16 January 2017

PhD Studentship available for application

Rapid climate change and its impact on biogeochemical cycling a carbon sequestration in Arctic sediments

PhD Supervisors:

Prof Ursula Witte (Oceanlab, University of Aberdeen), u.witte@abdn.ac.uk; http://www.abdn.ac.uk/oceanlab/research/ursula-witte.php

Dr. Greg Cowie, University of Edinburgh; dr.greg.cowie@ed.ac.uk; http://www.geos.ed.ac.uk/geosciences/people/glcowie

Background Marine sediments form a major reservoir in the global carbon (C) cycle and Nitrogen (N) cycles, and C and N cycling or burial in these sediments constitute important ecosystem services that can supply nutrients to primary producers or sequester them on geological time scales. Climate change is ongoing, and amongst the most striking evidence is the rapid reduction in Arctic Sea Ice cover, which has profound consequences for the timing and amplitude of primary production (PP), and the relative contribution of the various primary producers to overall PP. Due to close benthic-pelagic coupling in arctic marine ecosystems, changes in PP patterns are likely to cascade quickly to benthic food webs, and key ecosystem functions such as nutrient recycling or carbon storage.

Project description This PhD studentship will investigate the link between the timing and characteristics of the sedimentation of particulate organic matter (POM) to the seafloor and and the mediation of C and N cycling or burial rates by the benthic community. Specifically, OM sedimentation patterns and community response will be recorded year-round through deployment of an under-ice benthic observatory. In addition, yearly cruises with the Canadian icebreaker CCGS Amundsen will allow sampling of and experimentation with sediment and benthic fauna. The relative significance of different primary producers as food source for the benthos, as well as their relative contribution to nutrient cycling and sequestration will be assessed through analysis of biomarkers, compound specific isotope analysis, and benthic flux measurements. Biomarker analyses (including pigments, amino acids and lignin) of sinking particulates and surficial sediments will provide insights on the algal sources and the "quality" of OM delivered to the benthos. A highly resolved and dated down core sediment biomarker profile will provide a detailed record of recent changes in environmental conditions, OM sources and C, N and P burial at the site. The work will be carried out in close collaboration with the Canadian research network ArcticNet,and Professor Philippe Archambault (Laval University, Quebec) will serve as an external supervisor.

Research Training The successful candidate will work as part of an interdisciplinary team at the interface between benthic biogeochemistry, marine biology and modeling and will be trained in a wide range of field and laboratory techniques. Furthermore the student will have the opportunity to attend a wide variety of PDP courses offered by the Universities of Aberdeen and Edinburgh on generic or subject specific skills that are essential for the transition to employment.

To apply, please send a CV (including references) and covering letter to u.witte@abdn.ac.uk

Application deadline: 10.2.2017. Interviews will be held in Edinburgh 21– 24.2.2017.


Author: Prof. Ursula Witte


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