Earthgauge Kids Corner

All Eyes on Estuaries

There are more than 100 estuaries along the coasts of the United States—how many have you been to?

Great Bay, New Hampshire & Maine

Great Bay NH USFWS

Sometimes referred to as New Hampshire’s “hidden coast,” Great Bay does not open directly into the ocean or the Gulf of Maine—instead, saltwater has to travel 15 miles inland through the Piscataqua River before it reaches the bay. This estuary hosts the largest wintering population of bald eagles in all of New England. Learn more.

Kachemak Bay, Alaska

kachemak bay usfws

Kachemak is a fjord-type estuary, which refers to the way the bed of the estuary was carved out of the earth by the movement of glaciers many thousands of years ago, as well as to the unique pattern of water circulation found in the estuary. During Alaska’s six-month winter, the fresh water that had been pouring off of the land freezes, and the bay becomes almost completely marine. Learn more.

Elkhorn Slough, California

Elkhorn Slough NOAA

The slough (pronounced “slew”) is a small, shallow estuary that feeds out into Monterey Bay. Containing one of the few remaining saltwater wetlands on the Pacific Flyway (a general flight path for migratory birds), this estuary is a vital resting and feeding ground for migrant and year-round birds. During the dry seasons of summer and fall, the water in this estuary can become hypersaline, or saltier than ocean water.  Learn more.

Images courtesy of USFWS.

did you know

Learn fun facts about the importance of estuaries!

  • Estuaries are important habitats for plants and animals alike, serving as some of the most ecologically productive ecosystems on Earth. More than 75 percent of the commercial fish catch (fish caught to be used in grocery stores, restaurants, pet food, scientific research, bait, medicine, etc.) lives in estuarine habitat for a period of time.
  •  Estuaries aren’t only prime habitat for plants and animals, but also for humans! These areas are currently home to 22 of the largest 32 cities in the world, and they have been choice real estate for human communities since at least 3800 BCE, when the city of Ur sat near where the Euphrates River met the Persian Gulf.
  • Estuaries can be difficult places to live for plants and animals due to their changing salinity levels. Depending on the time of year, time of day and local weather patterns, the water in a particular spot in an estuary can be as salty as ocean water or as fresh as a river, making it difficult for wildlife that prefers or requires one type of water over the other. However, some species have special adaptations that allow them to adjust with the changing salinity—those that can tolerate such a range are referred to as “euryhaline,” a group which includes blue crabs, oysters and cordgrass. Learn more about these adaptations here.





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