organic detritus, nutrients, phytoplankton, and zooplankton

• write the missing information for A, B, C, and D:

  A → organic detritus

  B → zooplankton

  C → nutrients

  D → phytoplankton

  
• Phase I: spring phytoplankton bloom. The phytoplankton use the organic detritus in the ocean, as it provides a source of nitrogen and phosphorous. The amount of organic detritus decreases. NCP (net community production) is positive.
• Phase II: zooplankton bloom, trailing the phytoplankton bloom. Nutrients increase due to the phytoplankton bloom dying out. promoting food for the zooplankton.
• Phase III: as the zooplankton population eats through nutrients, their population begins to decline, parallel to the decline in nutrient concentrations. The NCP varies between positive and negative. It looks similar to the NCP found in tropical waters.
• Phase IV: as zooplankton populations die out, the amount of organic detritus in the water begins to increase. Note that the zooplankton population does not die out completely. Some species of zooplankton, such as Calanus store lipids that sustain them through the winter. NCP is negative.