Research Article

Marine Biology

, Volume 150, Issue 1, pp 17-28

First online:

Chlorophyll fluorescence as a proxy for microphytobenthic biomass: alternatives to the current methodology

  • B. JesusAffiliated withFaculdade de Ciências, Instituto de Oceanografia, Universidade de LisboaSediment Ecology Research Group, Gatty Marine labs, University of St. Andrews Email author 
  • , R. G. PerkinsAffiliated withSchool of Earth, Ocean and Planetary Sciences, Cardiff University
  • , C. R. MendesAffiliated withFaculdade de Ciências, Instituto de Oceanografia, Universidade de Lisboa
  • , V. BrotasAffiliated withFaculdade de Ciências, Instituto de Oceanografia, Universidade de Lisboa
  • , D. M. PatersonAffiliated withSediment Ecology Research Group, Gatty Marine labs, University of St. Andrews

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Pulse amplitude modulated (PAM) fluorescence has been used as a proxy of microphytobenthic biomass after a dark adaptation period of 15 min to stabilise the minimum fluorescence yield (F o 15 ). This methodology was investigated for in situ migratory and ex situ engineered non-migratory biofilms, comparing dark adaptation to low (5% ambient) and far-red light treatments over different emersion periods. Far-red and low light reduced potential errors resulting from light history effects, by reversal of non-photochemical quenching after 5 min of treatment, compared to over 10 min required by conventional dark adaptation. An in situ decline of minimum fluorescence yield over 15 min was observed during the dark adaptation for migratory biofilms, but was not observed in the non-migratory biofilms indicating that the major cause of decline was downward vertical migration of cells into the sediment. This pattern occurred in far-red light after 10 min, but not for the low light treatment, indicating that low light maintained the biomass at the surface of the sediment. It is therefore concluded that low light treatment is a better option than conventional dark adaptation for the measurement of minimum fluorescence as a proxy of microphytobenthic biomass.