Protists and protistology in the Anthropocene: challenges for a climate and ecological crisis

Abstract

Eukaryotic microorganisms, or "protists," while often inconspicuous, play fundamental roles in the Earth ecosystem, ranging from primary production and nutrient cycling to interactions with human health and society. In the backdrop of accelerating climate dysregulation, alongside anthropogenic disruption of natural ecosystems, understanding changes to protist functional and ecological diversity is of critical importance. In this review, we outline why protists matter to our understanding of the global ecosystem and challenges of predicting protist species resilience and fragility to climate change. Finally, we reflect on how protistology may adapt and evolve in a present and future characterized by rapid ecological change.

Keywords: Algae; Climate breakdown; Decarbonization of research; Decolonialization of science; Meta-genomics; Thermal niche.

Fig. 1

Importance of protists to the global earth ecosystem. The inner wheel of this figure shows 8 UN Sustainable Development Goals (SDGs), adapted freely from [59]. The outer wheel shows drawings of representative protists, adapted freely from [60], overlaid over SDGs to which they are particularly relevant. For clarity, each protist is only shown once even if it is relevant to multiple SDGs, and the visual organization of the drawings are independent of taxonomic affiliation, for which the reader is directed to [60]

Fig. 2

Temperature optima of phylogenetically distant Arctic algae from experimental and field data. The strains in this figure are derived from the NCMA and RCC culture collections [96, 140], alongside new ones (RCC7840-7856) isolated from seawater collected during the 2021 Amundsen Darkedge expedition. Top: heatmap of measured exponential growth rates, over seven temperatures (from 0 °C to 32 °C) under 35‰ salinity, and three additional salinities (from 14‰ to 3.5‰) at 4 °C. Species are shaded by taxonomic affiliation. Double-lined boxes show strains that show > 99% 18S rRNA sequence identity to one another and can be considered as species. Bottom: plot of Tara Oceans 18S v4 ribotype relative abundances of the most abundant diatom (Chaetoceros sp. RCC7850) and flagellate (Pyramimonas sp. RCC7841) shown relative to station latitude and temperature. Complete data for all distributions are provided in Table S1

Fig. 3

Temperature optima of and collection sites of phylogenetically close but geographically distant haptophytes. This figure shows (top) measured growth rates and (bottom) collection sites of 15 haptophyte strains from the genera Pavlova and Imantonia/ Pseudohaptolina, shown as per Fig. 2. Tara Oceans distributions for all strains are provided in Table S1

Fig. 4

Roles and actions for the protistologists of the Anthropocene. Different actions that the protistology community might consider taking, within and beyond our research. These are divided into what we study, how this research is performed, and actions we can take beyond scientific research to advocate for planetary ecology