Biotic Effects Research Articles

Transient negative biochar effects on plant growth are strongest after microbial species loss

Biochar has been explored as an organic amendment to improve soil quality and benefit plant growth. The overall positive effects of biochar on crop yields are generally attributed to abiotic changes, while the alternative causal pathway via changes in soil biota is unexplored. We compared plant growth effects of legumes in sterile soil inoculated with dilutions of soil and soil microbial suspensions to determine the direct effects of biochar-induced changes in soil biota on plant growth. Suspensions and soil were from soil amended with biochar and soil without biochar. By comparing consecutive plant growth phases on the same inoculated soils, we also determined the temporal effects of soil biota from biochar-amended and control soils. Biota from biochar-amended soil was less beneficial for Medicago sativa growth, especially with small amounts of inocula. Flowering was delayed in the presence of biota from biochar plots. Inoculum with either soil or soil suspension gave similar results for plant biomass, indicating that microorganisms play a major role. Vicia villosa growth did not respond to the various inocula, even though the inoculum quantity strongly affected nematode community composition and protozoan abundance. In a later growing phase the negative effect of biochar-associated biota on Medicago growth mostly disappeared, which leads to the conclusion that the benefits of biochar application via abiotic changes may outweigh the negative effects of biochar on soil biota.

Determination of Geochemical Bio-Signatures in Mars-Like Basaltic Environments.

Bio-signatures play a central role in determining whether life existed on early Mars. Using a terrestrial basalt as a compositional analog for the martian surface, we applied a combination of experimental microbiology and thermochemical modeling techniques to identify potential geochemical bio-signatures for life on early Mars. Laboratory experiments were used to determine the short-term effects of biota on the dissolution of terrestrial basalt, and the formation of secondary alteration minerals. The chemoorganoheterotrophic bacterium, Burkholderia sp. strain B_33, was grown in a minimal growth medium with and without terrestrial basalt as the sole nutrient source. No growth was detected in the absence of the basalt. In the presence of basalt, during exponential growth, the pH decreased rapidly from pH 7.0 to 3.6 and then gradually increased to a steady-state of equilibrium of between 6.8 and 7.1. Microbial growth coincided with an increase in key elements in the growth medium (Si, K, Ca, Mg, and Fe). Experimental results were compared with theoretical thermochemical modeling to predict growth of secondary alteration minerals, which can be used as bio-signatures, over a geological timescale. We thermochemically modeled the dissolution of the basalt (in the absence of biota) in very dilute brine at 25°C, 1 bar; the pH was buffered by the mineral dissolution and precipitation reactions. Preliminary results suggested that at the water to rock ratio of 1 × 107, zeolite, hematite, chlorite, kaolinite, and apatite formed abiotically. The biotic weathering processes were modeled by varying the pH conditions within the model to adjust for biologic influence. The results suggested that, for a basaltic system, the microbially-mediated dissolution of basalt would result in “simpler” secondary alteration, consisting of Fe-hydroxide and kaolinite, under conditions where the abiotic system would also form chlorite. The results from this study demonstrate that, by using laboratory-based experiments and thermochemical modeling, it is possible to identify secondary alteration minerals that could potentially be used to distinguish between abiotic and biotic weathering processes on early Mars. This work will contribute to the interpretation of data from past, present, and future life detection missions to Mars.

A Lab-on-Chip Analyzer for in Situ Measurement of Soluble Reactive Phosphate: Improved Phosphate Blue Assay and Application to Fluvial Monitoring.

Here, we present a new in situ microfluidic phosphate sensor that features an improved "phosphate blue" assay which includes polyvinylpyrrolidone in place of traditional surfactants-improving sensitivity and reducing temperature effects. The sensor features greater power economy and analytical performance relative to commercially available alternatives, with a mean power consumption of 1.8 W, a detection limit of 40 nM, a dynamic range of 0.14-10 μM, and an infield accuracy of 4 ± 4.5%. During field testing, the sensor was continuously deployed for 9 weeks in a chalk stream, revealing complex relations between flow rates and phosphate concentration that suggest changing dominance in phosphate sources. A distinct diel phosphorus signal was observed under low flow conditions, highlighting the ability of the sensor to decouple geochemical and biotic effects on phosphate dynamics in fluvial environments. This paper highlights the importance of high resolution in situ sensors in addressing the current gross under-sampling of aquatic environments.

Potential Bioleaching Effects in <i>In Situ</i> Recovery Applications

The potential role of microorganisms in the in-situ recovery (ISR) of technology metals, in particular from reduced ores, is not well understood, but attracts increasing interest worldwide. Based on the feasibility criteria for ISR applications in general, effects of biota on kinetic rates of leaching are systematized. The indirect catalysis of leaching by microbial (re-)oxidation of Fe2+ to Fe3+ as directly acting e- acceptor is a well verified mechanism, however, for practical applications this requires the availability of an oxidant in the leachant. The ex-situ bio-oxidation of Fe in an aerated bioreactor is considered as an alternative. Reactive transport simulations of ISR from sulfidic Cu ores based on kinetic rates as function of pH and oxidation potential (concentration of e- acceptors) in comparison with thermodynamically driven metal dissolution (constrained by oxidation potential) demonstrate the key parameters for (bio-)leaching productivity.

Intestinal dysbiosis and its correction in the practice of the doctor of the infectionist

In patients with acute intestinal infections receiving the drug Biolakt (manufacturer – Ildong Pharmaceuticals Co., Korea), there was a more rapid decrease in the severity of the intoxication syndrome: abdominal pain disappeared, fever duration decreased, and the normalized stool was faster than that of the control group. The drug contributes to suppression of the proteolytic type of fermentation in the lumen of the intestine. The positive effect of Biota / Biotax Forte is due to its ability to normalize the composition of the intestinal microflora and confirms the probiotic effect.

Belowground top-down and aboveground bottom-up effects structure multitrophic community relationships in a biodiverse forest

Ecosystem functioning and human well-being critically depend on numerous species interactions above- and belowground. However, unraveling the structure of multitrophic interaction webs at the ecosystem level is challenging for biodiverse ecosystems. Attempts to identify major relationships between trophic levels usually rely on simplified proxies, such as species diversity. Here, we propose to consider the full information on species composition across trophic levels, using Procrustes correlation and structural equation models. We show that species composition data of a highly diverse subtropical forest―with 5,716 taxa across 25 trophic groups― reveal strong interrelationships among plants, arthropods, and microorganisms, indicating complex multitrophic interactions. We found substantial support for top-down effects of microorganisms belowground, indicating important feedbacks of microbial symbionts, pathogens, and decomposers on plant communities. In contrast, aboveground pathways were characterized by bottom-up control of plants on arthropods, including many non-trophic links. Additional analyses based on diversity patterns revealed much weaker interrelationships. Our study suggests that multitrophic communities in our forest system are structured via top-down effects of belowground biota on plants, which in turn affect aboveground arthropod communities across trophic levels. Moreover, the study shows that the consequences of species loss will be more complex than indicated by studies based solely on diversity.

Column study of enhanced Cr(VI) removal and longevity by coupled abiotic and biotic processes using Fe0 and mixed anaerobic culture

In this study, Fe0 and mixed anaerobic culture were integrated in one column to investigate the coupled abiotic and biotic effects on hexa-valent chromium (Cr(VI)) removal and column longevity with an abiotic Fe0 column in the control experiments. According to the breakthrough study, a slower Cr(VI) breakthrough rate of 0.19 cm/PV was observed in the biotic Fe0 column whereas the value in the abiotic Fe0 column was 0.30 cm/PV, resulting in 64% longer life-span and 62% higher Cr(VI) removal capacity in the biotic Fe0 column than the abiotic one. The solid phase characterization by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) confirmed that this enhancement was attributed to the higher consumption of iron and greater production of diverse reactive minerals (e.g., green rust, magnetite and lepidocrocite) induced by the synergistic interaction of Fe0 and anaerobic culture, providing more reactive sites for Cr(VI) adsorption, reduction and co-precipitation. Furthermore, the decreasing breakthrough rates and growing iron corrosion along the biotic Fe0 column demonstrated an inhomogeneous distribution of reactive zones in the column and its latter 3/5 section was considered to be the most reactive area for Cr(VI) removal. These results indicate that the inoculation of microorganisms in Fe0-based permeable reactive barriers will enable this technology a higher removal capacity and longer life-span for the remediation of Cr(VI)-contaminated groundwater.

Of lemurs and louse flies: The biogeochemical and biotic effects of forest disturbance on Propithecus edwardsi and its obligate ectoparasite Allobosca crassipes in Ranomafana National Park, southeastern Madagascar.

From alleles to ecosystems and landscapes, anthropogenic activity continues to affect the environment, with particularly adverse effects on biodiversity hotspots such as Madagascar. Selective logging has been proposed as a "win-win" conservation strategy, yet its effects on different components of biodiversity are still not fully understood. Here we examine biotic factors (i.e., dietary differences) that may be driving differences in biogeochemical stocks between disturbed and undisturbed forests. We present the stable nitrogen (δ15 N) and carbon (δ13 C) isotope composition of hair from the lemur Propithecus edwardsi and of whole bodies of its obligate ectoparasite, the louse-fly Allobosca crassipes, from sites in Ranomafana National Park (RNP) that are comparable except for the history of logging and subsequent forest regeneration. P. edwardsi and A. crassipes from the disturbed (i.e., heavily selectively logged) site are lower in 15 N and 13 C relative to P. edwardsi and A. crassipes from sites that were minimally selectively logged or not commercially logged at all. There is a ∼3‰ decrease in 15 N between disturbed and undisturbed sites that corresponds to a difference of nearly a full trophic level. Flowers from Bakerella clavata, a staple food source for P. edwardsi in disturbed habitats and a fallback food for P. edwardsi in primary forests, were also analyzed isotopically. B. clavata is δ15 N-depleted in both disturbed and undisturbed sites. Data from longitudinal behavioral surveys of P. edwardsi in RNP and other forests in eastern Madagascar point to significant differences in consumption patterns of B. clavata, with P. edwardsi in disturbed forests consuming almost twice as much of this plant. Depletion of 15 N in animal tissues is a complex issue, but likely the result of the interaction of physiological and ecological factors. Anthropogenic disturbance in RNP from selective logging has had both biotic and biogeochemical effects that are observable trophically.

Technical Note: A minimally invasive experimental system for <i>p</i>CO<sub>2</sub> manipulation in plankton cultures using passive gas exchange (atmospheric carbon control simulator)

Abstract. As research into the biotic effects of ocean acidification has increased, the methods for simulating these environmental changes in the laboratory have multiplied. Here we describe the atmospheric carbon control simulator (ACCS) for the maintenance of plankton under controlled pCO2 conditions, designed for species sensitive to the physical disturbance introduced by the bubbling of cultures and for studies involving trophic interaction. The system consists of gas mixing and equilibration components coupled with large-volume atmospheric simulation chambers. These chambers allow gas exchange to counteract the changes in carbonate chemistry induced by the metabolic activity of the organisms. The system is relatively low cost, very flexible, and when used in conjunction with semi-continuous culture methods, it increases the density of organisms kept under realistic conditions, increases the allowable time interval between dilutions, and/or decreases the metabolically driven change in carbonate chemistry during these intervals. It accommodates a large number of culture vessels, which facilitate multi-trophic level studies and allow the tracking of variable responses within and across plankton populations to ocean acidification. It also includes components that increase the reliability of gas mixing systems using mass flow controllers.

Biotic effects on oxygen consumption during weathering: Implications for the second rise of oxygen

The oxygen concentration of the atmosphere likely increased substantially in the late Neoproterozoic. Although several studies have presented compelling geochemical evidence for this stepwise oxygenation, few have addressed the mechanisms behind it. Recently it was hypothesized that the advent of eukaryotic life on land, and the associated increase in soil respiration, led to a transient reduction in the supply of oxygen for rock weathering, temporarily reducing oxidative weathering rates, allowing atmospheric oxygen levels to rise to restore the oxygen supply. To evaluate this hypothesis quantitatively, we developed a simple one-dimensional diffusion-reaction soil model that reduces the many oxygen weathering sinks to one, pyrite, given that it is the dominant sink at low oxygen concentrations. In simulations with no biological respiration, pyrite weathering rates become oxygen independent at an atmospheric oxygen concentration between 10 –6 × the present-day atmospheric level (PAL) and 1 PAL. On the other hand, when biological respiration is considered, pyrite weathering remains oxygen dependent even at modern oxygen levels. Constrained by modern weathering profiles and soil respiration rates, we find that the atmospheric oxygen level may have increased by up to two orders of magnitude as biotic soil respiration increased. This may be sufficient to explain the second rise in atmospheric oxygen inferred for the Neoproterozoic.

Soil biota suppress positive plant diversity effects on productivity at high but not low soil fertility

SummaryPlant community productivity commonly increases with increasing plant diversity, which is explained by complementarity among plant species in resource utilization (complementarity effect), or by selection of particularly productive plant species in diverse plant communities (selection effect). Recent studies have also shown that soil biota can drive the positive plant diversity–productivity relationship by suppressing productivity more in low‐ than in high‐diversity plant communities. However, much remains unknown about whether soil fertility plays a role in determining how soil biota affect plant diversity–productivity relationships.We hypothesized that under high soil fertility conditions, negative soil biota effects dominate, which reduces plant monoculture biomass more than that of high‐diversity plant communities. Conversely, under low soil fertility conditions, we hypothesized positive soil biota effects dominate, which facilitates plant resource partitioning and enhances community‐level biomass in high‐diversity plant communities. Hence, we expected positive plant diversity–community productivity relationships under low and high soil fertility conditions but caused by different mechanisms.We tested these hypotheses using woody seedlings and set up plant assemblages with four species richness levels (one, two, four and eight species), and grew them in sterilized and unsterilized (sterilized soil + living soil inoculum) soils at two nutrient levels (low versus high fertility).We found that at high fertility negative soil biota effects dominated and suppressed plant community biomass more in high‐diversity plant communities than in monocultures, resulting in reduced complementarity effects of diverse plant communities and a non‐significant plant species richness–community biomass relationship in unsterilized soil. Whereas at low fertility soil biota had net neutral to positive effects on plant community biomass but the beneficial effects did not increase with increasing plant species richness. Instead, soil biota neutrally affected the positive plant species richness–community biomass relationship, presumably due to non‐specific effects of beneficial soil biota.Synthesis. Soil biota and soil fertility interactively determine plant species richness–community biomass relationships. Moreover, soil biota modulate the complementary resource use among plant species. These findings suggest that environmental context plays an important role in determining whether and how soil biota generate the biodiversity–productivity relationship. Future studies would benefit from revealing the mechanisms underlying the interactive effects of soil biota, soil fertility, and plant diversity on ecosystem functioning.

Exercise and Dietary Factors Affecting the Microbiota: Current Knowledge and Future Perspectives

Gut micro biota degrades complex polysaccharides and synthesizes short chain fatty acids that regulate the intestinal barrier by stimulating mucin synthesis. Mucin maintains the integrity of the gut by forming a mucus layer that covers and protects the intestinal epithelium. Lactate- and butyrate-producing bacteria maintain gut integrity in healthy individuals, while non-butyrate-producing, lactate-utilizing bacteria prevent optimal mucin synthesis. The effect of the micro biota on the host physiology was first observed with animal experiments involving fecal transplantation, in which impressive metabolic effects were passed from the donor to the host. These experiments showed that the micro biota from obese donors has an increased capacity to harvest energy from the diet, thus affecting body composition in the long term. One of the potential mechanisms through which the micro biota could affect body composition is by regulating the delivery of orexigenic and anorexigenic hormones, as it has been shown that the concentration of these hormones is correlated with several groups of the gut micro biota. Gut micro biota has not only been linked to body composition outcomes but also to the development and severity of certain metabolic abnormalities such as autoimmune diseases (type I diabetes and lupus), necrotizing enterocolitis, irritable bowel syndrome, ulcerative colitis, acute diarrheal infections, and frailty. It is well established that lifestyle factors such as exercise, diet, and supplementation with pre- and/or pro biotics affects the gut micro biota. The purpose of this review is to evaluate the effect of exercise, diet, and supplementation with pre- and/or pro biotics on the gut micro biota of humans and animals models. Clinical perspectives and future research areas will also be discussed.

Conceptual model diagrams as evidence scaffolds for environmental assessment and management

Sound environmental management relies on scientific evidence to indicate whether action is warranted and, if so, which actions will be most effective. We discuss conceptual model diagrams that schematically describe how sources or human activities lead to specific stressors and ultimately to biotic effects. They are useful for describing how undesirable effects are produced and identifying where management actions may be most effective in preventing unwanted effects or improving existing conditions. We illustrate the use of conceptual model diagrams in a literature-based assessment of the impacts of mountaintop removal mining on downstream aquatic systems. The diagram-development process combined extraction and evaluation of research results with iterative refinement of diagrams depicting source-to-stressor-to-effect causal pathways. Conceptual-model diagrams provided a useful scaffold for organizing and synthesizing multiple individual pieces of evidence extracted from different studies and an effective way to summarize and present the evidentiary foundation of the assessment’s conclusions.

Enhanced Cr(VI) removal from groundwater by Fe0-H2O system with bio-amended iron corrosion

A one-pot bio-iron system was established to investigate synergetic abiotic and biotic effects between iron and microorganisms on Cr(VI) removal. More diverse iron corrosion and reactive solids, such as green rusts, lepidocrocite and magnetite were found in the bio-iron system than in the Fe0-H2O system, leading to 4.3 times higher Cr(VI) removal efficiency in the bio-iron system than in the Fe0-H2O system. The cycling experiment also showed that the Cr(VI) removal capacity of Fe0 in the bio-iron system was 12.4 times higher than that in the Fe0-H2O system. A 62days of life-span could be achieved in the bio-iron system, while the Fe0-H2O system lost its efficacy after 30days. Enhanced effects of extra Fe2+ on Cr(VI) removal was observed, largely contributed to the adsorbed Fe2+ on iron surface, which could function as an extra reductant for Cr(VI) and promote the electron transfer on the solid phase. The results also showed that the reduction of Cr(VI) by microorganisms was insignificant, indicating the adsorption/co-precipitation of Cr by iron oxides on iron surface was responsible for the overall Cr(VI) removal. Our study demonstrated that the bio-amended iron corrosion could improve the performance of Fe0 for Cr(VI) removal from groundwater.

Incorporating exposure to pitch canker disease to support management decisions of Pinus pinaster Ait. in the face of climate change.

Climate change is gravely affecting forest ecosystems, resulting in large distribution shifts as well as in increasing infection diseases and biological invasions. Accordingly, forest management requires an evaluation of exposure to climate change that should integrate both its abiotic and biotic components. Here we address the implications of climate change in an emerging disease by analysing both the host species (Pinus pinaster, Maritime pine) and the pathogen’s (Fusarium circinatum, pitch canker) environmental suitability i.e. estimating the host’s risk of habitat loss and the disease`s future environmental range. We constrained our study area to the Spanish Iberian Peninsula, where accurate climate and pitch canker occurrence databases were available. While P. pinaster is widely distributed across the study area, the disease has only been detected in its north-central and north-western edges. We fitted species distribution models for the current distribution of the conifer and the disease. Then, these models were projected into nine Global Climate Models and two different climatic scenarios which totalled to 18 different future climate predictions representative of 2050. Based on the level of agreement among them, we created future suitability maps for the pine and for the disease independently, which were then used to assess exposure of current populations of P. pinaster to abiotic and biotic effects of climate change. Almost the entire distribution of P. pinaster in the Spanish Iberian Peninsula will be subjected to abiotic exposure likely to be driven by the predicted increase in drought events in the future. Furthermore, we detected a reduction in exposure to pitch canker that will be concentrated along the north-western edge of the study area. Setting up breeding programs is recommended in highly exposed and productive populations, while silvicultural methods and monitoring should be applied in those less productive, but still exposed, populations.

Impacts of invasive biota in forest ecosystems in an aboveground\u2013belowground context

Forest ecosystems world-wide are being subjected to invasion by organisms representing all domains of life. Here we use a combined aboveground-belowground approach to provide a conceptual framework for assessing how forests respond to biological invasions. We first address mechanisms by which invasive plants and aboveground and belowground consumers impact on forests, and highlight that although we have a growing understanding of the determinants of the effects of invasive plants, for invasive consumers we have yet to move from a series of iconic case studies to the development of general principles. We also address the effects of invasive biota in the context of the drivers of invasion, co-invasion and invasional meltdown, the issue of simultaneous species gains and losses, and forest restoration and recovery post-invasion. We then highlight areas that would benefit from further work, particularly regarding underlying mechanisms, determinants of context-dependency of invader effects, and linkages between causes and consequences of invasion. In concluding, we emphasize that biological invaders have the potential for large-scale and long-term impacts on forest processes, and consideration of these impacts in an aboveground-belowground context will enable better prediction of future responses of forests to invaders and their management as well as of restoration efforts.

Ideas and perspectives: climate-relevant marine biologically driven mechanisms in Earth system models

Abstract. The current generation of marine biogeochemical modules in Earth system models (ESMs) considers mainly the effect of marine biota on the carbon cycle. We propose to also implement other biologically driven mechanisms in ESMs so that more climate-relevant feedbacks are captured. We classify these mechanisms in three categories according to their functional role in the Earth system: (1) biogeochemical pumps, which affect the carbon cycling; (2) biological gas and particle shuttles, which affect the atmospheric composition; and (3) biogeophysical mechanisms, which affect the thermal, optical, and mechanical properties of the ocean. To resolve mechanisms from all three classes, we find it sufficient to include five functional groups: bulk phyto- and zooplankton, calcifiers, and coastal gas and surface mat producers. We strongly suggest to account for a larger mechanism diversity in ESMs in the future to improve the quality of climate projections.

Functional Richness and Identity Do Not Strongly Affect Invasibility of Constructed Dune Communities.

Biotic effects are often used to explain community structure and invasion resistance. We evaluated the contribution of functional richness and identity to invasion resistance and abiotic resource availability using a mesocosm experiment. We predicted that higher functional richness would confer greater invasion resistance through greater resource sequestration. We also predicted that niche pre-emption and invasion resistance would be higher in communities which included functional groups similar to the invader than communities where all functional groups were distinct from the invader. We constructed communities of different functional richness and identity but maintained constant species richness and numbers of individuals in the resident community. The constructed communities represented potential fore dune conditions following invader control activities along the Australian east coast. We then simulated an invasion event by bitou (Chrysanthemoides monilifera ssp. rotundata DC. Norl.), a South African shrub invader. We used the same bitou propagule pressure across all treatments and monitored invasion success and resource availability for 13 months. Contrary to our predictions, we found that functional richness did not mediate the number of bitou individuals or bitou cover and functional identity had little effect on invasion success: there was a trend for the grass single functional group treatment to supress bitou individuals, but this trend was obscured when grasses were in multi functional group treatments. We found that all constructed communities facilitated bitou establishment and suppressed bitou cover relative to unplanted mesocosms. Abiotic resource use was either similar among planted communities, or differences did not relate to invasion success (with the exception of light availability). We attribute invasion resistance to bulk plant biomass across planted treatments rather than their functional group arrangement.

Paradynamic Anthropogenic Landscape System of the Khmel'nitskiy Nuclear Power Plant

Purpose. Сonsider the Khmel’nitskiy nuclear power plant (KNPP) with the scope of its impact on the environment as a single paradynamic anthropogenic landscape system (PALS). Methods: field, literary and cartographic, analytical and cartographic analysis, logic, finding of empirical relationships, theoretical generalization. Results. The processes of formation and functioning of the paradynamic anthropogenic landscape system are described based on the KNPP. The influence of power plant on the air, surface and ground water, the soil, living creatures is analyzed. The paradynamic anthropogenic landscape zones of air, climatic, hydrological, hydrogeological, mineral and biotic effects of Khmel’nitskiy nuclear power plant on the environment are defined and characterized. Conclusions. Found that due to the construction and functioning of Khmelnitsky nuclear power plant the PALS was formed. The paradynamic anthropogenic landscape zones of air, climatic, hydrological, hydrogeological, mineral and biotic effects of nuclear power plant on the environment are defined in its structure. Power station carries out differently effect on the components of nature.

A regional assessment of chemicals of concern in surface waters of four Midwestern United States national parks.

Anthropogenic chemicals and their potential for adverse biological effects raise concern for aquatic ecosystem health in protected areas. During 2013-15, surface waters of four Midwestern United States national parks were sampled and analyzed for wastewater indicators, pharmaceuticals, personal care products, and pesticides. More chemicals and higher concentrations were detected at the two parks with greater urban influences (Mississippi National River and Recreation Area and Indiana Dunes National Lakeshore) than at the two more remote parks (Apostle Islands National Lakeshore and Isle Royale National Park). Atrazine (10-15ng/L) and N,N-diethyl-meta-toluamide (16-120ng/L) were the only chemicals detected in inland lakes of a remote island national park (Isle Royale National Park). Bisphenol A and organophosphate flame retardants were commonly detected at the other sampled parks. Gabapentin and simazine had the highest observed concentrations (>1000ng/L) in three and two samples, respectively. At the two parks with urban influences, metolachlor and simazine concentrations were similar to those reported for other major urban rivers in the United States. Environmental concentrations of detected chemicals were often orders of magnitude less than standards or reference values with three exceptions: (1) hydrochlorothiazide exceeded a human health-based screening value in seven samples, (2) estrone exceeded a predicted critical environmental concentration for fish pharmacological effects in one sample, and (3) simazine was approaching the 4000ng/L Maximum Contaminant Level in one sample even though this concentration is not expected to reflect peak pesticide use. Although few environmental concentrations were approaching or exceeded standards or reference values, concentrations were often in ranges reported to elicit effects in aquatic biota. Data from this study will assist in establishing a baseline for chemicals of concern in Midwestern national parks and highlight the need to better understand the sources, pathways, and potential adverse effects to aquatic systems in national parks.