The biomass, ammonia and urea release, and oxygen consumption of zooplankton were measured in the coastal upwelling ecosystem off northwest Africa (∼21° 40′N, 17° to 17°45′W). Zooplankton 102 to 505 μm in size dominated the biomass nearshore, while zooplankton larger than 1000 μm were the major component offshore. After correcting for depth, regeneration of nitrogen by zooplankton was greater nearshore than offshore. The zooplankton supplied an average of 44% of the ammonia demand of the phytoplankton and an average of 25% of the total nitrogen required by the phytoplankton. This upwelling is unusual among eutrophic systems that have been studied in having such a large percentage of the nitrogen necessary for primary production supplied as ammonia released by zooplankton.
ASJC Scopus subject areas
- Environmental Science(all)
- Earth and Planetary Sciences(all)