Sediment Phosphorus Release in a Shallow Eutrophic Reservoir Cove

2019 ◽  
Vol 62 (5) ◽  
pp. 1269-1281
Author(s):  
James A. McCarty

Abstract. Internal phosphorus (P) loading is a leading contributor to eutrophication in reservoirs and can cause harmful algal blooms as well as treatment issues for drinking water reservoirs. Coves are an area of reservoirs that have not received adequate attention, even though they experience higher nutrient and sediment deposition and primary production per unit area when compared to the pelagic zone of the reservoir. This study investigates a shallow eutrophic cove in a northwest Arkansas reservoir called Beaver Lake to better understand the cove’s potential to contribute to P loading and eutrophication within the reservoir. The study period was 3 to 16 July 2018. Water column profiles of depth, temperature, and dissolved oxygen were measured with a floating sensor platform that also contained a weather station. Cove bed sediment samples were collected at three locations in the cove and analyzed for chemical composition through Mehlich III extraction and P, nitrate + nitrite (N+N), and ammonia release rates with aerobic and anaerobic sediment core incubations. Bathymetry data were collected using a depth sonar system. Sensor platform profiles indicated dynamic bottom temperature and dissolved oxygen conditions with transient influxes of hypoxic waters that occurred several times for less than 24 h. The P release rates from bed sediment incubations were as high as 2.02 mg m-2 d-1 under aerobic conditions and 4.45 mg m-2 d-1 under anaerobic conditions. Upon initiation of nitrogen gas bubbling in the sediment cores, anaerobic conditions were delayed by the presence of N+N. Phosphorus release did not occur until denitrification decreased the N+N concentrations enough for reducing conditions to be present. For the study period, a P flux into the water of roughly 1 kg was determined using cove profiles, bathymetry, and P release rates. When compared to whole-lake P release averages for Beaver Lake, eutrophic coves are a disproportionate source of P per unit area within the reservoir. This may offer opportunities for more efficient use of internal loading remediation techniques, such as alum application. The results of this study also suggest that we should not continue to overlook shallow-area bed sediment P flux when considering the P mass balance of a reservoir. Keywords: Eutrophication, Sediment core incubation, Stratification.

2000 ◽  
Vol 57 (5) ◽  
pp. 1033-1041 ◽  
Author(s):  
Michael R Penn ◽  
Martin T Auer ◽  
Susan M Doerr ◽  
Charles T Driscoll ◽  
Carol M Brooks ◽  
...  

Phosphorus release rates were measured on intact sediment cores collected from the major depositional basin of Onondaga Lake, a dimictic, calcareous, hypereutrophic system in Syracuse, N.Y., U.S.A. Release experiments were conducted under a matrix of redox and pH conditions to investigate the importance of Ca- and Fe-related physicochemistry on sediment cores collected seasonally, i.e., during the spring, summer, fall, and winter periods. Strong seasonal variation in P release was observed, with rates ranging from ~3 to 38 mg P·m-2·day-1. This variation is attributed to changes in redox status and P concentration gradients at the sediment-water interface. An oxidized microlayer at the sediment-water interface partially inhibits sediment P release under isothermal, well-mixed conditions in the spring and fall. Phosphorus trapped in the oxic microlayer (sorption) is freed when the microlayer is chemically reduced at the onset of anoxia and high P release rates are observed. The oxidized microlayer serves to regulate seasonality in rates of sediment P release but does not influence long-term sediment-water exchange. It is proposed that the long-term P release process is best represented by a time-weighted annual average rate, calculated here to be ~10 mg P·m-2·day-1.


2011 ◽  
Vol 374-377 ◽  
pp. 899-904
Author(s):  
Li Jun Bi ◽  
Jing Yang ◽  
Shi Quan Sun

This paper test to processing lakes sediment by three kinds of in-situ control technology which including aeration, zeolite capping and calcium nitrate in situ treatments, and it study the influence of phosphorus release from sediment. The test results showed: (1) under anaerobic conditions, the phosphorus release content is as 4.26 times as it under aerobic conditions. Under aerobic condition (dissolved oxygen saturation ≥ 20%), the Dissolved oxygen is not important for phosphorus release in sediments.(2)zeolite capping can effectively control the phosphorus release from sediment, but Dissolved oxygen is important for that. Under dynamic condition, the phosphorus release content is stability.(3)Under aerobic conditions or anaerobic conditions, calcium nitrate in situ treatments can effectively control the phosphorus release from sediment. Under aerobic conditions, the phosphorus release content reduce by 53.6%.Under anaerobic conditions, it reduce by 83.4%.(4) The control effects of the phosphorus release content by three kinds of in-situ control technology was followed: under anaerobic condition, calcium nitrate in-situ treatment > zeolite capping> untreated; and under aerobic condition, calcium nitrate in-situ treatment > zeolite capping > aeration ≥ untreated; and under hydrodynamic condition, calcium nitrate in-situ treatment >zeolite coverage>zeolite capping> aeration >untreated.


2019 ◽  
Vol 62 (5) ◽  
pp. 1315-1324
Author(s):  
James A. McCarty

Abstract. Algae play an important role in the internal nutrient cycling of shallow lakes and coves. Algae of shallow water bodies have been shown to thrive and even lead to eutrophic conditions despite a lack of measurable quantities of biologically available phosphorus (P) in the water during summer months. To study how sediment P release and algal growth are connected, water and sediment samples were collected in a shallow eutrophic cove on Beaver Lake in northwest Arkansas. Water quality profiles depicting temperature, dissolved oxygen, nutrients, metals, and photic zone chlorophyll-a were collected weekly from 21 May to 10 July 2018 at three points in the cove: one shallow, one at the cove midpoint, and one at the deepest part of the cove. Cove sediment samples were collected at similar points as the water quality samples for equilibrium P concentration (EPCo) analysis, sediment core incubation, and sediment composition. EPCo for the sediments ranged from 0.024 to 0.027 mg L-1. Sediment cores exposed to aerobic conditions typical of shallow areas had P release rates ranging from 1.37 to 2.02 mg m-2 d-1. Concentrations of soluble reactive P (SRP) in the water column from the weekly water quality sampling averaged 0.002 ±0.003 mg L-1, and photic zone SRP concentrations averaged 0.002 ±0.004 mg L-1 for all sampling sites. The chlorophyll-a concentration increased from 10 to 40 µg L-1 during the period from 21 May to 25 June. When SRP << EPCo, conditions favor the release of SRP from sediments to the overlying water. This was confirmed with the aerobic sediment core incubation in which algal demand was controlled using dark conditions and the release rates were >1.37 mg L-1 d-1. Core aerobic release rates and EPCo conditions both confirmed the release of P under aerobic conditions; however, it appears that algal demand sustained low SRP conditions. This created a nutrient cycle in which algae imposed a nutrient gradient favoring P release by keeping SRP conditions below the EPCo. This study indicates that algal growth potential in shallow water bodies is not limited by SRP concentrations measured within the water column. Studies of shallow water bodies with low SRP concentrations and high productivity should look to the sediments as a source of P to fuel algal growth. Finally, these findings suggest that coves play an integral part in algal production and should not be overlooked when determining the overall P budget for a lake or reservoir. Keywords: Aerobic phosphorus release, Equilibrium phosphorus concentration, Sediment core incubation.


2020 ◽  
Vol 12 (9) ◽  
pp. 3575
Author(s):  
Thor Kolath ◽  
Lotte Reuss ◽  
Sara Egemose ◽  
Kasper Reitzel

New lakes are established or reestablished to provide ecosystem services such as limiting floods and nutrient discharge and to improve biodiversity. New lakes are often established on fertilized land formerly used for agricultural purposes, thereby posing a risk of issues such as phosphorus (P) release when inundated. Release of P from agricultural soil affects both the developing ecosystem of the new lake and may increase downstream eutrophication. To decrease P release following inundation, three simple and cost-effective soil pretreatments were tested through laboratory soil–water fluxes from the test sites in the new Lake Roennebaek and the fluxes of P, nitrogen (N), and iron (Fe) were compared. The pretreatments compared were sand-capping, depth-plowing, and addition of the commercial iron product CFH-12® (Kemira). Untreated agricultural soil incubated under laboratory conditions released 687 ± 88 mg P·m−2 over 207 days and 85% was released within 60 days from inundation followed by low soil–water P exchange during the remaining incubation period. However, P was still released from the untreated soil 180 days after inundation within the lake. The cumulated P flux of the three pretreatment methods was in comparison negative, between −12 ± 3 and −17 ± 4 mg P·m−2 over 207 days incubation and showed negative P fluxes from cores collected within the lake 180 days after inundation. This study showed that the release of P when establishing new lakes on former agricultural land could be minimized using these simple and cost-effective methods, which may improve the ecological status of future lakes and enable the establishment of new lakes without threatening vulnerable downstream ecosystems.


Author(s):  
Katarzyna Kowalczewska-Madura ◽  
Renata Dondajewska ◽  
Ryszard Gołdyn ◽  
Joanna Rosińska ◽  
Stanisław Podsiadłowski

The urban Swarzędzkie Lake, into which sewage had been diverted many years ago, was still characterised by low ecological status. Three restoration methods were used in order to improve the water quality, i.e. aeration of the waters overlying the bottom sediments, inactivation of phosphorus in the water column with iron sulphate and magnesium chloride and biomanipulation with pike stocking. The aim of the research was to define seasonal and spatial changes of phosphorus internal loading from bottom sediments and to compare this with previous years. We also considered changes in the process of P release when the restoration treatments were limited after 3 yr from 3 methods to 1 method. The highest phosphorus release from bottom sediments was found in the profundal zone, where in summer periods it would reach up to 29.2 mgP m−2 day−1. The lowest P release was observed in the littoral zone, down to a depth of 3 m, where it did not exceed 10.0 mgP m−2 day−1. 31% of the whole load of P released from the bottom sediments was originated from this zone. The research showed an increase of phosphorus release in the first years of restoration treatment and a systematic decrease at all stations in the following years.


1957 ◽  
Vol 8 (1) ◽  
pp. 55 ◽  
Author(s):  
SJ Edmonds

The consumption of oxygen of Dendrostomum cymodoceae at 22'C in aerated sea-water varied from 4-5-5.5 μl/g (wet weight)/hr for adults to 20-31 μ/g/hr for juveniles. The production of carbon dioxide was 13-17 μ/g/hr (juveniles) and the R.Q. varied from 0.55 to 0.67 (juveniles). The rate of consunlption of oxygen decreased as the tension of the dissolved oxygen decreased. The oxygen combined with the pigment of the blood was 2.1 vols. of oxygen per 100 vols. of blood and the ratio of blood volume (ml) to total weight (g) of the animal was 0.47. D. cymodoceae was able to live under anaerobic conditions in sea-water for as long as 5 days and in paraffin oil for 4 days. The haemerythrin in the blood of animals kept under oil was found to be reduced after about 6 hr. Lactic acid was identified as one of the end-products of anaerobiosis. The concentration of lactic acid in the blood of animals living under anaerobic conditions increased after 60 hr from 7-12 to 46-61 μg/ml of blood. The ability to revert to anaerobiosis may have survival value for the species.


2014 ◽  
Vol 69 (5) ◽  
pp. 1052-1058 ◽  
Author(s):  
Lichun Dai ◽  
Gang Pan

A natural red soil and a lanthanum-modified soil (LMS) were tested to compare their phosphorus (P) adsorption capacities and their effectiveness in removing P from the water column and reducing P release from sediment. The equilibrium of P adsorption demonstrated that the maximum P adsorption for the soil was 1.29 and 2.22 mg g−1 at pH 8.5 and 5.5, respectively, and for the LMS these were increased by 45.6 and 77.6% at pH 8.5 and 5.5, respectively, indicating that the soil was effective in P adsorption and the doping of lanthanum could substantially increase P adsorption. The sediment–water column incubation showed that, due to the P adsorption of the soil and LMS, the total P in the water column decreased by 58.5, 60.6, 68.2 and 77.2% for 180 g m−2 soil, 900 g m−2 soil, 180 g m−2 LMS and 900 g m−2 LMS treated systems, respectively, in a short time (6 h), and the capping layer substantially reduced the P release from sediment during column incubation, indicating that the soils were effective in reducing internal P load. However, considering the cost of LMS, the natural soil was suggested to be a cost-effective material to control internal P load.


1981 ◽  
Vol 38 (8) ◽  
pp. 978-981 ◽  
Author(s):  
Wayne S. Gardner ◽  
Thomas F. Nalepa ◽  
Michael A. Quigley ◽  
John M. Malczyk

Phosphate release rates by Stylodrilus heringianus, tubificids, and Chironomus spp. were quantified in laboratory experiments by incubating the animals in wet sand under two temperature regimes (5 and 20 °C) and under two nutritional states (full and empty guts). Inorganic phosphorus release rates (± SE) for animals incubated 24 h ranged from 0.12 ± 0.02 (n = 5) nmol phosphorus (P)∙(mg ash-free dry weight)−1∙h−1 for S. heringianus beginning with cleared guts at 5 °C to 0.81 ± 0.09 (n = 5) nmol P∙(mg ash-free dry weight)−1∙h−1 for chironomids beginning with full guts at 20 °C. Calculations based on total invertebrate bio-mass and mean basal release rate suggest that benthic invertebrate excretion could account for most P released from aerobic Lake Michigan sediments.Key words: phosphorus, benthic invertebrates, macroinvertebrates, excretion, nutrients, sediments, nutrient release


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