BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Molecular vibrations of water predict global distributions of phot otrophic organisms in lakes and oceans - Jef Huisman (Universiteit van Ams terdam) DTSTART:20221013T083500Z DTEND:20221013T091000Z UID:TALK179375@talks.cam.ac.uk DESCRIPTION:Authors: Jef Huisman\, Tadzio Holtrop\, Maayke Stomp\, Levi Bi ersteker\, Jeroen Aerts\, Thé\;ophile Gré\;bert\, Fré\;d é\;ric Partensky\, Laurence Garczarek and Hendrik Jan van der Woerd\ n \;\nWhich colours of light are available in the aquatic ecosystems o f our planet? And how do these colours affect the biogeographical distribu tions of phototrophic organisms\, such as cyanobacteria\, anoxygenic photo trophic bacteria and eukaryotic algae? Stretching and bending vibrations o f water molecules absorb photons of specific wavelengths\, a phenomenon th at constrains light energy available for aquatic photosynthesis. Previous work suggested that these absorption properties of water create a series o f underwater light colours or &lsquo\;spectral niches&rsquo\;. However\, t he theory was still too simplified to enable prediction of the spectral ni ches in real aquatic ecosystems. Here\, we show with a state-of-the-art ra diative transfer model that the vibrational modes of the water molecule de lineate a series of distinct spectral niches\, in the violet\, blue\, gree n\, orange\, red and infrared parts of the light spectrum. These distinct spectral niches are effectively captured by different photosynthetic pigme nts (chlorophylls\, bacteriochlorophylls\, phycobilin pigments)\, providin g insight into how different groups of phototrophic organisms can flourish in different underwater light environments. We predicted the global distr ibutions of the spectral niches by satellite remote sensing\, and show tha t they matched well with observed distribution patterns of cyanobacterial pigment types. Our findings provide an elegant explanation for the large-s cale biogeographical distributions of phototrophic organisms across the la kes and oceans of our planet. LOCATION:Seminar Room 1\, Newton Institute END:VEVENT END:VCALENDAR