Seawater samples between 2010-12-28 and 2020-02-28 were collected year-round and quasi-weekly in Ryder Bay, along the West Antarctic Peninsula, as part of the Rothera Oceanographic Time Series (RaTS). The majority of samples were collected at 15 m depth. At a lower frequency, samples were collected at additional depths, i.e., mostly at 40 m, 5, m, and 2 m. Samples have been analysed for dissolved inorganic carbon (DIC) and total alkalinity (TA) to study the carbonate chemistry of the upper ocean, from which the fugacity of CO2 (fCO2) is derived. This dataset also includes additional variables of the RaTS-array that are ancillary to DIC and TA results, and to fCO2 calculations: seawater temperature, salinity, and nutrients (nitrate, silicate, and phosphate). DIC/TA data between 2010-12-28 and 2014-02-21 have previously been published in NCEI by Bakker et al. (2017), and are included in this dataset. Physical variables and nutrient data have also been published in the UK Polar Data Centre by Clarke et al. (2022). Funding Sources: Funding sources for Rothera Time Series 2014-2020: - The Rothera Time Series has been funded by NERC through a sequence of National Capability awards, most recently PRESCIENT (NE/Y006178/1). - ESD: NE/L002582/1 and European Union''s Horizon 2020 research and innovation programme under grant agreement no. 821001 - DCEB: partly supported by the NERC PICCOLO award (NE/PO21395/1). - EJ: research programme 866.13.006 (partly) financed by the Netherlands Polar Programme at NWO. - MPM: partly funded by BIOPOLE award (NE/W004933/1). Funding sources for Rothera Time Series 2010-2014: - British Antarctic Survey (BAS) Polar Oceans funding from NERC - UK Ocean Acidification Research Programme (NE/H017046/1) funded by NERC, the Department for Energy and Climate Change and the Department for Environment, Food and Rural Affairs - OJL: PhD funding from NERC: NE/L50158X/1 - DCEB: NERC Shelf Sea Biogeochemistry Blue Carbon work package (NE/K00168X/1)

The fieldwork involved collection of fertile lichens from a range of sites across the Antarctic Peninsula and isolation of the lichen-forming fungi into pure culture in a laboratory at Rothera. Approximately 5,600 monospore cultures were isolated, including B frigida. Approximately 400 thalli of Usnea species, and 3 O. frigida thalli have also been collected for whole thallus analysis. Logarithmic sampling transects of B frigida were conducted at Rothera (2 transects) and on Anchorage Island (one transect) to examine the genetic variation and geographic variation. All thalli of B frigida collected from the transects were successfully used to generate viable spores from four individual apothecia from each thallus. 16 spores were subcultured and maintained from each apothecium.