Method of evaluating nutrient loads through the atmosphere onto lakes (original) (raw)
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Nutrient Atmospheric Deposition on Utah Lake: A Comparison of Sampling and Analytical Methods
Hydrology
We describe modified sampling and analysis methods to quantify nutrient atmospheric deposition (AD) and estimate Utah Lake nutrient loading. We address criticisms of previous published collection methods, specifically collection table height, screened buckets, and assumptions of AD spatial patterns. We generally follow National Atmospheric Deposition Program (NADP) recommendations but deviate to measure lake AD, which includes deposition from both local and long-range sources. The NADP guidelines are designed to eliminate local contributions to the extent possible, while lake AD loads should include local contributions. We collected side-by-side data with tables at 1 m (previous results) and 2 m (NADP guidelines) above the ground at two separate locations. We found no statistically significant difference between data collected at the different heights. Previous published work assumed AD rates would decrease rapidly from the shore. We collected data from the lake interior and show th...
Pilot Study Of Nutrient Loading In A Wet Detention Lake
2007
Florida is surrounded by water, and its many internal lakes and rivers have long been recognized for their excellent fishing and boating. This notoriety draws land developers to the lake shores to establish residential and commercial infrastructure. This land development brings with it flood plain alteration, water level stabilization, and increased nutrients which cause adverse impacts to our lakes. In response, the United States Environmental Protection Agency (EPA) passed the Federal Clean Water Act (CWA) in 1972 which set the framework for the water quality standards for the entire United States. As a result of the CWA many point sources were eliminated, but in the process it became apparent that nonpoint source loads represented even more of a threat. To further study the physical and chemical characteristics of urban runoff the Nationwide Urban Runoff Program (NURP) was established in 1978. This research lead to a series of management options, named Best Management Practices (BMPs) which proposed various structural and non-structural methods to reduce nutrient loads. But the research and data collection on the effectiveness of these systems to remove nutrients is in its infancy. The main objective of this study was to generate accurate and effective water quality and water quantity data that future stormwater management decisions can be based upon. More specific, this study established automatic monitoring sites throughout the City of Kissimmee, Florida to determine the pollutant loadings into the tributaries of Lake Tohopekaliga. These monitoring sites are located such that inflows from outside the city limits can be isolated and external pollutant loads quantified. Also, additional internal monitoring sites were established to determine the pollutant loads of internal sections of the city. Data from these internal monitoring sites will also be used to determine the variable pollutant removal efficiencies and hydraulic fluctuations of natural, irregular riverine systems. vii
Nutrient Loadings to Utah Lake from Precipitation-Related Atmospheric Deposition
Hydrology
Atmospheric deposition (AD) is a less understood and quantified source of nutrient loading to waterbodies. AD occurs via settling (large particulates), contact (smaller particulates and gaseous matter), and precipitation (rain, snow) transport pathways. Utah Lake is a shallow eutrophic freshwater lake located in central Utah, USA, with geophysical characteristics that make it particularly susceptible to AD-related nutrient loading. Studies have shown AD to be a significant contributor to the lake’s nutrient budget. This study analyzes nutrient samples from nine locations around the lake and four precipitation gauges over a 6-year study period using three different methods to estimate AD from the precipitation transport pathway. The methods used are simple averaging, Thiessen polygons, and inverse distance weighting, which we use to spatially interpolate point sample data to estimate nutrient lake loads. We hold that the inverse distance weighting method produces the most accurate re...
The atmospheric deposition of phosphorus and nitrogen on Lake Kivu
2016
Phosphorus and nitrogen are most often identified as the nutrients limiting algal biomass and productivity in aquatic ecosystems. Sources of new nutrients for lakes include riverine input, atmospheric deposition, N fixation, and occasionally groundwater. For many regions, the relative importance of atmospheric deposition is uncertain. Annual dynamics of wet and dry atmospheric nutrients (phosphorus and nitrogen) deposition on Lake Kivu were investigated at three land stations and one an island station to estimate lake wide atmospheric nutrient input to Lake Kivu. The highest dry P (TP) loading rates were recorded at the southern end of the Lake with lower rates in the north. Annual dry atmospheric deposition was higher than wet deposition in all the four sites. The estimation of dry TP and TN deposition to entire Lake Kivu (2370 km 2) is 14.5 ± 16.26 kg m-2 yr-1 of TP and 506.3 ± 590.7 kg m-2 yr-1 of TN. And the wet TP and TN estimation rate for the all Lake Kivu was respectively 0.09 ± 0.07 kg m-2 yr-1 and 2.02 ± 0.16 kg m-2 yr-1. Phosphorus and nitrogen deposition rates in atmospheric deposition around Lake Kivu were similar to the existing estimates of atmospheric phosphorus and nitrogen inputs to other African Lakes. Both biomass burning and soil suspension particles were suggested as possible sources. These estimates should be viewed as a first order approximation of actual phosphorus and nitrogen deposition on the Lake.
Atmospheric Environment, 1995
Alammct--Eight wet/dry precipitation collectors were modified to house four additional dryfall collectors and one bulk precipitation collector to sample atmospheric deposition for 12 weeks in a small area on the southwestern shore of Lake Okecchobee; sample contamination, primarily by insects, reduced the comparison to the last nine weeks. The deposition was determined for Ca 2+, Na +, CI-, and SO, 2-and nutrients including total phosphorus, orthophosphate, total ammonia plus organic nitrogen, and nitrite plus nitrate. In general, deposition was lower and less variable in wet precipitation than in bulk precipitation. The higher variability of the bulk precipitation was attributed to local contamination, particularly by dust and insects. Each wet/dry precipitation collector was fitted with dryfall collectors that consisted of the dry-side bucket on a wet/dry collector, which was preloaded with distilled and deionized water, and four glass dish collectors; two 3f the glass dishes were preloaded with water and the other two remained dry. The deposition to the dry dish collectors was not comparable in adjacent collectors for any constituent; however, the deposition in ~:he adjacent water-loaded dishes was comparable for most major constituents, except nutrients. A comparison of Ortho-P deposition with Total-P indicated that the P collected by the dryfall collectors was predominantly reactive, which also was reflected in the bulk deposition, whereas that in the wet deposition was mostly nonreactive. The large variability in deposition of P among the bulk and dr#all collectors suggests that alternative methods must be used to evaluate the P sources and processes of atmospheric transfer.
Environmental Pollution, 1998
The most important nitrogen source for isolated heathland lakes in the Netherlands is the atmospheric deposition of nitrogen compounds. Calculations were performed to relate in-lake concentrations with deposition. Using a dynamic retention model, all major components deposited (NH4+, NO,-and SO,%) appeared to be retained by the lake. Simulations with the aquatic ecosystem model AquAcid showed a big discrepancy between calculated and measured concentrations when using the estimated total deposition. However, using only wet deposition data, a reasonable fit with measured datawas obtained. It was concluded that the dry deposition of nitrate and ammonium actually entering the lakes was far lower than the deposition estimated. The reasons for the apparent absence of dry deposition of nitrogen compounds on heathland lakes in general, and the impact on estimates of critical nitrogen deposition, are discussed.
Hydrobiologia, 1997
This study assesses the effects of external and internal loading on the nutrient concentrations in an agriculturally loaded shallow lake. Using 13 years of observations of the lake's input and outflow, we calculated the long-term balances of Tot-P and Tot-N. A more detailed balance, which included dissolved nutrients and suspended solids, was estimated for an ice-free period of one year. The contribution of the external load was assessed using a mass-balance model. The internal load was estimated from the nutrient balances and on the basis of sedimentation measurements and bioassays. The drainage basin of the lake provided most of the external nutrient input; the remaining load was derived from atmospheric deposition to the lake. The proportions of river-transported P and N in dissolved form were 25% and 77%, respectively. The lake retained >80% of the external load. Particulate nutrients settled to the bottom and were probably resuspended several times before permanent sedimentation. Dissolved nutrients were bound by primary producers and a high proportion of dissolved P was removed with the fish catch. Dissolved N was also lost via denitrification. The mass-balance model showed that external loading only partly regulated the mean annual nutrient concentrations in the lake. The regulation was probably due to internal loading, which was high despite the efficient net retention of nutrients. During the ice-free period, the temporal variations in nutrient concentrations were controlled almost solely by internal processes, such as resuspension of inorganic and organic bottom matter. Although the internal load of bioavailable P may, under favourable conditions, exceed the external load, the mechanism by which bioavailable P is translocated from the bottom sediments to the water could not be fully identified.
BioScience, 2011
The ecological effects of elevated atmospheric nitrogen (N) deposition on high-elevation lakes of the western and northeastern United States include nutrient enrichment and acidification. The nutrient enrichment critical load for western lakes ranged from 1.0 to 3.0 kilograms (kg) of N per hectare (ha) per year, reflecting the nearly nonexistent watershed vegetation in complex, snowmelt-dominated terrain. The nutrient enrichment critical load for northeastern lakes ranged from 3.5 to 6.0 kg N per ha per year. The N acidification critical loads associated with episodic N pulses in waters with low values of acid neutralizing capacity were 4.0 kg N per ha per year (western) and 8.0 kg N per ha per year (northeastern). The empirical critical loads for N-caused acidification were difficult to determine because of a lack of observations in the West, and high sulfur deposition in the East. For both nutrient enrichment and acidification, the N critical load was a function of how atmospheric N deposition was determined.
Water Resources Research, 1994
Atmospheric deposition provides most of the dissolved inorganic nitrogen (DIN) and total nitrogen in the annual nutrient load of Lake Tahoe. Deposition also contributes significant amounts of soluble reactive phosphorus (SRP) and total phosphorus loading but plays less of a role than in the case of nitrogen. Most of the DIN probably originates outside of the drainage basin in urban and agricultural areas to the south and west. Spatial patterns of SRP deposition differ from those of DIN and suggest a within-basin terrestrial source, such as leachate from windblown dust or other particles. Because of atmospheric N deposition, the N:P (molar) ratio in combined loading is well above the Redfield ratio of 16 and consistent with an observed shift from colimitation by N and P to persistent P limitation in the lake phytoplankton. JASSBY ET AL.' ATMOSPHERIC DEPOSITION OF NITROGEN AND PHOSPHORUS 0 10 km i i Ward Ck. 120øW i _ • f•ird Ck.