Skip to main content

Free Content A one-dimensional physical-biological model study of the pelagic nitrogen cycling during the spring bloom in the northern North Sea (FLEX '76)

Download Article:
 Download
(PDF 3346.6552734375 kb)
 

Abstract:

A one-dimensional model of the pelagic ecosystem was developed and applied to the spring bloom in the northern North Sea making use of the data set obtained during the Fladenground experiment FLEX '76. The physical submodel is the second-order turbulence closure model of level 2 type developed by Mellor and Yamada (1974, 1982). The biological submodel is a depth-resolved version of the nitrogen flux model of the lower trophic levels in the pelagic proposed by Fasham et al. (1990).

The parameter set employed by Fasham et al. did not yield satisfying results. However, using a parameter set adapted to the North Sea ecosystem we obtained a realistic overall description of the development of the North Sea ecosystem during the spring bloom. We were able to hindcast successfully the onset, duration, magnitude and daily variability of the net primary production, the magnitude of the PON export flux to the sea bottom, of the bacterial production and of the nitrogen regeneration within the water column. From the results of the simulation a mass budget of nitrogen fluxes within the euphotic zone and the deeper water layers as well as between them was derived.

The results of the simulation suggest that strong herbivorous grazing caused the decay of the bloom. The comparison with the grazing by mesozooplankton as estimated from the observations favors the hypothesis that herbivorous microzooplankton was mainly responsible for the breakdown.

The depth dependence of the vertical particulate flux obtained from the simulation exhibits the hyperbolic character recently found in different oceanic regions. The vertical particulate nitrogen flux shows a stronger decrease than typically observed for the particulate carbon flux. This is in correspondence with the observation that there was a remarkable increase of the C/N ratio of POM with depth during FLEX '76.

Document Type: Research Article

DOI: https://doi.org/10.1357/0022240973224229

Publication date: 1997-07-01

More about this publication?
  • The Journal of Marine Research publishes peer-reviewed research articles covering a broad array of topics in physical, biological and chemical oceanography. Articles that deal with processes, as well as those that report significant observations, are welcome. In the area of biology, studies involving coupling between ecological and physical processes are preferred over those that report systematics. Authors benefit from thorough reviews of their manuscripts, where an attempt is made to maximize clarity. The time between submission and publication is kept to a minimum; there is no page charge.
  • Editorial Board
  • Information for Authors
  • Subscribe to this Title
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free ContentFree content
  • Partial Free ContentPartial Free content
  • New ContentNew content
  • Open Access ContentOpen access content
  • Partial Open Access ContentPartial Open access content
  • Subscribed ContentSubscribed content
  • Partial Subscribed ContentPartial Subscribed content
  • Free Trial ContentFree trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more