Nitrogen recycling by Rhodobacteraceae as an important factor determining diatom's community composition in the oceans?

Life in the marine environment has to face low nutrient conditions. To overcome this, heterotrophic bacteria associate with microalgae in order to utilize their fixed carbon via a mutualistic interaction. This algal benefit for bacteria is well described, whereas bacterial benefits for microalgae are more elusive. Recently, the utilisation of methylated amines originating from diatoms, being unable to recycle these compounds themselves, was shown for the bacterial family of the Rhodobacteraceae. This observation displays a likely metabolic linkage of diatoms towards specific heterotrophic bacteria. The bacterial recycling seems thereby not be a commensalistic process but rather precisely regulated by both partners.