Search USGS⌕ Search

SEARCH · Search USGS

Results for “One Ecosystem”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,189 records · Page 66Linked to original sources
USGS2016

Biological low pH Mn(II) oxidation in a manganese deposit influenced by metal-rich groundwater

The mechanisms, key organisms, and geochemical significance of biological low-pH Mn(II) oxidation are largely unexplored. Here, we investigated the structure of indigenous Mn(II)-oxidizing microbial communities in a secondary subsurface Mn oxide deposit influenced by acidic (pH 4.8) metal-rich groundwater in a former uranium mining area. Microbial diversity was highest in the Mn deposit compared to the adjacent soil layers and included the majority of known Mn(II)-oxidizing bacteria (MOB) and two genera of known Mn(II)-oxidizing fungi (MOF). Electron X-ray microanalysis showed that romanechite [(Ba,H 2 O) 2 (Mn 4+ ,Mn 3+ ) 5 O 10 ] was conspicuously enriched in the deposit. Canonical correspondence analysis revealed that certain fungal, bacterial, and archaeal groups were firmly associated with the autochthonous Mn oxides. Eight MOB within the Proteobacteria , Actinobacteria , and Bacteroidetes and one MOF strain belonging to Ascomycota were isolated at pH 5.5 or 7.2 from the acidic Mn deposit. Soil-groundwater microcosms demonstrated 2.5-fold-faster Mn(II) depletion in the Mn deposit than adjacent soil layers. No depletion was observed in the abiotic controls, suggesting that biological contribution is the main driver for Mn(II) oxidation at low pH. The composition and species specificity of the native low-pH Mn(II) oxidizers were highly adapted to in situ conditions, and these organisms may play a central role in the fundamental biogeochemical processes (e.g., metal natural attenuation) occurring in the acidic, oligotrophic, and metalliferous subsoil ecosystems.

Applied and Environmental Microbiology↗
USGS2004

Sierra Nevada bioregion

This chapter addresses the immediately south of the Cascades in the Sierra Nevada bioregion, extending nearly half the length of the state of California. This bioregion is one of the most striking features of the state of California, extending from the southern Cascade Mountains in the north to the Tehachapi Mountains and Mojave Desert 700 km to the south. Moreover, the fire responses of important species and fire regime-plant community interactions in the foothill shrubland and the woodland zone, the lower-montane forest ecological zone, the upper-montane forest, the subalpine forest, the alpine meadow, and the shrubland zone and eastside forest and woodland are explained. The success of the management of the Sierra Nevada is contingent on the ability and willingness to keep fire an integral part of these ecosystems.

California↗
USGS2002

Spatial scales of carbon flow in a river food web

Spatial extents of food webs that support stream and river consumers are largely unknown, but such information is essential for basic understanding and management of lotic ecosystems. We used predictable variation in algal δ 13 C with water velocity, and measurements of consumer δ 13 C and δ 15 N to examine carbon flow and trophic structure in food webs of the South Fork Eel River in Northern California. Analyses of δ 13 C showed that the most abundant macroinvertebrate groups (collector-gatherers and scrapers) relied on algae from local sources within their riffle or shallow pool habitats. In contrast, filter-feeding invertebrates in riffles relied in part on algal production derived from upstream shallow pools. Riffle invertebrate predators also relied in part on consumers of pool-derived algal carbon. One abundant taxon drifting from shallow pools and riffles (baetid mayflies) relied on algal production derived from the habitats from which they dispersed. The trophic linkage from pool algae to riffle invertebrate predators was thus mediated through either predation on pool herbivores dispersing into riffles, or on filter feeders. Algal production in shallow pool habitats dominated the resource base of vertebrate predators in all habitats at the end of the summer. We could not distinguish between the trophic roles of riffle algae and terrestrial detritus, but both carbon sources appeared to play minor roles for vertebrate consumers. In shallow pools, small vertebrates, including three-spined stickleback ( Gasterosteus aculeatus ), roach ( Hesperoleucas symmetricus ), and rough-skinned newts ( Taricha granulosa ), relied on invertebrate prey derived from local pool habitats. During the most productive summer period, growth of all size classes of steelhead and resident rainbow trout ( Oncorhynchus mykiss ) in all habitats (shallow pools, riffles, and deep unproductive pools) was largely derived from algal production in shallow pools. Preliminary data suggest that the strong role of shallow pool algae in riffle steelhead growth during summer periods was due to drift of pool invertebrates to riffles, rather than movement of riffle trout. Data for δ 15 N showed that resident rainbow trout (25-33 cm standard length) in deep pools preyed upon small size classes of juvenile steelhead that were most often found in riffles or shallow pools. While many invertebrate consumers relied primarily on algal production derived from local habitats, our study shows that growth of top predators in the river is strongly linked to food webs in adjacent habitats. These results suggest a key role for emigration of aquatic prey in determining carbon flow to top predators.

California↗
USGS2010

Submarine groundwater discharge and fate along the coast of Kaloko-Honokohau National Historical Park, Island of Hawai`i: Part 3, spatial and temporal patterns in nearshore waters and coastal groundwater plumes, December 2003-April 2006

During seven surveys between December 2003 and April 2006, 1,045 depth profiles of surface water temperature and salinity were collected to examine variability in water column properties and the influence of submarine groundwater discharge (SGD) on the nearshore waters and coral reef complex of Kaloko-Honokōhau National Historical Park, Island of Hawai‘i. This effort was made to characterize the variability in nearshore water properties with seasonality and hydrodynamic forcing (tides, winds, and waves) and to determine the spatial and vertical extent of influence of SGD plumes on the Park’s marine biological resources. The results of this study reveal that nearshore waters of the Park were persistently influenced by plumes of submarine groundwater discharge that are generally colder, less saline, and more concentrated in nutrients than the surrounding seawater. These plumes extended between 100 and 1,000 m offshore to depths ranging between 1 and 5 m and often contained several million to hundreds of millions of gallons of brackish water. In essence, the Park’s nearshore, like much of the arid west coast of Hawai‘i, is estuarine. Although the groundwater plumes were persistent over the years studied, their spatial extent and volume varied tidally, seasonally, and annually. In one season, April 2004, an inverse relation of decreasing salinity with increasing temperature was found in the upper 5 m of the water column, unlike the other seasons, when surface water temperature and salinity were positively correlated. These data provide the first comprehensive record of nearshore water column properties within the Park boundaries and a baseline for detecting and assessing future conditions. Various resort, industrial, and municipal developments, either planned or under construction around the Park, will require significant groundwater supplies and will likely alter groundwater quantity and quality. The flux and quality of groundwater through the National Park are critical to the rare anchialine (brackish) pool ecosystems and various ecosystem functions of the nearshore waters and coral reefs. Changes in groundwater discharge are expected to have significant impacts to the area’s coastal ecosystems, including decreased freshwater outflow to the brackish anchialine pools and coral reefs and increased nutrient and contaminant concentrations. In conjunction with two complementary studies of this series (Parts 1 and 2), these data provide insight into the patterns of influence and fate of SGD in the Park’s coastal waters. This information is important for determining water-resource management strategies that balance the needs of the ecosystem with those of human livelihood. This report describes the data, presents the general findings, and gives representative examples of seasonal and tidal variability in water column properties and SGD-fed plumes across the Park’s nearshore waters.

Hawaii↗
USGS2009

One Northwest community - People, salmon, rivers, and the sea: Towards sustainable salmon fisheries

Pacific salmon management is in crisis. Throughout their range, salmon and steelhead populations are being adversely affected by human activities. Without coordinated, effective, and timely action, the future of the Pacific salmon resource is most certainly in doubt. To address the challenges that are currently facing salmon management, concerned citizens representing a diverse array of government agencies and non-governmental organizations have agreed to cooperate in the development of a Sustainable Fisheries Strategy for west coast salmon and steelhead populations. The Strategy builds on the contents of this book, resulting from the Sustainable Fisheries Conference and subsequent community- and watershed-based citizen forums. This chapter presents the key elements of the Strategy including a common vision for the future, a series of guiding principles, and specific strategies for supporting sustainable fisheries. As such, the Strategy embraces an ecosystem-based approach to managing human activities, rather than the traditional egocentric approach to managing salmonid populations and associated habitats. A system of community-based, watershed-oriented councils, including all stakeholders and agency representatives, is proposed for effective transition to ecosystem-based salmon and steelhead management. It is our hope that everyone involved in Pacific salmon management will embrace both the spirit and the specific elements of the Sustainable Fisheries Strategy as we face the difficult challenges ahead.

Book chapter↗
USGS2004

Ecoregions and ecoregionalization: geographical and ecological perspectives

Ecoregions, i.e., areas exhibiting relative homogeneity of ecosystems, are units of analysis that are increasingly important in environmental assessment and management. Ecoregions provide a holistic framework for flexible, comparative analysis of complex environmental problems. Ecoregions mapping has intellectual foundations in both geography and ecology. However, a hallmark of ecoregions mapping is that it is a truly interdisciplinary endeavor that demands the integration of knowledge from a multitude of sciences. Geographers emphasize the role of place, scale, and both natural and social elements when delineating and characterizing regions. Ecologists tend to focus on environmental processes with special attention given to energy flows and nutrient cycling. Integration of disparate knowledge from the many key sciences has been one of the great challenges of ecoregions mapping, and may lie at the heart of the lack of consensus on the “optimal” approach and methods to use in such work. Through a review of the principal existing US ecoregion maps, issues that should be addressed in order to advance the state of the art are identified. Research related to needs, methods, data sources, data delivery, and validation is needed. It is also important that the academic system foster education so that there is an infusion of new expertise in ecoregion mapping and use.

Environmental Management↗
USGS2017

Maximizing establishment and survivorship of field-collected and greenhouse-cultivated biocrusts in a semi-cold desert

Aims Biological soil crusts (biocrusts) are soil-surface communities in drylands, dominated by cyanobacteria, mosses, and lichens. They provide key ecosystem functions by increasing soil stability and influencing soil hydrologic, nutrient, and carbon cycles. Because of this, methods to reestablish biocrusts in damaged drylands are needed. Here we test the reintroduction of field-collected vs. greenhouse-cultured biocrusts for rehabilitation. Methods We collected biocrusts for 1) direct reapplication, and 2) artificial cultivation under varying hydration regimes. We added field-collected and cultivated biocrusts (with and without hardening treatments) to bare field plots and monitored establishment. Results Both field-collected and cultivated cyanobacteria increased cover dramatically during the experimental period. Cultivated biocrusts established more rapidly than field-collected biocrusts, attaining ~82% cover in only one year, but addition of field-collected biocrusts led to higher species richness, biomass (as assessed by chlorophyll a) and level of development. Mosses and lichens did not establish well in either case, but late successional cover was affected by hardening and culture conditions. Conclusions This study provides further evidence that it is possible to culture biocrust components from later successional materials and reestablish cultured organisms in the field. However, more research is needed into effective reclamation techniques.

Plant and Soil↗
USGS2016

Differential heating in the Indian Ocean differentially modulates precipitation in the Ganges and Brahmaputra basins

Indo-Pacific sea surface temperature dynamics play a prominent role in Asian summer monsoon variability. Two interactive climate modes of the Indo-Pacific—the El Niño/Southern Oscillation (ENSO) and the Indian Ocean dipole mode—modulate the amount of precipitation over India, in addition to precipitation over Africa, Indonesia, and Australia. However, this modulation is not spatially uniform. The precipitation in southern India is strongly forced by the Indian Ocean dipole mode and ENSO. In contrast, across northern India, encompassing the Ganges and Brahmaputra basins, the climate mode influence on precipitation is much less. Understanding the forcing of precipitation in these river basins is vital for food security and ecosystem services for over half a billion people. Using 28 years of remote sensing observations, we demonstrate that (i) the tropical west-east differential heating in the Indian Ocean influences the Ganges precipitation and (ii) the north-south differential heating in the Indian Ocean influences the Brahmaputra precipitation. The El Niño phase induces warming in the warm pool of the Indian Ocean and exerts more influence on Ganges precipitation than Brahmaputra precipitation. The analyses indicate that both the magnitude and position of the sea surface temperature anomalies in the Indian Ocean are important drivers for precipitation dynamics that can be effectively summarized using two new indices, one tuned for each basin. These new indices have the potential to aid forecasting of drought and flooding, to contextualize land cover and land use change, and to assess the regional impacts of climate change.

Remote Sensing↗
USGS2025

Fish-assemblage and water-quality recovery with declining acidic deposition in Adirondack mountain streams, New York, USA

Long-term records of air-pollutant emissions and atmospheric deposition, as well as water quality in streams of the Adirondack Mountains of New York, USA, indicate that chemical recovery from acidic deposition is progressing. Although Brook Trout Salvelinus fontinalis (Mitchill, 1814) have recently repopulated several lakes, the degree to which fish assemblages and individual species populations have recovered in streams of the region is unknown. The United States Geological Survey sampled acid–base chemistry and fish assemblages at 42 Adirondack region streams (2014–2021), most of which were also sampled in 2 prior periods (primarily 1979–1984 and 1999), to determine the extent and degree of chemical and biological recovery and whether responses could be linked to regional declines in acidic deposition. Between 1990 and 2021, total annual emissions of SO 2 and NO x declined nationwide by 94% and 87%, respectively, and paralleled 88% and 70% decreases in SO 4 2− and NO 3 − concentrations, respectively, in wet deposition in the region. During this interval, mean acid neutralizing capacity increased by 19.9 µeq/L, pH increased by 0.33 units, and inorganic Al (Al i ) decreased by 6.0 µmol/L at one continuously monitored stream, whereas mean acid neutralizing capacity increased by 38.5 µeq/L and mean Al i concentration decreased by ∼3.0 µmol/L during springtime at all 42 Adirondack region streams. Between the 1 st and 3 rd periods, mean fish-assemblage richness, density, and biomass at 40 sites increased by 112%, 236%, and 66%, respectively. Although mean Brook Trout density and biomass did not meaningfully change among periods, their distribution expanded from 20 sites in the strongly impacted sampling period (1979–1984) to 33 sites in the recovery period (2014–2021). Trends in pollutant emissions and deposition, water quality, and fish-assemblage metrics indicate aquatic ecosystems in many Adirondack mountain streams improved markedly following implementation of the 1990 Clean Air Act Amendments and recent N and S allowance-trading and emissions regulations.

New York↗
USGS2019

Columbia Environmental Research Center

The U.S. Geological Survey Columbia Environmental Research Center performs research to solve challenging environmental problems related to contaminants and habitat alterations in aquatic and terrestrial ecosystems. The research is interdisciplinary and pursued through partnerships within the U.S. Geological Survey and with national, international, state, and local agencies; nongovernmental organizations; and universities. Research is prioritized to provide science to the U.S. Department of the Interior and other natural resource management agencies to inform rehabilitation of degraded habitats and imperiled fish and wildlife populations. The Columbia Environmental Research Center was established in 1966 in Columbia, Missouri, as the U.S. Fish and Wildlife Service’s Fish Pesticide Research Laboratory; the Columbia Environmental Research Center was incorporated into the U.S. Geological Survey in 1996. The U.S. Geological Survey’s staff of 130 includes 90 scientists of which one-half have advanced degrees in ecology, toxicology, biology, biochemistry, chemistry, hydrology, geology, and information technology.

Missouri↗
USGS2007

Mercury and methylmercury in water and bottom sediments of wetlands at Lostwood National Wildlife Refuge, North Dakota, 2003-04

Certain ecosystem types, particularly wetlands, have environmental characteristics that can make them particularly sensitive to mercury inputs and that can result in large mercury concentrations in fish or other aquatic biota. To provide information needed to make effective management decisions to decrease human and wildlife exposure to methylmercury in northern prairie pothole wetlands, the U.S. Geological Survey, in cooperation with the North Dakota Department of Health, conducted a study to assess mercury and methylmercury concentrations in wetlands at the Lostwood National Wildlife Refuge (the Refuge) in northwest North Dakota. In April 2003 and 2004, water and bottom-sediment samples were collected from 44 individual wetlands that were classified as one of four wetland types. Many factors that may affect methylmercury production were considered in the study. The prairie pothole wetlands at the Refuge had large ranges in major environmental characteristics. Hydrologic differences, most notably semiannual wetting and drying cycles, that are intrinsic to prairie pothole wetlands affected methylmercury concentrations. This likely resulted from the stimulation of anaerobic microbial activity following reflooding of soils, particularly soils containing substantial organic carbon. Among the four wetland types considered for this study, seasonal and semipermanent wetlands generally had the largest methylmercury concentrations. Regardless of wetland type, however, methylmercury concentrations at the Refuge are large in relation to reported concentrations for natural aquatic systems.

North Dakota↗
USGS2010

Effects of wastewater effluent discharge and treatment facility upgrades on environmental and biological conditions of the upper Blue River, Johnson County, Kansas and Jackson County, Missouri, January 2003 through March 2009

The Johnson County Blue River Main Wastewater Treatment Facility discharges into the upper Blue River near the border between Johnson County, Kansas and Jackson County, Missouri. During 2005 through 2007 the wastewater treatment facility underwent upgrades to increase capacity and include biological nutrient removal. The effects of wastewater effluent on environmental and biological conditions of the upper Blue River were assessed by comparing an upstream site to two sites located downstream from the wastewater treatment facility. Environmental conditions were evaluated using previously and newly collected discrete and continuous data, and were compared with an assessment of biological community composition and ecosystem function along the upstream-downstream gradient. This evaluation is useful for understanding the potential effects of wastewater effluent on water quality, biological community structure, and ecosystem function. In addition, this information can be used to help achieve National Pollution Discharge Elimination System (NPDES) wastewater effluent permit requirements after additional studies are conducted. The effects of wastewater effluent on the water-quality conditions of the upper Blue River were most evident during below-normal and normal streamflows (about 75 percent of the time), when wastewater effluent contributed more than 20 percent to total streamflow. The largest difference in water-quality conditions between the upstream and downstream sites was in nutrient concentrations. Total and inorganic nutrient concentrations at the downstream sites during below-normal and normal streamflows were 4 to 15 times larger than at the upstream site, even after upgrades to the wastewater treatment facility were completed. However, total nitrogen concentrations decreased in wastewater effluent and at the downstream site following wastewater treatment facility upgrades. Similar decreases in total phosphorus were not observed, likely because the biological phosphorus removal process was not optimized until after the study was completed. Total nitrogen and phosphorus from the wastewater treatment facility contributed a relatively small percentage (14 to 15 percent) to the annual nutrient load in the upper Blue River, but contributed substantially (as much as 75 percent) to monthly loads during seasonal low-flows in winter and summer. During 2007 and 2008, annual discharge from the wastewater treatment facility was about one-half maximum capacity, and estimated potential maximum annual loads were 1.6 to 2.4 times greater than annual loads before capacity upgrades. Even when target nutrient concentrations are met, annual nutrient loads will increase when the wastewater treatment facility is operated at full capacity. Regardless of changes in annual nutrient loads, the reduction of nutrient concentrations in the Blue River Main wastewater effluent will help prevent further degradation of the upper Blue River. The Blue River Main Wastewater Treatment Facility wastewater effluent caused changes in concentrations of several water-quality constituents that may affect biological community structure and function including larger concentrations of bioavailable nutrients (nitrate and orthophosphorus) and smaller turbidities. Streambed-sediment conditions were similar along the upstream-downstream gradient and measured constituents did not exceed probable effect concentrations. Habitat conditions declined along the upstream-downstream gradient, largely because of decreased canopy cover and riparian buffer width and increased riffle-substrate fouling. Algal biomass, primary production, and the abundance of nutrient-tolerant diatoms substantially increased downstream from the wastewater treatment facility. Likewise, the abundance of intolerant macroinvertebrate taxa and Kansas Department of Health and Environment aquatic-life-support scores, derived from macroinvertebrate data, significantly decreased downstream from the wastewater treatment facility. Ecosystem functional health, evaluated using a preliminary framework based on primary production and community respiration, downstream from the wastewater treatment facility was mildly impaired relative to the upstream site during summer 2008 but not during other times of the year. Upgrades to the Blue River Main Wastewater Treatment Facility improved wastewater effluent quality, but the wastewater effluent discharge still had negative effects on the water quality and biological conditions at the downstream sites. Wastewater effluent discharge into the upper Blue River likely contributed to changes in measures of ecosystem structure (streamflow, water chemistry, algal biomass, algal periphyton and macroinvertebrate community composition) and primary production, a measure of ecosystem function, along the upstream-downstream gradient. Because the Blue River Main Wastewater Treatment Facility is located in a rapidly urbanizing area, urbanization effects also may play a role in the decline in environmental and biological conditions along the upstream-downstream gradient. Despite these differences in environmental and biological conditions, ecosystem functional health was not impaired downstream from the WWTF during most times of the year, indicating the declines in environmental and biological conditions along the upstream-downstream gradient were not substantial enough to cause persistent changes in ecosystem function.

Kansas, Missouri↗
USGS2018

Resurgence of specialized shade coffee cultivation: Effects on pollination services and quality of coffee production

Since the early 2000s, there has been a resurgence in shade coffee production on the island of Puerto Rico. The newly restored specialized shade canopy consists of four native tree species, three of which are nitrogen fixers, and is intended to provide 30% shade cover once the trees are matured. Though much is known about the benefits of rustic and traditional shade plantations to coffee production, there is little information available for specialized shade plantations. Here, we investigate the ways in which fruit set, seed predation, bean weight, proportion of peaberries (i.e., malformed fruits), and beverage quality differ between sun and specialized shade plantations of Coffea arabica and Coffea canephora . Additionally, to assess whether coffee plants were pollen limited, we conducted a pollen supplementation experiment in which we compared pollen deposition and berry production on hand-pollinated branches to those of naturally, open-pollinated ones. We found that there was no evidence of pollen limitation on fruit set between sun and specialized shade plantations of C. arabica or C. canephora . We found that specialized shade benefits the proportion of C. arabica fruit set, without compromising bean weight or the proportion of peaberries produced. In comparison, C. canephora showed no improvement in the proportion of fruits set with specialized shade; however, beans from open-pollinated flowers weighed more in specialized shade than sun. Beverage quality was marginally better under shade, and for hand-pollinated flowers. Our results add to the limited body of work investigating the benefits of specialized shade coffee plantations on ecosystem services.

Puerto Rico↗
USGS2026

Comparative assessment of STIC sensors, streamflow and rain gauges for quantifying river connectivity in intermittent systems

In intermittent stream systems, including those occurring in Texas, USA, the severity of low-flow conditions, duration of seasonal disconnection, and frequency of no-flow events have been amplified by drought. Documentation of these no-flow events is necessary to evaluate ecosystem health. However, many intermittent reaches remain un-gauged given that perennial river sec-tions are often prioritized for gauge placement. Our objectives were to 1) document stream flow using Stream Temperature, Intermittency, and Conductivity (STIC) loggers to determine the frequency and duration of no-flow events in intermittent tributaries of the Colorado River, Texas and 2) compare logger data to publicly available data from streamflow discharge and precipitation gauge networks to understand differences among these data types for drying event characterization. We use these comparisons to summarize benefits and limitations of the application of in-stream data loggers. STIC loggers were deployed at 19 sites, one in each pool and riffle habitat of a stream reach. STIC loggers recorded a measurement of relative conductance every six hours from June 2022 to March 2024, which was used to determine the presence or absence of flow connectivity in a reach. No-flow duration among intermittent reaches varied between 37 and 270 days across tributaries during an ongoing drought in the study area. Overall, logger data was more precise than discharge data for characterizing no-flow events or precipitation data when documenting presence of water in the stream channel due to runoff. Lack of discharge gauges in intermittent tributaries left large sections of stream reaches undocumented and resulted in mischaracterization of flow patterns. Drought severity across the tributaries did not follow longitudinal patterns that would be expected by the climatic precipitation gradient of the study area. More research is needed to determine if factors such as population size affect severity. Likewise, precipitation data did not correlate well with logger water presence data, lacking consideration for groundwater recharge, soil hydrophobicity, and surface compaction. This study shows that to monitor no-flow events, detailed spatial datasets are necessary and that STIC loggers are useful tools that provide data to fill spatial information gaps and facilitate more accurate flow characterization and water presence data in intermittent systems.

Texas↗
USGS2016

Metformin and other pharmaceuticals widespread in wadeable streams of the southeastern United States

Pharmaceutical contaminants are growing aquatic-health concerns and largely attributed to wastewater treatment facility (WWTF) discharges. Five biweekly water samples from 59 small Piedmont (United States) streams were analyzed for 108 pharmaceuticals and degradates using high-performance liquid chromatography and tandem mass spectrometry. The antidiabetic metformin was detected in 89% of samples and at 97% of sites. At least one pharmaceutical was detected at every site (median of 6, maximum of 45), and several were detected at ≥10% of sites at concentrations reported to affect multiple aquatic end points. Maximal cumulative (all detected compounds) concentrations per site ranged from 17 to 16000 ng L –1 . Watershed urbanization, water table depth, soil thickness, and WWTF metrics correlated significantly with in-stream pharmaceutical contamination. Comparable pharmaceutical concentrations and detections at sites with and without permitted wastewater discharges demonstrate the importance of non-WWTF sources and the need for broad-scale mitigation. The results highlight a fundamental biochemical link between global human-health crises like diabetes and aquatic ecosystem health.

Environmental Science & Technology Letters↗
USGS2016

Disentangling the complexities of how legumes and their symbionts regulate plant nitrogen access and storage

Nitrogen (N) availability strongly influences the structure and function of ecosystems (e.g. Vitousek & Howarth, 1991), but only a relatively small number of microbial groups have the ability to convert the N 2 in our atmosphere into biologically available forms.This process, N 2 fixation, is the dominant source of new N to the biosphere outside of anthropogenic inputs (Vitousek et al., 2013).Some N 2 -fixing microorganisms live independently on plant leaves, on decomposing organic material, and in soil (Reed et al.,2011), while others have co-evolved with a few higher plant taxa to form symbioses that fix N 2 in root nodules (e.g. Sprent & Raven,1985). The relationship between these legumes and their root nodule symbionts (rhizobia) is one of the most well studied plant –microbe symbioses. Yet, many important questions about the controls, interactions, and implications of legume N 2 fixation remain unanswered. In this issue of New Phytologist (pp. 690–699),Wolf, Funk, & Menge elegantly address a fundamental set of questions about N 2 fixation in their examination of how herbaceous legumes, their symbionts, and external N availability interact to govern legume access and storage of N.

New Phytologist↗
USGS2020

Antibiotic resistance in marine microbial communities proximal to a Florida sewage outfall system

Water samples were collected at several wastewater treatment plants in southeast Florida, and water and sediment samples were collected along and around one outfall pipe, as well as along several transects extending both north and south of the respective outfall outlet. Two sets of samples were collected to address potential seasonal differences, including 38 in the wet season (June 2018) and 42 in the dry season (March 2019). Samples were screened for the presence/absence of 15 select antibiotic resistance gene targets using the polymerase chain reaction. A contrast between seasons was found, with a higher frequency of detections occurring in the wet season and fewer during the dry season. These data illustrate an anthropogenic influence on offshore microbial genetics and seasonal flux regarding associated health risks to recreational users and the regional ecosystem.

Florida↗
USGS2011

Responses of salt marsh ecosystems to mosquito control management practices along the Atlantic Coast (U.S.A.)

Open marsh water management (OMWM) of salt marshes modifies grid-ditched marshes by creating permanent ponds and radial ditches in the high marsh that reduce mosquito production and enhance fish predation on mosquitoes. It is preferable to using pesticides to control salt marsh mosquito production and is commonly presented as a restoration or habitat enhancement tool for grid-ditched salt marshes. Monitoring of nekton, vegetation, groundwater level, soil salinity, and bird communities before and after OMWM at 11 (six treatment and five reference sites) Atlantic Coast (U.S.A.) salt marshes revealed high variability within and among differing OMWM techniques (ditch-plugging, reengineering of sill ditches, and the creation of ponds and radial ditches). At three marshes, the dominant nekton shifted from fish (primarily Fundulidae species) to shrimp (Palaemonidae species) after manipulations and shrimp density increased at other treatment sites. Vegetation changed at only two sites, one with construction equipment impacts (not desired) and one with a decrease in woody vegetation along existing ditches (desired). One marsh had lower groundwater level and soil salinity, and bird use, although variable, was often unrelated to OMWM manipulations. The potential effects of OMWM manipulations on non-target salt marsh resources need to be carefully considered by resource planners when managing marshes for mosquito control.

Atlantic Coast↗