Browsing by Autor "Mark O. Gessner"

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A global analysis of terrestrial plant litter dynamics in non-perennial waterways
(Nature Portfolio, 2018) Thibault Datry; Arnaud Foulquier; Roland Corti; Daniel von Schiller; Klement Tockner; Clara Mendoza‐Lera; Jean‐Christophe Clément; Mark O. Gessner; Marcos Moleón; Rachel Stubbington
Author Correction: A global analysis of terrestrial plant litter dynamics in non-perennial waterways
(Nature Portfolio, 2018) Thibault Datry; Arnaud Foulquier; Roland Corti; Daniel von Schiller; Klement Tockner; Clara Mendoza‐Lera; Jean‐Christophe Clément; Mark O. Gessner; Marcos Moleón; Rachel Stubbington
Global Patterns and Controls of Nutrient Immobilization on Decomposing Cellulose in Riverine Ecosystems
(Wiley, 2022) David M. Costello; Scott D. Tiegs; Luz Boyero; Cristina Canhoto; Krista A. Capps; Michaël Danger; Paul C. Frost; Mark O. Gessner; Natalie A. Griffiths; Halvor M. Halvorson
Abstract Microbes play a critical role in plant litter decomposition and influence the fate of carbon in rivers and riparian zones. When decomposing low‐nutrient plant litter, microbes acquire nitrogen (N) and phosphorus (P) from the environment (i.e., nutrient immobilization), and this process is potentially sensitive to nutrient loading and changing climate. Nonetheless, environmental controls on immobilization are poorly understood because rates are also influenced by plant litter chemistry, which is coupled to the same environmental factors. Here we used a standardized, low‐nutrient organic matter substrate (cotton strips) to quantify nutrient immobilization at 100 paired stream and riparian sites representing 11 biomes worldwide. Immobilization rates varied by three orders of magnitude, were greater in rivers than riparian zones, and were strongly correlated to decomposition rates. In rivers, P immobilization rates were controlled by surface water phosphate concentrations, but N immobilization rates were not related to inorganic N. The N:P of immobilized nutrients was tightly constrained to a molar ratio of 10:1 despite wide variation in surface water N:P. Immobilization rates were temperature‐dependent in riparian zones but not related to temperature in rivers. However, in rivers nutrient supply ultimately controlled whether microbes could achieve the maximum expected decomposition rate at a given temperature. Collectively, we demonstrated that exogenous nutrient supply and immobilization are critical control points for decomposition of organic matter.
Unravelling large-scale patterns and drivers of biodiversity in dry rivers
(2023) Arnaud Foulquier; Thibault Datry; Roland Corti; Daniel von Schiller; Klement Tockner; Rachel Stubbington; Mark O. Gessner; Frédéric Boyer; Marc Ohlmann; Wilfried Thuiller
<title>Abstract</title> The lack of data from non-perennial rivers, which regularly cease to flow and dry up, poses a significant challenge in understanding river biodiversity. These dynamic ecosystems, accounting for over half of the global river network, remain understudied. To address this gap, we conducted a coordinated experiment and a metabarcoding approach on environmental DNA targeting multiple taxa (i.e. Archaea, Bacteria, Fungi, Algae, Protozoa, Nematoda, Arthropoda and Streptophyta). Dry sediments were collected from 84 non-perennial rivers across 19 countries on five continents to investigate biodiversity patterns and drivers. Our findings reveal that both direct (e.g., nutrient and carbon availability) and indirect (e.g., latitude and climate) drivers significantly influence local biodiversity for most taxa. In particular, we observed that low resource availability and extended dry phases promote the prevalence of oligotrophic microbial taxa, similar to soil microbial communities during drought events. Interestingly, our inferred partial correlation networks indicate that covariation among taxa, particularly Bacteria, Fungi, Algae, and Protozoa, plays a more substantial role in explaining variations in community composition than abiotic gradients. This unexpected result suggests that biotic interactions may drive community assembly in non-perennial rivers, potentially shaping biodiversity responses in the face of global changes like warming and altered hydrological patterns.
Unravelling large-scale patterns and drivers of biodiversity in dry rivers
(Nature Portfolio, 2024) Arnaud Foulquier; Thibault Datry; Roland Corti; Daniel von Schiller; Klement Tockner; Rachel Stubbington; Mark O. Gessner; Frédéric Boyer; Marc Ohlmann; Wilfried Thuiller