Mediterranean Institute of Oceanography AMU

Personal webpage for Dr Oliver Ross

Contact Information:

Oliver Ross, PhD (Senior Researcher)
Dept of Physical & Coastal Oceanography (OPLC)
Aix-Marseille University
Marseille, FRANCE
email: please add "oliver.ross" to @univ-amu.fr
Oliver Ross
www: MIO staff page · Google Scholar · Research Gate · LinkedIn
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Research Interests

I am a physical oceanographer, interested in the biological-physical interactions in the ocean. My work has been broadly concerned with the individual based (Lagrangian) modelling of phytoplankton dispersion in the ocean in response to turbulence mixing and the effect of the varying

Shelf Sea Schematic

Example schematic of a stratified shelf sea.

underwater light environment on phytoplankton physiology and primary production, including possible behavioural responses (motility). I currently work as a senior researcher on the AMICO project and am a current member of the scientific subcommittee of the IOC funded GEOHAB consortium.

I use a combination of modelling and observational approaches to study processes ranging from the small- to the meso-scales. Some of my main lines of research include:

Lagrangian (individual based) modelling

Example Particle trackExample Particle track

Example particle track of a cell following a combined nutrient-light optimising swimming strategy in a tidally energetic stratified shelf sea (from Ross & Sharples 2007). The colour represents the nutrient status while the dashed horizontal lines show the location of the nutricline (the thermocline is between 50 and 60m).

Example light history

Example particle trackds (top) and associated light histories (bottom) of a cell in a 150m SML with 2 different mixing intensities (from Ross et al 2008).

I have used individual based (Lagrangian) particle tracking models in combination with k-ε turbulence closure schemes in order to

  • study the diffusion of plankton cells in response to turbulence mixing
  • estimate the rate of sedimentation from the oceanic surface mixing layer
  • conduct competition experiments between motile and non-motile species in order to quantify the competitive advantage bestowed by motility in different turbulent environments
  • examine the effect of different mixing regimes on the light history and in situ growth and primary production.




Turbulence modelling and measurements

Mixing time scale

Illustration of the mixing time scale τm (from Ross et al 2011).

I have used a wide range of turbulence models that include

  • 1D k-ε schemes
  • kinematic simulations
  • Direct Numerical Simulation of turbulence
  • and the transilient matrix method
The method of choice always depends on the question at hand but mostly I have worked with 1D vertical turbulence schemes as my main interests were focused on the vertical mixing and its effect on marine biology. For in situ measurements I have used a SCAMP (microstructure profiler).

Phytoplankton photophysiology

Modelling reaction centres

Modelling reaction centres (from Ross et al 2008).

By combining the individual based particle tracking with a turbulence model and a biological growth model, it is possible to examine processes which depend on the individual light history of the cells, such as photoacclimation or photoinhibition.

Harmful Algal Blooms in a Mediterranean microtidal estuary

Modelling the redisdence time

Modelling the residence time of phytoplankton cells in Alfacs Bay.

Through a combined modelling and observational approach to examine the role that physics plays in the development and maintenance of blooms inside a Mediterranean bay which suffers recurring outbreaks of harmful algal blooms (HABs). It could be demonstrated that under certain meteorological conditions, the residence time of cells inside the bay is greatly increased which is advantageous for the cells, as the bay is relatively rich in nutrients compared to the rather oligotrophic (low nutrient) open Mediterranean Sea, and a longer residence time in the bay therefore means better growth conditions and a higher probability of bloom formation and maintenance.

3D biogeochemical modelling of the Gulf of Lion area

I am currently working on the AMICO-BIO project which deals with the 3D numerical biogeochemical simulation of the Western Mediterranean and the Bay of Biscay using a range of models such as MARS3D-ECO3M, Symphonie-ECO3M or PISCES.

Figure2

Satellite (MERIS) image of chlorophyll-a concentration. The dashed area shows the location of the Northern Current (NC). The sharp drop in Chl concentration near the shelf edge (arrows) indicates how the horizontal dispersal of Chl beyond the shelf edge is blocked by the NC.



(click to feed the fish)