Two PhD opportunities, University of Otago, New Zealand

(1) PhD opportunity: ”Effect of ocean acidification on nitrogen fixation in the South Pacific”, University of Otago, New Zealand

Marine nitrogen fixation plays a major role in the biogeochemical cycling of C and N. Climate change related stressors such as ocean acidification and ocean warming have shown to significantly affect marine nitrogen fixation rates however, it seems that iron availability plays an overpowering role. Most research on nitrogen fixation has been performed in laboratory experiments or in the northern parts of the Atlantic and Pacific Ocean but very little is known about the South Pacific where primary production is low due to limiting nutrient concentrations. Changes in nitrogen fixation rates would therefore have significant implications for the ecosystem here. This PhD project will investigate the distribution and activity of diazotrophs in the South Pacific and quantify their contribution to primary production. In detailed incubation experiments the PhD student would further investigate the effect of ocean acidification, ocean warming, and iron availability on nitrogen fixation in this region.

The PhD student will receive training in all aspects of this project from participating in research cruises and performing incubation experiments on board, using especially designed incubators with precise pH control, metagenomics, and metatranscriptomics.

The successful applicant would be expected to be eligible for and to apply for a University of Otago PhD scholarship.

For more information about the project please contact:

Dr. Tina Summerfield Department of Botany

University of Otago New Zealand

http://www.otago.ac.nz/botany/staff/tinasummerfield.html e-mail: tina.summerfield(at)otago.ac.nz

Dr. Linn Hoffmann Department of Botany University of Otago New Zealand http://www.otago.ac.nz/botany/staff/linnhoffmann.html e-mail: linn.hoffmann(at)otago.ac.nz

More information about scholarships at Otago can be found here: http://www.otago.ac.nz/study/scholarships/database/otago014687.html

(2) PhD opportunity: ”Effect of ocean acidification on phytoplankton – bacteria interactions in Southern Ocean waters”, University of Otago, New Zealand

Marine phytoplankton live in close contact with a variety of bacteria and interact in form of chemical signalling. Interactions between marine phytoplankton and bacteria can thereby be mutualistic, parasitic or even pathogenic and therefore have a major impact on primary production and carbon export. Climate change related stressors such as ocean acidification and ocean warming will expose marine phytoplankton to enormous changes in their environment and potentially also affect phytoplankton – bacteria interactions. This PhD project will investigate the effect of ocean acidification on phytoplankton – bacteria interactions in natural Southern Ocean phytoplankton communities as well as in laboratory experiments.

The PhD student will receive training in all aspects of this project from participating in collection of seawater samples on board the Otago research vessel Polaris, using especially designed incubators with precise pH control, and measuring phytoplankton and bacteria community composition and activity using a combination of different methods including: microscopy, flow cytometry, FRRF, metagenomics, and metatranscriptomics.