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Job Vacancy – NERC PhD Studentship (subject to funding) – Winners and losers in a more acidified ocean: impact on physiology and life history of two pteropod species

November 28, 2013

Supervisors: Clara Manno (BAS), Dorothee Bakker (UEA), Victoria Peck (BAS), Geraint Tarling (BAS)

Ocean acidification, induced by increasing anthropogenic carbon dioxide emissions, is recognized by reductions in pH, carbonate ion concentration, and calcium carbonate saturation state in the upper ocean. These effects are especially severe at high-latitudes, where cold temperatures enhance the solubility of CO2. Pteropods, the main planktonic producers of aragonite in the worlds’ oceans, are particularly vulnerable to forecasted changes in sea water carbonate chemistry. Although polar species L. helicina and sub-polar species L. retroversa belong to the same genus, their life-history and physiology are different. Biogeographic shifts in species distributions resulting from a change in environmental conditions are widely reported, particularly during the present era of rapid regional climatic change. Since L. helicina is the dominant calcifying species in some parts of the Southern Ocean, its potential regional extinction through ocean acidification can have wide biogeochemical implications. Whether or not L. retroversa will replace L. helicina is an important question for polar foodwebs and carbon budget.

The project rationale is to carry out comparative analyses on the physiology and life-history of L. helicina and L. retroversa mainly in the Southern Ocean, but also on existing Arctic datasets. The sensitivity of both species to ocean acidification will be investigated in incubation experiments, with manipulated seawater, in order to estimate the specific responses of these organisms under the combined impacts of increasing of CO2 levels and temperature.

The student will use sediment trap samples, within the BAS sample archives, to measure morphological features of both pteropod species over several annual cycles and to carry out analysis of population dynamics. During a sampling campaign (within the Scotia Sea and South Georgia region), the student will undertake incubations of both species in manipulated seawater to examine their physiological response to key anthropogenic stressors (increases in the CO2 level and temperature).The student will determine the vertical profiles of total alkalinity (TA), dissolved inorganic carbon (DIC), nutrients and the aragonite saturation state at sites where pteropods are collected. He/She will investigate existing net samples along a north-south transect from sub-polar to polar latitudes in the Arctic and Antarctic in order to compare the role of the key environmental variables in the abundance and distribution of both Limacina species.

The BAS Ecosystems programme (see BAS website) has been carrying out annual sampling campaigns in the vicinity of the northern Scotia Sea and South Georgia for more than 20 years and has a considerable archive of data with which to place a context around the present findings. It is also one of the most rapidly warming regions of the Southern Ocean and is therefore an ideal location within which to consider the impact of climate change on pteropod population dynamics.

The candidate will have at least a 2.1 honours degree in biology, or a branch of environmental science. He/She will participate in one Southern Ocean sampling campaign for which he/she will receive training in sea-survival techniques and field-laboratory health and safety. The student will be enrolled in the UEA Science Graduate School (www.uea.ac.uk/sci/gradschool/training).

Applications for this studentship should be addressed to Dr. Clara Manno clanno@bas.ac.uk and include a covering letter, CV and the e-mail addresses of two referees

Please note applications must be made directly to the supervisor (as indicated above), not via the online button

Closing date for applications is Monday 6th January 2014
https://www.uea.ac.uk/science/graduate-school/home/prospective-students/enveast-nerc-doctoral-training-partnership

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