Fatty acids as a tool to understand microbial diversity and their role in food webs of Mediterranean temporary ponds.
Temporary Mediterranean ponds are complex ecosystems which support a high diversity of organisms that include heterotrophic microorganisms, algae, crustaceans, amphibians and higher plants, and have the potential to supply food and a resting place to migratory birds. The role of heterotrophs at the base of the food web in providing energy to the higher trophic levels was studied in temporary ponds in Central and Southern Portugal. The relative quantification of the hetero and autotrophic biomass at the base of the food web in each pond was derived from the polar fatty acid (PLFA) composition of seston through the application of the matrix factorization program CHEMTAX that used specific PLFA and their relative proportion as markers for e.g., classes of bacteria, algae and fungi. The species composition of the culturable microbial communities was identified through their fatty acid profiles. The biomass in the lower trophic level of some ponds presented an even proportion of auto to heterotrophic organisms whilst either bacteria or algae dominated in others. In a selected subset of ponds, the incorporation of bacterial fatty acids was observed to occur in potentially herbivorous zooplankton crustacean. Zooplankton consumed and incorporated bacterial fatty acids into their body tissues, including into their phospholipids, which indicates that energy of heterotrophic origin contributes to the aquatic food webs of temporary ponds.
IBB-Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisbon 1049-001, Portugal. ccarvalho@ist.utl.pt.
Carla C C R
CC
de Carvalho
Centre for Environmental Biology, Faculty of Sciences, Universidade de Lisboa, Campo Grande C2, Lisbon 1749-016, Portugal. mariajose.caramujo@iss.it.
Maria-José
MJ
Caramujo
D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D017753:Ecosystem; D005227:Fatty Acids / Q000378:metabolism*; D020387:Food Chain; D019083:Mediterranean Region; D061005:Ponds / Q000737:chemistry / Q000382:microbiology; D011174:Portugal; D015048:Zooplankton / Q000378:metabolism
D005227:Fatty Acids