258 results match your criteria: "School of Freshwater Sciences[Affiliation]"

Article Synopsis
  • Patchy data on litter decomposition in wetlands limits understanding of carbon storage, prompting a global study involving over 180 wetlands across multiple countries and climates.
  • The study found that freshwater wetlands and tidal marshes had more organic matter remaining after decay, indicating better potential for carbon preservation in these areas.
  • Elevated temperatures positively affect the decomposition of resistant organic matter, with projections suggesting an increase in decay rates by 2050; however, the impact varies by ecosystem type and highlights the need to recognize both local and global factors influencing carbon storage.
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  • Researchers explored how different bacterial communities affect the growth and nutrient content of the purple pitcher plant, filling a gap in understanding microbial interactions with plants.
  • They found that a community enriched in decomposition resulted in larger leaves and significantly increased biomass compared to control plants.
  • The study highlights potential mechanisms, like chitinase activity, which explain how these bacterial functions support the growth of carnivorous plants.
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Benefiting from the advancements in monitoring and measuring terrestrial evapotranspiration (ET), diverse ET products have been proliferated. This study evaluated nine ET products from three types, namely remote sensing-based retrievals (GLEAM, PML and PLSH), gauge-based upscaling (FCCRU, FCGSW and FCWFD) and land surface model-based reanalysis (ERA5-Land, GLDAS and MERRA) over China and its seven climate zones. Both spatial and temporal change trends in ET were investigated, and period feature were analyzed.

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Understanding the fate of organic carbon in thawed permafrost is crucial for predicting climate feedback. While minerals and microbial necromass are known to play crucial roles in the long-term stability of organic carbon in subsoils, their exact influence on carbon persistence in Arctic permafrost remains uncertain. Our study, combining radiocarbon dating and biomarker analyses, showed that soil organic carbon in Alaskan permafrost had millennial-scale radiocarbon ages and contained only 10%-15% microbial necromass carbon, significantly lower than the global average of ~30%-60%.

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  • The study investigates the impact of environmental neurotoxicants on Atlantic killifish populations, focusing on how gene expression and behavior can predict growth and survival outcomes.
  • Methylmercury exposure in one population led to observable changes in gene expression and behavior without measurable effects on growth or survival, while PCB126 exposure resulted in decreased activity and predicted negative impacts on growth and survival for both populations.
  • The research connects molecular and behavioral findings to create models that quantitatively assess ecological risks, highlighting the importance of linking individual-level data to broader population outcomes.
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  • The Landscape Theory of Food Web Architecture (LTFWA) explores how body size, trophic position, and energy channels interconnect in diverse habitats to maintain system stability, but evidence has been inconsistent across different ecosystems.
  • In a study of the Lake Michigan food web, researchers found a positive correlation between body size and trophic position, with variations based on whether species were supported by pelagic or benthic energy sources.
  • The findings indicated that while native top predators contribute to food web stability by connecting energy pathways, introduced species may disrupt this structure, highlighting the complex impacts of human activity on ecosystem dynamics.
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Photodegradation Processes and Weathering Products of Microfibers in Aquatic Environments.

Environ Sci Technol

September 2024

School of Freshwater Sciences, University of Wisconsin─Milwaukee, Milwaukee, Wisconsin 53204, United States.

Microplastics, particularly microfibers (MFs), pose a significant threat to the environment. Despite their widespread presence, the photochemical reactivity, weathering products, and environmental fate of MFs remain poorly understood. To address this knowledge gap, photodegradation experiments were conducted on three prevalent MFs: polyester (POL), nylon (NYL), and acrylic (ACR), to elucidate their degradation pathways, changes in surface morphology and polymer structure, and chemical and colloidal characterization of weathering products during photochemical degradation of MFs.

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Understanding how sublethal impacts of toxicants affect population-relevant outcomes for organisms is challenging. We tested the hypotheses that the well-known sublethal impacts of methylmercury (MeHg) and a polychlorinated biphenyl (PCB126) would have meaningful impacts on cohort growth and survival in yellow perch (Perca flavescens) and Atlantic killifish (Fundulus heteroclitus) populations, that inclusion of model uncertainty is important for understanding the sublethal impacts of toxicants, and that a model organism (zebrafish Danio rerio) is an appropriate substitute for ecologically relevant species (yellow perch, killifish). Our simulations showed that MeHg did not have meaningful impacts on growth or survival in a simulated environment except to increase survival and growth in low mercury exposures in yellow perch and killifish.

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  • Researchers collected sediment cores from Green Bay to analyze various phosphorus species, noting that total phosphorus decreased with depth but exhibited unique distribution patterns for different phosphorus types, especially those that are bioavailable.* -
  • Bioavailable phosphorus species like exchangeable-P and iron-bound-P showed significant variation, while organic-P and detrital-apatite-P were stable, indicating that the latter two act as major sinks for phosphorus in the sediment.* -
  • The study found that phosphorus accumulation and regeneration rates varied across regions, with a noted decrease in detrital-apatite-P over recent decades likely linked to human activities, while an increase in organic carbon levels suggests rising trophic status and changes in bottom water conditions.*
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Natural river flooding events can mobilize contaminants from the vadose zone and lead to increased concentrations in groundwater. Characterizing the mass and transport mechanisms of contaminants released from the vadose zone to groundwater during these recharge events is particularly challenging. Therefore, conducting highly-controlled in-situ experiments that simulate natural flooding events can help increase the knowledge of where contaminants can be stored and how they can move between hydrological compartments.

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Molecular weight-dependent differences in spectral properties and metal-binding behaviors of dissolved organic matter from different lakes.

Sci Total Environ

October 2024

Key Laboratory of Green and High-end Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, China; Qinghai Provincial Key Laboratory of Resources and Chemistry of Salt Lakes, Xining, China.

Dissolved organic matter (DOM) plays an important role in governing metal speciation and migration in aquatic systems. In this study, various DOM samples were collected from Lakes Erhai, Kokonor, and Chaka, and size-fractionated into high molecular weight (HMW, 1 kDa-0.7 μm) and low molecular weight (LMW, <1 kDa) fractions for measurements of dissolved organic carbon (DOC), spectral properties, and metal binding behaviors.

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Organic matter composition and stability in estuarine wetlands depending on soil salinity.

Sci Total Environ

October 2024

School of Environmental and Chemical Engineering, Foshan University, Foshan, China; Guangdong Provincial Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.

Coastal wetlands are key players in mitigating global climate change by sequestering soil organic matter. Soil organic matter consists of less stable particulate organic matter (POM) and more stable mineral-associated organic matter (MAOM). The distribution and drivers of MAOM and POM in coastal wetlands have received little attention, despite the processes and mechanisms differ from that in the upland soils.

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Human sewage contaminates waterways, delivering excess nutrients, pathogens, chemicals, and other toxic contaminants. Contaminants and various sewage indicators are measured to monitor and assess water quality, but these analytes vary in their representation of sewage contamination and the inferences about water quality they support. We measured the occurrence and concentration of multiple microbiological (n = 21) and chemical (n = 106) markers at two urban stream locations in Milwaukee, Wisconsin, USA over two years.

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The goal of the University of Wisconsin-Milwaukee WInSTEP SEPA program is to provide valuable and relevant research experiences to students and instructors in diverse secondary educational settings. Introducing an online experience allows the expansion of a proven instructional research program to a national scale and removes many common barriers. These can include lack of access to zebrafish embryos, laboratory equipment, and modern classroom facilities, which often deny disadvantaged and underrepresented students from urban and rural school districts valuable inquiry-based learning opportunities.

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Anthropogenic particles (AP), which include microplastics and other synthetic, semisynthetic, and anthropogenically modified materials, are pollutants of concern in aquatic ecosystems worldwide. Rivers are important conduits and retention sites for AP, and time series data on the movement of these particles in lotic ecosystems are needed to assess the role of rivers in the global AP cycle. Much research assessing AP pollution extrapolates stream loads based on single time point measurements, but lotic ecosystems are highly variable over time (e.

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Antibiotic resistance remains one of the most pressing public health issues facing the world today. At the forefront of this battle lies the ever-increasing identification of extended-spectrum beta-lactamases and carbapenemases within human pathogens, conferring resistance towards broad-spectrum and last-resort antimicrobials. This study was prompted due to the identification of a pathogenic isolate (strain MAH-4) collected from abdominal fluid, which presented a robust resistance pattern against second-, third-, and fourth-generation cephalosporins, ertapenem, ciprofloxacin, gentamicin, levofloxacin and moxifloxacin, and beta lactam/beta-lactamase inhibitor combinations.

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Low-oxygen levels (hypoxia) in aquatic habitats are becoming more common because of global warming and eutrophication. However, the effects on the health/disease status of fishes, the world's largest group of vertebrates, are unclear. Therefore, we assessed how long-term hypoxia affected the immune function of sablefish, an ecologically and economically important North Pacific species, including the response to a formalin-killed Aeromonas salmonicida bacterin.

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High-throughput phenotypic profiling assays, popular for their ability to characterize alternations in single-cell morphological feature data, have been useful in recent years for predicting cellular targets and mechanisms of action (MoAs) for different chemicals and novel drugs. However, this approach has not been extensively used in environmental toxicology due to the lack of studies and established methods for performing this kind of assay in environmentally relevant species. Here, we developed a multiplexed algal cytological imaging (MACI) assay, based on the subcellular structures of the unicellular microalgae, , a toxicology and ecological model species.

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Understanding microbial roles in ecosystem function requires integrating microscopic processes into food webs. The carnivorous pitcher plant, Sarracenia purpurea, offers a tractable study system where diverse food webs of macroinvertebrates and microbes facilitate digestion of captured insect prey, releasing nutrients supporting the food web and host plant. However, how interactions between these macroinvertebrate and microbial communities contribute to ecosystem functions remains unclear.

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A cryptic plasmid is among the most numerous genetic elements in the human gut.

Cell

February 2024

Department of Medicine, University of Chicago, Chicago, IL 60637, USA; Marine Biological Laboratory, Woods Hole, MA 02543, USA; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 27570 Bremerhaven, Germany; Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, 26129 Oldenburg, Germany; Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany; Helmholtz Institute for Functional Marine Biodiversity, 26129 Oldenburg, Germany. Electronic address:

Plasmids are extrachromosomal genetic elements that often encode fitness-enhancing features. However, many bacteria carry "cryptic" plasmids that do not confer clear beneficial functions. We identified one such cryptic plasmid, pBI143, which is ubiquitous across industrialized gut microbiomes and is 14 times as numerous as crAssphage, currently established as the most abundant extrachromosomal genetic element in the human gut.

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Effects of Cu(II)-DOM complexation on DOM degradation: Insights from spectroscopic evidence.

Sci Total Environ

April 2024

School of Earth System Science, Tianjin University, Tianjin 300072, PR China; Haihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, PR China; Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Tianjin 300072, PR China. Electronic address:

The fate of dissolved organic matter (DOM) is primarily governed by its sources, degradation, and transformation processes within the environment. However, the influence of metal-DOM complexation on DOM degradation remains ambiguous. In this study, controlled laboratory experiments were conducted using Cu(II) and natural water from the Duliujian River and the Beidagang Wetland to examine the effects of metal-DOM binding on the degradation pathway of DOM.

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Photochemical reactivity of water-soluble dissolved organic matter from microplastics and microfibers.

Sci Total Environ

February 2024

School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 E. Greenfield Ave., Milwaukee, WI 53204, USA. Electronic address:

Plastics in aquatic environments are a source of dissolved organic matter (DOM). However, its production pathways and environmental fate remain poorly understood. This study investigated the yields, characterization, and photochemical reactivities of water-soluble DOM from seven pristine microplastics (MPs) and three microfibers (MFs).

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Demands to manage the risks of artificial intelligence (AI) are growing. These demands and the government standards arising from them both call for trustworthy AI. In response, we adopt a convergent approach to review, evaluate, and synthesize research on the trust and trustworthiness of AI in the environmental sciences and propose a research agenda.

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Design of Pectin-Based Hydrogel Microspheres for Targeted Pulmonary Delivery.

Gels

September 2023

Chemical and Biomolecular Engineering Program, Department of Physics and Chemistry, Milwaukee School of Engineering, Milwaukee, WI 53202, USA.

Pulmonary drug delivery via microspheres has gained growing interest as a noninvasive method for therapy. However, drug delivery through the lungs via inhalation faces great challenges due to the natural defense mechanisms of the respiratory tract, such as the removal or deactivation of drugs. This study aims to develop a natural polymer-based microsphere system with a diameter of around 3 μm for encapsulating pulmonary drugs and facilitating their delivery to the deep lungs.

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