Particle camera and settling chamber measurements at site PC (GeoB11834-3) and SC (GeoB12914-4) off Cape Blanc/Mauritania

Particles sinking out of the euphotic zone are important vehicles of carbon export from the surface ocean. Most of the particles produce heavier aggregates by coagulating with each other before they sink. We implemented an aggregation model into the biogeochemical model of Regional Oceanic Modelling System (ROMS) to simulate the distribution of particles in the water column and their downward transport in the Northwest African upwelling region. Accompanying settling chamber, sediment trap and particle camera measurements provide data for model validation. In situ aggregate settling velocities measured by the settling chamber were around 55 m d-1. Aggregate sizes recorded by the particle camera hardly exceeded 1 mm. The model is based on a continuous size spectrum of aggregates, characterised by the prognostic aggregate mass and aggregate number concentration. Phytoplankton and detritus make up the aggregation pool, which has an averaged, prognostic and size dependent sinking. Model experiments were performed with dense and porous approximations of aggregates with varying maximum aggregate size and stickiness as well as with the inclusion of a disaggregation term. Similar surface productivity in all experiments has been generated in order to find the best combination of parameters that produce measured deep water fluxes. Although the experiments failed to represent surface particle number spectra, in the deep water some of them gave very similar slope and spectrum range as the particle camera observations. Particle fluxes at the mesotrophic sediment trap site off Cape Blanc (CB) have been successfully reproduced by the porous experiment with disaggregation term when particle remineralisation rate was 0.2 d-1. The aggregation-disaggregation model improves the prediction capability of the original biogeochemical model significantly by giving much better estimates of fluxes for both upper and lower trap. The results also point to the need for more studies to enhance our knowledge on particle decay and its variation and to the role that stickiness play in the distribution of vertical fluxes.

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Karakas, Gökay, Nowald, Nicolas, Schäfer-Neth, Christian, Iversen, Morten Hvitfeldt, Barkmann, W, Fischer, Gerhard, Marchesiello, P, Schlitzer, Reiner (2009). Dataset: Particle camera and settling chamber measurements at site PC (GeoB11834-3) and SC (GeoB12914-4) off Cape Blanc/Mauritania. https://doi.org/10.1594/PANGAEA.755951

DOI retrieved: 2009

Additional Info

Field Value
Imported on November 30, 2024
Last update November 30, 2024
License CC-BY-3.0
Source https://doi.org/10.1594/PANGAEA.755951
Author Karakas, Gökay
Given Name Gökay
Family Name Karakas
More Authors
Nowald, Nicolas
Schäfer-Neth, Christian
Iversen, Morten Hvitfeldt
Barkmann, W
Fischer, Gerhard
Marchesiello, P
Schlitzer, Reiner
Source Creation 2009
Publication Year 2009
Resource Type application/zip - filename: Karakas_2009
Subject Areas
Name: Oceans

Related Identifiers
Title: Impact of particle aggregation on fluxes of organic matter
Identifier: https://doi.org/10.1016/j.pocean.2009.07.047
Type: DOI
Relation: References
Year: 2009
Source: Progress in Oceanography
Authors: Karakas Gökay , Nowald Nicolas , Schäfer-Neth Christian , Iversen Morten Hvitfeldt , Barkmann W , Fischer Gerhard , Marchesiello P , Schlitzer Reiner .