We present a bathymetric compilation of Ryder Bay here defined by the following bounding box: 68.48 to 68W, 67.7 to 67.46S. This bathymetry grid was compiled from a variety of multibeam swath bathymetry data acquired during 18 different cruises (see lineage) undertaken by the RRS James Clark Ross. The data is available as a grid of 0.0005 degrees resolution in two different formats: a GMT-compatible (2-D) NetCDF and Arc/Info and ArcView ASCII grid format using geographic coordinates on the WGS84 datum.
Conductivity-Temperature-Depth casts were conducted at Ryder Bay and Marguerite Bay from the James Clark Ross (cruise numbers: JR112/113, JR136/137, JR155 and JR174). The CTD casts at each site were made at a range of depths from the bottom to the surface waters with samples collected for macronutrients, particulate biogenic silica,carbon and nitrogen for later analysis.
Box core samples were analysed for carbon and nitrogen isotopes, barium, aluminium and uranium and other lithogenic dust. Core dating was calculated and population analyses were used to determine species composition. The box cores were collected on the James Clark Ross (cruise numbers: JR112/113, JR136/137 and JR155) in January 2005 and December 2006. Swath bathymetry was also taken to identify optimum coring sites.
Conductivity-Temperature-Depth (CTD) casts were conducted to describe the physical structure of the water column and to provide water samples for nutrient and particulate matter analyses from the James Clark Ross. A CTD transect was also conducted on a cruise across the mouth of Marguerite Bay (it was the intention to cover the entire mouth, but sea ice prevented this from happening), and through the trough leading towards the mooring sites. These casts were used to sample nutrients (NO3-, NO2-, Si(OH)4); nutrient isotopes 13DIC (dissolved inorganic carbon) 15NO3; bulk organic POC/PON (particulate organic carbon/nitrogen); bulk organic delta 13POC and delta 15PON.
Sediment traps were deployed and recovered and CTD/rosette casts were taken at two sites, one in Ryder Bay and one in Marguerite Bay. Biogeochemical proxy signals of nutrients and organic matter were assessed in sea ice compared to the open water column. The flux of this material in time series sediment traps located to two depths below the sampling site was also followed. Past changes in these proxy signals in Ryder Bay were also investigated from box core material taken from the study site.
Water samples were collected for chlorophyll and nutrient concentrations, biogenic and lithogenic silica concentrations, particulate organic carbon and nitrogen (POC/PON) concentrations, phytoplankton identification, Si, C, N, and Ge isotopes, particulate Ba, and other trace elements associated with suspended particles. Some samples were collected by small boat launched from Rothera research station and other seawater samples were collected from under the ice by divers. Water was also collected from RaTs (Rothera Oceanographic and Biological Time Series) CTD sites 1 and 2, and from Honeybucket (off Rothera Point). Brine was collected by drilling a hole, washing out and waiting for the hole to fill (sack-hole drilling). Blocks of ice were also collected and stored at -80 degrees C before being thawed for analysis. The sea-ice and brine was analysed for trace metals (Al, Zn, Cd and Co) for 5 different collection dates in 2004/2005.
Two moorings were deployed and recovered using the James Clark Ross (cruise numbers: JR112/113, JR155). One was deployed in Ryder Bay at the Rothera Oceanographic and Biological Time Series (RaTS) oceanographic station midway between Rothera Point and Leonie Islands. The other was deployed in deep water in northern Marguerite Bay. The moorings were used to monitor particle flux, currents, salinity and temperature. Two sediment traps on each mooring were used to measure biogenic flux from surface waters to the seafloor and quantify changes down the water column.
Water samples were collected from Ryder Bay at the Rothera Time-Series (RaTS) site, using a small boat. A biogeochemical profile was performed at the following 5 depths: 0m (surface), 5m, 10m, 15m and 25m, for four RaTS events on: 7 January, 13 January, 19 January and 1 February 2005. Samples were taken for: phytoplankton nitrate, ammonium and urea uptake measurements, using stable isotope incubations and also primary production PvE curves were produced using 14C radioisotope incubations; Dissolved macronutrients (nitrate, silicate, phosphate, and urea); Surface dissolved iron. A scaled-down sampling RaTS event was performed by the Rothera Marine Assistants involving sampling for all above measurements once every 3 weeks at the 5m depth only at the RaTS site.