Global drivers of eukaryotic plankton biogeography in the sunlit ocean

Abstract

Circulating in the sunlit ocean Marine plankton, which lie at the base of oceanic food chains, drive global biogeochemical fluxes, and knowledge of their distribution is key to understanding the response of oceans to environmental changes. Sommeria-Klein et al . explored the patterns and drivers of biogeography in eukaryotic plankton using a probabilistic model of taxon co-occurrence to compare the biogeography of 70 major groups, including a variety of size fractions and ecologies. The analysis is based on metabarcoding data from 129 stations in several oceanic provinces worldwide. Samples are from sunlit surface waters and, in about half of the stations, from the deep chlorophyll maximum. An essential message is that small phototrophs distribute mostly by latitude and bigger consumers are partitioned by ocean basin. —CA

metaPR2: a database of eukaryotic 18S rRNA metabarcodes with an emphasis on protists

“…In terrestrial environments, Hacrobia are almost completely absent while Amoebozoa are present but in contrast absent in all the others environments (Figure 6A). If we use the ecological function, as defined for each major taxonomic group by Sommeria-Klein et al (2021), the five environments clearly differ by the abundance of parasites, small number of phototrophs and absence of dinoflagellates in soils. While parasites are abundant in soils, they are not as abundant in freshwater and increase from coastal to oceanic waters (Figure 6B).…”

“…In marine waters, metabarcoding studies extended quickly and now tackle more focused questions, for example analysing the distribution of protist groups in the ocean as a function of their size (De Vargas et al 2015), the diversity of heterotrophic protists in the deep layers of the ocean (Giner et al 2020; Obiol et al 2021), detailed biogeographic distribution of specific taxa (e.g. Malviya et al 2016; Yau et al 2020), factors structuring marine plankton communities (Logares et al 2020; Sommeria-Klein et al 2021), and the seasonal succession of taxa (e.g. Giner et al 2019; Lambert et al 2019).…”

“…Many studies that performed analyses on the global ocean microbiota have used one or several of these three datasets, in particular Tara Oceans (e.g. Ibarbalz et al 2019; Sommeria-Klein et al 2021). Many more smaller-scale metabarcoding studies have also been carried out, in particular for environments that have been not sampled by these expeditions, such as soils or freshwater lakes and rivers (Lopes dos Santos et al 2021).…”

Copepod functional traits and groups show divergent biogeographies in the global ocean

“…Unfortunately, we cannot disentangle the effects of dispersal by currents on the observed community trait expression (and their modelled spatial patterns) from the effects of gradients in temperature and/or productivity, which select species based on their physiological requirements. Although ocean basin connectivity is rather high at the scale of our study (Jönsson & Watson, 2016), dispersal by marine currents and mesoscale processes are known to impact plankton community structure (Richter et al, 2020; Sommeria-Klein et al, 2021). For instance, the Antarctic Polar Front seems to be the main delimiter between regions 3 and 4, which coincides with the view that it imposes a strong physical barrier on passively drifting zooplankton (Murphy et al, 2021).…”

“…4). This uncertainty calls for more studies combining distribution models with dispersal rates and limitations (D’Amen et al, 2018; Shipley et al, 2021) to study the link between zooplankton functional traits and the “seascape” (Sommeria-Klein et al, 2021; Richter et al, 2020).…”