A vertical model of particle size distributions and fluxes in the midwater column that includes biological and physical processes - Part II: application to a three year survey in the NW Mediterranean Sea - Université Pierre et Marie Curie Accéder directement au contenu
Article Dans Une Revue Deep Sea Research Part I: Oceanographic Research Papers Année : 2004

A vertical model of particle size distributions and fluxes in the midwater column that includes biological and physical processes - Part II: application to a three year survey in the NW Mediterranean Sea

L Stemmann
Ga Jackson
  • Fonction : Auteur

Résumé

The largest decrease in the particle vertical flux occurs in the mesopelagic zone where particles are transformed by biological and physical mechanisms. Particle size distributions provide important clues into those processes affecting particle transformations in this region. We have studied them using an inter-annual data set showing the evolution of particle size distributions between 100 and 1000 m, comparing them to results from a series of size-resolved models of particle dynamics that include physical coagulation and biological remineralization. The formulation that best fits the observations consists of a combination of settling, microbial activity and zooplankton feeding. The calculated particulate organic carbon losses to microbial activity and zooplankton feeding are consistent with independent estimates of these rates. The model shows that it is possible to predict the particle size distribution at 1000 m depth knowing the particle size distribution at 100 m depth and the rates of transformation in the mesopelagic. The mesozooplankton appears to be important in decreasing the high flux of large particles in the upper midwater zone, microbes becomes more important in the deeper midwater zone as zooplankton become rarer. The results suggest that the mesozooplankton have a much greater effect on particle flux than the macrozooplankton. Their importance requires the mesozooplankton to feed preferentially on large settling particles, probably using remote detection. The present work shows that using particle size spectra is a useful way to understand the transformation of the vertical flux of element in the midwater zone. However, most of the assumptions on particle properties and processes are based on surface studies and more data from the midwater zone are needed to confirm the hypotheses. The model allows us to formulate crucial questions regarding particle dynamics in the midwater zone. (C) 2004 Elsevier Ltd. All rights reserved.

Domaines

Océanographie

Dates et versions

hal-03506669 , version 1 (02-01-2022)

Identifiants

Citer

L Stemmann, Ga Jackson, G Gorsky. A vertical model of particle size distributions and fluxes in the midwater column that includes biological and physical processes - Part II: application to a three year survey in the NW Mediterranean Sea. Deep Sea Research Part I: Oceanographic Research Papers, 2004, 51 (7), pp.885-908. ⟨10.1016/j.dsr.2004.03.002⟩. ⟨hal-03506669⟩
11 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More