Distribution, Source, and Function of Hopanoids in the Ocean 20 22 24 26 28 30 32 34 36 38 Time (min) 5m Core Top 60m I II III IV V - N 22º 30’ - N 12º 30’ - N 17º 30’ - N 27º 30’ - N 32º 30’ N.W. Africa N. Atlantic Left: Results of growth experiments designed to test the effect of nitrogen replete (+ N) and limiting (- N) conditions on cellular abundance of hopanoids in Crocosphaera WH 8501 and Trichodesmium erythraeum. The abundance of BHPs are reported as peak area normalized to total lipid extract mass. Cells were harvested and extracted during exponential growth phase. BHP cellular abundance is reduced by 3-10 fold during N limiting conditions. Above: Total base peak chromatograms and partial ion chromatograms of extracts from 5 meters and 60 meters below sea surface, and from a core top sediment sample (see map at left for location). Filter and sediment samples were extracted using a modified Bligh Dyer protocol, and analyzed as acetates by HPLC-APCI/MSn (See Talbot et al., 2008 for LC-MS conditions). Structures were determined by comparison of mass spectra with published spectra from previously reported and characterized BHP compounds and to spectra from extracts of pure cultures of R. Palustris, and Crocosphaera WH8501. Distribution, Source, and Function of Hopanoids in the Ocean 655 669 1002 613 627