Author: Jon  Lapeyra Martin, Sr. PhD (Université Libre de Bruxelles)

Designation: 

Description:
Protist plankton engaging  photo- and phago- mixotrophy (mixoplankton) are common and important members of the global plankton community. Based upon the origin of their chloroplasts in an eco-physiological context, two main types are considered: constitutive-mixoplankton (CM) and non-constitutive mixoplankton (NCM). Regardless of their significance, little attention has been paid to the characterization, diversity and temporal succession of these two major mixoplankton types. We performed Illumina MiSeq sequencing of V4-18S rRNA in 155 samples from the North Sea collected in 2018-2019, divided into three subsets: (i) >1 year time-series in the Belgian Coastal Zone, (ii) summertime period covering a broad latitudinal area, (iii) late spring post-phytoplankton bloom snapshot in Southern North Sea. Contextual environmental data: nutrients, T°, chl-a, and light were collected and evaluated for their influences over community changes. Dataset revealed that Dinophyta and Ciliophora were the major mixoplankton contributors. Data showed a significance of CM over the time-series, accounting for a high proportion (33.6%) of the reads, against  the low contribution of NCM (2.31%). CMs <em>Heterocapsa rotundata</em> and <em>Karlodinium veneficum</em> dominated, and co-occurred with strictly autotrophic plankton, especially in spring. Correlations of barcoding results with environmental data indicated that mixoplankton thrive in stratified and/or warm waters in North Sea summer, and their contribution dramatically decreases throughout the (low-nutrient) end phase of Phaeocystis blooms in SNS.

Category: Scientific Program Abstract > Special Sessions > SS52 New frontiers in mixoplankton research – lab, modeling, and field approaches