1. Microbial rhodopsins are major contributors to the solar energy captured in the sea
- Author
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Gómez-Consarnau, L, Raven, JA, Levine, NM, Cutter, LS, Wang, D, Seegers, B, Arístegui, J, Fuhrman, JA, Gasol, JM, Sañudo-Wilhelmy, SA, Gómez-Consarnau, L, Raven, JA, Levine, NM, Cutter, LS, Wang, D, Seegers, B, Arístegui, J, Fuhrman, JA, Gasol, JM, and Sañudo-Wilhelmy, SA
- Abstract
Copyright © 2019 The Authors, some rights reserved; All known phototrophic metabolisms on Earth rely on one of three categories of energy-converting pigments: chlorophyll-a (rarely -d), bacteriochlorophyll-a (rarely -b), and retinal, which is the chromophore in rhodopsins. While the significance of chlorophylls in solar energy capture has been studied for decades, the contribution of retinal-based phototrophy to this process remains largely unexplored. We report the first vertical distributions of the three energy-converting pigments measured along a contrasting nutrient gradient through the Mediterranean Sea and the Atlantic Ocean. The highest rhodopsin concentrations were observed above the deep chlorophyll-a maxima, and their geographical distribution tended to be inversely related to that of chlorophyll-a. We further show that proton-pumping proteorhodopsins potentially absorb as much light energy as chlorophyll-a–based phototrophy and that this energy is sufficient to sustain bacterial basal metabolism. This suggests that proteorhodopsins are a major energy-transducing mechanism to harvest solar energy in the surface ocean.
- Published
- 2019