Lake Ecosystem Robustness and Resilience Inferred from a Climate-Stressed Protistan Plankton Network

Abstract

Network analyses of biological communities allow for identifying potential consequences of climate change on the resilience of ecosystems and their robustness to resist stressors. Using DNA metabarcoding datasets from a three-year-sampling (73 samples), we constructed the protistan plankton co-occurrence network of Lake Zurich, a model lake ecosystem subjected to climate change. Despite several documentations of dramatic lake warming in Lake Zurich, our study provides an unprecedented perspective by linking changes in biotic association patterns to climate stress. Water temperature belonged to the strongest environmental parameters splitting the data into two distinct seasonal networks (October–April; May–September). The expected ecological niche of phytoplankton, weakened through nutrient depletion because of permanent thermal stratification and through parasitic fungi, was occupied by the cyanobacterium Planktothrix rubescens and mixotrophic nanoflagellates. Instead of phytoplankton, bacteria and nanoflagellates were the main prey organisms associated with key predators (ciliates), which contrasts traditional views of biological associations in lake plankton. In a species extinction scenario, the warm season network emerged as more vulnerable than the cold season network, indicating a time-lagged effect of warmer winter temperatures on the communities. We conclude that climate stressors compromise lake ecosystem robustness and resilience through species replacement, richness differences, and succession as indicated by key network properties.

Destabilization of the Bacterial Interactome Identifies Nutrient Restriction-Induced Dysbiosis in Insect Guts

“…Network stability was assessed as network robustness calculated with the R package NetSwan ( 100 ) using the function “ swan_combinatory () ” by calculating the loss of connectivity among OTUs once nodes are removed. We stepwise removed the nodes from the network and recorded the loss of connections, measured as the decrease of the overall betweenness centrality and as decreased betweenness centrality recalculated in a cascading scenario after removal of each node ( 101 , 102 ).…”

Molecular Data Reveal a Cryptic Diversity in the Genus Urotricha (Alveolata, Ciliophora, Prostomatida), a Key Player in Freshwater Lakes, With Remarks on Morphology, Food Preferences, and Distribution

“…The present study combines morphological, ecological, and genetic approaches and offers a valuable basis for future ciliate research (Spanner et al, 2020;Forster et al, 2021;Pröschold et al, 2021;Qu et al, 2021). It provides the first single cell barcodes of morphologically investigated urotrich ciliates.…”

“…Linking taxa/species with more or less known ecological preferences to DNA metabarcoding datasets is essential for inferring food web structures and processes from HTS datasets (e.g., Forster et al, 2021;Pröschold et al, 2021;Qu et al, 2021). Therefore, we performed an experiment for at least one of our barcoded urotrichs, i.e., strain CIL-2017/25 to gain insights into the ciliate's autecology.…”

Detection of the Deep-Sea Plankton Community in Marine Ecosystem with Underwater Robotic Platform

“…Plankton are organisms that live in oceans and fresh water [1] that play an important role in the material and energy recycling within the marine food chain [2]. The study of plankton community and plankton itself is indispensable for understanding of marine resources and the impacts of climate change on ecosystems [3]. In addition, the number of plankton is a key indicator of carbon and energy cycling [4], and of great significance to species diversity and ecosystem diversity [5].…”