Coral Reef – Virtual Field Trip Notes

Definition: Coral reefs are complex, beautiful, and essential ecosystems, often referred to as the "rainforests of the sea."
Significance:
- Biodiversity: These structures are home to a large variety of marine life.
- Timeframe: It takes thousands of years for corals to build these ecosystems.
Current Crisis:
- Destruction: Over the past 70 years, more than 50% of coral reefs have died, with ongoing fatalities.
- Call to Action: Understanding and preserving coral reefs is crucial.

Animals that make up a coral reef: The animals are referred to as coral polyps.
Size range of a polyp: Polyp sizes can range from a few millimeters to several centimeters.
Limestone skeleton of a polyp: The skeleton is known as the coral exoskeleton.
Formation of a coral colony: A colony of corals is formed when multiple polyps genetically identical to each other grow and connect through a shared skeleton.
Length of coral reefs: True or False: True; coral reefs can extend for hundreds of miles.
Largest coral reef: The largest coral reef in the world is the Great Barrier Reef.
Coverage of the ocean floor: Coral reefs cover about 0.1% of the ocean floor.
Home to marine creatures: Coral reefs are home to approximately 25% of all marine creatures.
Young fish benefits: Reefs provide shelter and breeding grounds for young fish, increasing their chances of survival.
Appearance without zooxanthellae: Without zooxanthellae algae, corals would appear pale or white due to lack of pigmentation.
Benefits of zooxanthellae: Besides providing color, zooxanthellae supply corals with essential nutrients through photosynthesis.
Climate change effects on corals: Climate change leads to increased water temperatures and ocean acidification, which negatively impact coral health and growth.

Age of oldest corals: The oldest corals date back around 500 million years.
Species diversity in the Great Barrier Reef:
- Coral: Approximately 400 species.
- Fish: Over 1,500 species.
- Mollusks: About 4,000 species.
- Turtles: Several species of marine turtles inhabit the area.
Conditions treated by coral extracts: Extracts from coral have been used to treat conditions like cancer, arthritis, cardiovascular diseases, and infections.
Global economic value: Coral reefs have an estimated global value of £5.7 trillion annually (approximately $7 trillion USD).
Protection from natural disasters: Coral reefs act as natural barriers, absorbing wave energy and protecting coastlines from tsunamis and hurricanes.

Ecological relationships:
- Symbiotic relationship: Example - Corals and zooxanthellae algae have a mutually beneficial relationship: corals provide a safe habitat for algae, while algae provide nutrients to corals.
- Predator-prey relationship: For instance, crown-of-thorns starfish preying on coral can disrupt the reef’s health.
- Competition: Different coral species often compete for space and light on the reef, impacting their growth and survival.

How coral polyps eat: Coral polyps capture plankton and small fish using their stinging tentacles, which they then bring to their mouths.
Energy source: True or False: False; most energy comes from zooxanthellae, not solely from prey.
Habitat of zooxanthellae: Zooxanthellae live within the tissues of coral polyps.
Food abundance from zooxanthellae: Zooxanthellae photosynthesize, producing glucose that provides energy for the corals.
Benefits to zooxanthellae: They receive shelter and carbon dioxide from the coral, facilitating their photosynthetic processes.

Causes of coral bleaching: Coral bleaching is caused primarily by increased water temperature and ocean acidification.
Definition of coral bleaching: Coral bleaching occurs when corals expel their zooxanthellae algae, leading to a loss of color and vital nutrients.
Impact of global warming: Global warming raises water temperatures, causing stress to corals which leads to bleaching.
Recovery conditions: For algae to recolonize, water temperatures must stabilize, and environmental conditions must improve.

Coral color: Most corals are a brownish-green color due to the presence of zooxanthellae.
Causes of bleaching: Four main factors can cause bleaching:
- Increased sea surface temperatures
- Ocean acidification
- Pollution
- Overexposure to sunlight
Mass bleaching factor: The primary driver of mass coral bleaching is environmental stress, specifically rising sea temperatures.
Frequency of events: True or False: True; there is an increase in the frequency of mass bleaching events.

Active bleaching explanation: The coral is expelling zooxanthellae due to stress from increased temperatures and pollutants, leading to its pale appearance and nutrient shortage.

Mass bleaching years: Starting in 1998, significant mass bleaching events occurred in 2002, 2016, and 2017.
Reef Recovery: Some coral reefs did not recover effectively from the mass bleaching events, as highlighted in post-event surveys.
Back-to-back events: The 2016 and 2017 events were closely linked due to prolonged high sea temperatures.
2020 bleaching impact: During the 2020 event, over 50% of surveyed reefs reported moderate or severe bleaching.

Living inland: True or False: False; even if you live inland, you can contribute by advocating for policies that protect marine ecosystems.
Vacation impact: When snorkeling, avoid stepping on corals and never touch or collect marine life.
Everyday actions: Three actions to help save coral reefs include:
- Reducing plastic use to decrease ocean pollution.
- Conserving water to lessen runoff and pollution.
- Supporting sustainable seafood choices to reduce overfishing and habitat destruction.