Protist Diversity and Seasonal Dynamics in Skagerrak Plankton Communities as Revealed by Metabarcoding and Microscopy

Abstract

Protist community composition and seasonal dynamics are of major importance for the production of higher trophic levels, such as zooplankton and fish. Our aim was to reveal how the protist community in the Skagerrak changes through the seasons by combining high‐throughput sequencing and microscopy of plankton collected monthly over two years. The V4 region of the 18S rRNA gene was amplified by eukaryote universal primers from the total RNA / cDNA . We found a strong seasonal variation in protist composition and proportional abundances, and a difference between two depths within the euphotic zone. Highest protist richness was found in late summer‐early autumn, and lowest in winter. Temperature was the abiotic factor explaining most of the variation in diversity. Dinoflagellates was the most abundant and diverse group followed by ciliates and diatoms. We found about 70 new taxa recorded for the first time in the Skagerrak. The seasonal pattern in relative read abundance of major phytoplankton groups was well in accordance with microscopical biovolumes. This is the first metabarcoding study of the protist plankton community of all taxonomic groups and through seasons in the Skagerrak, which may serve as a baseline for future surveys to reveal effects of climate and environmental changes.

Large seasonal and spatial variation in nano- and microphytoplankton diversity along a Baltic Sea—North Sea salinity gradient

“…Specifically, picoplankton comprised, on average, 30% of the chlorophyll biomass across 29 stations in the Baltic Sea and the North Sea 41 and between 0 and 52% in the Kiel Bight, with the highest proportions observed during summer 42 . Recent studies have shown that species diversity estimates based on metabarcoding (also including picoplankton) are higher than estimates based on light microscopy but that direct conversions to species can be challenging 43 , 44 . Therefore, a combination of microscopy and genetic methods likely will more fully capture total phytoplankton community structure.…”

Seasonal Dynamics of Algae-Infecting Viruses and Their Inferred Interactions with Protists

“…Then, 10 × 250 µL of the virus concentrate were transferred into sterile cryo-tubes, flash-frozen in liquid nitrogen, and stored at −80 °C until further processing. Water for protist samples were filtered as described previously [34].…”

Monitoring of the toxic dinoflagellate Alexandrium catenella in Osaka Bay, Japan using a massively parallel sequencing (MPS)-based technique

“…Unfortunately, the change in the abundances of diatoms and dinoflagellates cannot be directly compared based on the relative sequence abundances as it may be influenced by the variations in copy number in different groups (e.g. Zhu et al, 2005;Gran-Stadniczeñko et al, 2018) and there is no phytoplankton community composition data obtained by light microscopy available from the sampling occasions. At the same time, diatom blooms generally display high species diversity (Guillard and Kilham, 1977;Smayda, 1980) compared to dinoflagellate blooms (Smayda and Reynolds, 2003) and thus the decline in species diversity detected during 2013-2015 may be regarded as a potential indicator for A. catenella bloom development in Osaka Bay.…”

“…Massively parallel sequencing (MPS) is a powerful method enabling detection of species unidentifiable by LM (e.g. Sogin et al, 2006;Caron et al, 2012;Nagai et al, 2017;Gran-Stadniczeñko et al, 2018) and revealing the hidden diversity of microbial communities in environmental samples (Tanabe et al, 2016;Nagai et al, 2016a;Dzhembekova et al, 2017;Sze et al, 2018).…”