What Exactly Is Coral?

ABC Science

5 Oct 201706:57

Summary

TLDRThe 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.

Outlines

00:00

🌊 What is Coral? An Introduction to Coral Polyps

This paragraph explains what coral is, describing it as a colony of coral polyps, small animal organisms that build a skeleton of calcium carbonate, which forms reefs. The polyps are genetically identical and are connected in colonies. They use their tentacles lined with stinging cells to catch prey. However, in the nutrient-poor waters where they live, they rely heavily on a symbiotic relationship with algae that live inside their cells to produce up to 90% of their food through photosynthesis.

05:01

🔥 Coral Bleaching: The Breakdown of a Symbiotic Relationship

This paragraph delves into the process of coral bleaching, which occurs when ocean temperatures rise, disrupting the relationship between coral and the algae living inside them. As a response to stress, the coral expels the algae, which leads to bleaching, a phenomenon where the coral loses its color and vitality. Without this symbiosis, coral reefs—essential to marine life—cannot survive, putting entire ecosystems at risk. The paragraph describes how scientists are studying this process to understand and combat coral bleaching.

Mindmap

Keywords

💡Coral

Coral is a marine organism that, from a distance, appears like mossy rock but up close is seen as tiny flowers, which are actually individual animals called coral polyps. Coral plays a central role in reef ecosystems by forming calcium carbonate skeletons, which build the reef structure. In the video, corals are described as foundation species essential for the survival of reef ecosystems.

💡Polyp

A coral polyp is a tiny, individual animal that makes up coral colonies. Each polyp has a round body topped with a mouth and surrounded by tentacles. These polyps share a genetically identical connection with others, contributing to the growth of coral reefs. The video explains that polyps are vital for coral's colonial structure, helping build the reef by budding off new polyps.

💡Calcium carbonate

Calcium carbonate is the material that reef-building corals use to form their skeletons, which essentially becomes the rocky foundation of coral reefs. This rock-like structure provides a habitat for countless marine species. In the video, calcium carbonate is highlighted as the substance that corals lay down to form reefs, emphasizing their role as 'living veneer' on these structures.

💡Symbiosis

Symbiosis refers to the mutually beneficial relationship between coral and algae (symbionts), where the algae live inside the coral's cells and photosynthesize, providing up to 90% of the coral's food. The video emphasizes this relationship as crucial for coral survival and reef-building, illustrating how both organisms depend on each other to thrive.

💡Algae

Algae, or symbionts, are tiny plant cells that live inside coral polyps and produce food through photosynthesis. They provide the coral with essential nutrients, while the coral gives the algae a protected environment. In the video, algae are described as playing a critical role in coral nutrition, supplying up to 90% of the coral's energy, which allows the reef to flourish.

💡Bleaching

Coral bleaching occurs when corals expel their symbiotic algae due to stress, typically caused by rising ocean temperatures. Without the algae, corals lose their color and become more vulnerable to death. In the video, bleaching is presented as a dire consequence of warming oceans, threatening the survival of coral reefs and the ecosystems they support.

💡Foundation species

A foundation species is one that creates and defines an ecosystem, providing habitat and resources for other organisms. Coral is described as a foundation species in the video because it builds the reef structure, which supports numerous marine species. Without coral, the entire reef ecosystem would collapse.

💡Keystone species

Keystone species are organisms that have a disproportionately large impact on their environment relative to their abundance. The video refers to the symbiotic algae as a keystone species because their relationship with corals is vital for reef survival; without the algae, corals cannot survive, and the reef ecosystem would deteriorate.

💡Coral bleaching microscope

The coral bleaching microscope is a specialized tool that allows scientists to simulate future ocean conditions, such as higher temperatures, and observe how living coral responds to stress and bleaching. In the video, this tool is highlighted as a key instrument in Ruth Gates’ research to understand and visualize the bleaching process.

💡Climate change

Climate change refers to the long-term alteration of temperature and typical weather patterns, often caused by human activities. In the video, rising ocean temperatures due to climate change are a central issue, as they cause coral bleaching by disrupting the delicate symbiotic relationship between corals and algae, threatening the survival of reefs worldwide.

Highlights

Coral from a distance appears like mossy rock, but up close, each flower-like structure is actually an animal known as a coral polyp.

A coral polyp has a round body, a mouth, and tentacles; inside it has a simple gut that helps digest food.

Reef-building corals create a calcium carbonate skeleton, essentially forming rock-like structures.

Corals are colonial animals, genetically identical, connected to each other to form a living veneer.

Corals are hunters, using millions of stinging cells on their tentacles to capture prey, although food is scarce in warm, clear waters.

Coral survival relies on symbiosis with tiny algae (symbionts) living inside their cells. These algae photosynthesize, providing up to 90% of the coral's food.

The coral-algae relationship is critical for reef building, with the algae producing sugars for the coral through photosynthesis.

Due to warming oceans, coral reefs are rapidly disappearing as coral bleaching becomes more frequent.

Scientists are working on ways to help reefs survive by understanding the connection between corals and their symbiotic algae.

At the Hawaiian Institute of Marine Biology, researchers are studying coral bleaching and the coral-algae relationship.

Dr. Ruth Gates has been studying coral reefs for over 25 years, focusing on how coral bleaching occurs and its effects.

Researchers use a specialized microscope to simulate future ocean conditions, enabling them to observe coral bleaching as it happens.

Coral reefs are foundation species, essential for the survival of many marine ecosystems.

When ocean temperatures rise, corals expel their algae, leading to bleaching and a breakdown in their symbiotic relationship.

Some corals expel their algae in clouds, while others do so in tiny clumps over days, causing the coral to turn pale and lose its vibrant color.