Responses of marine phytoplankton in iron enrichment experiments in the northern North Sea and northeast Atlantic Ocean

Klaas R. Timmermans, Martha Gledhill, Rob F. Nolting, Marcel J.W. Veldhuis, Hein J.W. de Baar, Constant M.G. van den Berg

Research output: Contribution to journalArticleAcademicpeer-review

32 Citations (Scopus)
391 Downloads (Pure)


Short-term iron enrichment experiments were carried out with samples collected in areas with different phytoplankton activity in the northern North Sea and northeast Atlantic Ocean in the summer of 1993. The research area was dominated by high numbers of pico-phytoplankton, up to 70,000 ml−1. Maximum chlorophyll a concentrations varied from about 1.0 μg l−1 in a high-reflectance zone (caused by loose coccoliths, remnants from a bloom of Emiliania huxleyi) and about 3.5 μg l−1 in a zone in which the phytoplankton were growing, to about 0.5 μg l−1 in the northeast Atlantic Ocean. From the high-reflectance zone to the northeast Atlantic Ocean, nitrate concentrations increased from 0.5 μM to 6.0 μM. Concentrations of reactive iron in surface water showed an opposite trend and decreased from about 2.6 nM in the high-reflectance zone to
Original languageEnglish
Pages (from-to)229 - 242
Number of pages14
JournalMarine Chemistry
Issue number3
Publication statusPublished - 1998


  • Iron enrichment experiments
  • Marine phytoplankton
  • North Sea

Cite this