Nilsson, C. C. Marine Botany, Bot. Inst., Goteborg University,
Sundback, K. C. Marine Botany, Bot. Inst., Goteborg University,
Wulff, A. A. Marine Botany, Bot. Inst., Goteborg University,
Odmark, S. S. Marine Botany, Bot. Inst., Goteborg University,
Wangberg, S. S-A. Plant Physiology, Bot. Inst., Goteborg University,
Underwood, G. G. Dept. of Biological Sciences, Univ. of Essex,

The effect of UVB-radiation and inorganic nutrient limitation on a natural sediment-living microbenthic community was studied using an outdoor experimental system.The microbenthic community,dominated by diatoms and cyanobacteria , was sampled from a shallow microtidal sandy bay on the west coast of Sweden. The community was isolated from the sediment and allowed to settle onto acid-cleaned sand placed in petridishes . The petridishes were placed in individual aquaria and given one of the four treatments :ambient or enhanced UVB radiation with no nutrient addition, ambient or enhanced UVB radiation with nutrient addition (N,P, and Si). Enhanced UVB (= +20% enhancement of ambient UVB) was provided using a system in which the UVB dose given was controlled by a computer system linked to a UVB sensor that measured continously the natural ambient UVB. The experiment lasted for 9 days and the variables studied were biomass, composition of algae and pigments, carbohydrate fractions, amount of UV-absorbing compounds, primary productivity, carbon allocation and bacterial productivity. Significant differences were found for primary productivity and carbon allocation between treatments with ambient and enhanced UVB with no nutrient addition, whereas for treatments with nutrient addition the effect of enhanced UVB radiation was not significant. It is hypothesised that the availability of inorganic nutrients is an important factor that regulates the effect of UVB radiation.
Day: Friday, Feb. 5
Time: 10:45 - 11:00am
Location: Eldorado Hotel
Code: SS46FR1045E