SAHFOS-NOC PhD opp: Climate change and changes in zooplankton biomass in the North Atlantic

Climate change and changes in zooplankton biomass in the North Atlantic

Lead Supervisor – Claudia Castellani (SAHFOS), Dr Cathy Lucas (Ocean & Earth Science, Uos) and Martin Edwards (SAHFOS)

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Sir Alister Hardy Foundation for Ocean Science, Plymouth, United Kingdom

Recent studies have indicated that global warming will result in a spatial reorganisation of marine communities favoring an increase in smaller species (1, 2, 3). Such changes are predicted to impact both marine food-webs and biogeochemical cycling through decreases in total biomass, in the size fraction available to higher trophic levels (i.e. fish, birds and mammals) and in downward carbon export due to increased microbial remineralisation at the ocean surface. Zooplankton body size is a key parameter for the estimation of biomass, productivity and energy flux within marine ecological systems. However, zooplankton size and body composition can vary greatly both seasonally and spatially as a result of differences in environmental conditions under which the organism grow and develop.  Yet, accurate estimates of zooplankton body size and biomass particularly over wide spatial and temporal scales are rare. Consequently, ecological and modelling studies calculate zooplankton biomass and productivity using mean body sizes reported in the literature or determined from published allometric equations (1). This approach is likely to result in gross estimate errors, which at the present remain unquantified. The aim of this study is to quantify spatial and temporal changes in zooplankton size and biomass in the North Atlantic using a fast imaged-based automatic device (4).


Zooplankton body size has been classically determined through labor intensive microscopic measurements of the organism. From this, biovolume can then be estimated by approximating specimens to geometrical shapes and biomass by determining the weight or elemental composition (i.e. usually C and N). Microscopic measurements are time consuming and hence such determinations are rare in the literature. Recent development of automated optical systems, such as FlowCAM has enabled faster routine measurement of zooplankton size and their identification (4). The student will determine the basin scale variability in zooplankton taxa size and biomass by automatic analysis with Macro-flowCAM of preserved zooplankton samples collected by the Continuous Plankton Recorder (CPR) in the North Atlantic between 1960 and 2016. Zooplankton biomass will be determined through the analysis of CPR material using a C/N analyser. Both size and biomass measurements of zooplankton from CPR samples will be calibrated against non-preserved zooplankton samples collected at the same time of the year and in the same area using both fixed sampling stations in the English Channel (i.e. L4 and E1) and field work opportunities planned in the North Atlantic between 2017-2019 (NERC Arctic Food-webs program; AtlantOS


The SPITFIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at the Sir Alister Hardy Foundation for Ocean Science (SAHFOS). SAHFOS operates the Continuous Plankton Recorder (CPR) survey which is recognised as the longest and geographically most extensive marine biological survey in the world. The dataset comprises of ~1000 taxa recorded over multi-decadal periods. Training will include plankton ecology, global climate change and statistical techniques in spatial and temporal data analysis.

Specific training will include: 1) taxonomic identification of North Atlantic zooplankton taxa, 2) operation of the image-based analyser, Macro-FlowCam for automatic determination of the size and identification of the taxa of zooplankton, 3) determination of carbon and nitrogen content of zooplankton using C/N analyser.

We anticipate that the student will also partake in planned research cruises in recently funded projects (NERC Arctic, EU-project AtlantOS). Opportunities also exists with colleagues at NOC or other institutes (IMR, Norway; HAFRO, Iceland; DFO, Canada) to partake in additional cruises in the Arctic and in temperate North Atlantic areas.

Eligibility & Funding Details: 

This SPITFIRE project is open to applicants who meet the SPITFIRE eligibility, alongside other exceptional applicants and will come with a fully funded studentship for UK students and EU students who meet the RCUK eligibility criteria.  To check your eligibility and find information on how to apply click here.

UK applicants and EU students who meet the RCUK eligibility criteria please apply to SPITFIRE . This project is also open to applicants who DO NOT meet the SPITFIRE funding eligibility criteria via GSNOCS by applying to GSNOCS . Please make sure you apply to the correct programme and applications from non SPITFIRE eligible applicants will be rejected automatically.

Apply  here

Background Reading: 

  1. Beaugrand G., Edwards M. and Louis Legendre (2009) Marine biodiversity, ecosystem functioning, and carbon cycles. PNAS, 107: 10120–10124
  2. Daufresne M., Lengfellner K and Sommer U. (2009) Global warming benefits the small in aquatic ecosystems. PNAS, 106: 12788–12793
  3. Sheridan J.A. and Bickford D. (2011) Shrinking body size as an ecological response to climate change. Nature Climate Change, 1: 401-406.
  4. Alvarez E., Lopez-Urrutia A. and Nogueira E. (2011) Improvement of plankton biovolume estimates derived from image-based automatic sampling devices: application to FlowCAM, Journal of Plankton Research, 34: 454-469.

About Abigail McQuatters-Gollop

Marine biologist, guitarist, cat lover, red wine drinker. I like plankton.
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