Vernal sedimentation trends in north Norwegian fjords: temporary anomaly in 234Th particulate fluxes related to Phaeocystis pouchetii proliferation
Schmidt, S.; Belviso, S.; Wassmann, P.; Thouzeau, G.; Stefels, J. (2007). Vernal sedimentation trends in north Norwegian fjords: temporary anomaly in 234Th particulate fluxes related to Phaeocystis pouchetii proliferation. Biogeochemistry 83(1-3): 235-244. https://dx.doi.org/10.1007/s10533-007-9094-2 In: Biogeochemistry. Springer: Dordrecht; Lancaster; Boston. ISSN 0168-2563; e-ISSN 1573-515X, more Also appears in:Van Leeuwe, M.A.; Stefels, J.; Belviso, S.; Lancelot, C.; Verity, P.G.; Gieskes, W.W.C. (Ed.) (2007). Phaeocystis, major link in the biogeochemical cycling of climate-relevant elements. Biogeochemistry, 83(1-3). Springer: Dordrecht. ISBN 978-1-4020-6213-1. 330 pp. https://dx.doi.org/10.1007/978-1-4020-6214-8, more |  |
| Keywords | Isotopes > Thorium isotopes
Organic matter > Particulates > Particulate organic matter > Organic carbon > Particulate organic carbon
Particulate flux
Sediment traps
Water bodies > Coastal waters > Coastal landforms > Coastal inlets > Fjords
Phaeocystis Lagerheim, 1893 [WoRMS]
ANE, Norway [Marine Regions]; ANE, Norway, Balsfjord [Marine Regions]
Marine/Coastal | | Author keywords | fjord; Northern Norwegian shelf waters; particle flux; Phaeocystis;sediment trap; Th-234 |
| Authors | | Top | - Schmidt, S.
- Belviso, S.
- Wassmann, P.
| | |
| Abstract | We report data of a naturally occurring radionuclide, 234Th, an in situ tracer, to investigate vertical export of biogenic matter during a vernal bloom of Phaeocystis pouchetii in the fjords of northern Norway. To optimise sampling of different stages of the bloom, three fjords with increasing oceanic influence (Balsfjord, Malangen fjord and Ullsfjord, respectively) were investigated in April 1997. Contrasting situations were encountered between the three fjords: the proliferation of P. pouchetii in Ullsfjord surface waters coincided with a drastic reduction of particulate 234Th fluxes in traps, although particulate organic carbon (POC) and dimethylsulphoniopropionate (DMSP) were exported and 234Th was available in surface waters. When large colonies make up a significant fraction of the vertical flux, as observed in Ullsfjord in April 1997, there may be a large and rapid change in the POC/234Th ratio, further complicating the use of 234Th as a tracer for POC export. The results suggest that the proliferation of Phaeocystis pouchetii during vernal bloom could temporary increase OC/234Th ratio of particles and delay the particulate export of 234Th, and probably of other particle-reactive species, from surface waters. |
|
