Tönnesson, K. M.. Kristineberg Marine Research Station, k.tonnesson@kmf.gu.se
, . M.. ,

 
EFFECTS OF UV-B EXPOSURE ON THE DIATOM THALASSIOSIRA WEISSFLOGII: CHANGES IN FOOD QUALITY FOR THE COPEPOD ACARTIA TONSA
 
UV-B can affect the chemical composition and growth rate of algae, which in turn may influence zooplankton grazing and growth rates. To investigate this, specific growth rate and size of the diatom Thalassiosira weissflogii were studied at four different levels of UV-B exposure, in both long- and short-term laboratory experiments. UV-B exposed algae had a significantly lower growth rate, but no differences in cell size were observed between exposed and unexposed algae. To investigate if there was a change in the quality of the algae as food for the calanoid copepod Acartia tonsa, copepod grazing and reproduction were studied. Algae from the short-term algal growth experiments were given to adult females at 3000 cells/ml, which is nearly saturated food concentration. Algae exposed to the strongest UV-B radiation induced a significantly higher ingestion rate whilst no difference in egg production or egg hatching was observed between the treatments. Since ingestion was higher, and egg production constant, the efficiency with which the copepods transformed food into growth was reduced with a UV-B exposed diet.
 
Day: Wednesday, Feb. 3
Time: Poster
Location: Sweeney Center
 
Code: SS21WE0338S