28 September 2026, by RTG 2530

Photo: UHH/RTG2530/Lengert

The annual RTG 2530 photo contest gives doctoral researchers the opportunity to showcase their research through an artistic lens. Entries can take the form of photographs, graphics, or illustrations. This year, Anna Lengert won the contest with her photograph, “The Ecosystem's Trapped Breath.” It will be displayed in the “Hall of Fame” on the ground floor of the Institute of Plant Science and Microbiology, in the corridor near Room E.084. Many thanks to everyone who took part and contributed such diverse and original work.

The photograph was taken in the “Kronenloch” nature reserve, in the Speicherkoog Dithmarschen near Meldorf. It draws the viewer’s eye beneath a dense layer of filamentous algae, revealing a fascinating interplay of forms. Gas bubbles form, grow, and escape beneath the surface. Some cluster together to form a delicate network, while individual strands of algae remain visible between them. The restrained colour palette and repeating structures give the image a harmonious, quiet aesthetic. Yet beneath this seemingly still scene lies a highly dynamic process that is central to Anna’s research.

She investigates the temporal coupling between carbon dioxide (CO₂) and methane (CH₄) exchange in the pioneer zone of a tidal freshwater marsh in the Elbe estuary, using continuous eddy covariance measurements. With this method, she monitors the exchange of gases between the ecosystem and the atmosphere. Her central question is how tidal forcing and water table dynamics influence these two gas fluxes across timescales ranging from minutes to weeks.

“This photo captures that coupling in miniature: gas bubbles trapped beneath a dense mat of filamentous algae, likely a mix of oxygen from algal photosynthesis and CH4/CO2 from microbial activity in the reduced sediment below. Two opposing metabolic pathways sit side by side, only centimeters apart, both mediated by biota and both ultimately expressed as atmospheric flux,” the doctoral researcher explains.

UHH/RTG2530/Grebe

This year’s competition focused on the theme of “Dynamics”. Anna offers a concise reflection on the theme: “For me, ‘dynamics’ means exactly this: bubbles forming, growing, and escaping in a rhythm set by light, tide, vegetation and microbial turnover, never reaching equilibrium.”