Fig. 1: Geographical location, colony age and metagenomics.

A Location of study sites, eastern Victoria Land bordering the western Ross Sea, Antarctica (inset in top map). B Percentage of sedimentary ancient DNA (sedaDNA) reads assigned to Eukaryota and depth of sample below the ground surface. Note that an outlier (0.5 cm Cape Crozier, with 0.511% Eukaryota reads) is not shown. C Adélie penguin (Pygoscelis adeliae) genome coverage from sedaDNA across all samples (combined) and by colony age grouped based on soil/sediment type (Orn, ornithogenic soil; Min, minerogenic sand/silt). D Adélie penguin genome coverage and total reads per sample. Note that an outlier (0.5 cm Cape Crozier, with 8.51% coverage) is not shown; E 5’ terminal cytosine deamination rates for Adélie penguin DNA. F DNA fragment length distributions for reads mapping to the Adélie penguin genome. Samples and groups in all plots are coloured based on colony age, as shown in the legend in Fig. 1A. The colony age grouping “RA” denotes recently abandoned colonies, while “Mid” and “Late” denote mid-Holocene and late-Holocene age colonies respectively. Italicised numbers refer to the number of samples (Fig. 1C, E) or reads (Fig. 1F; see Supplementary Data 2) in each group. Boxplot elements are median (solid line), interquartile range (grey box), minimum and maximum values excluding outliers (whiskers) and outliers (circles).