Description

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Context:

An extreme marine heatwave linked to climate change devastated Alaska’s common murre (Uria aalge) population, wiping out nearly four million seabirds — about half of their global numbers — over three years.

**About Common Murre (Uria aalge)**

The common murre (Uria aalge) is a species of seabird found in the Northern Hemisphere, especially in the cold waters of the North Atlantic and North Pacific Oceans.

Characteristics: They have black and white plumage-like penguins, with a black head, back and wings, a white belly, and a long, slender, pointed black beak. They use their wings to "fly" underwater and can dive as deep as 100 meters (330 ft).

Food: Feeds on small fish such as grayling, herring, and sand lance. The heat wave caused fish populations and plankton to collapse, leading to food shortages.

Ocean	Geographical Features
North Atlantic Ocean	Continental Margins: Includes the continental shelves of Europe, North America, and Africa.
	Mid-Atlantic Ridge: A divergent tectonic plate boundary running down the center of the ocean.
	Gulf Stream: A major warm ocean current originating in the Gulf of Mexico and flowing towards Europe.
	Sargasso Sea: A region in the central North Atlantic characterized by floating seaweed and calm waters.
	Caribbean Sea and Gulf of Mexico: Part of the western basin of the Atlantic with coral reefs and rich biodiversity.
	Labrador Sea and Greenland Sea: Located in the northern reaches, characterized by cold water currents and sea ice.
North Pacific Ocean	Ring of Fire: A region of frequent earthquakes and volcanic activity surrounding the ocean basin.
	Kuroshio Current: A warm current flowing northward along Japan's coast, influencing regional climate and marine life.
	Bering Sea: A subarctic sea between Alaska and Russia, rich in marine biodiversity.
	Mariana Trench: The deepest part of the world's oceans, located in the western Pacific.
	Alaskan Gulf: A region in the northeast with fjords, glaciers, and diverse marine ecosystems.
	Great Barrier of Ice (Arctic Pacific Connection): Northern connection to the Arctic, significant for polar ice dynamics.

Source:

DOWN TO EARTH

PRACTICE QUESTION

Q.Consider the following statements regarding the Common Murre (Uria aalge) and its habitat:

The Common Murre is found primarily in the cold waters of the North Atlantic and North Pacific Oceans.
Common Murres dive as deep as 100 meters and use their wings to "fly" underwater.
The collapse of fish populations due to heat waves has not significantly affected the food sources of the Common Murre.
The North Atlantic Ocean includes features like the Mid-Atlantic Ridge, the Gulf Stream, and the Sargasso Sea.

Which of the above statements are correct?

(a) 1, 2, and 4 only

(b) 1, 3, and 4 only

(d) 1, 2, 3 and 4

Answer: a

Explanation:

Statement 1 is correct: The Common Murre is found in the cold waters of the North Atlantic and North Pacific Oceans.

Statement 2 is correct: The Common Murre can dive as deep as 100 meters and uses its wings to fly underwater.

Statement 3 is incorrect: The collapse of fish populations and plankton due to heat waves has led to food shortages for the Common Murre.

Statement 4 is correct: The North Atlantic Ocean includes features such as the Mid-Atlantic Ridge, the Gulf Stream and the Sargasso Sea.