Mixotrophic activity and diversity of Antarctic marine protists in austral summer
MetadataShow full item record
Identifying putative mixotrophic protist species in the environment is important for understanding their behavior, with the recovery of these species in culture essential for determining the triggers of feeding, grazing rates, and overall impact on bacterial standing stocks. In this project, mixotroph abundances determined using tracer ingestion in water and sea ice samples collected in the Ross Sea, Antarctica during the summer of 2011 were compared with data from the spring (Ross Sea) and fall (Arctic) to examine the impacts of bacterivory/mixotrophy. Mixotrophic nanoplankton (MNAN) were usually less abundant than heterotrophs, but consumed more of the bacterial standing stock per day due to relatively higher ingestion rates (1–7 bacteria mixotroph−1 h−1 vs. 0.1–4 bacteria heterotroph−1 h−1). Yet, even with these high rates observed in the Antarctic summer, mixotrophs appeared to have a smaller contribution to bacterivory than in the Antarctic spring. Additionally, putative mixotroph taxa were identified through incubation experiments accomplished with bromodeoxyuridine-labeled bacteria as food, immunoprecipitation (IP) of labeled DNA, and amplification and high throughput sequencing of the eukaryotic ribosomal V9 region. Putative mixotroph OTUs were identified in the IP samples by taxonomic similarity to known phototroph taxa. OTUs that had increased abundance in IP samples compared to the non-IP samples from both surface and chlorophyll maximum (CM) depths were considered to represent active mixotrophy and include ones taxonomically similar to Dictyocha, Gymnodinium, Pentapharsodinium, and Symbiodinium. These OTUs represent target taxa for isolation and laboratory experiments on triggers for mixotrophy, to be combined with qPCR to estimate their abundance, seasonal distribution and potential impact.
© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Marine Science 5 (2018): 13, doi:10.3389/fmars.2018.00013.
Suggested CitationFrontiers in Marine Science 5 (2018): 13
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
Linking bacterivory and phyletic diversity of protists with a marker gene survey and experimental feeding with BrdU-labeled bacteria Fay, Scott A.; Gast, Rebecca J.; Sanders, Robert W. (Inter-Research, 2013-12-16)Over the last few decades, molecular methods have vastly improved our ability to study the diversity of microbial communities. In molecular diversity surveys, the function of protists is often inferred from phylogeny. Yet ...
Defining planktonic protist functional groups on mechanisms for energy and nutrient acquisition : incorporation of diverse mixotrophic strategies Mitra, Aditee; Flynn, Kevin J.; Tillmann, Urban; Raven, John A.; Caron, David A.; Stoecker, Diane K.; Not, Fabrice; Hansen, Per J.; Hallegraeff, Gustaaf M.; Sanders, Robert W.; Wilken, Susanne; McManus, George; Johnson, Matthew D.; Pitta, Paraskevi; Våge, Selina; Berge, Terje; Calbet, Albert; Thingstad, Frede; Jeong, Hae Jin; Burkholder, JoAnn M.; Glibert, Patricia M.; Graneli, Edna; Lundgren, Veronica (Elsevier, 2016-01-03)Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally ...
Orsi, William D.; Song, Young C.; Hallam, Steven J.; Edgcomb, Virginia P. (2012-01-10)Changes in ocean temperature and circulation patterns compounded by human activities are leading to oxygen minimum zone expansion with concomitant alteration in nutrient and climate active trace gas cycling. Here, we ...