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(a) Dominant anthropogenic sources of nitrogen to surface water for HUC 8 (Hydrologic Unit Code) watersheds. BNF denotes biological nitrogen fixation. (b) Atmospheric nitrogen deposition expressed as a percentage (0 to 100%) of all anthropogenic nitrogen inputs. Source: Compton et al. 20
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Excess nitrogen and phosphorus (i.e., nutrients) environmental loadings continue to affect ecosystem function and human health across the U.S. Our ability to connect atmospheric inputs of nutrients to aquatic endpoints remains limited due to uncoupled air and water quality monitoring. Where connections exist, the information provides insights about...
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... persistent hypoxic zone in the Gulf of Mexico was the size of New Jersey in 2017, the largest in the 15-year record. 10 The U.S. Environmental Protection Agency's Science Advisory Board recently concluded a national strategy integrating air and water monitoring is needed to understand sources, transport, and fate of excess nutrients. 11 Atmospheric deposition dominates nitrogen inputs to surface waters over much of the conterminous U.S. 12 ( Figure 1). Atmo- spheric deposition physically delivers nitrogen and phosphorus to land and water surfaces by wet (e.g., rain, snow) and dry (e.g., gases and particulates) processes. ...
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The classical Bayesian Optimization approach for optimizing costly and unknown functions is used in this work for monitoring multiple water quality parameters. Since multiple models (one for each water quality parameter) are obtained, we combine BO with a Multi-Objective Optimization method so that optimal measurement locations are determined. Thes...
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... Lag times between nutrient inputs and chlorophyll concentration in this study system remains an area of current research (e.g., Balint et al., 2021;Oviatt et al., 2022), and future work should utilize high temporal resolution water, sediment, and atmospheric flux measurements to further investigate the potential relationship between water column inorganic nitrogen concentration, NH 3(g) concentration, and NH 3(g) flux. Co-located deposition and water quality monitoring would provide information on source allocation, trends, risk to sensitive ecosystems, and efficacy of pollution reduction efforts (Amos et al., 2018). Interestingly, NH 3(g) flux and concentration were not correlated with environmental variables such as wind speed, wind direction, air temperature, water temperature, or time (from both seasonal and diurnal perspectives) (Table S5 and Figure S3 in Supporting Information S1). ...
Narragansett Bay, the largest estuary in New England, is a heavily urbanized watershed impacted by deposition and runoff. Nutrient budgets and local policy rely on deposition data from a 1990 study that did not include any direct observations of dry deposition of gaseous ammonia (NH3(g)) and particulate ammonium (p‐NH4⁺) due to uncertainties in their flux direction and measurement difficulty. Recent work has shown that wet deposition of ammonium (NH4⁺) to the Bay has increased by a factor of 6 over the past three decades, leading to a 2.5‐fold increase in wet nitrogen (N) deposition. This documented increase in wet deposition of NH4⁺ is concurrent with managed nutrient reductions in urbanized estuaries but has potentially increased the impacts of atmospheric N deposition, including the dry deposition of NH3(g) and p‐NH4⁺. However, the lack of NH3(g) and p‐NH4⁺ measurements hinders our interpretation of this important N source. For the first time over Narragansett Bay, and to our knowledge over open water, dry (particulate and gas phase) total ammonia (NHx = NH3(g) + p‐NH4⁺) and the bidirectional NH3(g) flux were quantified using a relaxed eddy accumulation sampling technique. We find that dry deposition of NHx comprises 9.6% of total (wet + dry) N deposition. During the fall season, the dominant flux direction for NH3(g) is upward, which also has implications for urban air quality. We estimate that NH3(g) emitted from the Bay to the atmosphere makes up to 10% of the local NH3(g) emission budget for fall.
... This situation can be explained by the air quality in the area. According to Berthold et al. [31] and Amos at al. [32], the content of phosphorus in precipitation is constantly increasing. It is reported that phosphate concentrations in rain are so high (almost 1.5 mg PO4/L) that they exceed the amounts discharged into surface runoff waters. ...
The research was carried out on the flow-through Lake Mielenko (7.8 ha; 1.9 m), which also acts as a stormwater receiver. In 2015, a disposal for road salts was created in the lake’s catchment area. As a result of the inflow of salt-contaminated stormwater, there was a significant increase in the concentration of calcium (57 mg Ca/L), chloride (220 mg Cl/L) and electrolytic conductivity (790 µS/cm). Increased calcium concentrations in lake waters changed their hardness from low to medium-hard. The ecological effect of the change in hydrochemical conditions in Lake Mielenko is the Potamogeton crispus that grows abundantly in this reservoir, which prefer calcium-rich water. The overall aesthetics of the lake have deteriorated significantly, and the availability of water for recreation has also been limited.
... While spatial variation in the stream NO 3 − concentration is frequently attributed to land use (van Breemen et al. 2002) and/or geology (Holloway et al. 1998) in the watershed, the effect of such variables was not significant in our watersheds. In addition, other factors affecting the NO 3 − concentration such as climatic condition (Watmough et al. 2004), nitrogen deposition (Nishina et al. 2017;Amos et al. 2018), and forest age (Pardo et al. 1995;Tokuchi and Fukushima 2009) are almost the same within the range of our study watersheds. While the excretion of nitrogen from benthos was in the form of NH 4 + , we assume that NH 4 + Content courtesy of Springer Nature, terms of use apply. ...
Animals affect element cycling in ecosystems by consumption and excretion. Amphidromous shrimps frequently dominate low-mid altitude streams, where downstream connectivity to oceans is sustained. Although shrimps’ direct influence on benthic communities has been studied, little is known about their influences on nutrient cycling. Here, we hypothesized that the dominance of shrimps alters nutrient mineralization by benthic macroinvertebrates in streams due to the difference in the quality and quantity of excretion between shrimps and aquatic insects. We tested this hypothesis through a field manipulative experiment, excretion measurements of animals, and field surveys. In the field manipulative experiment, the presence of shrimps slightly decreased the biomass of aquatic insects but tripled total benthic macroinvertebrate biomass directly through their own biomass. The mass-specific NH4+ excretion rate by shrimps was similar to aquatic insects, and the areal NH4+ excretion by benthic macroinvertebrates was increased by 2.5 times in the presence of shrimps. In contrast, shrimps excreted significantly less soluble reactive phosphorus (SRP) than aquatic insects, and the presence of shrimps did not affect areal SRP excretion by benthic macroinvertebrates. The field survey showed a positive correlation of NO3− concentration with the shrimp density, inferring the excess NH4+ was nitrified. Although the nutrient concentration of stream water is frequently attributed to watershed conditions, the results of this study indicate that downstream connectivity to oceans may also influence nutrient dynamics of the stream through the density of amphidromous shrimps.
... In contrast, we observed that the concentration of chlorophyll a decreased in the water extracts of PM 2.5 samples when the experiment was on. The levels of chlorophyll a in the water extracts of PM 2.5 samples with four levels of aerosol acidity (in situ pH: 2.8, 3.1, 3.5, 3.8) were measured at scheduled times (2,4,6,8,10,12,14,16,18,20,22,24,30,36,42,48,54, and 60 h) (Figure 2A). Soon after, mixing levels of chlorophyll a were observed to decrease by 20−40% following exposures to water extracts of PM 2.5 samples with different levels of aerosol acidities. ...
... As enforcement of new data management policies has intensified by journals and funding agencies, submissions to geochemical data repositories have increased for rock chemistry (Albarede and . In addition, papers are beginning to appear that describe meta-analyses for topics as wideranging as arsenic and methane in groundwater (Podgorski and Berg, 2020;Wen et al., 2021), soil organic carbon , and nutrients in rain and groundwater (Amos et al., 2018), and these papers highlight the utility of more extensive data sharing. Nonetheless, resistance to data management in repositories remains in the LTG community, as it does for other communities. ...
Data sharing benefits the researcher, the scientific community, and the public by allowing the impact of data to be generalized beyond one project and by making science more transparent. However, many scientific communities have not developed protocols or standards for publishing, citing, and versioning datasets. One community that lags in data management is that of low-temperature geochemistry (LTG). This paper resulted from an initiative from 2018 through 2020 to convene LTG and data scientists in the U.S. to strategize future management of LTG data. Through webinars, a workshop, a preprint, a townhall, and a community survey, the group of U.S. scientists discussed the landscape of data management for LTG – the data-scape. Currently this data-scape includes a “street bazaar” of data repositories. This was deemed appropriate in the same way that LTG scientists publish articles in many journals. The variety of data repositories and journals reflect that LTG scientists target many different scientific questions, produce data with extremely different structures and volumes, and utilize copious and complex metadata. Nonetheless, the group agreed that publication of LTG science must be accompanied by sharing of data in publicly accessible repositories, and, for sample-based data, registration of samples with globally unique persistent identifiers. LTG scientists should use certified data repositories that are either highly structured databases designed for specialized types of data, or unstructured generalized data systems. Recognizing the need for tools to enable search and cross-referencing across the proliferating data repositories, the group proposed that the overall data informatics paradigm in LTG should shift from “build data repository, data will come” to “publish data online, cybertools will find”. Funding agencies could also provide portals for LTG scientists to register funded projects and datasets, and forge approaches that cross national boundaries. The needed transformation of the LTG data culture requires emphasis in student education on science and management of data.
... Despite this, there are limited atmospheric measurements of NH 3 concentrations and fluxes in coastal areas of the Eastern and Mid-Atlantic U.S (Amos et al., 2018;Larsen et al., 2001;Poor et al., 2001;Siefert et al., 2002). The few experimental studies in the literature used a combination of conventional air sampling techniques such as annular denuders, filter packs, and passive filter badges to calculate the NH 3 concentrations. ...
... This new technology provides improved temporal resolution of NH 3 measurements, which is necessary given the dynamic response of NH 3 to changing environmental conditions (Kamp et al., 2019). Continuous and high temporal resolution measurements of atmospheric NH 3 concentrations in salt marsh ecosystems along the east coast of the US are needed to provide details of the fluctuations of NH 3 concentrations (Amos et al., 2018). Such detailed measurements will make it possible to accurately calculate the NH 3 flux between the atmosphere and the surface in salt marshes. ...
Measurements of atmospheric ammonia (NH3) concentrations and fluxes are limited in coastal regions in the eastern U.S. In this study, continuous and high temporal resolution measurements (5s) of atmospheric NH3 concentrations were recorded using a cavity ring-down spectrometer in a temperate tidal salt marsh at the St Jones Reserve (Dover, DE). Micrometeorological variables were measured using an eddy covariance system which is part of the AmeriFlux network (US-StJ). Soil, plant, and water chemistry were also analyzed to characterize the sources and sinks of atmospheric NH3. A new analytical methodology was used to estimate the average ecosystem-scale diurnal cycle of NH3 fluxes by replicating the characteristics of a chamber experiment. This virtual chamber approach estimates positive surface fluxes in continuing strongly stable conditions when mixing with the air above is minimal. Our findings show that tidal water level may have a significant impact on NH3 emissions from the marsh. The largest fluxes were observed at low tide when more soil was exposed. While it is expected that NH3 fluxes will peak when the air temperature maximizes, high tide occurred concurrently with midday peaks in solar irradiance led to a decrease in NH3 fluxes. Furthermore, soil, plant, and water chemistry measurements underpinning the NH3 concentrations and fluxes lead us to conclude that this coastal wetland ecosystem can act as either a sink or a source of NH3. Such measurements provide novel data on which we can base reliable parameterizations to simulate NH3 emissions from coastal salt marsh ecosystems using surface-atmosphere transfer models.
... In some respects, P inventories are less complex than N because of the general lack of gaseous forms of P and fewer transformations (Metson et al., 2017). However, the lack of attention to atmospheric P measurements, emission sources, and atmospheric transport poses a substantial challenge to understanding P dynamics in less disturbed catchments that may be more sensitive to shifts in atmospheric deposition (Amos et al., 2018;Mahowald et al., 2008;Stoddard et al., 2016). Recent work has speculated that the continental-wide increases in lake and stream TP concentrations may have been driven by increased rates of atmospheric P deposition (Stoddard et al., 2016). ...
... Unlike atmospheric nitrogen deposition, atmospheric P deposition is not actively monitored by the National Atmospheric Deposition Program or similar observation networks (Amos et al., 2018). Thus, we relied on modeled estimates of atmospheric P deposition. ...
... Generally, the model was able to capture broad regional patterns observed in these two datasets with some positive bias (R 2 = 0.25) despite some concerns of contamination in the validation data set (Wang et al., 2017). Echoing calls of recent research policy articles, developing protocols and maintaining monitoring networks that maintain measurements of atmospheric P deposition across the contiguous United States should be developed to constrain this flux (Amos et al., 2018). ...
Published reports suggest efforts designed to prevent the occurrence of harmful algal blooms and hypoxia by reducing non‐point and point source phosphorus (P) pollution are not delivering water quality improvements in many areas. Part of the uncertainty in evaluating watershed responses to management practices is the lack of standardized estimates of phosphorus inputs and outputs. To assess P trends across the conterminous United States, we compiled an inventory using publicly available datasets of agricultural P fluxes, atmospheric P deposition, human P demand and waste, and point source discharges for 2002, 2007, and 2012 at the scale of the 8‐digit Hydrologic Unit Code subbasin (∼1,800 km²). Estimates of agricultural legacy P surplus accumulated from 1945 to 2001 were also developed. Fertilizer and manure inputs were found to exceed crop removal rates by up to 50% in many agricultural regions. This excess in inputs has led to the continued accumulation of legacy P in agricultural lands. Atmospheric P deposition increased throughout the Rockies, potentially contributing to reported increases in surface water P concentrations in undisturbed watersheds. In some urban areas, P fluxes associated with human waste and non‐farm fertilizer use has declined despite population growth, likely due, in part, to various sales bans on P‐containing detergents and fertilizers. Although regions and individual subbasins have different contemporary and legacy P sources, a standardized method of accounting for large and small fluxes and ready to use inventory numbers provide essential infromation to coordinate targeted interventions to reduce P concentrations in the nation's waters.
... We also did not include total P atmospheric deposition as an input. In some areas (e.g., pristine forests) these flows may have significant effects on (and sometimes complex interactions with) water quality (Amos et al., 2018;Stoddard et al., 2016). We also did not consider N fixation by red alder trees or nutrient sources from runoff and erosion from non-agricultural lands (e.g., bedrock, forest, urban runoff), which have been shown to be important sources in some parts of the Pacific Northwest U.S. (Compton et al., 2003;Wise & Johnson, 2013). ...
Better documentation and understanding of long-term temporal dynamics of nitrogen (N) and phosphorus (P) in watersheds is necessary to support effective water quality management, in part because studies have identified time lags between terrestrial nutrient balances and water quality. We present annual time series data from 1969 to 2012 for terrestrial N and P sources and monthly data from 1972 to 2013 for river N and P for the Willamette River Basin, Oregon, United States. Inputs to the watershed increased by factors of 3 for N and 1.2 for P. Synthetic fertilizer inputs increased in total and relative importance over time, while sewage inputs decreased. For N, increased fertilizer application was not matched by a proportionate increase in crop harvest; N use efficiency decreased from 69% to 38%. P use efficiency increased from 52% to 67%. As nutrient inputs to terrestrial systems increased, river concentrations and loads of total N, total P, and dissolved inorganic P decreased, and annual nutrient loads were strongly related to discharge. The N:P ratio of both sewage and fertilizer doubled over time but there was no similar trend in riverine export; river N:P concentrations declined dramatically during storms. River nutrient export over time was related to hydrology and waste discharge, with relatively little influence of watershed balances, suggesting that accumulation within soils or groundwater over time is mediating watershed export. Simply managing yearly nutrient balances is unlikely to improve water quality; rather, many factors must be considered, including soil and groundwater storage capacity, and gaseous loss pathways.
... The abundance, diversity, and nutrient sensitivity of diatoms are reasons why they are used by many states to assess stream health and to develop numeric-nutrient criteria (Zheng et al. 2008;Smith and Tran 2010;Charles et al. 2019). In the western U.S., diatoms can be the dominant algae in a river (Crayton and Sommerfeld 1979;Fisher et al. 1982) and nutrient enrichment is increasingly becoming a problem in the western U.S. (Sickman et al. 2003; Baron et al. 2011), making the problem a national issue (U.S. Environmental Protection Agency 2016; Amos et al. 2018). Thus, to make generalized model parameters applicable to a wide variety of environmental conditions and assemblage composition, we set out to estimate growth rate parameters derived from an underrepresented type of algal community, a diatom-dominant community from a western U.S. river. ...
Nitrogen (N) and phosphorus (P) are significant pollutants that can stimulate nuisance blooms of algae. Water quality models (e.g., Water Quality Simulation Program, CE‐QUAL‐R1, CE‐QUAL‐ICM, QUAL2k) are valuable and widely used management tools for algal accrual due to excess nutrients in the presence of other limiting factors. These models utilize the Monod and Droop equations to associate algal growth rate with dissolved nutrient concentration and intracellular nutrient content. Having accurate parameter values is essential to model performance; however, published values for model parameterization are limited, particularly for benthic (periphyton) algae. We conducted a 10‐day mesocosm experiment and measured diatom‐dominated periphyton biomass accrual through time as chlorophyll a (chl a) and ash‐free dry mass (AFDM) in response to additions of N (range 5–11,995 µg nitrate as nitrogen [NO3‐N]/L) and P (range 0.89–59.51 µg soluble reactive phosphorus/L). Resulting half‐saturation coefficients and growth rates are similar to other published values, but minimum nutrient quotas are higher than those previously reported. Saturation concentration for N ranged from 150 to 2,450 µg NO3‐N/L based on chl a and from 8.5 to 60 µg NO3‐N/L when based on AFDM. Similarly, the saturation concentration for P ranged from 12 to 29 µg‐P/L based on chl a, and from 2.5 to 6.1 µg‐P/L based on AFDM. These saturation concentrations provide an upper limit for streams where diatom growth can be expected to respond to nutrient levels and a benchmark for reducing nutrient concentrations to a point where benthic algal growth will be limited. Research Impact Statement: Parameter estimates for water quality models predictive of periphyton growth rates and accrual in streams were derived from a diatom‐dominated community in a nutrient addition mescocosm experiment.
... However, both measurements and models show urban areas (Figure 1, lower right) as hot-spots for deposition of oxidized and reduced forms of Nr, owing to a high Walker Expanded routine monitoring is needed to better understand the role of atmospheric Nr deposition in urban water quality and to better inform management of total maximum daily loads (TMDL) and other water quality issues downstream 25 . This would involve expansion of networks such as NADP National Trends Network (NTN) in urban areas, which would benefit from coordination of deposition and water quality monitoring 26 . Air concentrations of oxidized Nr (NO x , NO y , NO 2 ) are already monitored in many urban areas (EPA Air Quality System, https://www.epa.gov/aqs). ...
