Medium-to-Large scale Physical-Biological Linkages in the Ocean

My research group considers physical variability as a controlling factor in the dynamics of life in the ocean. Large-scale physical processes can be shown to impact marine organisms at all trophic levels, but these commonalities can often only be seen by starting from the large scale and looking down to finer scales. For example, the collapse of the North-Atlantic sub-polar gyre in 1996 impacted many species, from phytoplankton to pilot whales and puffins, across the entire North Atlantic basin. However, a traditional species- or population-centric approach would not have detected such a major shift against the noisy background of local variability: only by looking across large spatial and temporal scales can we see such dynamics. It is this “big-picture” approach, using large-scale physical variability as a “red-thread”, that forms the core of the group.

The group works with three main applied research themes
•    Recruitment to fish stocks. Variations in the recruitment processes in fish are traditionally explained in terms of large-scale physical variability. Whilst this approach has not been particularly successful in the past, technological advances are opening up new avenues of investigation. In particular, the development of oceanographic circulation models provides the potential to perform investigations (particle tracking experiments, reanalysis of existing observations, scenario analysis) that were not previously possible, and thereby generate new insights into this perplexing question.
•    Phytoplankton phenology: causes and consequences. The annual cycle of phytoplankton growth and decay is strongly coupled to physical and chemical processes in the ocean. Variability in the physical environment, both in terms of seasonal cycles and inter-annual variation, therefore propagates directly into the biological realm. Furthermore, all organisms further up the food chain are exposed to this variability: the “match-mismatch hypothesis” in particular suggests that the recruitment of juvenile fish is directly influenced by variations in the synchronicity of the spring bloom and the emergence of the larvae. Research into phytoplankton phenology therefore links many different trophic levels to the physical processes in the ocean, and fits well within the research group.
•    Sub-decadal to climate-scale predictions of biological variability. Modern oceanographic circulation models are approaching a level of precision and accuracy whereby 5-20 year forecasts of key oceanographic variables are becoming feasible, especially in the North Atlantic. However, translating these forecasts of physical properties into biological outcomes remains challenging. In this research theme I aim to develop a set of methods and tools whereby systems that exhibit strong and predictable physical-biological coupling can be identified. These linkages can then be used together with the output from climate models to generate biological forecasts and to evaluate their robustness. In the initial phases, the work will focus on identifying the “low-hanging fruit”, and therefore will not be limited to a specific trophic level, population, or biological response: the goal is simply to identify what is predictable. Although the major focus of such work is on the sub-decadal to decadal scale, the same questions also apply at the multi-decadal to centennial scale (i.e.  climatic time-scales). Such work therefore also contributes to, and can benefit from, research on the impacts of climate change upon the biological elements in the worlds oceans.

The group is strongly tied to the tools and approaches that it uses.  In particular, the following tools are key to this work
•    Satellite remote-sensing products, with particular focus on ocean-colour.
•    Oceanographic circulation models
•    Individual-based models
•    Statistical modeling techniques, particularly for the analysis of observational data.
•    Inverse modeling techniques, particularly for adding value to exisiting biological observations.
In most cases, these existing technologies are applied as an end-user, rather than a developer (e.g. satellite products, circulation models). However, in some cases (e.g. inverse modeling techniques, individual-based modeling)  new tools are also developed: this balance between applying existing tools and developing new ones is a key feature of the work.
 

Open Positions

We always welcome applications from skilled and motivated candidates for PhD and PostDoc positions. We are also very interested in advising master thesis students. If you are interested, please get in touch with us.