Responsible: Sandra Irén Bongo
E-mail: sandrib@student.ibv.uio.no
Supervisors: Adriana Lopes dos Santos, Bente Edvardsen and Daniel Vaulot
Aim
To define the genetic diversity of the class Labyrinthulomycetes based on DNA sequencing from references sequences obtained from cultures and the environment, including samples from the the Oslofjord. With this DNA sequencing data, further investigations of their biogeography can be made and by linking their diversity across distinct planktonic communities such that one can gain a better understanding of their functional role in various ecosystems. This understanding is important as this class of protist is cosmopolitan and therefore potentially serve a critical role in the interactions of large parts of the world’s ocean, especially as key players in the detrial food web.
Background
Protists, single-celled eukaryotic organisms, make up the bulk of the diversity in the eukaryotic domain and cover a great range of morphologies, life-histories, trophic modes (e.g. autotrophs, heterotrophs and mixotrophs) and are major participants in marine biogeochemical cycles [Sherr et al., 2007]. And yet, they have been historically neglected from eukaryotic community assessments and taxonomic studies in favour of their multicellular siblings [Burki et al., 2020]. This gap in knowledge makes the stability of the protist community especially vulnerable in the face of climate change and other global change drivers.
Labyrinthulomycetes is a group of ubiquitous protists that is present in an extremely diverse range of habitats, including both marine and freshwater, as well as soil environments [Raghukumar and Damare, 2011]. From polar to tropical regions, spanning depths from the uppermost pelagic surface to the deep sea, and also present in various kinds of biotic substrates such as inside of algae, mangrove leaves, seagrasses, coral mucus and molluscs. Additionally, they are similar to fungi, in that they are key players in the detrital food web, breaking down and absorbing decaying organic matter that is otherwise inaccessible to other small grazing organisms. On the other hand, they are also infamous for some of the species’ parasitic behaviour and are to blame for the seagrass wasting disease in the 1930s, decimating up to 90% of eelgrass meadows throughout the North Atlantic [Graham et al., 2021].
Whether positive or negative, Labyrinthulomycetes play a crucial part in the oceanic ecosystem, and it is therefore important to gain a better understanding of this group in order to, among other things, create a monitoring program that provides a framework for detective invasive species and early outbreaks.