MEPS 160:57-62 (1997)  -  doi:10.3354/meps160057

The vertical nitrogen flux caused by zooplankton diel vertical migration

Graeme C. Hays1,*, Roger P. Harris2, Robert N. Head2

1School of Biological Sciences, University of Wales Swansea, Singleton Park, Swansea SA2 8PP, United Kingdom
2Plymouth Marine Laboratory, Prospect Place, Plymouth PL1 3DH, United Kingdom

Three species of vertically migrating copepods (Pleuromamma pisekii, P. gracilis and P. abdominalis) were collected at dawn and at dusk from the upper 200 m in the North Atlantic (36.5°N, 19.2°W) between 11 and 18 July 1996. For all 3 species, the nitrogen content of individuals caught at dawn was significantly greater than for individuals caught at dusk. Theoretical considerations suggest that this dawn-dusk difference in nitrogen content represents material that is exported from the surface each day (the so called active N-flux). The rate of this active N-flux was 0.46 µg N ind.-1 d-1 for P. pisekii, 0.34 µg N ind.-1 d-1 for P. gracilis and 5.17 µg N ind.-1 d-1 for P. abdominalis.


Zooplankton · Diel vertical migration · Nitrogen · Vertical export · Biogeochemical impact · N-flux · Atlantic · PRIME


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