DC5 - Antagonistic symbionts and their potential role in controlling HABs in coastal areas

Advisors: Oddur Vilhelmsson, Justyna Wolinska, Bettina Scholz

Location: University of Akureyri

How to apply for this position
The submission deadline for this project is May 15th, 2024 and we are not accepting any more application at this time.

Context:

Blue mussels (Mytilus edulis) have been grown experimentally around the coast of Iceland with approximately 12 t harvested in 2009, up to 130.5 t in 2012. But the further expansion was hampered by recurrent harmful algal blooms (HABs) and today only very few mussel farms exist. Alexandrium spp., Dinophysis spp. and Pseudo-nitzschia spp. are known to produce different classes of toxins, which are bio-accumulated in filter feeders such as M. edulis. If theses mussels are consumed by humans and other organisms, the accumulated toxins can cause different illnesses and, in some cases, lead to death (e.g., paralytic, diarrhetic, neurotoxic, amnesic, and azaspiracid shellfish poisoning). Also, non-toxic HABs are occurring regularly around Icelandic coastal areas causing damage to ecosystems, fisheries resources, and recreational facilities, often due to the sheer biomass of the accumulated algae and oxygen depletion in bottom waters after the bloom. Bloom control is the most challenging and controversial aspect of HAB management, and it is the one area where HAB science is rudimentary and very slow moving. Focusing on ecological solutions, in the present project potentially antagonistic species groups such as grazers, parasites, algicidal bacteria and competitors will be identified, isolated, cultured and tested for their effectiveness against selected HAB species in microcosm experiments. Comparative exometabolomics and transcriptomics will additionally shed light on underlying mechanisms of the HAB control process.

Objectives: 
1) Identify, through microscopic identification and meta-barcode sequencing, and in vitro culturing HAB species and their associated antagonists such as chytrids, oomycetes, algicidal bacteria and zooplankton over a one-year sampling period collected from affected blue mussel farms in Iceland. 
2) Record, through in vitro experimentation, the different inter-species interactions between HAB and their antagonists. 
3) Investigate the infection process, at the microscopic level of at least three HAB antagonists and perform preliminary laboratory tests of biological control of harmful dinoflagellates and/or diatoms using the identified pathogens.

Expected Results: 
1) Completion of HAB and associated antagonists community profiles through eDNA sequencing.
2) Purification and identification of HAB species and their associated antagonists. 
3) Microscopic and molecular characterisation of the molecular mechanisms (during secondment at FVB-IGB) of the most voracious HAB-disruptive antagonists.

Planned secondment(s): 
At BioPol with Bettina Scholz for sampling campaigns, microscopic identification, isolation of individual HAB-pathogen pairs 
At FVB-IGB (twice) with Hans Peter Grossart for microcosm experiments, exometabolome analysis, and comparative transcriptomics of the herbivores.