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Barnacles and Biofouling — Reading Comprehension

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This engaging, audio-integrated reading passage, 'Barnacles and Biofouling,' delves into the fascinating world of how tiny marine organisms, specifically barnacles, interact with and alter their environment. Aligned with NGSS standard LS2.A: Interdependent Relationships, the passage explains what biofouling is and its significant impact on human activities, particularly shipping. Students will learn about the life cycle of barnacles, how they attach to surfaces, and the challenges they create for marine vessels. Key terms like 'larvae,' 'sessile,' and 'biofouling' are defined, providing a strong foundation for understanding these ecological interactions. The passage also touches upon the broader implications of these relationships within aquatic ecosystems, making it a valuable resource for grade 6 science education.

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Barnacles attach to ships, rocks, and animals, causing biofouling and increased drag. — Barnacle life cycle and biofouling effects on ships, rocks, and marine animals.

Imagine a world where tiny creatures stick to everything, slowing down giant ships and making them use more fuel. This is the reality of barnacles and a process called biofouling. Barnacles are small, crustacean animals, related to crabs and lobsters, but they live a very different life. Instead of scuttling around, adult barnacles are sessile, meaning they stay fixed in one place for their entire lives.

How do these tiny creatures cause such big problems? It all starts when they are young. Barnacles begin their lives as free-swimming larvae. These microscopic larvae float around in the ocean, searching for a hard surface to attach to. They look for rocks, piers, or even the bottoms of ships. Once a suitable spot is found, the larva uses a special glue, one of the strongest natural glues known, to cement itself permanently to the surface.

After attaching, the larva undergoes a transformation, developing a hard, protective shell made of calcium carbonate. This shell shields the soft-bodied barnacle inside. Over time, many barnacles will attach to the same surface, creating a rough, bumpy layer. This accumulation of marine organisms on underwater surfaces is what we call biofouling. It's not just barnacles; algae, mussels, and other tiny creatures also contribute to this buildup.

Biofouling is a major headache for the shipping industry. When a ship's hull becomes covered in barnacles and other marine growth, it increases the ship's drag in the water. Drag is the force that resists movement. More drag means the ship has to work harder, using more fuel to maintain its speed. This leads to higher fuel costs and increased carbon emissions, which are harmful to the environment. To fight biofouling, ships are often painted with special anti-fouling paints that prevent marine organisms from attaching.

Beyond ships, barnacles also attach to whales, sea turtles, and even other marine organisms. While they generally don't harm these animals, they show just how widespread and persistent these tiny architects of the marine world can be. Their ability to find and cling to surfaces is a fascinating example of how organisms interact with and alter their environment.

Interesting Fact: Some species of barnacles can live for over 10 years, constantly filtering food from the water while cemented to their chosen spot.

What are barnacles related to?

FishCrabs and lobstersJellyfishSeaweed

What is the main material of a barnacle's protective shell?

ClayWoodCalcium carbonatePlastic

Why is biofouling a problem for ships?

Makes ships look dirtyIncreases drag and fuel useAttracts piratesMakes ships too heavy

How do barnacles initially attach to a surface?

They swim into placeThey use suction cupsThey secrete strong glueThey dig a hole

What does 'sessile' mean in the context of adult barnacles?

They can swim fastThey stay in one placeThey eat seaweedThey are very small

Which of these is NOT typically part of biofouling?

AlgaeMusselsBarnaclesSeabirds