What Exactly Is Coral?

Summary

The video explores the fascinating world of coral, which from a distance appears as mossy rock, but up close reveals tiny animals called coral polyps. These polyps build reefs using calcium carbonate skeletons and have a symbiotic relationship with algae living inside them. The algae provide up to 90% of the coral's food through photosynthesis, but warming oceans are disrupting this vital connection, leading to coral bleaching. Scientists in Hawaii are studying coral bleaching and its effects, aiming to use this knowledge to help reefs survive in a changing climate.

Takeaways

• 🌿 Coral, from a distance, looks like mossy rock or bone, but up close, it appears to be covered in tiny animals called coral polyps.
• 🐙 Each coral polyp has a round body with a mouth surrounded by tentacles, and a simple gut to digest food.
• 🏗️ Reef-building corals create a skeleton of calcium carbonate, essentially forming rock-like structures.
• 🌍 Corals are colonial organisms, where new polyps bud off, creating a living, genetically identical colony.
• 🎯 Corals are hunters, using tentacles lined with stinging cells to capture prey, though there’s little to catch in clear warm waters.
• 🌞 Corals have a symbiotic relationship with tiny algae living inside their cells, which photosynthesize and provide up to 90% of the coral's food.
• ⚠️ Rising ocean temperatures disrupt the symbiosis between corals and algae, leading to coral bleaching.
• 🔬 Scientists are studying coral bleaching, simulating future ocean conditions to understand how warming oceans affect coral-algae relationships.
• 🏛️ Corals are a foundation species, building reef structures that support a wide variety of marine life.
• 👻 Coral bleaching leaves corals pale and ghost-like, as they lose their vibrant algae but still retain their structural skeleton.

Q & A

What does coral look like from a distance and up close?

From a distance, coral looks like mossy rock or bone. Up close, it appears to be covered in tiny flowers, which are actually coral polyps—small animals.

What is a coral polyp and how is it structured?

A coral polyp is a small animal with a round body, a mouth on top surrounded by a ring of tentacles. Inside, it has a simple gut lined with tissue that helps digest food.

How do reef-building corals create their skeleton?

Reef-building corals lay down a skeleton made of calcium carbonate, essentially forming rock. These corals are colonial, with new polyps budding off and connecting to one another, forming a living veneer.

How do coral polyps feed in nutrient-poor waters?

Corals have a symbiotic relationship with algae called symbionts. The algae photosynthesize, producing sugars that provide up to 90% of the coral's food. In return, the algae get a protected home inside the coral's cells.

What happens to corals when ocean temperatures rise too high?

When ocean temperatures rise, corals experience 'bleaching,' a process where they expel the algae living in their cells. Without these algae, corals lose their primary food source and become pale as the animal's clear tissues reveal the white skeleton beneath.

What is the role of the symbiotic algae in coral survival?

The algae living inside coral cells are vital for the coral's survival. They photosynthesize, providing up to 90% of the coral's food. Without them, the coral would struggle to survive, and without coral, the reef ecosystem would collapse.

How does coral bleaching affect the coral's appearance?

During bleaching, the coral loses its vibrant color as the algae are expelled. The coral's clear tissue reveals its white calcium carbonate skeleton, giving it a ghost-like appearance.

What are scientists studying at the Hawaiian Institute of Marine Biology?

Scientists, including Dr. Ruth Gates, are studying the mechanism of coral bleaching and how to help corals adapt to rising ocean temperatures. They simulate future ocean conditions to observe how living corals respond to environmental stress.

Why are corals considered foundation species?

Corals are considered foundation species because they build the reef structures that support a vast array of other marine life. Without coral, the reef ecosystem would collapse.

What is the significance of the symbiosis between corals and algae?

The symbiosis between corals and algae is crucial because the coral relies on the algae for most of its food, while the algae receive shelter. This relationship is essential for the health of coral reefs and the biodiversity they support.