Barrons AP Environmental Science

(Marvins-Underground-K-12) #1

  1. (B) Stratospheric ozone depletion describes two distinct but related
    phenomena observed since the late 1970s: a steady decline of about 4% per
    decade in the total volume of ozone in Earth’s stratosphere (the ozone layer),
    and a much larger springtime decrease in stratospheric ozone over Earth’s
    polar regions (“ozone hole”). Effects of decreases in stratospheric ozone that
    result in increased UV radiation reaching Earth include: (1) reduction in the
    growth and population of phytoplankton; (2) damage to DNA of
    phytoplankton; (3) reduced numbers of phytoplankton, so less krill is
    available for higher-order consumers; (4) reduction in leaf growth and
    surface area; and (5) decrease in photosynthetic activity.

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