Alternating Drying and Flowing Phases Control Stream Metabolism Through Short‐ and Long‐Term Effects: Insights From a River Network

Journal of Geophysical Research Biogeosciences, Journal Year: 2025, Volume and Issue: 130(3)

Published: March 1, 2025

Abstract Stream metabolism is a key biogeochemical process in river networks, synthesizing the balance between gross primary production (GPP) and ecosystem respiration (ER). Globally, more rivers streams are drying due to climate change water abstraction for human uses this can alter organic carbon residence time leading decoupled ER terrestrial matter supply. Although consequences of on CO 2 emissions have been recently quantified, its effects stream still poorly studied. We addressed long‐term rewetting events by monitoring oxygen dynamics at 20 reaches across network, including perennial (PR) nonperennial (NPR) one year. also calculated several climatic land use variables characterized local abiotic conditions biofilm sediment communities five sampling dates. was significantly higher NPR than PR demonstrating situ metabolism. When analyzing drivers GPP, we found direct positive effect negative GPP. Drying altered microbial community composition with algal from NPRs being different those PRs. In short‐term, total consumption (respiration) during positively related duration precedent nonflow period. Our results show that had an important both short‐ long term, supporting need global estimates

Language: Английский

Functional macroinvertebrate diversity stabilizes decomposition among leaf litter resources across a river network

Ecological Monographs, Journal Year: 2025, Volume and Issue: 95(1)

Published: Feb. 1, 2025

Abstract Biodiversity underpins the functional integrity of ecosystems. At present, our understanding relationship between biodiversity and ecosystem functioning (BEF) is essentially based on manipulative experiments. Compelling data at large spatial scales are scarce, especially for river networks. BEF patterns across landscapes complex because they unfold in context environmental gradients compositional turnover natural communities. Leaf litter decomposition, a pivotal process streams, no exception to this dependency. The dendritic structure networks plus unidirectional water flow shape both conditions distribution leaf resources consumers. However, it difficult predict how resource consumer composition can overlap network, thus govern decomposition. Here, we investigated capacity macroinvertebrate control decomposition rates heterogeneous river‐network scale. We deployed five litterbags containing either one four single species or mixture all 51 sites Thur River network (Switzerland). measured rates, variation among resources, effect diversity found that decreased from headwaters downstream reaches mainly due parallel decrease abundance key shredder taxa (namely, Amphinemura , Nemoura Leuctra Habroleptoides Stenophylacini). Macroinvertebrate had minor, negative rates. high reach scale reduced alleviating nutritional constraints exerted by nutrient‐poor resources. Furthermore, mixtures were preferably decomposed communities with low evenness dominated few taxa. These findings point critical role macroinvertebrates controlling beyond effects. While community determining important decreasing Our results stress importance not only local but also

Language: Английский

Temporal Changes in Freshwater Invertebrate Communities During the Drying Phase of a Newly Intermittent River in Central Italy

Environments, Journal Year: 2024, Volume and Issue: 11(12), P. 295 - 295

Published: Dec. 20, 2024

The transition from a perennial to an intermittent regime in newly rivers (nIRs) negatively affects both taxonomic and functional diversity, with significant repercussions on freshwater ecosystem processes services. However, better understand how changes the natural flow may influence structure functioning of ecosystems, it is fundamental assess variations abiotic biotic parameters throughout hydrological phases characterizing nIRs. For these reasons, we evaluated temporal community composition during drying phase Central Apennines stream (Italy) over two consecutive drought years. We demonstrated that different pre-drought profoundly affected communities. reduced discharge low-flow conditions 2024 led insect- non-insect-dominated communities, small-sized, lentic-adapted generalist taxa replacing rheophile more sensitive insect taxa. also found marked interannual differences beta diversity. years, richness did not exhibit negative stepped response pattern sequence channel contraction, cessation pools formation. Consequently, can assume Apennine rivers, communities strictly dependent local variable context. This study emphasizes need for further investigation ecological impacts increasing intermittence formerly streams rivers.

Language: Английский