Ocean acidification accelerates Nitrogen cycling on seagrass leaves

News   •   May 22, 2023

Seagrass meadows form highly productive and diverse ecosystems in coastal areas worldwide, where they are increasingly exposed to ocean acidification (OA).

In seagrasses, efficient nitrogen (N) cycling and uptake are essential to maintain plant productivity, but the effects of OA on N transformations in these systems are poorly understood.

Here we conducted an experiment at the natural CO2 vents off Ischia Island, which mimic conditions that resemble intermediate to high acidification levels as predicted for our future oceans. Have a look at this video we made at one of these underwater vents to see for yourself how special these places are!

With these experiments, we could show that complete N cycling occurs on leaves of the Mediterranean seagrass Posidonia oceanica, with OA affecting both N gain and loss while the prokaryotic community structure remains largely unaffected.

Daily leaf-associated N2 fixation contributed to 35% of the plant’s N demand under ambient pH, whereas it contributed to 45% under OA. Nitrification potential was only detected under OA, and N-loss via N2 production increased, although the balance remained decisively in favor of enhanced N gain.

Overall, our work highlights the role of the N-cycling microbiome in seagrass adaptation to OA, with key N transformations accelerating towards increased N gain.

If you are curious to read more, click HERE for the link to the preprint of our study.

And here the link to the peer-reviewed article: https://www.nature.com/articles/s42003-024-06011-0