@article{Bokhorst_van Logtestijn_Convey_Aerts_2019, title={Nitrogen isotope fractionation explains the <sup>15</sup>N enrichment of Antarctic cryptogams by volatilized ammonia from penguin and seal colonies}, volume={38}, url={https://polarresearch.net/index.php/polar/article/view/3355}, DOI={10.33265/polar.v38.3355}, abstractNote={<p>Vegetation near bird and seal rookeries typically has high δ<sup>15</sup>N signatures and these high values are linked to the enriched δ<sup>15</sup>N values of rookery soils. However, Antarctic cryptogams are mostly dependent on atmospheric ammonia (NH<sub>3</sub>) and volatized NH<sub>3</sub>&nbsp;from rookeries is severely depleted in δ<sup>15</sup>N-NH<sub>3</sub>. So there is an apparent discrepancy between the isotopically depleted source (NH<sub>3</sub>) and δ<sup>15</sup>N-enriched vegetation. In this article, we aim to resolve this discrepancy to better understand the mechanisms and processes involved in isotopic changes during nitrogen transfer between Antarctic marine and terrestrial ecosystems. Under laboratory conditions, we quantified whether volatized NH<sub>3</sub>&nbsp;affects the isotopic signature of cryptogams. NH<sub>3</sub>&nbsp;volatilizing from penguin guano and elephant seal dung was depleted (44–49‰) in δ<sup>15</sup>N when captured on acidified filters, compared to the source itself. Cryptogams exposed to the volatized NH<sub>3</sub>&nbsp;were enriched (18.8–23.9‰) in δ<sup>15</sup>N. The moss&nbsp;<em>Andreaea regularis</em>&nbsp;gained more nitrogen (0.9%) than the lichen&nbsp;<em>Usnea antarctica</em>&nbsp;(0.4%) from volatilized NH<sub>3</sub>, indicating a potential difference in atmospheric NH<sub>3</sub>&nbsp;acquisition that is consistent with existing field differences in nitrogen concentrations and δ<sup>15</sup>N between mosses and lichens in general. This study clarifies the δ<sup>15</sup>N enrichment of cryptogams resulting from one of the most important nitrogen pathways for Antarctic vegetation.</p&gt;}, journal={Polar Research}, author={Bokhorst Stef and van Logtestijn Richard and Convey Peter and Aerts Rien}, year={2019}, month={Nov.} }