2014/15 field season
It has been an amazing and unique start to the 2014/15 field season with new possibilities for our sampling as parts of Ryder Bay were still covered in sea ice and conditions were quite ‘winter like’. This allowed us to drill for ice cores as well as continuing the seawater sampling, capturing the transition from Antarctic winter to spring.
The ice cores were drilled at the same location to look at changes of biology and chemistry in the sea ice from winter up to the springtime melt; investigating the effects of sea ice on the seawater CO2 chemistry of Ryder Bay.
Continuing what we started during the 2013/14 field season is the ongoing weekly collection of seawater samples at certain locations across Ryder Bay, e.g., in front of the glaciers, over the deep central part of the bay, furthest offshore. This is building up a time series of data across the bay to look at the influence of different seasonal processes on the seawater CO2 chemistry.
Another exciting opportunity this season was the possibility to be able to join a short research cruise on the RRS James Clark Ross, sailing from Rothera on 31.12.14 and returning on 08.01.15. The cruise completed a 200 km transect out from the shelf break of the West Antarctic Peninsula, following the deep waters that flow into the coastal area along the deeper parts of the shelf. This was to investigate the effect of deep waters that contain high concentrations of nutrients and CO2, on the seawater chemistry of the inshore regions such as Ryder Bay. We sampled at 11 sites from the surface to the deep ocean, which was up to 1500 m deep, to capture the different layers of the ocean.
The second part of the season (February-March) brings something else new as we have started some incubation experiments of the seawater phytoplankton community with different CO2 conditions, i.e., changing the atmospheric CO2 concentrations to stimulate past, present and future atmospheric CO2 conditions. Here we took a large volume of water from central Ryder Bay and put it into several different incubation bottles that sit in a large tank outside with a flow-through of natural seawater to maintain natural seawater and day-night light conditions.
Every 24-48 hours the bottles are sampled for numerous chemical and biological parameters to monitor the response of the phytoplankton under the different CO2 conditions. We will repeat this set-up using seawater with low iron concentrations from the offshore part of Ryder Bay to look at the effect of low iron and different CO2 conditions on the phytoplankton. To follow this work, we will continue the time series of iron and trace metal sampling in central Ryder Bay, as was started during the 2012/13 field season by the NIOZ trace metal team J. Bown and P. Laan.