide from combustion that remains in the atmosphere. The Keeling record of the increase in atmospheric carbon dioxide measured at Mauna Loa, Hawaii, and at other "pristine air" locations, represents what many believe to be the most important time-series data set for the study of global change.

4. www.ssqq.com/travel/ hawaii200702.htm
This map demonstrates how far away this region is from all major land masses, making it an ideal spot for atmospheric measurements of CO2.

7. Coral Reefs
Coral Reefs are most diverse and productive communities on Earth.
They are referred to as the “Tropical Rainforest of the Ocean”
Found in warm, clear, shallow waters.
Provide zooxanthellae with a protected environment, steady supply of carbon dioxide, and nitrogen.

9. These images show what a healthy coral reef system (from the Coral Triangle – Indonesia) look like. Note: the abundance of various species in the lower right photo.

14. Coral Anatomy and Physiology

19. Asexual Coral Budding

20. Zooxanthellae
Zooxanthellae are dinoflagellate algae of the genus Symbiodinium, and live in coral tissue.
They provide nutrients such as sugars and oxygen that are essential for the production of calcium carbonate (coral reef skeleton).
Provide coral with beautiful coloration (without them corals are clear or white; phenomenon known as coral bleaching).
More than 50% of the corals’ nutrients are derived from photosynthetic products produced by zooxanthellae.

22. Coral Bleaching Unbleached coral Bleached coral CaCO3 → CaO + CO2
Coral bleaching is the whitening ofcorals, due to stress-induced expulsion or death of symbiotic, algae-like protozoa, or due to the loss of pigmentation within the protozoa.[1] The corals that form the structure of the great reef ecosystems of tropical seas depend upon a symbiotic relationship with unicellular flagellate protozoa, called zooxanthellae, that are photosynthetic and live within their tissues. Zooxanthellae give coral its coloration, with the specific color depending on the particular clade. Under stress, corals may expel their zooxanthellae, which leads to a lighter or completely white appearance, hence the term "bleached".[2]
Reference:^ a b c Rosenberg E, Ben Haim Y (2002). "Microbial Diseases of Corals and Global Warming". Environ. Microbiol. 4 (6): 318–26. doi: /j x. PMID 
Unbleached coral
Bleached coral
CaCO3 → CaO + CO2

23. Coral Bleaching
Coral Bleaching is a stress condition in coral reefs that involves the breakdown of zooxanthellae.

24. How is atmospheric CO2 responsible for ocean acidification?
When CO2 dissolves in seawater, carbonic acid is produced via the reaction:
This carbonic acid dissociates in the water, releasing hydrogen ions and bicarbonate:
One result of the release of hydrogen ions is that they combine with any carbonate ions in the water to form bicarbonate:
This is a slide meant to help teachers or curious students to understand the chemical reactions going on as CO2 enters the ocean and dissociated in water.

25. The increase in the hydrogen ion concentration causes an increase in acidity, since acidity is defined by the pH scale, where pH = -log [H+] (so as hydrogen increases, the pH decreases). This log scale means that for every unit decrease on the pH scale, the hydrogen ion concentration has increased 10-fold.
This removes carbonate ions from the water, making it more difficult for organisms to form the CaCO3 they need for their shells.

27. Factors Affecting Coral Bleaching
Temperature: Fluctuation of low and high sea temperature accompanying intense upwelling.
Winter: Change from -3 C to -5 C for 5 to 10 days
Summer: Change from 1 to 2 C for 5 C to 10 days (more common)
Salinity: Zooxanthellae are sensitive to low salinity due to precipitation and runoff. Therefore, they tend to live near shallow, clear waters (no deeper than 100m) with plenty of sunlight.
UV radiation: High levels of photosynthesis leads to high amounts of nitric oxide production by zooxanthellae.

28. More Factors
Natural Phenomenon: Violent storms, flooding, ENSO (El Niño Southern Oscillation), predatory outbreaks, and tsunami are devastating to coral reefs.
Anthropogenic Phenomenon: Overexploitation, overfishing, increased sedimentation, and nutrient overloading.
Map of coral bleaching over the past 15 years, and major coral bleaching events (yellow dots).

29. Research Study done by Rosenberg and Ben-Haim (2002):
The actual agent leading to bleaching of hard coral, Oculina patagonia, is caused by an infectious bacteria called Vibrio shiloi.
Purpose of the experiment was to test the growth of bacteria within two different sea water temperatures in an aquaria environment.
Results showed bacteria produced an extracellular toxin that blocked photosynthesis within the zooxanthellae
The toxin would bind to the algal membranes and prevent the ammonia and lead to the destruction of pH gradient across the thylakoid membrane.

30. Research 2 Study done by Rosenberg and Falkovitz, 2004:
Similar study done with Oculina patagonica, hard coral and Vibrio shiloi, bacteria.
Results showed the inability of the bacteria to bleach the coral at cold temperatures due to increased resistance of the coral and in hot temperatures the bacteria was able to produce.
Laboratory experiment demonstrated high temperature would cause bleaching by the bacteria.
Temperature at 29 C there was rapid and complete bleaching
At 25 C bleaching was slower and incomplete
Below 20 C there was no bleaching, even with large amounts of the bacteria exposed.