Antarctic Polar Biome
475
Synopsis
Case 1—Polar irradiance-mediated production peak—In open water, the mixed layer is
relatively deep at all seasons with a brief shoaling in January–February, so the pycnocline
is illuminated only briefly in late austral summer. Darkness from May to July sets
productivity to zero, and the return of light is immediately followed by a sustained
linear increase to a midsummer maximum in December; subsequently, a sustained linear
decline is initiated. Chlorophyll biomass tracks the linear increase and decrease very
closely. Consumption does not balance production during the bloom and is inferred to
decline even further from balance when copepods descend to overwintering depths at
the end of summer (Fig. 12.6).
475
Synopsis
Case 1—Polar irradiance-mediated production peak—In open water, the mixed layer is
relatively deep at all seasons with a brief shoaling in January–February, so the pycnocline
is illuminated only briefly in late austral summer. Darkness from May to July sets
productivity to zero, and the return of light is immediately followed by a sustained
linear increase to a midsummer maximum in December; subsequently, a sustained linear
decline is initiated. Chlorophyll biomass tracks the linear increase and decrease very
closely. Consumption does not balance production during the bloom and is inferred to
decline even further from balance when copepods descend to overwintering depths at
the end of summer (Fig. 12.6).