Marine biologyLesson 2 of 2 in the course Marine ecosystems

Estuaries: Formation, Circulation, Ecology, and Human Impacts

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

This lesson introduces estuaries as transitional coastal ecosystems and explains how they form and how their landforms are classified.

An estuary is a coastal body of water where freshwater from rivers or streams mixes with saltwater from the sea. In a widely used definition, it is semi-enclosed, remains connected to the open sea, and contains seawater measurably diluted by freshwater from land drainage. Broader definitions also include places where freshwater inflow is seasonal, tidal influence is weak, or a sea connection closes temporarily.

All flashcards

What is an estuary?
A coastal body of water connected to the sea where freshwater mixes with seawater.
What is an ecotone?
A transition zone where different ecosystems overlap.
What is a salt-wedge estuary?
An estuary where less-dense freshwater flows seaward above denser seawater moving landward.
How do osmoconformers respond to surrounding salinity?
They allow their internal salt concentration to change with the surrounding water.
What is bioaccumulation?
The accumulation of contaminants in an organism's tissues.

Quiz questions

  1. Which circulation pattern can result when tidal mixing is strong relative to river flow?Answer: A well-mixed pattern with little vertical salinity difference.
  2. How can decomposition following excessive algal growth affect estuarine water?Answer: It can consume dissolved oxygen and produce hypoxic conditions.
  3. What is one water-filtering service provided by estuarine wetlands?Answer: They trap or process some sediment, nutrients, and pollutants.
  4. What does overfishing an estuarine species that filters suspended material risk doing?Answer: Reducing a natural filtering function in local waters.
  5. Why does effective estuary protection often require watershed-wide action?Answer: Rivers can carry pollutants and other impacts from far upstream.

Based on the Wikipedia article Estuary, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

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