Aquariums Miniature Oceans part 2 Photosynthesis Respiration and

Aquariums – Miniature Oceans (part 2)

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

Ocean Acidification • Increasing CO 2 leads to more carbonic acid (H 2 CO 3) and p. H of the ocean decreases • Impacts organisms with calcium carbonate components – Corals, Snails, some phytoplankton, etc… • This is a problem as trends in CO 2 production are increasing How could photosynthesis affect p. H in a closed system like an aquarium? If photosynthesis uses CO 2, CO 2 should decrease and p. H should increase (become more basic)

Activity 1 – Bromothymol Blue Assay • Add 50 m. L 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

Activity 1 – Questions • How does our breath turn water into a weak acid? No, microbes and plants break • Is respiration done only by down organic matter with oxygen producing CO 2 (i. e. animals? respiration) • What other human activities produce CO 2? Why are they so impactful? Burning fossil fuels and deforestation. These disrupt the balance between photosynthesis and respiration, leading to excess CO 2

Activity 2 – Checking p. H between light and dark aquariums • Check p. H using test strips between the light and dark aquariums • Check p. H using a p. H 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?

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? )

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

Coral Polyp Anatomy

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

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

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?

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

Bioluminescence Videos https: //www. youtube. com/watch? v=9 HXXQBz 6 Vv 0 https: //www. youtube. com/watch? v=o. Kj. FVBVGad 0 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?

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? Fluorescence

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

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?