1. Aquariums – Miniature Oceans (part 2)

2. Photosynthesis, Respiration, and pH
Goals
Challenge students to link CO2 concentrations and pH values
Challenge students to think of photosynthesis as a sink for CO2 and buffer against acidification
Expose students to simple experiments that connect respiration and CO2 to increasing acid levels

3. Ocean Acidification
Increasing CO2 leads to more carbonic acid (H2CO3) and pH of the ocean decreases
Impacts organisms with calcium carbonate components
Corals, Snails, some phytoplankton, etc…
This is a problem as trends in CO2 production are increasing
How could photosynthesis affect pH in a closed system like an aquarium?
If photosynthesis uses CO2, CO2 should decrease and pH should increase (become more basic)

4. Activity 1 – Bromothymol Blue Assay
Add 50mL water to a clear bottle
Add ~20 drops of BTB or enough until solution becomes blue
Using a straw, gently blow into the solution for 30 seconds. The solution will become yellow, indicating that the solution has become a weak acid.
Do not inhale! Or drink the BTB solution

5. Activity 1 – Questions
How does our breath turn water into a weak acid?
Is respiration done only by animals?
What other human activities produce CO2? Why are they so impactful?
No, microbes and plants break down organic matter with oxygen producing CO2 (i.e. respiration)
Burning fossil fuels and deforestation. These disrupt the balance between photosynthesis and respiration, leading to excess CO2

6. Activity 2 – Checking pH between light and dark aquariums
Check pH using test strips between the light and dark aquariums
Check pH using a pH probe
Questions
Is there a difference between the two tanks? Why?
Is this difference large enough to make an impact on organisms or food webs?

7. Coral Dissections Goals
Introduce students to microbial symbioses and corals
Provide basic introduction on microscope use
Encourage students to think about the importance of organism interactions and their roles in ecosystem health (e.g., why does bleaching occur?)

8. Coral – The great host Micro Zooxanthellae photosynthesis Bacteria
Stained bacteria
Photosynthetic zooxanthellae
Micro
Zooxanthellae
photosynthesis
Bacteria
Antibacterials
Gut microbiome
Macro
Invertebrates
Fish
Anemone fish will host them
As will shrimp and crabs

9. Coral Polyp Anatomy

10. The coral we’ll be working with
Discosoma
Palythoa
Large polyp
No tentacles
Soft coral (does not have a calcium skeleton)
Common in the aquarium trade
Highly diverse
Small polyp
Short thin tentacles
Soft coral (does not have a calcium skeleton)
Common in the aquarium trade
Highly diverse

11. Activity – Coral Dissection
Select 1 polyp of each specimen (Actinodiscus and Palythoa)
Examine structure of each intact coral under the dissection scope
Using a scalpel, carefully make an incision around the edge of the coral
Identify zooxanthellae symbionts

12. Coral Dissection – follow up questions
Are there any differences between zooxanthellae symbionts in the two species?
Why is coral bleaching an indicator of reef health?
Why is the symbiosis between the zooxanthellae and coral important?

13. Bioluminescence & Coral Fluorescence
Goals
Introduce students to the topic of bioluminescence and fluorescence
Challenge students to critically think about biologically produced light in the oceans and its potential uses
Link microbial symbioses and bioluminescence to living strategies

14. Bioluminescence What are some of the purposes of bioluminescence?
Videos
What are some of the purposes of bioluminescence?
Are bacteria the only organisms that can bioluminesce?
Do you think it would be more/less beneficial to bioluminesce yourself, or to host bioluminscent bacteria in a symbiotic relationship? Cost/benefits?

15. Fluorescence Corals fluoresce under certain light wavelengths
This a relatively common phenomenon, although the benefit of coral fluorescence remains unclear
What are some potential reasons why corals fluoresce?

16. Activity
View a culture of Vibrio harveyi in the dark and discuss bioluminescence
View coral under 460nm light to view fluorescence discuss fluorescence

17. Bioluminescence & Coral Fluorescence – Follow up questions
Does bioluminescence begin immediately after the lights go out? Why or why not? How does bioluminescence differ between V. harveyi in liquid culture, versus on agar plates?
Is all bioluminescence caused by symbionts?
What are the possible benefits to producing your own light in the deep ocean?
Compare benefits of deep bioluminescence to surface planktonic bioluminescence
How can predators and prey utilize bioluminescence?
Why would some corals reflect certain wavelengths of light to emit their own light?
What could be some drawbacks?