Discovery Science

Discovery Science showcases new and exciting developments on specific features of ERSEM. Here we focus on the scientific advancements that set ERSEM apart from, and ahead of, other existing marine ecosystem models making it one of the most powerful ecosystem models in the field.

 

Plankton physiology

Plankton are organisms that drift in oceans, seas, and fresh water. Although often invisible to the human eye, planktonic organisms are the ‘engine’ of the ocean, sustaining the whole food chain and modulating carbon and nutrient cycles.

Plankton live in a challenging environment where light, temperature and nutrient concentrations vary constantly. To cope with such variability these tiny organisms have developed specific physiological mechanisms on which, ultimately, the functioning of the whole marine system depends. The study of plankton physiology and plankton's resilience to change is therefore crucial if we want to understand, exploit and preserve the marine ecosystem.

We develop model formulations that describe plankton physiology with the aim of capturing the key features affecting growth and fitness of these crucial organisms.

Further information

Please contact: Luca Polimene

Related publications

  • Polimene L, Brunet C, Butenschön M, Martinez-Vicente V, Widdicombe C, Torres R and Allen JI. 2014. Modelling a light-driven phytoplankton succession Journal of Plankton Research, DOI:10.1093/plankt/fbt086
  • Talmy D, Blackford J, Hardman-Mountford NJ, Polimene L, Follows MJ and Geider RJ. 2014. Flexible C:N ratio enhances metabolism of large phytoplankton when resource supply is intermittent. Biogeosciences, 11 5881-4895. DOI: 10.5194/bg-11-4881-2014
  • Polimene L, Mitra A, Sailley SF, Ciavatta S, Widdicombe CE, Atkinson A, Allen JI. 2015. Decrease in diatom palatability contributes to bloom formation in the Western English Channel. Progress in Oceanography, in press. DOI:10.1016/j.pocean.2015.04.026
  • Pinna A, Pezzolesi L, Pistocchi R, Vanucci S, Ciavatta S, Polimene L. 2015. Modelling the Stoichiometric Regulation of C-Rich Toxins in Marine Dinoflagellates. PLoS ONE 10(9): e0139046. doi:10.1371/journal.pone.0139046
  • Polimene L, Brunet C, Allen JI, Butenschon M, White DA and Llewellyn CA. 2012. Modelling xanthophyll photoprotective activity in phytoplankton. Journal of Plankton Research, 34(3):196-207 DOI: 10.1093/plankt/fbr102
  • Polimene L, Archer SD, Butenschon M, Allen JI. 2012. A mechanistic explanation of the Sargasso Sea DMS “Summer Paradox” Biogeochemistry. DOI 10.1007/s10533-011-9674
  • Allen JI and Polimene L. 2011. Linking physiology to ecology: toward a new generation of plankton models Journal of Plankton Research 33(7): 989-997 DOI: 10.1093/plankt/fbr032
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Zooplankton

Zooplankton are marine animals that range in size from the microscopic (0.02mm) to about 2cm or more. This broad definition includes animals like copepods, krill and jellyfish. The variety in size and appearance is complemented by the variety of feeding behaviour possessed by zooplankton. Some use net-like structures to capture their prey, others ambush, whilst some are hunters. These are just a few of the traits that characterise different zooplankton.

Zooplankton are a vital link in the food chain from phytoplankton to fish. Representation of zooplankton in marine ecosystem models is usually very simple and just based on their size. At PML, we are in the process of improving their representation by incorporating their nutrient content (carbon, nitrogen and phosphorus) into our model and plan to follow this with inclusion of feeding behaviour. This will allow us to better represent the variety of zooplankton that exists in nature and the impact they have on the rest of the marine ecosystem. Further information

Please contact: Sevrine Sailley

Related publications

  • Sailley SF, Polimene L, Mitra A, Atkinson A and Allen JI. 2015. Impact of zooplankton food selectivity on plankton dynamics and nutrient cycling. J. Plankton Res. (May/June 2015) 37 (3): 519-529. doi:10.1093/plankt/fbv020
  • Polimene L, Mitra A, Sailley SF, Ciavatta S, Widdicombe CE, Atkinson A, Allen JI. 2015. Decrease in diatom palatability contributes to bloom formation in the Western English Channel. Progress in Oceanography 137: 484-497. doi:10.1016/j.pocean.2015.04.026
  • Sailley SF, Vogt M, Doney SC,  Aita MN, Bopp L, Buitenhuis ET, Hashioka T, Lima I, Le Quéré C and Yamanaka Y. 2013.  Comparing food web structures and dynamics across a suite of global marine ecosystem models. Ecological modelling 261-262: 43-57. doi:10.1016/j.ecolmodel.2013.04.006
Zooplankton imagesTop left: Copepod, Top Right: Krill, Bottom: Jellyfish
 

Microbial Processes

Marine microorganisms (phytoplankton and bacteria) have the potential to affect the global climate by using CO2 which dissolves in the oceans from the atmosphere. Once fixed by photosynthesis, a large portion of this carbon is respired back to the atmosphere while a minor (highly variable) fraction is retained in the ocean interior for extended time frames, contributing to the capacity of the ocean to sequester atmospheric CO2. The sinking of biological particles (living organisms and/or detritus) from the surface to the deep-ocean and sediments is traditionally regarded as the main biologically-driven mechanism of carbon sequestration. However, a separate process, which scientists have only recently conceptualised, provides another way of removing and storing atmospheric CO2. This process is termed the Microbial Carbon Pump (MCP) and describes the bacterially- mediated production of recalcitrant dissolved organic matter, a mixture of (still largely uncharacterised) organic compounds which are resistant to further degradation. The MCP is not considered in global models and this makes current estimates of the ocean carbon budget potentially incorrect. By using ad hoc performed experiments, we aim to develop robust model formulations able to capture the key mechanisms driving the MCP with the final goal to represent this potentially crucial process in global ocean simulations.

Please contact: Luca Polimene

Related publications

  • Polimene, L., Clark, D., Kimmance, S. and P. McCormack. 2017. A substantial fraction of phytoplankton-derived DON is resistant to degradation by a metabolically versatile, widely distributed marine bacterium. PLoS ONE, 12(2): e0171391. doi:10.1371/journal.pone.0171391
  • Polimene, L., Rivkin, R.B., Luo, Y.-W., Kwon, E.Y., Gehlen, M., Peña, M.A., Wang, N., Liang, Y., Kaartokallio, H. and N. Jiao. 2018. Modelling marine DOC degradation time scales. National Science Review, 5(4): 468–474.doi:10.1093/nsr/nwy066
  • Polimene, L., Sailley, S., Clark, D., Mitra, A. and J.I. Allen. 2017. Biological or microbial carbon pump? The role of phytoplankton stoichiometry in ocean carbon sequestration. Journal of Plankton Research, 39(2): 180–186. doi:10.1093/plankt/fbw091