Dear UK Colleagues,
Could you pass this information on to any potential applicants who are still
around your departments. If we cannot fill the position for a January
start, NERC will allow us to consider a start date of next October,
especially if we have a good candidate lined up.=20
Ph.D. studentship available (start Jan 1997 or later)
Detecting sublethal herbicide effects on saltmarsh microalgae using in situ
CCD fluorescence.
NERC Environmental Diagnostics Special Topic. CASE award with the
Environment Agency.
Supervisors Dr. Graham Underwood, Prof. Neil Baker
University of Essex
Department of Biological and Chemical Sciences
Microalgae (epipelic diatoms and cyanobacteria) are important primary
producers in saltmarshes, providing much of the food of benthic
invertebrates and influencing sediment processes by the production of
stabilising exopolymer films and filamentous mats. The high surface
area:volume ratio, rapid growth rates, and physical location of algae on the
surface of sediments suggests that algae will be among the first organisms
affected by herbicide runoff, especially herbicides entering marshes after
period of rain. Therefore, microalgae may be sensitive indicator organisms
for the sublethal herbicide effects hypothesised to be important in
saltmarsh loss. Concentrations of herbicides which exert sublethal effects
on plants have been measured in saltmarshes and concentrations of MCPP as
high as 25*g l-1 have been measured in water entering salt marshes after
heavy rain. There are no data on the toxicity of herbicides, singly, or in
combination, on saltmarsh benthic microalgae.=20
Using a unique charge-coupled device (CCD) fluorescence image analysis
system developed at Essex (with BBSRC funding) we will quantify the changes
in photosynthetic activity of microalgal biofilms under different
experimental levels of herbicide stress, and in natural communities taken
from different saltmarshes, with differing species composition, and over
seasonal cycles. The CCD system allows the calculation of fPSII
(photosynthetic efficiency) for individual cells within undisturbed
sediments and can also integrate over larger areas. Thus the complex
physical and chemical gradients present with the biofilms, and the migratory
and photosynthetic rhythms of the algae are maintained. We are unaware of
any other research group who is able to make these novel types of
measurements. These measures will be combined with quantification of rates
of algal exopolymer production, and the effects of longer term sublethal
herbicide stress of community composition to assess the overall impact on
microalgal systems of herbicide stress.
The student will have the advantage of joining two very active research
groups and will be trained in relevant scientific areas and transferable
skills (microbial ecology and physiology, photochemistry, imaging and
computing). Students attend a graduate seminar course (training in IT, IPR
and patent law etc.), group and departmental seminars, appropriate lecture
units and are encouraged to attend conferences.
The value of the studentship will be =A36,400 p.a.
Further information : contact Dr. Graham Underwood, Department of Biological
and Chemical Sciences, University of Essex, Colchester. CO4 3SQ (Tel. 01206
873337 email gjcu at essex.ac.uk). To obtain an application form and details of
the Department contact the Graduate Secretary (email gradbiol at essex.ac.uk or
telephone 01206 873320; fax 01206 - 873416). Applications must be sent to
The Graduate Secretary, Department of Biological and Chemical Sciences, John
Tabor Building, University of Essex, Colchester, Essex. CO4 3SQ
Dr. Graham J. C. Underwood,
Department of Biological and Chemical Sciences,
John Tabor Laboratories,
University of Essex, Colchester, Essex. CO4 3 SQ
Tel . +44 1206 873337, FAX +44 1206 873416, email gjcu at essex.ac.uk
