A note on the differences found between examining whole water vs. phytoplankton net (52 μm mesh) samples to characterize abundance and community composition of tintinnid ciliates (marine microzooplankton)

Abstract

A note on the differences found between examining whole water vs. phytoplankton net (52 μm mesh) samples to characterize abundance and community composition of tintinnid ciliates (marine microzooplankton) AbstractMost tintinnid species have a shortest linear dimension < 50 μm. Hence, a priori, nets of mesh sizes ≥ 50 μm will likely under-sample most tintinnid species. However, studies often appear (23 since 2015) using sampling with nets of meshes sizes ≥ 50 μm, reporting both tintinnid concentrations, and community composition. How biased are results from using coarse mesh nets? We provide a comparison of whole water vs. net sampling based on fortuitous, that is, unplanned, parallel sampling. Pairs of samples from a standard monitoring station in the Bay of Villefranche (N.W. Mediterranean Sea) taken on 44 dates from 2013 to 2018 were compared. Tintinnids were enumerated in settled material from a water column sample, an integration of six discrete depth samples between 5 and 70 m, prepared for analysis of phytoplankton composition and in material from a plankton net (52 μm mesh) tow from 70 to 0 m, taken the same day. Despite the large confidence limits due to low raw cell counts from whole water samples, cell concentration estimates were about an order of magnitude higher than those from plankton net samples and frequently biomass estimates as well. Community composition also differed. The most common species in whole water samples were small (diameter ≤ 20 μm), and some common forms were absent, or nearly, from the net samples. We show that, while valuable for collecting larger and rarer species, coarse net samples do not yield robust estimations of overall concentrations, nor allow identification of the dominant tintinnid species.

Insights into freshwater ciliate diversity through high throughput DNA metabarcoding

“…Coleps and Colpoda from classes Prostomatea and Colpodea respectively, were also observed in the present study in all the sites. Levicoleps, Cryptocaryon , and Prorodon were observed from the class Prostomatea, which were not observed in microscopic study from the same sites, possibly due to their small size, making them difficult to capture (Dolan and Marro 2020 ).…”

Micro-/Meso-Scale Distinction and Horizontal Migration of Tintinnid (Ciliophora: Tintinnida) Assemblages in Three Regions Around the North Pacific Ocean

“…Ciliates and heterotrophic flagellates have a pivotal position as they are expected to be the main grazers of both phytoplankton and bacteria (Marshall, 1973;Lynn, 2008;Olson and Daly, 2013;Christaki et al, 2015;Forster et al, 2015). Recent studies have focused on molecular diversity and distribution patterns of ciliates (Santoferrara et al, 2016;Dolan and Marro, 2020;Ganser et al, 2021;Liu et al, 2021;Song et al, 2021). Ciliate abundances vary greatly, and form patches on meso-(km), fine-(m), micro-(cm) scales (Haury et al, 1978), or meso to large scale view (Yang et al, 2012;Varotsos et al, 2015).…”