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What are the primary ways dissolved oxygen is lost from an aquatic ecosystem?

  1. Through respiration by aquatic organisms.
  2. Through the air-water interface.
  3. Through photosynthesis by aquatic plants.
  4. Through absorption by the substrate at the bottom of the water body.

    Ai, ii

    BAll

    Cii only

    Dii, iii

    Answer:

    A. i, ii

    Read Explanation:

    • Oxygen in the terrestrial ecosystems occurs in the atmosphere along with other gases in a certain fixed concentration.

    • In aquatic ecosystems it is dissolved in water, where its concentration varies constantly depending on factors that influence the input and output of oxygen in water.

    • Dissolved oxygen escapes the water body through air-water interface and through respiration of organisms (fish, decomposers, zooplanktons, etc).

    • When the dissolved oxygen level falls below 3-5 ppm, many aquatic organisms will die.

    Related Questions:

    What are static water ecosystems called?

    Which of the following are direct consequences of the extraction of wood from forest areas?

    1. The opening of new roads through forest areas.
    2. Increased noise pollution within the forest.
    3. Reduced pressure on plant and animal resources.
    4. Improved habitat connectivity for wildlife.

      Which of the following statements accurately describes natural vegetation?

      1. It is a plant community that grows naturally without human aid
      2. It requires significant human aid for its development into a unique forest type.
      3. If left undisturbed, it can develop into a unique forest type.

        What factors contributed to the emergence and growth of cities in desert regions, according to the provided text?

        1. Ancient cities developed in desert regions primarily due to their proximity to major river systems, allowing for extensive agriculture.
        2. Key ancient cities served as central points for administration, education, religion, commerce, and transportation.
        3. Modern urban development in areas like West Asia and North Africa has been significantly driven by oil wealth.
        4. The appeal of entertainment, such as casinos and golf courses, was a primary factor in the establishment of ancient desert cities.

          Regarding the chemical alteration of dead organic matter, identify the correct statement(s):

          1. Chemical alteration is primarily a consequence of the activity of bacteria and fungi.
          2. Chemical alteration refers to the spontaneous breakdown of organic matter without any microbial mediation.
          3. Only spontaneous chemical reactions contribute to the chemical alteration of detritus.