Aquatic Sciences Meeting, Albuquerque 2001

SS08 Processes at the Benthic Interface (Environmental Connections)

Date: Tuesday, February 13, 2001, Time: 2:45:00 PM

Location: Ruidoso/Pecos

Consalvey, M, , University of St Andrews, St Andrews, United Kingdom, mc6@st-andrews.ac.uk

Paterson, D, M, University of St Andrews, St Andrews, United Kingdom, d.paterson@st-and.ac.uk

Perkins, R, G, University of Essex, Colchester, United Kingdom, rgperk@essex.ac.uk

Underwood, G, J, University of Essex, Colchester, United Kingdom, gjcu@hotmail.com

DIATOMS GOT RHYTHM? THE MIGRATORY BEHAVIOUR OF MICROPHYTOBENTHOS AND CONTROLLING FACTORS.

Microphytobenthic biofilms in estuarine sediments exhibit high rates of primary production with periodicity resulting from migratory behaviour stimulated by tidal and diurnal rhythms. Migration may also increase the efficiency of nutrient sequestering and be a photo-adaptive response to changes in the light environment. The dynamics of selected natural biofilms were studied in terms of microstructure (Low-temperature SEM), light penetration (fibre-optic light micro-spheres), microspatial pigment distribution (HPLC) and photosynthetic electron transport of biofilms and individual cells (pulse modulated fluorescence and high resolution imaging) over diel and tidal cycles. LTSEM confirmed that species altered their spatial position within transient biofilms over time. The response was related to site, assemblage structure and environmental conditions (e.g. light). Changes in light penetration (extinction coefficients) were associated with cell position. Changes in photosynthetic parameters are discussed with reference to cell depth in the biofilm Chlorophyll a content of vertical sediment sections correlated with changes in cell position. The work demonstrates the complex nature and dynamics of transient biofilms and the need to examine individual cells as components of the biofilm.

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Aquatic Sciences Meeting, Albuquerque 2001

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