Effects of bio-optical factors on the attenuation of ultraviolet and photosynthetically available radiation in the North Water Polynya, nothern Baffin Bay

Christophe Vasseur, Behzad Mostajir, Christian Nozais, Michel Denis, Eric Fouilland, Bert Klein, Serge Demers

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Abstract

Recently, the Arctic has experienced a recurrent springtime thinning of the stratospheric ozone layer resulting in increasing ultraviolet-B radiation (UVBR, 280 to 320 nm). However, little is known about the effect of such UVBR enhancement on the Arctic ecosystem. In spring-summer 1998 and fall 1999, 40 stations were investigated in the North Water Polynya (NOW), High Arctic. In the course of this study, 3 periods (pre-bloom, bloom and post-bloom) were distinguished based on chlorophyll a (chl a) concentrations. The attenuation of ultraviolet radiation (UVR) and photosynthetically available radiation (PAR) are reported here. Bio-optical factors, namely particulate organic carbon (POC), dissolved organic carbon (DOC) and chl a concentrations were related to the attenuation coefficient, K-d(lambda), of both UVR and PAR. During the pre-bloom period (9 April to 12 May 1998), all bio-optical factors except chl a concentrations were unrelated to K-d(lambda). However, the absorption of colored dissolved organic matter might prevail. During the bloom period (15 May to 29 June 1998), both chl a and POC were strongly correlated to K-d(lambda). During the post-bloom period (27 August to 25 September 1999), POC contributed from 57 to 83 % of the K-d(lambda). Under stratification conditions, an inverse relationship was observed in the UVR and PAR ranges, between K-d(lambda) and the depth of the subsurface chlorophyll maximum (SCM). This could be a consequence of cell migration below the penetration depth of UVR where they are protected from UVR-induced physiological damages.
Original languageEnglish
Pages (from-to)1-13
Number of pages13
JournalMAR ECOL-PROG SER
Issue number2
Publication statusPublished - 2003

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Keywords

  • DISSOLVED ORGANIC-MATTER
  • LAKE
  • STRATOSPHERIC OZONE
  • Marine & Freshwater Biology
  • Oceanography
  • MIXED-LAYER
  • CHLOROPHYLL MAXIMUM
  • Ecology
  • APRIL-JULY 1998
  • ARCTIC WINTER
  • PHYTOPLANKTON BIOMASS
  • ICE
  • B RADIATION

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