Biodiversity Corals the Bright Colors and Variety of Exotic Life Lab Report
This lab has been modified from SERC Integrate EarthLabs: Corals: http://serc.carleton.edu/eslabs/corals/index.html
Why Study Corals: The bright colors, unique shapes, and variety of exotic life in and around coral reefs make them a natural source of wonder and delight. But coral reefs are much more than just ornamental showpieces along the ocean floor. Coral reefs are often compared to rainforests for the vast biodiversity they support. Despite covering only one five-hundredth of the ocean floor, more than one fourth of all marine fish species call coral reefs home. Reefs also support economies by attracting tourists, protect coastal communities from the potentially damaging effects of storms, and may hold the secrets to curing fatal diseases.
With 40% of the planet’s coral reefs now in critical condition or already degraded beyond recovery and our marine fisheries under severe threat, the very wellbeing of our planet depends on students like you gaining a working knowledge of coral ecosystems and acting in ways to preserve them.
Answer the following questions based on your lecture notes or online sources if necessary:
- What is coral?
- Why do coral reefs matter to humans? Provide at least 3 reasons.
- Where does coral thrive, survive, and die?
- What factors influence coral reef health?
- How will coral reefs respond to projected global warming?
Part 1: Coral Reefs, the Human View
Coral reefs are unique and beautiful ecosystems that serve as nursery, farm, and home to untold numbers of marine species. The incredible biodiversity supported by healthy coral reefs has earned them the nickname “rainforests of the sea.”
Short Coral Reef Video: https://youtu.be/hHCCih9cHxw
Coral reefs provide a wealth of benefits to humans. In certain parts of the world, coastal residents rely on coral reef fisheries for a significant portion of their protein intake. Tropical coral reefs and islands help make tourism the world’s largest industry by attracting millions of visitors each year. Coral reefs have also contributed to major pharmaceutical breakthroughs. For example, the drug AZT, used for the treatment of HIV infections, is based on chemicals found in Caribbean reef sponges. Today, the majority of cancer drug research is focused on tapping resources from marine organisms, many of which inhabit coral reefs.
- Explain the role of symbiosis in reef ecosystems
- Explain the differences between living corals in the ocean and the pieces of coral one might see washed up on a beach.
Watch the Netflix film “Chasing Coral”. This film should also be available on youtube.com
Full Film: https://www.youtube.com/watch?v=aGGBGcjdjXA
- According to the film, coral reefs have “perhaps the greatest concentration of symbiosis within one single habitat on the planet.” Describe at least two examples of symbiosis on a coral reef as depicted in the film Chasing Coral. Explain which organism(s) benefit or are harmed by these relationships.
- What human relationships with coral reefs were depicted in the film? Would you classify any of these relationships as symbiotic? Explain.
Part 2. A Closer Look at Coral: Corals live in the sea, but sometimes we find pieces of them on land. Perhaps you’ve stumbled across a fragment of coral on a beach or have seen a piece of coral jewelry. Although you should never remove coral from the ocean or buy precious coral jewelry, studying the skeletal remains of coral can help us learn about what they were like when they were still alive.
Look at these images of coral that has been washed up on the beach:
- After examining the photos above or others that are similar:
- Where do you think the coral sample came from? Is it a fossil or modern coral?
- Is the coral sample bleached white or colorful?
- How do the corals seen in these images differ from those seen in the Coral reef film? What makes them similar or different?
Coral reefs are teeming with life on every surface, in every crevice, and in the surrounding waters. Examine a living coral reef ecosystem by visiting the following web cams with live streaming video:
Explore the New England Aquarium Giant Ocean Webcam: http://www.neaq.org/giant-ocean-tank-web-cam/
- What reefs did you look at? What differences did you notice?
- Describe the biodiversity you observed on those reefs. (Were there only a few organisms or many different types?)
Part 3: Finding Coral’s Ideal Environment
Corals, like other living animals, require a particular range of environmental conditions to survive. During this lab, you will examine temperature, depth, and ocean chemistry data to discover coral reefs’ favored environments.
Ocean Temperature: When you think of coral reefs you probably envision a tropical location, sandy beaches, and brightly colored fish. This is not just because the travel industry has persuasive advertising. Corals reefs are only found in the regions of the ocean where the conditions are just right for zooxanthellae to photosynthesize and build up the limestone skeletons that form reef structures. Start your investigation of coral’s ideal living conditions by exploring the ocean temperatures at which coral reefs are found.
Examine the map below of coral reef locations around the world. Each red dot on the map represents a reef.
- Describe the global distribution of coral reefs. Are they evenly distributed throughout the world’s oceans or concentrated in a particular region?
- Describe where reefs are found in relation to land. Are they located primarily along coastlines, in the open ocean, or both? Are they evenly distributed among the world’s oceans?
- What do you think the observed distribution of coral reefs indicates about coral’s favored environment?
Examine the map below of global sea surface temperature (SST). Compare the SST map with the coral reef distribution map above. Click on the SST map to open a larger image in a new window to help make the scale more visible. Global sea surface temperature (NOAA link):
- What is the range of ocean temperatures in the swath of ocean in which corals are most commonly found?
- Do you think seasonal variations in ocean temperature affect coral reef health? Explain.
Ocean Depth: Temperature is just one measurable quantity that can be used to characterize coral reefs’ favored environment. Ocean depth is another important factor in determining why coral reefs are found in specific areas of the world. Continue your investigation by exploring ocean depth. Examine the combined bathymetry (ocean depth) and topography (land surface features) map below. Take a minute to familiarize yourself with the color-coded elevation (height) scale.
- Why are there negative values on the elevation scale? What does an elevation of zero mean?
- Do coral reefs seem to favor deeper or shallower waters? (Refer back to the previous maps) Based on what you know about the life processes of coral, explain why you think coral reefs thrive at these depths.