Green Hydra (Hydra viridissima) are small freshwater hydrozoans living in a close symbiosis with green algae residing inside their gastrodermal cells. In this symbiosis, constant nitrogen limitation ensures that the algae release photosynthetic products such as sugars to the host. This image consists of more than 120 NanoSIMS images to visualize the uptake of ammonium throughout the entire body of Green Hydra. This enables to investigate how algae compete with each other and their host for available nitrogen and how this competition affects the symbiosis.
Recorded on CAMECA NanoSIMS 50L at Ecole Polytechnique Fédérale de Lausanne, Switzerland. Image courtesy of N. Rädecker and S. Escrig.