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)

Marine mammal sightings in Ryder Bay, an inlet of northern Marguerite Bay on the Western Antarctic Peninsula, were collated for the period 1998 - 2023. The weekly maximum number recorded for each species are presented here, alongside the weekly maximum score for sea ice coverage. Observations of marine mammals and sea ice were undertaken as part of the Rothera Time Series (RaTS), a long-term year-round programme of oceanographic and biological sampling of the Antarctic marine environment. Whales and seals are an important component of the Southern Ocean pelagic fauna, but winter data are very sparse. Long series of observations such as this enable patterns of interannual variability and/or long-term change to be revealed. Presenting the marine mammal data alongside sea ice coverage data enables investigation of the relationship between the two variables. Sightings of eight species were collated; Antarctic minke whale (Balaenoptera bonaerensis), humpback whale (Megaptera novaeangliae), common killer whale (Orcinus orca), Antarctic fur seal (Arctocephalus gazella), leopard seal (Hydrurga leptonyx), Weddell seal (Leptonychotes weddellii), crabeater seal (Lobodon carcinophaga), and Southern elephant seal (Mirounga leonina). Data collection has been supported since 1997 by the Natural Environment Research Council (NERC) through core funding supplied to the British Antarctic Survey. Since 2017, it has been supported by NERC award "National Capability - Polar Expertise Supporting UK Research" (NE/R016038/1).

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.