SS4.07 Lipids/Fatty Acids in Ecological Research
Date: Tuesday, June 11, 2002
Time: 12:00:00 PM
Location: Saanich
 
ArtsMT, Environment Canada, Burlington, Canada, Michael.Arts@EC.GC.CA
Robarts, R, D, Environment Canada, Saskatoon, Canada, Richard.Robarts@EC.GC.CA
Sommaruga, R, , University of Innsbruck, Innsbruck, Austria, Ruben.Sommaruga@UIBK.AC.AT
Frenette, J, J, University of Quebec in Trois Rivieres, Trois Rivieres, Canada, Jean-Jacques_Frenette@UQTR.UQuebec.CA
Quesada, A, , University Autonema of Madrid, Madrid, Spain, Antonio.Quesada@uam.es
Zohary, T, , Y. Allon Kinneret Limnological Laboratory, Tiberias, Israel, tamarz@ocean.org.il
Bossard, P, , EAWAG Limnological Institute, Kastanienbaum, Switzerland, Peter.Bossard@eawag.ch
 
EVIDENCE FOR UV EFFECTS ON TOTAL LIPIDS AND FATTY ACID COMPOSITION IN AQUATIC BIOFILMS
image
Complex and highly dynamic, biofilms form an essential foundation for life in aquatic ecosystems. Biofilm organisms are relatively immobile and thus may be particularly vulnerable to harsh light conditions; because they cannot simply escape to more benign conditions. Previous work has suggested that UV-B radiation may alter fatty acid composition of marine algae. If this is a general phenomenon it could have far-reaching implications for aquatic food webs. Some fatty acids (termed essential fatty acids; EFA) cannot be effectively synthesized by higher organisms. The EFA are primarily produced by algae and are assimilated into consumers through their diets. They play an important role in the physiological competencies of organisms at higher trophic levels and may be important drivers of ecosystem health/stability. We will review the evidence for (and against) UV effects on fatty acid composition in aquatic biofilms and also provide specific results from a recent field experiment undertaken in Lake Lucerne, Switzerland. Biofilms in Lake Lucerne, grown under the various UV radiation regimes, showed reduced productivity (as measured by leucine uptake)and total lipid and EFA concentrations.