Th-234 as a tracer of particle flux and POC export in the northern North Sea during a coccolithophore bloom

Jane Foster, Graham B Shimmield

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

A multidisciplinary cruise to the northern North Sea was undertaken during June 1999 to carry out a Lagrangian study of an Emiliania huxleyi bloom. During this experiment, the naturally occurring radionuclide, Th-234, was measured in the water column to estimate particle fluxes and resulting residence times. Simple steady state modelling of changes in Th-234 activity suggests an increase in scavenging efficiency over an 8 day period. The steady state Th-234 flux ranges from 357 to a maximum of 1390 dpm m(-2) d(-1) on the 25th June 1999, with a corresponding particulate organic carbon (POC) flux from 9.5-48 mmol C m(-2) d(-1), estimated from POC/(234) Th ratios on filtered particulate material. Scavenging of the Th-234 by the bloom occurs immediately. The maximum POC fluxes follow the peak in primary production and the maximum coccolithophore cell abundance within a few days. The Th-234 and POC fluxes illustrate the rapid response of export with biological activity. (C) 2002 Elsevier Science Ltd. All rights reserved.
Original languageEnglish
Pages (from-to)2965-2977
Number of pages13
JournalDEEP-SEA RES PT I
Issue number9
DOIs
Publication statusPublished - 2002

Keywords

  • SAMPLES
  • SEAWATER
  • RATES
  • SULFUR
  • NITROGEN
  • Oceanography
  • TRANSPORT
  • DISEQUILIBRIA
  • CYCLE
  • ATLANTIC-OCEAN
  • ORGANIC-CARBON EXPORT

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