Exploration of community dynamics of protists during the autumn season through metabarcoding

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Supervisor: Prof. Bente Edvardsen

Co-supervisorSimon Hassel? Kline (PhD-student)

This Master’s project will be integrated into the cross-disciplinary “Coastal Ecosystems under anthropogenic pressures” research project.

Background

Single-celled protists constitute the majority of the diversity found within the Eukaryota domain of life and contain the oldest form of eukaryote life (Knoll, 1992). In our oceans, marine protists can be primary producers, consumers, decomposers or parasites serving as vital links between the various trophic levels and contributing to the biogeochemical cycles (Caron et al., 2012). As aquatic protists and microbes compose approximately 90% of the biomass in our oceans (Biddanda et al., 2021), any changes within the protist community are likely to have reverberating effects throughout the remaining ecosystem, which in turn may affect the overall resilience of marine ecosystems to changing conditions. The photosynthetic single-celled protists, the microalgae, and cyanobacteria in the free water masses (phytoplankton) form the basis of most marine food webs.

The yearly spring and autumn blooms that occur are one of the dominant features of the population growth pattern of phytoplankton in temperate waters and are events that have triggering effects throughout the remaining food web and ecosystem. The timing of phytoplankton blooms is often initiated through changes in the light regime or in the stratification of the water masses. In the Oslofjord the spring and autumn bloom have seen considerable delays since 2006 (Lunds?r et al., 2020). As phytoplankton represent the foundation of the marine ecosystem, any changes within the community composition or timing of the blooms will likely impact the remaining food web.

One of the major drawbacks of the traditional monitoring programs examining phytoplankton communities is that they are done through monthly samplings. There is therefore an inherent risk that certain aspects of the population dynamics are overlooked, as they may happen in the timespan between the sampling times. This is especially true during the spring and autumn blooms of phytoplankton in the Oslofjord.

Project description

In this Master’s project, the student will investigate the bloom dynamics of the less-studied autumn bloom in the Oslofjord through intensive sampling during a short period (exact timing to be decided, but approximately 2-3 times a week for one month). The genetic diversity of the phytoplankton community will be examined through metabarcoding of a specific marker gene. The intensive sampling will be compared with previous research projects which have done monthly sampling to examine any potential differences in the community composition. Samples for microscopical observations will also be collected and analysed.

Possible questions to be answered:

  1. What is the composition of the phytoplankton community seen through metabarcoding with intensive sampling in the autumn of 2023?
  2. Do we see any differences in the community composition with monthly sampling vs a more intensive sampling approach?
  3. Can we detect species in the autumn that are considered allochthonous warm water species?
  4. Through trait table analyses, how is the relative abundance of autotrophic versus heterotrophic species through the sampling period, and compared to previous research samplings in Oslofjorden?

Learning Outcomes

You will have the opportunity to:

  • Join the monthly sampling cruises conducted in the Oslofjorden
  • Collaborate with a PhD-student, postdoc and other Master’s students participating in the “Coastal Ecosystems Dynamics under anthropogenic pressures” research project.
  • Collect data that may be used in a scientific publication, along with a potential co-authorship.

You will learn:

  • Sampling methods used in the field to collect planktonic samples.
  • How to process and analyze collected samples by molecular biological methods in the lab.  
  • How to analyse large metabarcoding datasets by bioinformatics and statistics.
  • How to perform phylogenetic reconstructions to identify microbial eukaryotes.
  • Identify some of the common protist/microalgal species by microscopy.

What we offer

We offer an inclusive and stimulating research environment where the student is encouraged to join the research group activities and engage with other students and researchers in the group. 

If you are interested:

Please send us a brief description of yourself and of your motivation for this project (max 500 words) to bente.edvardsen@ibv.uio.no and simonhk@ibv.uio.no.

References:

Biddanda, B., Dila, D., Weinke, A., Mancuso, J., Villar-Argaiz, M., Medina-Sánchez, J. M., González-Olalla, J. M., & Carrillo, P. (2021). Housekeeping in the hydrosphere: Microbial cooking, cleaning, and control under stress. Life, 11(2), 152.

Caron, D. A., Countway, P. D., Jones, A. C., Kim, D. Y., & Schnetzer, A. (2012). Marine protistan diversity. Annual review of marine science, 4(1), 467-493.

Knoll, A. H. (1992). The early evolution of eukaryotes: a geological perspective. Science, 256(5057), 622-627.

Lunds?r, E., Stige, L. C., S?rensen, K., & Edvardsen, B. (2020). Long-term coastal monitoring data show nutrient-driven reduction in chlorophyll. Journal of Sea Research, 164, 101925.

 

Publisert 11. juni 2023 15:53 - Sist endret 11. juni 2023 15:55

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