Journal of the Marine Biological Association of the United Kingdom

Research Article

Diurnal changes of photoadaptive pigments in microphytobenthos

Leonie Jordana1, Andrew McMinna1 c1 and Peter Thompsona2

a1 Institute of Antarctic and Southern Ocean studies, University of Tasmania, Box 252-77, Hobart 7001, Tasmania, Australia

a2 Marine and Atmospheric Research, CSIRO, Hobart 7001, Tasmania, Australia

Abstract

Microphytobenthos need photoadaptive strategies to survive the highly dynamic light environment in which they reside. Xanthophyll pigments can provide photoprotection by cycling electrons between epoxide and de-epoxide forms, dissipating excess light energy as heat. This study examined the xanthophyll cycle in microphytobenthos on a tidally exposed substrate at Browns River, Tasmania. Fv/Fm decreased from 0.52±0.01 to 0.47±0.01 at noon in surface samples and a decrease in the diadinoxanthin:chlorophyll-a ratio from 0.022±0.003 to 0.015±0.005 also suggests that the microphytobenthos was under physiological stress at noon. The results indicate that the cells exposed to light at the surface migrated deeper into the sediments and replenished the epoxide form of their xanthophylls. The results suggest that micrphytobenthos utilizes both behavioural and physiological strategies to survive in the dynamic intertidal environment.

(Received February 17 2009)

(Accepted July 08 2009)

(Online publication October 21 2009)

Correspondence:

c1 Correspondence should be addressed to: Andrew McMinn, Institute of Antarctic and Southern Ocean studies, University of Tasmania, Box 252-77, Hobart 7001, Tasmania, Australia email: Andrew.McMinn@utas.edu.au