Interplay between temperature and redox conditions regulates wetland biogeochemistry and greenhouse gas emissions.

Wetlands play a crucial role in global greenhouse gas (GHG) dynamics, yet their response to climate change is not yet fully understood. Here, we investigate how increasing temperature and oxygen availability interact to regulate wetland GHG emissions through combined analysis of biogeochemical and functional gene measurements. We found distinct temperature-dependent shifts in carbon emission pathways, with CO emissions unexpectedly declining as temperature rose from 15 to 25 °C, while increasing consistently at higher temperatures (25-35 °C), reflecting a transition to more thermally-driven processes.

Consumer health risk assessment of per- and polyfluoroalkyl substances (PFAS) and polycyclic aromatic hydrocarbon (PAH) in the Ecuadorian red mangrove crab.

Anthropogenic pollutant accumulation is a concern in Ecuador's Guayas Estuary. In this study, we investigated per- and polyfluoroalkyl substances (PFAS) and polycyclic aromatic hydrocarbons (PAHs) in the meat of the red mangrove crab (Ucides occidentalis), an Ecuadorian commercial food product. This study examined contaminant levels in crabs from two mangrove reserves and assessed associated health risks to consumers.

Evaluating Mathematical Concordance Between Taxonomic and Functional Diversity Metrics in Benthic Macroinvertebrate Communities.

Understanding the structural concordance between taxonomic and functional diversity (FD) metrics is essential for improving the ecological interpretation of community patterns in biomonitoring programs. This study evaluated the concordance between taxonomic and FD metrics of benthic macroinvertebrates along a fluvial habitat quality gradient in the Paute River Basin, Ecuador. Macroinvertebrate communities were sampled over six years at twelve sampling points and assessed using four taxonomic metrics: Shannon diversity (H), the Margalef index (D), family richness (N), and the Andean Biotic Index (ABI).

Chemical and microbiological analysis of urban and associated natural water systems of inhabited volcanic islands of the Galapagos (Ecuador).

The Galapagos Islands, known for their unique ecology, are confronted with significant challenges in water management and freshwater scarcity. These challenges are further exacerbated by a lack of comprehensive monitoring, assessment and understanding of the quality of water systems on inhabited islands. This study examines the urban and associated natural water systems of the remote volcanic islands of Floreana, Isabela and Santa Cruz in the Pacific Ocean through an unprecedented combination of comprehensive physicochemical analysis, including nutrient measurements, microbiological analyses and isotope-based source detection of nitrate (NO) contamination.

How do varying nitrogen fertilization rates affect crop yields and riverine NO emissions? A hybrid modeling study.

Headwater streams in agricultural areas constitute significant sources of nitrous oxide (NO) due to nutrient enrichment; however, their emissions are often overlooked in current environmental impact assessments. This scarcity highlights the importance of developing advanced decision tools to evaluate these contributions and create effective mitigation strategies. Our study establishes the first integrated modeling framework that combines a process-based model SWAT+ with a linear mixed model (LMM) to predict NO emissions from a headwater agricultural river system in Belgium under diverse climate change and fertilization scenarios.

The impacts of alien species on river bioassessment.

The extent of alien taxa impacts on river ecosystem health is unclear, but their frequency continues to rise. We investigated 1) the prevalence of including alien taxa in common bioindicators used in river bioassessment, 2) the effect of alien taxa on the richness and abundance of natives, and 3) whether including alien taxa in bioassessment tools increased their sensitivity to river degradation. In the 17 countries analyzed fish represented the greatest number of alien species (1726), followed by macrophytes (925), macroinvertebrates (556), and diatoms (7).

Unravelling spatiotemporal NO dynamics in an urbanized estuary system using natural abundance isotopes.

Estuaries are strong sources of NO to the atmosphere; yet we still lack insights into the impact of their biogeochemical dynamics on the emissions of this powerful greenhouse gas. Here, we investigated the spatiotemporal dynamics of the N cycle in an estuary with a focus on the emission mechanisms and pathways of NO. By coupling NO isotopocule analysis and substrate NO isotope analysis, we found that nutrient availability, oxygen level, salinity gradient and temperature variation were major drivers of the NO emissions from the Scheldt Estuary.

Fish habitat models for a future of novel riverscapes.

Multiple anthropogenic forces have pushed river ecosystems into undesirable states with no clear understanding of how they should be best managed. The advancement of riverine fish habitat models intended to provide management insights has slowed. Investigations into theoretical and empirical gaps to define habitat more comprehensively across different scales and ecological organizations are crucial in managing the freshwater biodiversity crisis.

Proactive policies are the key to reversing desertification in the main stream of the Tarim River in the past 30 years.

The main stream of the Tarim River is a crucial part of China's ecological security strategy within the "two screens and three belts" framework, serving the "northern sand control belt" and the ecological civilization corridor. Evaluating and understanding desertification dynamics and driving factors is essential for achieving the United Nations Sustainable Development Goals and promoting ecological civilization. This study, based on the United Nations Convention to Combat Desertification, quantified the desertification process of the Tarim River's main stream from 1990 to 2020 using Landsat series satellite imagery from Google Earth Engine.

Regulating greenhouse gas dynamics in tidal wetlands: Impacts of salinity gradients and water pollution.

Tidal wetlands play a critical role in emitting greenhouse gases (GHGs) into the atmosphere; our understanding of the intricate interplay between natural processes and human activities shaping their biogeochemistry and GHG emissions remains lacking. In this study, we delve into the spatiotemporal dynamics and key drivers of the GHG emissions from five tidal wetlands in the Scheldt Estuary by focusing on the interactive impacts of salinity and water pollution, two factors exhibiting contrasting gradients in this estuarine system: pollution escalates as salinity declines. Our findings reveal a marked escalation in GHG emissions when moving upstream, primarily attributed to increased concentrations of organic matter and nutrients, coupled with reduced levels of dissolved oxygen and pH.

Effect of agriculture on surface water quantity and quality in Gilgel Gibe watershed, southwestern Ethiopia.

Monitoring water quality and quantity is crucial to be sure that water resources are sustainably used. However, there is no monitoring system of water quantity and quality in southwestern Ethiopia, despite expansion of agricultural activities demanding water resources. The objective of this study was to investigate the effect of agriculture on water quantity and quality with special emphasis on irrigation in southwestern Ethiopia.

Inland navigation and land use interact to impact European freshwater biodiversity.

Inland navigation in Europe is proposed to increase in the coming years, being promoted as a low-carbon form of transport. However, we currently lack knowledge on how this would impact biodiversity at large scales and interact with existing stressors. Here we addressed this knowledge gap by analysing fish and macroinvertebrate community time series across large European rivers comprising 19,592 observations from 4,049 sampling sites spanning the past 32 years.

Introduction of Native Submerged Macrophytes to Restore Biodiversity in Streams.

Streams are biodiversity hotspots that provide numerous ecosystem services. Safeguarding this biodiversity is crucial to uphold sustainable ecosystem functioning and to ensure the continuation of these ecosystem services in the future. However, in recent decades, streams have witnessed a disproportionate decline in biodiversity compared to other ecosystems, and are currently considered among the most threatened ecosystems worldwide.

Multi-decadal improvements in the ecological quality of European rivers are not consistently reflected in biodiversity metrics.

Humans impact terrestrial, marine and freshwater ecosystems, yet many broad-scale studies have found no systematic, negative biodiversity changes (for example, decreasing abundance or taxon richness). Here we show that mixed biodiversity responses may arise because community metrics show variable responses to anthropogenic impacts across broad spatial scales. We first quantified temporal trends in anthropogenic impacts for 1,365 riverine invertebrate communities from 23 European countries, based on similarity to least-impacted reference communities.

Modeling greenhouse gas emissions from riverine systems: A review.

Despite the recognized importance of flowing waters in global greenhouse gas (GHG) budgets, riverine GHG models remain oversimplified, consequently restraining the development of effective prediction for riverine GHG emissions feedbacks. Here we elucidate the state of the art of riverine GHG models by investigating 148 models from 122 papers published from 2010 to 2021. Our findings indicate that riverine GHG models have been mostly data-driven models (83%), while mechanistic and hybrid models were uncommonly applied (12% and 5%, respectively).

Taxonomic and Feeding Trait-Based Analysis of Macroinvertebrates in the Antisana River Basin (Ecuadorian Andean Region).

High-elevation tropical streams are under increasing threat from human activities and climate change. Specifically, Ecuadorian Andean streams require priority actions such as bioassessment (e.g.

Finding navigation cues near fishways.

Many fish species depend on migration for various parts of their life cycle. Well-known examples include diadromous fish such as salmon and eels that need both fresh water and salt water to complete their life cycle. Migration also occurs within species that depend only on fresh water.

Impact of salinity gradient, water pollution and land use types on greenhouse gas emissions from an urbanized estuary.

Estuaries have been recognized as one of the major sources of greenhouse gases (GHGs) in aquatic systems; yet we still lack insights into the impact of both anthropogenic and natural factors on the dynamics of GHG emissions. Here, we assessed the spatiotemporal dynamics and underlying drivers of the GHG emissions from the Scheldt Estuary with a focus on the effects of salinity gradient, water pollution, and land use types, together with their interaction. Overall, we found a negative impact of salinity on carbon dioxide (CO) and nitrous oxide (NO) emissions which can be due to the decrease of both salinity and water quality when moving upstream.

The recovery of European freshwater biodiversity has come to a halt.

Owing to a long history of anthropogenic pressures, freshwater ecosystems are among the most vulnerable to biodiversity loss. Mitigation measures, including wastewater treatment and hydromorphological restoration, have aimed to improve environmental quality and foster the recovery of freshwater biodiversity. Here, using 1,816 time series of freshwater invertebrate communities collected across 22 European countries between 1968 and 2020, we quantified temporal trends in taxonomic and functional diversity and their responses to environmental pressures and gradients.

Individual variation in the habitat selection of upstream migrating fish near a barrier.

Background: Migration is a vital element of the life cycle of many freshwater fish species but is increasingly hampered globally by riverine barriers. Fish passes are a common approach to enable migration past barriers but are often ineffective. More knowledge is required on fish behaviour as they approach barriers such as habitat preferences.

Pesticide concentration in three selected fish species and human health risk in the Lake Tana sub-basin, Ethiopia.

Pesticide use has increased in the Lake Tana sub-basin due to increased agricultural activity, potentially endangering nontargeted organisms. To assess its potential impact on fish health and fish-consuming human populations, pesticide concentrations in the fillet and liver tissue of three fish species, namely Labeobarbus megastoma, Labeobarbus tsanensis, and Oreochromis niloticus, were investigated in Lake Tana. Fish samples were taken from the lake near the rivers of Ribb and Gumara, which flow through agricultural areas where considerable amounts of pesticides have been applied.

Determining Tipping Points and Responses of Macroinvertebrate Traits to Abiotic Factors in Support of River Management.

Although the trait concept is increasingly used in research, quantitative relations that can support in determining ecological tipping points and serve as a basis for environmental standards are lacking. This study determines changes in trait abundance along a gradient of flow velocity, turbidity and elevation, and develops trait-response curves, which facilitate the identification of ecological tipping points. Aquatic macroinvertebrates and abiotic conditions were determined at 88 different locations in the streams of the Guayas basin.